Joyce/K0JJW and I have been doing Parks On The Air (POTA), in addition to our normal Summits On The Air (SOTA) activations. Sometimes we do both simultaneously. (See More on SOTA and POTA.) SOTA will probably continue to be our top priority because, well, you just can’t beat operating from the summit of a mountain.
Bob/K0NR doing a SOTA plus POTA activation on Threemile Mountain (W0C/SP-107) and Pike National Forest (K-4404).
SOTA and POTA
The programs have a lot in common but still have some significant differences. One of the key differences is that SOTA inherently puts you outdoors and away from your vehicle. This happens naturally if you hike some distance to get to a summit. But even on a drive-up mountain, the rules (W0C ARM) say:
Operations must not be in, or in the close vicinity of a motor vehicle, cannot use a permanent electrical power source, nor use a fossil fuel generator in any fashion. No part of the station may be connected in any way with the motor vehicle. All equipment must be operated from portable power source (batteries, solar cells, etc).
I have come to appreciate the wisdom of these restrictions as it helps keep the program “backpack portable,” without being overly restrictive. POTA does not have these restrictions, so it is common to see POTA activators operating from inside vehicles, inside RVs, even inside buildings using commercial power. Quite different from SOTA and I suppose that’s just fine. It does provide a higher degree of flexibility and radio hams can choose to participate in a manner that works for them. Certainly, this is a good thing for physically challenged individuals.
Joyce/K0JJW operating from a park picnic table, using the FT-991 and a Bioenno battery pack.
Here is a definition of “park” as it applies to national, state and local parks.
Park (noun):
an area of land, usually in a largely natural state, for the enjoyment of the public, having facilities for rest and recreation, often owned, set apart, and managed by a city, state, or nation.
The main idea of visiting a park is for people to enjoy being outdoors in a natural setting.
My POTA Rules Guidelines
Everyone gets to decide “how to POTA” as long as they stay inside the POTA rules. We’ve adopted these guidelines to keep POTA oriented towards outdoor, portable radio operating.
Set up outdoors Get outside the vehicle and find a place to set up outdoors. At a picnic area or campsite, this might be using a picnic table or it might be setting up on a stump, on a rock, or on the ground. Whatever works. Even a tailgate-style operation is better than just sitting in the car.
Take a hike Before or after the activation, take a hike. Get some exercise and explore the park. A mile or two of walking in the forest is usually a good thing.
See the park Some parks are not very hikeable, but you can still explore what is special about the place. Look around to see what is interesting about the park and why it exists.
Note that these are guidelines and not strict rules. This is what we try to do for a POTA activation. There will be times when this is not practical and that’s OK, too. Sometimes we’ll do a Drive-Up/Drive-By activation when time is limited or the weather is bad. For example, I recall a recent winter activation in K-4407 where the temperate was -3 deg F. We stayed in the truck for that one!
So keep on POTAing and having fun with ham radio.
These are my thoughts, what do you think?
Last weekend we held the Colorado 14er Event (Aug 7 and 8), the annual mountaintop event in Colorado. A group of us used this weekend as an opportunity to make 1.2 GHz (23 cm) Summits On The Air (SOTA) contacts: K0NR, K0JJW, KM4PEH, K5RHD, W0ADV, KL7IZW, W0RW, KC5RW, and K0BEJ.
The Alinco DJ-G7T
Many of the 1.2 GHz operators used the Alinco DJ-G7T triband handheld transceiver. This radio covers the 2m, 70cm and 23cm bands. The RF output on 23 cm is only 1 watt but it is the lowest-cost way of getting a signal on that band.
Pikes to Uncompahgre
On Saturday, Joyce/K0JJW and I were on Pikes Peak (W0C/FR-004) and worked Randy/K5RHD on Mount Evans (W0C/FR-003) at a distance of 97 km (60 miles). Signals were strong and we had no problem making those contacts.
We also worked David/W0ADV on Uncompahgre Peak (W0C/RG-001) at a distance of 227 km (141 miles). David used the Alinco HT driving a 16-element Comet Yagi. We had a bit more power (10 watts) from our Kenwood TM-541A transceiver, also driving a Comet Yagi antenna. Signals were strong in both directions and these QSOs were a new personal best for both Joyce and me on 1.2 GHz.
Evans to Sunshine
On Sunday, we moved to Mount Evans and Randy/K5RHD activated Pikes Peak. We worked Randy on that peak, the reverse of the QSO on the previous day. Meanwhile, David/W0ADV was climbing two 14ers in the San Juan Mountains: Redcloud Peak (W0C/RG-002) and Sunshine Peak (W0C/RG-004). These two summits are close to each other, separated by a saddle, so it is common to climb them as a pair.
David/W0ADV aims his 16-element Yagi on Sunshine Peak.
David’s route had him climbing Redcloud first and then continuing on to Sunshine, then returning to Redcloud on the way back down. We worked him on Sunshine and on the return trip over Redcloud, as he headed back to the trailhead.
Map of the radio contact between Sunshine Peak and Mount Evans.
We had trouble hearing David on Sunshine Peak but his signal was just strong enough that we could complete the contact. His signal was stronger from Redcloud, a surprise because the two summits are close in elevation. I expected them to be about the same in terms of signal path and strength. David reported that there was a ridge to the northeast of Sunshine that might be blocking the signal, but it was not in the way for Redcloud.
So these contacts with Sunshine Peak set a new personal best for both Joyce and me on 1.2 GHz (244 km, 152.6 miles). David clearly did the hard work, summiting two 14ers in a day. (We were on a drive-up mountain with a short hike.) Thanks, David/W0ADV!
I was very pleased with the results from the 14er weekend. Now I am wondering what’s next for us concerning 1.2 GHz. We can probably make radio contacts further out but it is going to depend on the topography of the path. We will have to do some investigation on additional summits to try.
The Summits On The Air (SOTA) program originated in the United Kingdom but has propagated to most countries around the world. The program came to Colorado on May 1st, 2010 with Steve/WGØAT sending a CQ from Mount Herman, just west of Monument. Today, the SOTA program in Colorado (called WØC-SOTA) is very active with roughly 180 activators that operate from Colorado summits.
To celebrate our 10th Anniversary, WØC-SOTAis organizing a 10-10-10 Event with a challenge for Activators and Chasers alike. (Activators operate from summits, Chasers try to contact them.)
Activator challenge: Activate 10 (or more) 10K feet (or higher) summits (in Colorado/WØC) within 10days.
Chaser challenge: Chase Activators on 10 different (or more) qualifying WØC summits (10K or higher) within the 10 days.
Event Date: We will kick-off the event in conjunction with the Colorado 14er event on August 7th, 2021 and conclude on August 16th.
Everybody is invited to participate, either as an Activator or a Chaser. Block off these days in your calendar now and start planning for how you can participate. Feel free to operate as much or as little as you would like. It is all about having fun messing around with radios. Any HF, VHF or UHF band can be used for making SOTA contacts, with the most popular ones being 40m (CW & SSB), 20m (CW & SSB) and 2m (FM).
