This morning, the ISS flew nearly directly overhead and I set up to listen in. As I was doing my best to get the antenna pointed correctly, a perfectly empty carrier broke the static for about 2 seconds. Then a few seconds later, RS0ISS came through saying hello. A few seconds more and a clean SSTV signal came through. I even remembered to record the audio this time! I decoded the audio with my phone, and besides receiving two phone notifications during the recording (note to self: silence all alerts when using my phone to record audio!), the image came out OK for my first try.
While I wait for my Arrow antenna to arrive, I thought I would experiment and build a dual band tape measure yagi since I already had most of the parts on hand. The Arrow antenna can be broken down and carried in a bag, and it will be my primary antenna to work satellites, but the 70cm part of this antenna came out perfectly resonant at 436.6 MHz. I had to really go outside the box on the 70cm director lengths, but I finished with a combination that tests well.
The 2m portion did not turn out so well, but at 146.600 I ended up with a 1.5 SWR at best. It receives well enough. I’ll tinker with it again and see what I can come up with.
Yesterday, I was able to receive SO-50 (Saudisat 1C) just fine and in my excitement I forgot to start recording on my phone. I didn’t try to make contact, but a lot of what I heard was very clear, and the operators that were hitting the bird with full quieting came back to me the same. Pretty neat stuff!
Today, SO-50 flew overhead and I was better prepared to record the audio and even make contact. What I discovered, however, is that something nearby was transmitting a nice clean carrier on 436.785 thru 486.795 while I was attempting to receive the bird. Well, given that I was out in the driveway using a highly directional antenna, I found that it was coming from my house! I was able to hear a couple transmissions from SO-50, but the rogue carrier pretty much ruined the session. I had not experienced this yesterday…
I set out on a little fox hunt in the house to hunt down the source and found that the downstairs desktop PC was the culprit. Note to self: put that damn thing to sleep next time!
I referenced these sources for the build:
This is a very limited test and review of the DJB-1 dual band HAM antenna that I purchased from Dr. Ed Fong (WB6IQN) on eBay. I recommend buying directly from his eBay store since the proceeds goes towards his students. They often make the antennas as an exercise under his supervision. Mine was well-made and performs nicely.
After installing the antenna in the peak of my attic away from all electrical wires and air conditioning, I connected about 50 feet of LMR-400 to it. I then connected my Chinese antenna analyzer and tested both 2m and 70cm bands. Everything looked good and I was just in time to check in to the SE Linked Repeater Net and give it a whirl with my Baofeng UV-5R V2+ HT.
The day after, I set out to see which 2m repeaters I could hit on low power (1 watt), and get some signal reports. The first try was 23 miles away with great reports. The second attempt was 32 miles away with great reports. The third try was 42 miles away and I was able to hit that repeater with 1 watt and full quieting. Pretty good! There were some repeaters I could not hit that were a bit closer, but I cannot verify if they are up and running. I’m located at one of the highest points in my town, and I think this is what is helping the DBJ-1 perform so well for me. They are a relatively horizontal pattern antenna and mine is located at a decent elevation with respect to my surroundings (and area repeaters). I’ll try for more distance on both low and high transmit power when I have more time. I will also plot not only distance, but direction and elevation differences between my station and repeaters. From there, I will rotate the antenna and see how this affects performance to fringe repeaters.
Below are a series of images showing the test result using my Chinese made KVE 520A analyzer. This small box shows 1:1 SWR with two different 50Ω terminators. Good enough for me since I compare antennas instead of relying on accurate numbers for each antenna. I would love to someday find out how well this little box is calibrated.
Please excuse the crappy smart phone pics.