VKV PA – August 2021

After missing the OM VHF LOW POWER Contest—which I had planned to participate in from Považský Inovec, JN98as—I was once again looking forward to the August VHF Operating Event. The weather forecast promised a hot day.

Preparing the Antenna and Transceiver for the VHF PA

I’ve already practiced setting up the YU7EF antenna and the entire setup, but there’s certainly room to improve some things. I like setting up the antenna using the OK1FJZ mast. These are small details like the support bracket on the car’s trunk, tightening the guy lines, and so on. I use a telescoping mast with a relatively small antenna, so it’s not too difficult to raise the antenna.

I also managed to start the generator. Following advice from more experienced operators, I loosened the lid on the intake to allow air to flow in and prevent a vacuum from forming. There were about 20 minutes left until the start of the VHF Operational Event. I was configuring my logbook and scanning the band when the generator shut off—again. I moved it to a different spot and carefully started it up again. A minute later, it shut off again. I started it up once more—one last try. It started on the first try. This time, I adjusted the choke just a little.

Since it was running, I started the contest with an R2CW transceiver and a new MRF9180-based amplifier. However, the initial contacts didn’t seem to indicate at all that I had better equipment or higher power. One station pointed out my “narrow” modulation. It’s hard to verify that up on the hill. But since I can’t simply move the amplifier over to the TR-751E, I decided to continue with the R2CW.

R2CW Frequency Offset

I wasn’t having any success making contacts, either on calls or on scheduled skeds. It wasn’t until a later contact with a 9A station that it became clear the problem was with the frequency reading. The sked was set for 144.222 MHz, but the R2CW display showed 144.118 MHz!

I focused on scanning, but contacts were still coming in very slowly. I also heard some DL stations. Propagation conditions seemed better than in previous months, but things weren’t going well. So in the afternoon, I pulled out my Kenwood TR-751E, and it felt like things improved. This is also confirmed by the number of contacts, which was higher in the third hour than in the second.

Directions in VHF Operating Activity – August 2021

Number of contacts and grid squares in the VHF PA

In the end, the log showed 50 contacts and only 14 locator squares. Not far away, below Mikulčin Hill, OK2DTF/p performed much better. And I managed to make a contact to KN19 with OM0FC, which I don’t usually work. Contact map: http://www.opencontest.org/edi/map/20210816155218000511CUPMYI

At home, I compared the frequency reading accuracy of the R2CW against the TR-751E. The initial deviation of 1 kHz after power-up rose to 2 kHz within a few minutes. The transmitted signal seems stable; it’s just the frequency reading. According to the manual, however, such a deviation is within the limit.

At the same time, I compared the modulation. It didn’t seem bad to me, but there are some background noises that aren’t present on the TR-751E. It’s as if there’s some kind of interference in the modulation path. So there’s still work to be done before the next VHF event.

OM0AAO VHF PA Log