Steve/WG0AT operating from the summit of Mount Herman (W0C/FR-063)
Note that the recommended 2m FM frequencies for the 14er event have changed to:
146.580 FM North America Adventure Frequency
146.550 FM Simplex Alternate
146.490 FM Simplex Alternate
146.520 FM National 2m FM Calling Frequency
(as needed, please don’t hog the calling frequency)
There will be a leaderboard on the W0C-SOTA website showing all participants who meet one of the challenges. More details will be announced on the WØC-SOTA Website as soon as they are hashed out.
The Summits On The Air (SOTA) program was designed with hiking/climbing in mind but some SOTA summits have roads that go to the top. Some notable ones that come to mind are Pikes Peak (W0C/FR-004), Mount Scott (W5O/WI-002), Mount Coolidge (W0D/BB-012), Sandia Crest (W5N/SI-001), Mount Greylock (W1/MB-001) and Mount Mitchell (W4C/CM-001). There are also summits that have trams, trains and chairlifts that provide easy access.
Joyce/K0JJW operating on Pikes Peak.
Some SOTA activators dismiss drive-up summits as not being the real SOTA experience. Everyone is entitled to their point of view and can choose their summits accordingly. I am too pragmatic (read: lazy) to worry about that. If there’s a road to the top, I am probably going to use it, whether it’s a serious 4WD road or a well-paved surface.
The Rules
The specific terminology used in the various SOTA Association Reference Manuals (ARMs) may vary a bit so I will refer to the Colorado (W0C) ARM:
The SOTA General Rules state that the method of final access to the radio operating location must be nonmotorized. The General Rules do not specify the distance, either vertical or horizontal, that this final access must cover. The use of non-motorized vehicles (e.g. bicycle) or pack animals to enter the Activation Zone (AZ) is permitted. Operations must not be in, or in the close vicinity of a motor vehicle, cannot use a permanent electrical power source, nor use a fossil fuel generator in any fashion. No part of the station may be connected in any way with the motor vehicle. All equipment must be operated from portable power source (batteries, solar cells, etc).
The intent of the rules is quite clear: SOTA is not a motorized activity…you need to operate independently of a motor vehicle. Like most rules though, there are shades of grade on the interpretation. Just how independent do we need to be? Unless you started your hike from your home location, all SOTA activations have some form of mechanized transport involved. It is just a question of how far you ride and how far you walk.
Some SOTA Associations used to suggest or require a qualifying hike for drive-up summits. This means that you hike down from the summit for some minimal vertical distance (100 feet or so) and then hike back up to “qualify” your activation. This idea seems to be on the way out and this language was removed from the W0C ARM some years ago. However, your Association may still encourage it or you could just decide that it is a practice that you want to do. (You can find ARMs here.)
Some new SOTA activators look at the rules and suggest they are too restrictive. They argue that people with limited mobility should be allowed to operate from a vehicle. These requests have been heard before and are immediately rejected. I do think the SOTA Management Team has crafted a workable approach that keeps SOTA oriented towards backpack portable operating while still allowing for minimal mobility.
Our Approach
The guiding principle that we use on our drive-up or tram-up summits is to use our normal backpack-portable SOTA station. However we get to the summit, everything goes into a pack which is carried for some minimal distance away from the vehicle, tram or chairlift. This keeps the drive-up SOTA station configured just like the hike-in variety: compact, lightweight, no chairs, no tables (unless they fit into our packs.) This avoids the “Field Day” style set up with lots of gear carried from the vehicle via multiple trips to create a Big Portable Station. Sometimes the drive-up summits are overrun with people, so a short hike away from the crowds can get you to a quieter spot.
A perpetual ham radio question is always which antenna is best? I have several different antennas and antenna configurations for working VHF SOTA and decided to do some comparisons.
Eagle Rock – W0C/SP-113
To test out some of our 2m SOTA antennas, Joyce/K0JJW and I went to Eagle Rock (W0C/SP-113) with an elevation of 9710 feet. I did the radio operating while Joyce collected the data. Eagle Rock pokes up out of South Park, which is a broad, high plain in central Colorado. This summit is kind of “mid-range” for Colorado…not as high as the 14ers but with significant elevation and prominence (~500 feet). It also was close enough to a number of SOTA chasers so I could get some good S-meter readings to compare antennas. On the summit, there is a clear 360-degree horizon, dropping off quickly in all directions.
Antennas Tested
Antenna A is our GO-TO antenna for VHF SOTA is the 3-element Yagi from Arrow Antenna, handheld so the boom is about 5 feet off the ground. Arrow does not specify the gain on this antenna but it has been measured at the Central States VHF Society conference to be ~6dBd.
Antenna A: Arrow 3-element Yagi for 2 meters.
Antenna B is a dual-band J-pole manufactured by N9TAX, supported by a telescoping fishing pole commonly used by SOTA activators. A J-pole has a halfwave radiator, so the gain is about 0 dBd, the same as a dipole.
Antenna B: Rollup J-pole (N9TAX) on a fishing pole.
Antenna C is an RH770 telescopic antenna mounted on a monopod, using a bracket that I made. See VHF/UHF Omni Antenna for SOTA Use. This antenna is a halfwave on 2 meters, so again we’d expect the gain to be ~0 dBd. The antenna is supported by a monopod which I usually just stick into the ground or strap to a bush.
Antenna C: RH770 Telescopic BNC dualband antenna on a monopod.
The three antennas being tested were driven with short coaxial cables fitting with BNC connectors for easy changes. The transceiver was a Yaesu FT-90 powered by a small Bioenno battery.
Chaser Stations
I put the word out that I’d be doing some antenna comparisons and five chasers showed up to assist. (There were are few other chasers that were too close to Eagle Rock such that the S meter readings would have all been “full scale” and not useful.)
Most of these stations were not line-of-sight because there is mountainous terrain blocking the direct path. This makes for a good test because this is often the situation when doing SOTA activations in Colorado. We often have mountains in the way, even on the high summits. Said another way, line of sight contacts are easy-peasy and the antenna performance is not critical. Getting the signal to punch through or around mountains is when the antenna really matters.
WZ0N was line-of-sight from Eagle Rock. KN0MAP was not line-of-sight and he had his Yagi antenna pointed at Pikes Peak (away from Eagle Rock). This is a common technique on VHF…point at a high summit and hope you get enough of a reflection to make the contact. The chasers are listed below.
Callsign
Equipment
Distance/Terrain
W0BV
Icom IC-2730, X200A antenna, 35 watts
42 miles, blocked by a ridge
AD0WB
Kenwood TH72A, X300A antenna, 5 watts
39 miles, blocked by mountains
KN0MAP
Yaesu FT-857, 10-element Yagi pointed at Pikes Peak
Your typical FM VHF/UHF radio doesn’t have a real S meter, just a bar graph display, so we worked in terms of “number of bars”. This does not give us a calibrated measurement but it does provide for a valid comparison. A signal that is 5 bars is stronger than one with 3 bars, but we don’t really know how much better (in terms of dB or S units). We recorded meter readings at both ends of the radio contact. My Yaesu FT-90 meter has 7 bars as full scale. On transmit, I was running the FT-90 at 20 watts.
