Monday, June 13, 2011

June VHF Contest - Mt Diablo

The ARRL June VHF QSO Party is a contest where hams try to make as many contacts, on as many different VHF and UHF bands, with as many different locations (grid squares) as possible. For the contest, I operated "Low-Power Portable" (QRP and battery power) from the summit of Mt Diablo. Mt Diablo State Park is a beautiful location, and the 3950' summit has clear views across the San Francisco Bay Area, as well as north and south along the California Central Valley.

I took along the Yaesu FT-817ND QRP (5-watt) radio. For power, I used the PowerFilm solar panels and LiFePO4 battery(described earlier in this blog). Antennas used were the Elk 2m/70cm log-periodic antenna and a 6m HO-Loop. The system was easily backpack-portable, and also worked well when operating from the back of my truck.

Here's the portable station on the south side of the summit:

A night shot of the campsite:

Listening to the radio while in the tent -- since the fog was rolling over the mountain on the first night, it was pretty wet outside!

On the second day, I operated trailside for a few hours, right next to the summit parking lot:

The 30W solar panels provided more than enough power to run the radio during the contest. In sunlight, the battery voltage would keep climbing until the charge controller disconnected the panels (14.0V). During the evening hours, the 6.4-AH LiFePO4 battery dropped to 12.8V, indicating roughly 70% capacity remaining (100% charge = 13.2V, 50% = 12.6V, 0% = 12.0V). The pack was recharged after about 2 hours in the sunlight while simultaneously running the radio.

The FT-817ND worked extremely well in the field. 5 watts was plenty to work almost every station that I could hear from this location.

Later on I set up the system in the bed of the truck, and operated from the lower summit parking lot:

I used a paper logbook. Rather hard to check if a contact is a duplicate (requires lots of flipping pages) but it worked pretty well:

By 8:00PM (PST) the contest was finished, and it was time to get back to the campsite and enjoy the great views of the surrounding area for one last night on the mountain!

Overall, the contest was a lot of fun -- I met a number of nice people on the mountain, and had a great time making over 200 contacts on the three bands. There were brief 6m openings that gave me contacts with stations as far away as Alberta, Canada, but most of the contacts were direct line-of-site with stations throughout California.

The map below shows the grid-square locations of the contacts. The ones in California are all line-of-sight from the summit of Mt. Diablo (a huge area!!), whereas the ones in Canada and Texas were a result of Sporadic-E propagation (high-altitude clouds of ionized gas refracting the radio waves thousands of miles):


  1. Very nice portable, pretty contest.
    I love to do like this too.

    so, where did you get the solar panels and how about it cost?


  2. Paper logging can indeed be a pain..

    One way to deal with dupes is to use a separate sheet for each band.

    Maybe also a sheet to list stations that you have already swept, or stations that you have worked, with bands checked off (worked), or crossed out (does not have).


  3. I'm interested in how you made the yellow antenna tripod?

  4. The antenna tripod appears to be from a set of halogen worklights.


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