For the past few years, I’ve operated Field Day with the Northern Virginia QRP Club under the club call WA4MM.  Since other club members are well equipped with gear and antennas for the HF bands, I’ve been contributing a VHF station to the festivities.  I enjoy VHF operation, and including a station “on the Ultra-Highs” with a multi-station club Field Day operation doesn’t change the entry class as determined by the number of  HF stations.  Thus “free” QSO points are added to the final score.

In recent years I’ve also done a bit of  “hilltopping” in VHF contests, including the September 2004 ARRL VHF/UHF Contest and the 2006 CQ Worldwide VHF Contest.  My first hilltopping ventures were on 2 Meters in the mid-1950s, from locations in central New York State.  The equipment then was a Gonset Communicator, which was a very popular QRP AM transceiver of the day.  I later added homebrew 6 meter gear for such excursions.  As the years passed, I transitioned to solid-state VHF and UHF transceivers.

I have antennas and feedlines for such portable operation, and have been putting them to work, along with my Yaesu FT-817 in Field Day as well.  For Field Day 2007, I used an ancient, homebrew 3 El Yagi on 6 Meters, and a Cushcraft 124WB 4 El Yagi on 2 Meters.  They were supported on three, 5 foot long aluminum mast sections, as shown in Figure 1.  I fasten the mast to an existing support with bungee cords.  I did recently acquire a base which is intended to be held in place by one of the wheels on my car, but have yet to use it.  I’ve also added a small KLM Yagi for 432 MHz, but  only for the ARRL event I mentioned above. I use “armstrong rotation” to point the antennas, which does entail hopping in and out of the car frequently.  Note that a compass and maps are also very useful.

VHF contests aside, there’s considerable VHF activity on SSB and CW during Field Day.  For that reason, I used these weak signal modes as opposed to FM.  Now I’m not sure one could classify my VHF hilltopping as adventure radio, since I operate from my car or in close proximity to it.  At one time I did a bit of backpacking, but  didn’t do much amateur radio operation on such excursions, except for using an FM handheld transceiver on a couple of these forays.

So what can be expected from QRP VHF on Field Day?  First, long distance contacts on 6 Meters are likely, since Field Day falls during the prime time of the year for sporadic-E propagation.  This is due to ionization of the E-layer in the Ionosphere, and  isn’t  too dependent on where we are in the solar cycle.  Contacts over paths of around 1000 Miles are common, and sometimes the E-layer ionization pattern is such that so-called double-hop sporadic-E is possible.  The latter can provide transcontinental and even intercontinental QSOs on 6 Meters.  More infrequently, sporadic-E can extend to 2 Meters and above.

Secondly, there is a good chance for propagation enhancement, or ducting, in the Troposphere, especially at dawn and around local sunset.  This is due to creation of a differential in air density as the atmosphere heats and cools, and can provide propagation paths over distances of as much as several hundred miles.

One other point is worthy of mention.  Use good quality coaxial cable for your feedline.  Such cable types as RG-213 and 9913 are good.  For smaller, handier cable I recommend LMR-240, or even RG-8X.  Keeping the length relatively short, say 40 Feet, also helps to minimize losses.

WA4MM operates Field Day from a local high spot in northern Virginia.  A bit of extra elevation, the more the better, is good for VHF operation, hence the term hilltopping.  Two years ago, during Field Day 2005, propagation conditions were quite good, allowing a considerable number of  6 Meter QSOs  via sporadic-E and 2 Meter QSOs with Connecticut and New Jersey.  In Field Day 2007, we weren’t as fortunate. There was only one brief sporadic-E opening to Florida, which allowed my FT-817 to snag two of the three Florida stations heard.  On 2 Meters, I was only able to work stations in Maryland and Virginia this year.  Still, the VHF station contributed 27 QSOs on 6 Meters, and 10 QSOs on 2 Meters to the WA4MM total.  Even at that, I was happy, as you can see from Figure 2.  A high point of this year’s Field Day was working KI3DS;  their VHF station was being operated by a group of enthusiastic young amateurs, probably in their early- to mid-teens.

My most memorable hilltopping expedition on 2 Meters took place in the mid-1980s,  I took my Santec LS-202A FM/SSB handheld and 30 Watt amplifier to the top of Spruce Knob, which at about 4800 Feet above sea level is probably the highest elevation in West Virginia.  There was extensive tropospheric enhancement over much of the eastern USA that September evening, and when I wrapped up at about 0300 hours local time, I had 98 QSOs with stations from Missouri to Maine in my log.  My lone trans-Mississippi River QSO with Missouri took place in no small part because the operator called me on CW, thus standing out among the many SSB stations I was hearing.  In last year’s CQ World Wide VHF Contest, there were strong single-hop and double-hop sporadic-E openings, and from a hilltop in western Pennsylvania, I worked grid squares all over the mid-west, the south-east and up and down the Pacific Coast.

I hope that this article has put thoughts of VHF/UHF operation into your minds.  I’m sure a lot of you have such rigs as the Yaesu FT-817/857/897, the Icom IC-706, or other gear capable of VHF/UHF SSB/CW operation.  If you want to homebrew an inexpensive, but good 2 Meter, 222 MHz or 432 MHz antenna, I suggest you “Google” the call WA5VJB.  He’s published Yagi designs for several of the VHF and UHF bands that are made from a wooden boom and wire elements.  I’ve used such homebrew wood and wire Yagis, though not of WA5VJB’s design, on that magical night on Spruce Knob, as well as many times before that.  And there are plenty of designs for small, homebrew 6 Meter Yagis to be found on the Internet.  Why not give QRP on VHF/UHF a try?

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Cal Cotner, K4JSI,  was first licensed in 1955 as KN2ODL.  Before retiring in 2002, he worked as an RF Engineer and Technical Manager for COMSAT for some 35 years.  In addition to “VHFing”, he enjoys QRP CW operation on the High Frequency bands.

 

Figure 1: Field Day 2007 VHF antennas at WA4MM (Photo courtesy Bill Harding, K4AHK)

 

 Figure 2: Is This Fun, or What?  (Photo courtesy Bill Harding, K4AHK)