Antenna A
Yagi
Antenna B
J-pole
Antenna C
RH770
Callsign
Report Sent by K0NR
Report Received by K0NR
Report Sent by K0NR
Report Received by K0NR
Report Sent by K0NR
Report Received by K0NR
W0BV
4
6
3
2
2
2
AD0WB
5
Full scale
3
Full scale, a little noisy
4
Full scale
KN0MAP
4
6
nil
nil
WZ0N
7
5
5
4
5
4
K0MGL
7
6
1
1, very noisy
1
0, very noisy
A quick look at the Antenna A column shows that the Yagi had consistently better signal levels than the other two antennas. For each contact, I did point the Yagi in the direction of the strongest signal, taking care to maximize the signal. This is an advantage and disadvantage…you have to point the antenna but you do get a stronger signal.
The two omnidirectional antennas (B and C) did not require pointing and they performed about the same. My impression is that Antenna B had slightly better overall performance based on listening to the FM noise. But note that the AD0WB readings were slightly better with Antenna C.
As is very common in the mountains, we experienced multipath distortion. This occurs when the signal takes multiple paths to the other station (reflecting off mountains) and then recombines at the receiver creating distortion and variation in signal level. Small changes in antenna position can cause a change in the signal level and amount of distortion. Multipath distortion was much more noticeable on the omnidirectional antennas. The Yagi antenna exhibited multipath but at a much-reduced level. This is a well-known phenomenon: directional antennas reduce multipath effects.
Another factor that I believe is important is that Eagle Rock pokes up quite dramatically compared to the surrounding terrain. Compare this to a large, flat summit that could shadow your signal at some angle of radiation. Antenna height relative to the immediate summit terrain might be more important. Another factor is that Eagle Rock is pretty much granite and not very conductive. So there is not much difference between having an antenna 5 feet off the ground (rock) vs putting it up on a mast.
Previously, I wrote about Charlie/NJ7V’s video that compared a roll-up J-pole with a 3-element Arrow Yagi antenna on two meters. Charlie’s results were a bit different, indicating that the J-pole was about the same or in some cases better than the Yagi.
Conclusions
The Yagi antenna clearly outperformed the two other antennas. So the Arrow 2m Yagi will continue to be our antenna of choice.
The paths to K0MGL and KN0MAP were the most difficult and this is where the Yagi performance really came through. For KN0MAP, we were both pointed at Pikes Peak and working off the reflection. This method worked well with the Yagi but had significant signal loss such that the omni antennas could not make it. Working K0MGL on the omni antennas was not much better but we did squeak out two contacts.
I was a bit surprised that Antenna B did not do significantly better than Antenna C, due to antenna height. This all seems to indicate that once you are on top of a rocky SOTA summit, additional antenna height does not matter. (It would be interesting to do some experiments with the same antenna set at different heights.) I do like having an omni antenna available so that we can monitor in all directions while eating lunch, etc. If we only have the Yagi at lunch time, it is usually laying on the ground or stuck into a tree, certainly not effective in all directions. Antenna C is so easy to deploy, it will probably be my preferred omnidirectional antenna.
This is just one test and one set of results. It will be interesting to do some further comparisons from other locations. Thanks to the chasers for assisting with these tests.
Getting out on the road and exploring is always fun, especially if you have ham radio on board. Joyce/K0JJW and I have been doing quite a bit of travel lately and we just completed our longest road trip so far with our RV.
Overview of the trip: Colorado to Key West, Florida and back again.
Our main destinations for the trip were four national parks: Congaree NP, Biscayne NP, Everglades NP, and Dry Tortugas NP. This determined the main route but we also found plenty of other things to do along the way. We started in Colorado, cut the corner across New Mexico into Texas, then east through Oklahoma, Arkansas, Mississippi, Alabama, Georgia and South Carolina. Then we headed south to Florida and ended up in Key West. Our return trip followed the gulf coast back to Texas, then back home.
Travel Philosopy
Planning a trip is full of trade-offs, so it is useful to have a general approach that the participants agree on. Our approach to this trip was to not drive too far every day but drive enough to hit the various places we wanted to visit. We are still working to find the right balance. This trip lasted 39 days, covering 6000 miles, which is about 150 miles per day. Some days we drove very little and other days were longer, maybe 400 miles.
Although the trip was created around the national parks, we filled in with interesting stops along the way. In particular, we like to camp at state parks: the campgrounds are great and there’s usually something interesting about the park to enjoy. And did I mention they are natural Parks On The Air (POTA) opportunities? We also tried to work in some Summits On The Air (SOTA) activations that are relatively easy to access.
Rocky Victoria
Our recreational vehicle (RV) is a 2018 Winnebago Paseo, built on a Ford Transit chassis. We named her Rocky Victoria, using non-standard phonetics, but usually just refer to her as “Rocky”.
Rocky Victoria is our Winnebago Paseo RV.
Compared to your typical car or SUV, this Class B RV is huge. Compared to other RVs, this vehicle is small, about 22 feet long, usually fits in a standard parking space. With all of the normal RV stuff installed (stove, microwave, sink, refrigerator, toilet/shower combo, bed, etc.) there is not a lot of room left for personal gear.
Rocky fits us really well because it is easy to drive, getting in and out of places without much hassle. Also, setup and tear-down time at a campsite is minimal. One limitation is poor ground clearance, which is fine for forest service roads in good condition but not appropriate for offroad use. This affects what SOTA and POTA activations we do.
Radio Gear
We have an ICOM IC-2730A in Rocky, for normal 2m/70cm FM comms while running down the road. The antenna (not visible in the photo) is just a short whip on the driver’s side of the hood.
Rocky is not a big RV so by the time we load up all of our stuff, it is full. So the radio gear (and everything else we take along) must follow the backpacker principle of “take only what you need, use what you take.” No room for extra stuff you don’t use.
For this trip, we took along two ham stations: A basic VHF SOTA station and a capable, picnic-table POTA station.
VHF SOTA Station
The VHF SOTA station is very compact and easy to carry. It covers the 2m and 70cm bands on FM, which is usually sufficient for us. The RF output power is only 5W, so it does not have the punch of one of our higher power radios. Not a bad tradeoff though.
Two Yaesu FT-1DR 2m/70cm handheld transceivers
Arrow 3-element Yagi 2m antenna
Two RH 770 dualband SMA antennas
HT chargers and other accessories
Picnic Table POTA Station
The POTA station is built around the FT-991, which is a 100 watt transceiver (HF/VHF/UHF) that is reasonably compact. We use a 20 Ah LFP battery to power the radio so it is portable and independent of the RV power sources.
Yaesu FT-991 Transceiver (HF, 6m, 2m, 70cm)
End-fed halfwave antennas for 40m, 20m, 17m, 15m, 10m
Roll-up j-pole antenna for 2m/70cm
20-foot fishing pole to support antennas
Two 25-foot lengths of RG-8X coaxial cable
12V, 20 Ah LFP Battery (Bioenno Power)
Joyce/K0JJW operates the picnic-table POTA station.
The POTA station does a great job at a campsite, usually on a picnic table. The POTA station fits inside my Kelty backpack so it can be taken for a hike. It is a bit heavy for a typical SOTA summit but works OK for drive-up and short-hike summits. It can also be set up inside the RV if required.
Single-band end-fed halfwave antenna (PAR EndFedz) for 20 meters.
