Monthly Archives: June 2011

Next kit project: OHR 100A 20m QRP CW XCVR

Although I really enjoy my NorCal 40A 40m CW QRP XCVR, I’ve been wanting to expand my operating horizons and be able to operate during more than night time hours. So I decided to build the Oak Hills Research 100A 20M QRP CW transceiver.

I opted for the the memory keyer as well as the 10-turn pot for finer tuning.

I had been considering the NorCal Sierra, and really liked its ability to accommodate multiple bands, but decided to go with the OHR 100A for a different kit building experience.

The rig operates in the 12-13.8V range which is perfect for the power sources I use.

Not sure if I will add the frequency counter, although it might be a good piece of gear to own since it serves as test gear too.

I’m hoping to receive the OHR 100A by June 25 and complete it by mid-July or so. Looking forward to operating 20M again, not to mention working with my S9 and trying other smaller antennas that I really can’t erect at the house due to space restrictions.

S9 v31 vs. a dipole at 20 feet

I set up the S9 for a nighttime test comparison with one of my dipoles mounted about 20 feet up and touching my house. I was running my NorCal 40a on battery power. Skies were clear at about 65 degrees F. There was a fair amount of activity on 40 meters, conditions were good for a test.

The result? The vertical was, at least this time out, a superior performer. There was no comparison. The ground-mounted S9 v31 was significantly quieter and heard more signals as well. The other thing about the S9 is that signals are so strong I typically have to reduce my RF gain by 25-50% so my eardrums don’t get blown out. It’s amazing how much louder many signals are on the vertical vs. the dipole.

While comparing the two antennas,I worked Kevin, K7KHC, in Aberdeen, Washington using the vertical. Had a nice QSO but discovered that trying to use my key mounted on a clipboard was a bit awkward. Still need to optimize that set-up.

After that experiment I moved my NorCal 40, power supply and cables up to my second floor outside porch to enjoy the night sky and see if I could catch any DX. Right around 0500Z I chanced on ZL2AGY, Tony in New Zealand! He was in a QSO so I waited till they finished, but was unable to contact him. Not sure if my signal was not getting out strongly enough or whether he had gone QRT. Anyway it was great to hear propagation working so well into Moscow, Idaho for my S9.

I hope to receive my new radial plate this coming week and am interested to learn whether it will improve the strength of my transmissions. My current radial plate is nothing more than a plumbing fixture with some paint scraped off so the screws and wires all make good contact. Not optimal.

It was great sitting out under the stars, tuning around just by feel. The NorCal 40a has no display so I was able to sit in total darkness, watch up at the sky and tune quietly around the CW portion of 40m. Any time I needed to write, I just clicked on my Petzl headlamp with the red filter on to minimize getting blinded. Worked great.

Looking forward to many more evening sessions like this.