First SOTA Activation – Using VHF FM

VHF SOTA

Finally… FINALLY… I activated a summit for Summits on the Air (SOTA).

I fell into the “I need HF Portable” slump. With the economy like it is, and clearly will be for a while, HF portable is out of the question for now. Would VHF SOTA be an option?

I’ve been doing mountain top APRS for a few years with success. This uses a Kenwood D710 as the transceiver. I developed antennas for the VHF packet links and UHF comms. The VHF antenna continues to evolve with the most recent iteration a full blown collinear J-Pole with proper phasing stub. I wondered how difficult VHF FM would be with SOTA.

Get in the car and Go!

With a mind to walk off some Thanksgiving Feast I grabbed two HTs, the collinear J-Pole, my pack and the usual hiking stuff and off I went to Shenandoah National Park. My targets were Hawksbill Mountain or Stony Man Mountain… or maybe both.

The car doth protest

During the drive out, the car suspension made new noises, heat stopped working and, sure enough, I found the anti-freeze overflow tank leaking. At 230,000 miles, I know this Taurus all too well. The engine cooling system was still doing its primary job of cooling the engine perfectly well. Onward I traveled scrapping the idea of two hikes.

Stony Man was the choice

Stony Man is closest to US211 so that became the first target. I parked at Skyland near the southern trail head.

Despite the fact this hike is only about 1.6 miles, Stony Man is a ten point summit. Go figure.

This prototype of my QSO card shows the great views from atop Stony Man Mountain.

When I was up here in July 2012 for the APRS Golden Packet 2012 Attempt, the clouds hid the beautiful views…

Needless to say, the July 2012 APRS Golden Packet event was four hours of staring into gloom while the APRS gear did its thing.

The rocky outcrop is actually not the peak of Stony Man. The top is hidden in the trees 100 or so feet away. I searched for a marker, but in the end simply set up 50 feet from the rocks… very well within SOTA limits.

The VHF SOTA Station?

Click on the image to examine the details. The dark brown of the copper antenna makes it almost invisible in the trees. The white PVC helps find it though.

The VHF SOTA Antenna

There’s not a lot to this VHF SOTA setup: 2m HT, coax, antenna. The antenna is no HT rubber ducky. It is a home-brew collinear J-Pole. The design came about to make sure RF links north and south for the APRS Golden Packet station were solid… and Rock Solid the signals are with this antenna. Here is another view with a bit more detail of the coil…

The VHF SOTA Radio

Now let’s focus on the <cough> HT…

This is a blast from the past for many of you I bet. I purchased this thing right after obtaining my license in 1985. Being in college, money was more tight than even now; I used rolled pennies to fund part of this purchase. An HT with only a phone pad on the front you say? Yes… the ‘controls’ are on the top…

Yes… yes that’s right… THUMBWHEELS! Wait… it gets even better with these controls for power, simplex/duplex and +/-…

Simple eh?

The evil DUP/SIMP switch

The Duplex/Simplex switch is one that is 100% always in the wrong position… this time being no exception. My initial calls were on 146.520+… oops.

Pondering a moment I remembered to set the switch to simplex and gave a call on, this time, 146.520.

Anyone out there?

Would anyone be monitoring? Yes! The following QSOs were quickly made…

• 1708 UT – KK4LBU – Doug in Singers Glen, VA. Doug gave me an S3 signal report, but my signal was up and down.
• 1714 UT – K3XI – Tim in Stephens City, VA. Tim heard me fine. I immediately knew his QTH when he confirmed he lived across the street from Gores Meats where I picked up a side just two weeks ago.
• 1721 UT – WA4KEB/M – Ross driving in Burke, VA. Ross says I was strong.
• 1735 UT – W4NA – Nate in Winchester, VA. Nate gave me an S9+20 signal report.

Except for Doug, I maintained communication with the power switch set to low on my HT. For the IC-2AT HIGH means 1.5 watts and LOW means 150 milliwatts! My power is likely slightly higher thanks to the 8 AA battery pack.

My signal strength meter report to them was, well, nothing since the IC-2AT doesn’t have a meter to read 😐 . I assured them their signals were 59 sounding with no issues, static or noise.

As these are VHF signals, we can compare observations with calculations based on Longley-Rice…

The map is about 97 x 97 miles. This simulation was thrown together quickly and lacks tweaks. That said, it suggests the link to Doug, KK4LBU, would have been more predictable than what he observed of my signal. Oh well. There is no doubt being on a mountain top with VHF can be fun.

Thank you for the SOTA QSOs and great conversation gentlemen. You impressed the hikers passing by.

Fellow Hikers

Shenandoah is busy all year round and today was no exception. I met many folks. Two non-hams expressed interest in what I was doing. Of these, one was on the bubble of whether to get his ticket asking about today’s exam difficulty. I encouraged him to proceed with some self study and maybe looking up a local club for study help.

Another gentleman on a hike with his wife immediately knew what I was up to and introduced himself as a ham. I can’t recall his callsign, but appreciated not being the only ham on the mountain.

Final thoughts

This was fun and a good reason to get out and work off some of that Thanksgiving meal. Being my first VHF SOTA, let along any band SOTA, activation, I was a little worried VHF FM would be inadequate to get my four contacts. My concerns were unfounded as several hams monitor 146.520 and enjoy the varied contacts found there. Apparently the Appalachian Trail hikers call on 146.520 often.

HF would add more fun to SOTA, but don’t be held back if you only have VHF gear. Just go and do it.

SOTA rocks.