Typically, we are going to try operating on 20m or 17m so that the halfwave antenna easily hangs from the fishing pole support. Depending on conditions, we often have to use 40m which takes a little more work to hang. Not a huge problem, though.
Collapsible fishing pole for supporting wire antennas.
For portable operating, I’ve tended to use a variety of end-fed wire antennas supported by a non-conductive pole of various sizes. For this trip, we used a 7 meter (21 feet) telescoping fishing pole that collapses to about 30 inches. This pole will fit into my SOTA backpack.
20m halfwave antenna supported by the fishing pole mounted on the RV. (The 20m halfwave needs to be hung at an angle to be supported off the ground.)
To support the fishing pole directly from the RV, I attached a short length of plastic pipe to the ladder. It is a simple matter to slide the pole into pipe, resulting in the top of the pole being about 26 feet off the ground.
A short piece of plastic pipe is attached to the RV ladder so the fishing pole can be easily inserted.
The combination of the two stations gives us a lot of options for ham radio operating.
Summits On The Air
We activated three summits along the way: Mount Scott (W5O/WI-002) in Oklahoma, Choctaw County HP (W5M/MS-001) in Mississippi, and Monte Sano Mountain (W4A/HR-002) near Huntsville, AL.
Monte Sano Mountain is just east of Huntsville, AL inside Monte Sano State Park.
Monte Sano Mountain turned out to be a unique location because it is located in the Monte Sano State Park. The park surrounds the summit, which is broad and flat. We determined that the park campground is within the activation zone, so we camped there and did both SOTA and POTA activations.
Parks On The Air
We did a number of POTA activations along the way. This was done opportunistically, typically in the afternoon after we had set up our campsite. Our radio operating used SSB on 20m or 40m, along with a few 2m FM contacts.
K-0688 Lake Meredith National Recreation Area US-TX
K-1090 Lake Chicot State Park US-AR
K-1048 Monte Sano State Park US-AL
K-0017 Congaree National Park US-SC
K-1832 Anastasia State Park US-FL
K-0024 Everglades National Park US-FL
K-0635 St. George State Park US-FL
K-2992 Brazos Bend State Park US-TX
Every one of these activations was a lot of fun. There’s nothing like sitting outdoors in the sunshine working a pileup of enthusiastic POTA hunter stations.
Summary
In this post, I emphasized the ham radio activity during this trip. Radio operating was not our main goal but it was a big part of the overall experience. Joyce and I had a fantastic time touring this section of the country, and we are looking forward to our next trip.
The Summits On The Air (SOTA) program originated in the United Kingdom but has propagated to most countries around the world. The program came to Colorado on May 1st, 2010 with Steve/WGØAT sending a CQ from Mount Herman, just west of Monument. Today, the SOTA program in Colorado (called WØC-SOTA) is very active with roughly 180 activators that operate from Colorado summits.
To celebrate our 10th Anniversary, WØC-SOTAis organizing a 10-10-10 Event with a challenge for Activators and Chasers alike. (Activators operate from summits, Chasers try to contact them.)
Steve/WG0AT on a SOTA activation with pack goat Rooster.
Activator challenge: Activate 10 (or more) 10K feet (or higher) summits (in Colorado/WØC) within 10days.
Chaser challenge: Chase Activators on 10 different (or more) qualifying WØC summits (10K or higher) within the 10 days.
Event Date: We will kick-off the event in conjunction with the Colorado 14er event on August 7th, 2021 and conclude on August 16th.
Everybody is invited to participate, either as an Activator or a Chaser. Block off these days in your calendar now and start planning for how you can participate. Feel free to operate as much or as little as you would like. It is all about having fun messing around with radios. Any HF, VHF or UHF band can be used for making SOTA contacts, with the most popular ones being 40m (CW & SSB), 20m (CW & SSB) and 2m (FM).
There will be a leaderboard on the W0C-SOTA website showing all participants who meet one of the challenges. More details will be announced on the WØC-SOTA Website as soon as they are hashed out.
Joyce/K0JJW and I did another activation of Mt Herman (W0C/FR-063) today. This is a repeat summit for us this year but we were looking for an easy hike not too far from home.
The Yaesu FT-90 transceiver is small and lightweight, perfect for portable operating when you need a little more RF power.
As usual, we were just using the VHF/UHF bands for the activation. My favorite rig for this type of SOTA activation is a Yaesu FT-90, a very compact mobile transceiver (4 x 1.2 x 5.4 inches) that is no longer manufactured. It has a unique heatsink with an integral fan that can handle the heat from the 50-watt transmitter. We use a Bioenno 4.5 Ah LFP battery to supply the power for the radio.
I was trying to work Bob/W0BV about 65 miles away and we were not able to complete the contact. The distance is not too difficult but there are several mountain ranges in the way. Sometimes we can get the electromagnetic waves to sneak through, but not today. Hiking down the mountain, I was thinking about how we could have probably made the QSO on SSB or CW, instead of FM. I chose not to bring the all-mode transceiver (FT-817) along today, so that was not an option.
That is when the idea hit me. The FT-90 is the right form-factor and power level for VHF/UHF SOTA but it is limited to FM. Yaesu, if you are listening, here’s what I’d really like to see in a small mobile transceiver:
FT-90 size radio, perhaps a little larger but not much
2m and 70 cm bands (include 1.25m if you’d like)
At least 25 watts of output power, more would be better (say 50 watts)
All mode capability (CW/SSB/FM/Digital), sure go ahead and toss C4FM in too.
No internal battery…I’m going to have to use an external battery anyway to get enough battery capacity
At various times, I have had people ask “why don’t they put SSB in handheld radios?” They recognize that SSB has weak-signal advantages over FM, so they wish their handheld transceiver (HT) could do it. I say rather than shove more features into an HT, put it in an FT-90 size radio. It would be a much more usable solution.
Although I arrived at this radio concept thinking about SOTA, it would also be a great mobile rig for general use. The FT-90 was popular because it was very compact AND it had a removable faceplate that could be mounted almost anywhere. There really is no way to get VHF/UHF SSB into a vehicle other than those all-band radios like the FT-857 and the IC-7100. Oh, did I say FT-857? Sorry, that model has been discontinued. The satellite operators will love it, too, especially if it could work 2m/70cm crossband full-duplex.
So there you go, Yaesu (or Icom)…a fantastic product concept at no charge. I would be happy to beta test it for you.
On Twitter, someone recently commented that it would be nice to have more 2m SSB activity for Summits On The Air (SOTA). It is well known that FM is a more commonly used mode but that its performance suffers for weak signals. This got me wondering about which bands and modes are being used for SOTA above 50 MHz.
Above and Below 50 MHz
First off, I wondered what portion of SOTA radio contacts are on VHF/UHF. Looking at the SOTA database Facts and Figures page, I simply grouped the number of QSOs as “Above 50 MHz” and “Below 50 MHz.”
Frequency
QSOs
% of Total
Above 50 MHz
1,346,206
21%
Below 50 MHz
5,144,547
79%
Total
6,490,753
100%
So we can see that about 1/5th of the SOTA QSOs are done using VHF and higher frequencies. Certainly, we’d expect that the HF bands would dominate the total but this VHF+ percentage is higher than I expected.
