Current Projects–
It’s 7/23/2022 and I’m below ground trying to escape the 100F heat. Surrounded by prototyping parts and between satellite passes, things begin to happen in the shack. Just recently I completed a 2m RHCP/LHCP switch for my portable tracker. W6PQL had some nice DPDT medium power (100w) relays already mounted on a thick PCB, so I bought a couple. The contacts are rated at 17 amps and are switched with 12v @ approx. 15ma each. Okay now, what? So, I sketched out how I was going to split the 50-ohm input, and create 2 phase lines input to lead or lag at 90 deg. Default would be RHCP & switched on LHCP. I have a control line dedicated to switching this configuration from the radio at 28m (100 ft) away. I had my thinking cap on when I planned out the controller. It was created with an experimenter’s mindset. Not only can you have (C1) RHCP or (C2) LHCP, but you can also utilize the power splitter (S1 & S2) to stack like yagis. ‘ZW3’ has a 30 amp FET switch which can be toggled by the controller. Here is a pictorial of the Power splitter, RHCP/LHCP project.
Note: The coax to the 2 identical yagis must be the same length, and one yagi needs to be 90 degrees from the other.
Here is the finished product with the lid off and connecting (C1) & (C2) to 50-ohm dummy loads. Tests were performed with a SAA2N VNA obtained at a great price from R & L Electronics in OH.
Well, how does it work? Well, at first not so good.. . Using Triaxial 8233 works great for 70cm, but (2) 17inch pieces of this thick coax it in a 9.5-inch box is a challenge. Anyway, it handles power. The VNA showed 3+:1 SWR which prompted me to open it up and check the wiring. I thought I did it right… and I did. Why wasn’t giving me the 1.4:1 I was looking for? As you can see, I bundled up the coax and put a couple of zip ties on it to see it that would help. Bingo, RHCP was 1.37 to 1 and LHCP was showing 1.49 to 1. Huh… Glad I didn’t dismantle it! Okay, on goes the lid. Checking with the VNA, everything is working and switching correctly. Now, to test it on the SAT-TRAC 32 rotor, ‘ZW3’. Wow, CAS-4A, CAS-4B had solid uploads as they approach and continue to work great flipping to LHCP when they were running away. What was interesting is that some satellite signals magically appeared when the switch was changed correctly. Flippling it back, they were gone… huh… Looks like it’s working correctly and installed for use.
Here is what it looks like on the ‘ZW3’ rotor:
Well, another happy ending… It’s always a good thing when a plan works out… More projects in the wings… 73, Mike