VHF Contest

The KØNR Radio Site

How to Work A VHF Contest

A Basic Introduction to VHF Contesting with a Colorado Emphasis

Bob Witte, KØNR
10 April 2006

This is a brief introduction into how to operate during a VHF contest. The main contests, roughly in order of popularity, are the ARRL June VHF QSO Party, the ARRL January VHF Sweepstakes, the ARRL September VHF QSO Party and the CQ Worldwide VHF Contest in July.

I prefer to think of these "contests' as "activity weekends" because the word "contest" often makes people think of the fast-paced, chaotic, band-crushing experience of HF contests. VHF contests usually have a much different feel. The problem with the VHF bands is that they are often underutilized. You put out a call on simplex and nobody is there. Dead silence. But on VHF contest weekend, you are sure someone is going to be on the air, so the event tends to increase the activity, bringing people out of the woodwork. A VHF contest is more like a friendly reunion of local VHF enthusiasts.

(Sometimes a VHF contest can get pretty intense, especially if there is a significant band opening on 6 Meters. Then things start to sound like the HF bands with signals coming in from across the country.)

Frequencies

Frequencies above 50 MHz (6M and higher) are used during the contest. Most of the operation will be on 6 Meters, 2 Meters and less on higher bands. Most of the operation will be on the SSB portion of the band, so if you have an all-mode VHF rig, you'll want to use it. Perhaps you have one of those HF rigs that also does VHF, such as the ICOM IC-706 or the Yaesu FT-100D. This weekend will be a great time to try it out.

The standard SSB calling frequencies are:
    50.125 MHz
   144.200 MHz
   432.100 MHz

Most SSB operation on VHF is done using horizontal antenna polarization. A yagi or dipole antenna with radiating elements parallel to the ground produces a horizontally-polarized signal. A vertical whip antenna, commonly used for FM, produces a vertically-polarized signal. Working a station with opposite antenna polarity causes a substantial signal loss, so it is best to maintain the same polarity. For serious SSB operators, this means horizontal polarization. Kent Britain WA5VJB designed a series of homebrew yagi antennas, that are cheap and easy to construct. See http://www.clarc.org/Articles/uhf.htm

CW (Morse Code) is used on the weak-signal VHF bands, often intermingled with SSB operation. It is fairly common to have a station switch from SSB to CW when signals are very weak, since CW will get through at lower signal levels. You don't need to be able to work CW to enjoy a VHF contest but it does have advantages.

If you only have FM gear, you will be at a disadvantage but you may still be able to work a bunch of stations. Unfortunately, the contest has a rule that we cannot use 146.52 MHz (the 2M FM Calling Frequency). You can use any of the other standard simplex frequencies (and never use a repeater during a contest). I recommend we use 147.42 MHz, which is the calling frequency used in the Colorado 14er Event.

We can use the FM calling frequencies on the other bands:
52.525 MHz
446.000 MHz

Making A Contact
OK, so you get on the right frequency and the right mode. Now what? You need to make a contact. An official contact requires that the two operators exchange callsigns and grid squares. VHF grid squares are a system that divides the world up into rectangles that are 1 degree of latitude by 2 degrees of longitude. You can work each station once per band for contest credit.

For a map of Colorado with Grid Squares shown, see
http://www.k0nr.com/rwitte/vhf_grids.html

All of Colorado Springs and Pueblo are in grid DM78.
All of greater Denver and Castle Rock are in DM79.
Longmont, Loveland and Fort Collins are in DN70.

If you are close to the edge of a grid, you will need a good map or a GPS receiver to figure out your grid.

The rules for the ARRL Contests are found at http://www.arrl.org/contests/forms/

The rules for the CQ Worldwide VHF Contest are found at http://www.cq-amateur-radio.com/World%20Wide%20VHF%20Contest.html

More information on VHF operating can be found at the Rocky Mountain VHF Plus web site
http://www.qsl.net/rmvhf

Plug it in, turn it on and work someone on VHF this weekend.