Breaking Down > 50MHz
That leads to the question of what bands are used above 50 MHz? The table below shows the >50 MHz data broken out by band. The % of Total column indicates the percent of all QSOs (Above and Below 50 MHz), while the % of >50 MHz column shows the percentage relative to only >50 MHz radio contacts. Simply put, the % of Total column will sum to 21%, matching the number in the first table. The % of >50 MHz column sums to 100%.
Frequency
QSOs
% of Total
% of >50 MHz
50MHZ
48,035
0.74%
3.57%
70MHZ
10,921
0.17%
0.81%
144MHZ
1,202,311
18.5%
89.3%
220MHz
1064
0.02%
0.08%
433MHZ
126,202
1.94%
9.37%
900MHz
204
0.00%
0.02%
1240MHZ
12,526
0.19%
0.93%
2.3GHZ
1554
0.02%
0.12%
3.4GHz
142
0.00%
0.01%
5.6GHZ
468
0.01%
0.03%
10GHZ
1186
0.02%
0.09%
24GHZ
167
0.00%
0.01%
Microwave
382
0.01%
0.03%
Well, it doesn’t take a degree in statistics to see that the 144 MHz band (2 meters) is the most popular VHF/UHF band for SOTA. Almost 90% of the QSOs are on this band. The next most used band is 433 MHz (70 cm) at a little over 9%. The 6m band (50 MHz) comes in at third with about 3.5%. The other bands are so small, they don’t really add much to the total.
The data on the SOTA page does not break out mode used by band but it does provide some aggregate mode numbers. The number of FM contacts (using any band) is 1,186,542. It is reasonable to assume that almost all of these FM QSOs were made above 50 MHz. (FM is used a bit on the 10m band but that combination is rare in SOTA.) That means, for frequencies >50 MHz, 88% of the QSOs (186542/1346206) were completed using FM. We don’t know how the remaining 12% splits out but I would expect them to be a mix of SSB and CW, but dominated by SSB.
Given the high number of 144 MHz contacts in the mix, it is safe to say that 2m FM is the dominant mode for VHF/UHF SOTA. After all, it is The Utility Mode. The reasons are obvious…almost every radio ham has a handheld transceiver that can do 2m FM. It makes for an easy way to get on the air and activate a summit. More importantly, it is an easy way to chase a summit. When I plan a SOTA activation, I think about the kinds of operators that will be within range and what kind of gear they are likely to have. It does me no good to drag along equipment for 2m SSB/CW if there is no one around to work that band/mode.
This analysis does confirm that the number of non-FM QSOs on VHF/UHF is relatively small. The 12% of non-FM QSOs above 50 MHz corresponds to only 2.5% of all SOTA QSOs. So why is this? Clearly, the affordability and popularity of the FM handheld transceiver is a big factor. There are portable radios that can do “all modes” on VHF/UHF such as the Elecraft KX3 (2m option), Yaesu FT-818, and the Icom IC-705, but these are much more expensive.
What About 70cm and 6m?
Now, it is interesting that the 70cm numbers are small compared to 2m. Many of those handheld transceivers that get used for 2m also have 70cm included, so you might expect there to be more 70cm QSOs in the mix. For a given boom length, a 70 cm Yagi antenna will have more gain than a 2m Yagi. So gain is easier to come by on the higher band. However, 2m propagation tends to be a little better than 70cm, on average.
Note that the SOTA rules do not encourage working the same station on more than one band. You only get credit for working a station once on an activation. (Compare this to VHF contest scoring which usually adds in additional credit for working stations on multiple bands.) So if a chaser works someone on 2m, they typically don’t bother working them on other bands. I am not saying this is bad, I am just trying to explain why we don’t see more QSOs on 70cm.
The other band you might expect to see more activity is 50 MHz (6 meters). This band is available to Technicians in the US and, when the band opens up, you can easily work a thousand miles or more via Sporadic-e propagation. (Sometimes F-layer propagation, too, but we’ll need a whole bunch more solar activity for that to happen.) Many HF rigs include 6m as a “bonus band”, including some of the QRP radios popular with the SOTA crowd (KX3, IC-705, etc.) So why are the 6m numbers so low? This band offers a metric ton of fun, but it dishes it out randomly. There is a reason they call it the Magic Band…sometimes the Magic is there and sometimes it is dead quiet. When it’s dead quiet, it is a poor imitation of the 2m band. It also requires larger antennas, so if an activator decides to use antenna gain to help their signal, a portable Yagi for 2 meters is going to be a lot handier than one for 6 meters.
CW and SSB
This data does show that CW and SSB are lightly used for SOTA on the VHF/UHF bands. This is an opportunity. If more of us used these modes, it would improve our ability to squeeze out contacts when the signals are weak.
While I did not originate the idea, I have been promoting the use of 146.58 MHz as the North America Adventure Frequency. (Rex/KE6MT and George/Kj6VU came up with the idea.) My previous blog post explained the thinking behind it, along with my own personal biases, I’m sure.
When presented with the idea of The Other Simplex Frequency, I generally get three types of reactions:
1. Great idea! These people generally live or operate in locations where the 2m FM calling frequency (146.52 MHz) can get kind of busy, so they see that having an alternate frequency that everyone knows about has value. They may or may not still call on .52 but having another designated frequency is a plus.
2. It will never get used in my area This reaction comes from locations where people tend to congregate on 146.52 MHz and will probably not monitor any other frequency. The SOTA activators say stuff like “I’ll never contact anyone on 146.58 MHz so I’ll have to just use keep using 146.52.” This is not a problem, do whatever makes sense. The North America Adventure Frequency will probably not get used everywhere and that is just fine.
3. What, people actually talk on 2m FM simplex? These folks are just plain missing out. I don’t know how to help them.
Lately, for the ARRL January VHF contest, I try to find a SOTA summit to activate. Operating time is usually just a few hours, so it does not make for a big score. The main advantage is for VHF SOTA (Summits On The Air) because there is a lot more activity on 2m CW and SSB. This year, I wanted to go for the mountaintop trifecta of SOTA, POTA (Parks On The Air) and VHF contest in one activation.
Threemile Mountain is an easy SOTA summit: easy to access via forest service roads and an easy hike.Joyce/K0JJW operating the portable station on 2m FM.
Threemile Mountain (W0C/SP-107) emerged as the activation summit because it is not too far from our cabin and accessible in the winter. (This time of year, the roads to many of our favorite summits are blocked.) For POTA, it is located in the Pike National Forest (K-4404). Because it is a short hike, I concluded that I could carry the Yaesu FT-911 and the 20 Ah Bionno battery. This would cover all the bands, give us more RF punch and still have plenty of battery capacity.
The portable station with 100 watts on HF, 50 watts on 2m/70 cm.
I carried quite a collection of antennas which gave us plenty of operating choices. We started out on 2m and 70 cm FM, working mostly local stations. This quickly got us enough contacts for SOTA and POTA points. We used a rollup J-pole for 2 meters and 70 cm, until it became intermittent and the SWR went wild. Then we switched to the Arrow 3-element Yagi for 2 meters.
Bob/K0NR operating from Threemile Mountain.
About that time, I decided to see what was happening on 2m SSB. There were a number of contest stations on the air, mostly from the front range cities (Denver, Boulder, Colorado Springs, …). I worked a bunch of them using 50 watts from the FT-991 to the 2m Yagi antenna (horizontally polarized).
The QSO between K0NR on Threemile Mountain (DM78) and Larry/N0LL near Smith Center, Kansas (EM09).
Suddenly, I was surprised to hear N0LL from Kansas calling me. I’ve worked Larry before from Colorado but it usually was from a really good location such as Mt Herman or Pikes Peak. Even then, we often had to switch to CW to complete the contact. Today he was louder than many of the Denver stations. We easily worked on SSB, which turned out to be a new personal best DX for me from a SOTA summit (372 miles).
We deployed both the SOTA and POTA flags today.
After things slowed down on 2m SSB, I decided to make some HF contacts. The North American QSO Party (SSB) was active, so I decided to set up for 20m and see who I could work. Running 100 watts to an endfed halfwave kept me competitive with the contest stations. Then I moved up to 17m SSB and worked non-contest POTA and SOTA chasers.
Bob/K0NR and Joyce/K0JJW hanging out on the summit of Threemile Mountain.
We both accomplished the three-in-one mountaintop activation for SOTA, POTA, and the VHF contest. I also worked the NA QSO Party, so that makes it four-in-one, but who is counting? The January weather cooperated with us with almost no wind on the summit, about 28 degrees F. We sat there in the sunshine and just enjoyed the view before hiking back down.
Charlie/NJ7V and Gaston/KT1RUN did a comparison of VHF antennas during a SOTA activation. Specifically, they compared a rubber duck antenna, a J-pole antenna on a tall mast, and a 3-element Yagi antenna. Spoiler Alert: the rubber duck sucks (they all do) but the Yagi and J-pole performed about the same.
Joyce/K0JJW and I use the Arrow 3-element Yagi antenna for most of our SOTA activations, so I am very familiar with that one. We also have a rollup J-pole that we use once in a while.
Charlie used the Yagi the same way we do: handheld at ground level. The J-pole was on a mast, maybe 12 feet (?) in the air. Although they were on a summit, there is some performance improvement getting the antenna higher than the surrounding terrain. The gain of the Arrow 3-element Yagi has been measured at about 6 dBd. The gain of a J-pole, being a halfwave radiator, is 0 dBd. The additional height of the J-pole has to make up this 6 dB of gain difference to be roughly equivalent.
A big difference, though, is that the Yagi antenna has to be held and pointed. The J-pole is always pointing in the right direction so you can just focus on operating and logging. We may have to consider using a omni antenna instead of the Yagi.
Recently, on the nasota group, there was a discussion about designating an alternative 2m FM frequency for Summits On The Air (SOTA) use (instead of 146.52 MHz). The main driver for this is that 146.52 MHz can get busy with other radio traffic and/or a busy SOTA activation can tie up the calling frequency for a long time.
Rex KE6MT (SOTA W6 Association Manager) kicked it off with:
A friend of mine, George KJ6VU, has been talking with me and several others about the idea of an FM “Adventure Frequency.” It would be for more than just SOTA – other *OTA’s could also use it. There are other ideas to layer on top of it, such as tone signaling so that you don’t have to hear traffic you don’t want to hear, and repeater infrastructure for announcing someone’s on the frequency with a given tone, etc. But the core thing would be to decide on a frequency and really get it in use. The National Calling Frequency (146.52) can be great for a few contacts sometimes, but other times it’s problematic either because it’s being hogged or because nobody’s listening. Of course, this Adventure Frequency could have the same issues present themselves differently, but would alleviate some and pave the path for future additions mentioned above.
I have previously written about the challenges of using 146.52: The Use of 146.52 MHz
One important idea is to include the other “OTAs” in adopting this frequency, most notably Parks On The Air (POTA). Hence the name “Adventure Frequency,” and not “SOTA Frequency.” It is really about hams operating portable in an outdoor setting. Of course, like all amateur spectrum, this frequency must be shared with other users.
It may seem like a simple thing to choose a nationwide simplex frequency but VHF band plans are managed regionally. In particular, there is a mix of 15-kHz and 20-kHz channel spacings. (For more background on this see Simplex Channel Confusion on 2 Meters.)
After some discussion, the group settled on 146.58 MHz. There was some dialog around using CTCSS for signaling but nothing specific surfaced.
Some key points:
The NAAF is 146.58 MHz.
This frequency is in addition to, not a replacement for, the National Simplex Calling Frequency 146.52 MHz.
Local usage will likely vary depending on needs.
Program 146.58 MHz as The Other Simplex Frequency in your radio.
What does this mean to you?
Program 146.58 MHz into your radio and have it available. If you are doing SOTA (or POTA) activations, consider using this frequency, especially if you are in an area where 146.52 is used a lot. (I’ve already started using this frequency for SOTA activations near urban areas.)
After seeing some videos about small HF transceivers for Summits On The Air (SOTA), I feel I need to set the record straight.
The following video shows the World’s Smallest SOTA Transceiver in use. Of course, it uses the UHF spectrum because shorter wavelengths enable smaller ham radio stations.
The radio shown in the video is the NKTech NK-M1 UHF transceiver.
This radio is a 16-channel UHF transceiver, available from multiple online vendors. I programmed it to operate in the 70 cm band on 446.0 MHz.
Recently, I commented on participating in the Parks On The Air (POTA) program: How About Parks On The Air? Since then Joyce/K0JJW and I have done a few POTA activations, including a few combination SOTA (Summits On The Air) + POTA activations. We are starting to sort out how SOTA and POTA work for us. I am sure this will evolve over time as there are many operating options with both programs. But here is what we’ve done so far.
Recall that we’ve been focusing on VHF/UHF operating for SOTA, although I did break down and actually made some HF contacts from a SOTA summit recently. VHF/UHF is a good match for SOTA (Height Above Average Terrain). However, for some remote summits, it can be a challenge to get enough radio contacts (4) to qualify for the SOTA points. Using HF can be a big help in generating contacts. POTA can also be done with VHF, some parks have high elevation, but many of them are not attractive VHF locations. POTA requires 10 radio contacts to qualify for points, so that raises the bar a bit, too.
Bob/K0NR on Mount Herman, displaying the SOTA and POTA flags.
Yesterday, we decided to hike up Mt Herman (W0C/FR-063) for a short afternoon VHF/UHF activation. I posted both a SOTA alert and a POTA alert. We made plenty of radio contacts (40 total) and submitted logs to both the SOTA and POTA websites. I know there were SOTA chasers out there but I’m not sure if anyone worked us specifically for POTA. As usual, a lot of hams give us a call just because it is fun to work someone on a summit (without any SOTA or POTA interest).
The majority of our SOTA activations in Colorado are in national forests, which count as “parks” for POTA. So it is easy to tack on a POTA activation when doing SOTA.
Vehicle-Based POTA
Joyce and I also did some POTA activations from a vehicle. It is pretty easy for us to get to Pike National Forest (K-4404) or San Isabel National Forest (K-4407) and set up a portable station.
The vehicle-based POTA station, as used in Yellowstone National Park during the year of the ARRL NPOTA program.
We used a Yaesu FT-991 and endfed halfwave antennas for 20m and 15m, supported by a SOTAbeams pole. This is the same configuration I’ve used for portable operating from many locations, including some Caribbean islands. I recently purchased a 20 Ah LFP battery from Bioenno Power to use as a power source so that we don’t rely on the vehicle battery.
We focused on HF for these POTA activations and were pleased to have decent pileups of stations calling us on the 20m and 15m bands. Fifty watts to a halfwave antenna works just fine. We also made it a point to call on 2m FM and usually picked up a handle of contacts on that band, too.
What’s Next?
At this point, our outdoorsy portable operating is looking like this:
SOTA Summits – if the summit is in a park, we will probably go ahead and submit a POTA log along with the SOTA log. Many of the W0C SOTA summits are in national forests, national parks or state parks. VHF-only activations will probably have less impact on POTA…those chasers/hunters tend to be on HF. On HF, we will be running QRP power levels.
POTA Parks (day trip) – another option is for us to just stop by one of the national forests or a state park and get on the air. (Pike National Forest is about 2 miles from our home.) This will be focused on the HF bands but we can always make a call or two on VHF. This will be operating from or close to a vehicle, so probably running 50 watts on HF with a wire antenna.
POTA (RV camping) – we’ve been RV camping in state parks and national forests this past year. An obvious additional activity is to set up on HF for a POTA activation. We haven’t done this yet.
I’ve already done a combination VHF Contest and SOTA activation, so this could be extended to include POTA. Three Things In One. In fact, some locations qualify for more than one POTA park, so maybe it is time for a Four-In-One.
Charlie/NJ7V invited Joyce/K0JJW and me to be on the All Portable Discussion Zone, on the Red Summit RF YouTube channel. We talked mostly about Summits On The AIr (SOTA) using VHF/UHF. It was a fun experience for both of us.
Recently, I gave a presentation to the ARROW radio club in Ann Arbor, MI on the topic of “Having Fun With VHF”. I’ve given this talk several times now, highlighting some of the topics in my book, VHF, Summits and More: Having Fun With Ham Radio. When I discussed my Summits On The Air (SOTA) activities, Thom/W8TAM mentioned that Parks On The Air (POTA) was probably a better fit for Michigan. (There are SOTA summits in Michigan but most of them are in the upper peninsula or the northern part of the lower peninsula.) This got me thinking about POTA and I followed up with Thom via email a few days later to get a bit more information.
Being a fan of the US National Parks, I had done a few activations during the ARRL National Parks On The Air event in 2016. (Holy decibels, was that really 4 years ago?) The POTA program is similar but is an ongoing program, kind of like SOTA.
What’s A Park?
I am not sure of the specific criteria for parks to be included in POTA, but it seems to be pretty much National Parks (including National Forests) and State Parks. The POTA website talks about these typical categories of POTA stations: backpack, picnic table, campground and Field Day. Backpack looks very much like a typical SOTA activation, a small portable station carried by humans (or maybe goats) to the activation site. Picnic Table is a little bit different, with more gear and less hiking. Campground and Field Day take advantage of operating close to or inside a vehicle.
I see quite a bit of overlap with other activities that I like: SOTA, hiking, camping, parks and travel.
Colorado
To get a handle on local opportunities, I looked at the 85 POTA parks listed for Colorado. (Compare this to over 1805 SOTA summits in the state.) These are National Parks, National Monuments, National Wildlife Refuges, National Recreation Areas, National Grasslands, National Scenic Trails, National Historic Trails, National Forests, and Colorado State Parks. In short, POTA includes the National Park System, National Forests, and State Parks. Cool!
POTA parks are spread across the state of Colorado.
We see a similar picture in Kansas, which has zero SOTA summits. (Sorry, it’s just too flat.)
Kansas has its fair share of parks to activate in the POTA program.
SOTA activation opportunities are obviously skewed toward mountainous areas. Islands On The Air (IOTA) is generally near large bodies of water. However, POTA is available everywhere. Americans like parks and we have lots of them.
First impressions
I have been heavy into SOTA, so that’s the perspective I have when checking out POTA. POTA requires 10 QSOs to obtain points for an activation, while SOTA requires only four. SOTA activations must not be in, or in the close vicinity of a motor vehicle, cannot use a permanent electrical power source, nor use a fossil fuel generator. Also, no part of the station may be connected in any way with the motor vehicle. All equipment must be operated from portable power source (batteries, solar cells, etc). The POTA rules don’t have these restrictions.
The SOTA points system and logging database are pretty much on the honor system. Send in a log (Activator or Chaser) and you’ll get credit for the points you claim. POTA only collects logs from the Activators. So if you are a Chaser (Hunter, in POTA terminology), you don’t submit a log and your points are dependent on the Activator getting a log submitted. POTA log submission is via email and may take up to two weeks to get processed, while SOTA is instantaneous.
What’s Next
I have not quite figured out how I will participate in POTA. For starters, it can be a nice overlap with SOTA. Most of the SOTA summits we activate are on National Forest land, so they also count as POTA activations. Lately, Joyce/K0JJW and I have been RV camping in state parks, so that sets us up for an easy POTA activation. We are also working on visiting all of the US National Parks. POTA probably isn’t a great match for VHF operating, unless it has some Height Above Average Terrain.
I can appreciate the accessibility of the POTA program. It does not require a lot of physical ability to do an activation. If you want to hike into a remote area, that works, too. The flexible rules allow hams to set up a station in a variety of ways and it seems most hams have a park nearby they can activate.
For Summits On The Air activations, I have been exclusively using the VHF/UHF spectrum. I like the HF bands but for SOTA, I just think that Height Above Average Terrain (HAAT) of a summit is an ideal match for frequencies above 50 MHz. See Summits On The Air VHF Mountain Goat.
Threemile Mountain, viewed from the east.
After much naggingpeer pressure encouragement from my fellow W0C SOTA activators, I decided to give HF a try. (The solar index had markedly increased in the past week, so the timing seemed right.) I chose an easy summit to hike (Threemile Mountain), so I could just focus on the radio operating. Plus, Joyce/K0JJW and I were carrying a bit more radio gear, the usual VHF station plus my Yaesu FT-817 for the HF bands. For HF antennas, I dug up two single-band EndFedz halfwave antennas for 20m and 15m from the basement. I’ve used these for portable HF work in the past and they have performed well.
The summit was an easy hike, as expected. Once on top, we quickly made four contacts on 2m FM and then set up the HF station. I used a telescoping fishing pole as the antenna support, strapped to a conveniently-located pine tree. The halfwave antennas were mostly horizontal and not that far off the ground (maybe 15 feet at the highest point).
This SOTA activation was on Halloween, so we chose costumes that blended in with the wildlife (Joyce/K0JJW, Bob/K0NR).
A quick check of the SWR using the internal FT-817 meter showed that the transmitter was happy. Then, I called Bob/W0BV on 14.346 MHz to see if I was radiating anything. I was not real strong at his location but we made the contact just fine. As soon as he spotted me on SOTAwatch, I had a nice pileup of stations calling. In the meantime, Joyce kept working stations on 2m FM.
The FT-817 transceiver operating on 20m powered by Bioenno battery (not shown).
I quickly made 12 QSOs on 20m, including F4WBN in France (best DX for the day). Before I left 20m, Bob/W0BV met me on 14.061 for a CW contact. Just because. Then, I took the 20m antenna down and hoisted the 15m halfwave, the same configuration but a bit shorter in length. The 15m band was not quite as good and had more fading but I made 7 QSOs there.
Map of K0NR SOTA contacts from Threemile Mountain.
I was very pleased with the results, especially being able to use 15 meters, my favorite HF band. I could have brought along additional antennas to try 17m, 12m and 10m, but there’s always next time. I had a great time working the SOTA chasers on HF, so I will surely do it again.
On some SOTA summits that are established radio sites, there can be significant RFI on 2 meters. I recently wrote about that here: RFI on SOTA Summits. There have also been discussions from time to time among VHF SOTA activators on which handheld transceiver (HT) has the most robust receiver for use in high RF environments. (Hint: a Baofeng is not going to be your best choice.)
This led me to an excellent web page by Razvan/YO9IRF that tabulates the receiver performance of HTs as measured in the ARRL lab. This is arguably the most objective look at HT performance out there. You can do a sort on a particular parameter and see which models are best.
Probably the parameter to start with is wide 3rd-order intermodulation on the 2-meter band. (I am going to ignore the 70 cm performance because most VHF SOTA contacts are on 2 meters.) The wide 3rd-order intermod performance relates to interference rejection from outside the amateur band.
Here are the best performing HTs for this parameter. (Go to the website directly to see other models listed.)
Interestingly, the Icom IC-V8 jumps to the top of the list. This is an older single-band 2m radio…and I happen to have one hiding somewhere in the basement. I am a bit surprised there are two Wouxun radios near the top of the list but they performed well. No surprise that the Yaesu FT-60 shows up…it seems to be well-regarded by SOTA activators.
The narrow 3rd-order intermod performance relates to the receiver performance inside the amateur band. Sorting based on that parameter shows these radios at the top:
The Kenwood TH-22AT takes the top position, followed by the Yaesu FT-10R, both older single-band radios. The general trend here is that some of the older radios, especially single-band rigs, have better front end filtering. Newer radios tend to include reception of a wider range of frequencies outside the ham band and have receiver front ends that are correspondingly more open. The Radio Shack HTX-202 gets a lot of positive comments from the SOTA crowd and is on the shortlist. Again, the well-regarded FT-60 makes the list.
Let’s check a few of my favorite HTs to see how they rate.
My usual SOTA handheld is the Yaesu FT-1DR. The wide 3rd-order intermod is 73 dB, or 12 dB worse than the FT-60 (85 dB). For narrow 3rd-order intermod, the FT-1DR is 58 dB vs 67 dB for the FT-60. This matches my impression that the FT-1DR does OK for most summits but is not the best radio for high RF environments.
Another radio to consider is the Yaesu FT-4XR. I often have this radio on at the house but I don’t use it for SOTA. This radio uses the same receiver IC as the Baofeng UV-5R but has better input filtering. The wide 3rd-order intermod is only 63 dB and the narrow 3rd-order is 61 dB (about the same as the FT-1DR). The table does not list any Baofeng radios but I would expect them to perform worse than the FT-4XR.
Regular readers of this blog know that I use a Yaesu FT-90 mini-mobile transceiver for most SOTA activations. I looked up the ARRL tests on it. The wide and narrow 3rd-order intermod are 85 dB and 65 dB respectively, not better than the best handhelds but near the top. My experience is that the FT-90 receiver is better than my FT-60 and FT-1DR, consistent with the ARRL lab measurements.
Another radio of interest is the Yaesu FT-818, which the ARRL measured as 96 dB (wide 3rd-order intermod) and 72 dB (narrow 3rd-order intermod) on the 2m band. This puts the FT-818 at the top of the list with the best handhelds. Actually, I would have expected it to be even better, far superior to an HT, but apparently not.
So I need to dig out that old Icom IC-V8 that is hiding in the basement. It may be a good piece of equipment to have along on SOTA activations.
One thing to watch out for when doing SOTA activations is the presence of strong Radio Frequency Interference (RFI) on some peaks. The typical scenario is that the summit is also an established radio site with transmitters that interfere with your ham radio operations.
Bob/K0NR checking out the radio gear on Mount Bailey (W0C/FR-062).
I use the VHF/UHF bands for SOTA, so I am writing from that perspective. My impression is that HF interference is much less likely because these radio sites don’t usually have any HF transmitters. However, they may have broadband noise sources such as networking equipment, power line arcing or switching power supplies that can create problems on HF. Anyway, this post is focused on 2 meters and higher bands.
In my experience, the transmitters at radio sites may include land mobile repeaters (VHF or UHF), NOAA Weather (162.xx MHz), TV/FM broadcast stations and mobile wireless (cellular) systems. The TV/FM broad stations are really bad news because they run a crapton of RF power.
The worst summit I have encountered is Sandia Crest (W5N/SI-001) near Albuquerque, NM. See trip report here. They even have a sign in the parking lot to warn you that the RFI may wipe out your car’s keyless remote.
Well, this sign did warn me of radio interference at Sandia Crest.
In a high RFI environment, your radio receiver gets overloaded such that you can’t hear stations calling you but they can hear you just fine. This results in the SOTA activator calling and calling while the chasers get frustrated that the activator never hears their call. Not good. It may not be obvious that this is happening. This blocking of the receiver may come and go, depending on which transmitters happen to be active.
Mitigation Strategies
There are a few things that you can do to deal with the RFI:
Move Away From The Source
Probably the first thing to try is just moving away from the source of interference. This may mean moving away from the highest point on the summit but it may be better overall to give up a few feet of elevation to not have the interference. You’ll need to stay in the activation zone to be a legitimate SOTA activation.
Use A Better Radio
Some radios are better than others when it comes to receiver performance including the ability to reject unwanted signals. The low cost radios from China (Baofeng or similar) generally have lousy receivers so they are a poor choice for operating from an RFI-intense summit. Many people report better results with the Yaesu FT-60, a solid performer. Commerical radios from Motorola are even more robust. I’ve been using a small mobile radio for SOTA (Yaesu FT-90) which outperforms most handheld radios.
Change Your Antenna
Using a directional antenna can help…just point it away from the source of the interference. Oddly enough, using a worse performing antenna can help improve your ability to communicate. For example, a rubber duck antenna on a handheld radio will allow less of the interfering signal to get into your receiver which may improve your ability to receive. As long as the antenna is “good enough” to complete the radio contact, it may be the way to go. One trick I’ve used is to deploy two radios, one for receive with a crummy antenna and the other for transmit with a better antenna. That way, you still radiate a stronger signal while reducing the interference into the receiver.
Use A Bandpass Filter
You can insert a filter into your antenna feedline to reduce the interfering signal. The best approach is to use a bandpass filter that passes the frequency you are operating on but attenuates other signals. SOTABeams offers a compact bandpass filter for the 2m band. (Note that it has a 5W power rating which is fine for handheld radios but not more powerful transceivers.) DCI Digital Communications offers higher power filters but they are much larger in size.
Change Frequency
Sometimes a small change in frequency might help a bit if the interference is limited to certain frequencies. Another tip is to try another band. That is, if you are getting interference on 2 meters, you may find that the 70 cm band is better. Or vice versa. It all depends on the transmitters at the site.
