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second TM-D710After I bought my first Kenwood TM-D710 in 2012 I discovered this was the ideal rig for me, mobile as well as stationary. I use it primarily in the shack and took it with me in the car when went mobile. I figured it would be convenient to have a second TM-D710 main-unit in the car, then I only have switch the front panel between shack and car. In order to help me trace a second TM-D710 unit, I set a Google Alert on Kenwood TM-D710.
Forget totally about this alert until a few weeks ago I received a mail there was a new entry for my search term. I clicked it and it was an ad on a local sales site. After a short bid I got a message from it’s previous owner Rudy PD1RVM. So a long story short: a few days later my second TM-D710 arrived. It was still in it’s original box and in mint condition. After some short tests the rig seems fine and I had to determine which one to put in the car and which one stays in the shack.
I did some modifications (adding GPS to the display-unit, swapping the noisy fan of the main-unit). After some thinking I decided to use my old front-panel (with GPS-module) and the main-unit from the second TM-D710(with slightly more noisy fan) in the car. The front-panel of the second TM-D710 went to my old main-unit in the shack. No sooner said then done I tested the config in the car. Worked excellent!
But when testing the setup in the shack, it fails to connect to my weather station. That’s weird! Tried different things but nothing helps. I suspected the GPS-port on the front-panel of the second TM-D710. It had to do something to do with the port. Finally I took apart the front-panel from my old radio, connected the GPS-module to the standard Kenwood wire and connected it to the new front-panel. Indeed, also nothing.
Next step: take apart the new panel and find something blackened. But to my total surprise it wasn’t broke; there was a beautiful build in GPS-module as well! That explains a lot, when there is a GPS-module in it, the serial port is occupied from the inside. I’m never able to see any device I connect from the outside.
Tested the new front-panel in the car to see which GPS-module performed better. No doubt about it: it’s the one in the second TM-D710! It has a fix within 2 second where I had to wait at least a minute for my old GPS-module to get a fix.
Disassembled the GPS-module from my old front-panel and connected the weather-station again. Now it plays immediately.

Now I’m a proud owner of two TM-D710’s. One for mobile and one for my shack.

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Double quad 23cmWith the 23cm transceiver still in development, I need a 23cm antenna. I got interested in a double quad for 23cm.

Advantage of a double quad for 23cm over other designs is a great front/back-ratio and a large opening angle. I will use the 23cm transceiver mainly for chatting on a local repeater PI6NOS. There is a free-line-of-site from my roof to PI6NOS. No need for a huge gain to open the repeater. I’ve chosen a fixed antenna position.

A few guys at my local club build a 23 cm double quad themselves. It isn’t a very difficult job. Only thing I didn’t like about it is it has to be placed in a plastic container to be weather proof.
Last radio market I attended I walked by a stand of EPS-antennas. The owner Paul PA3EPS, builds beautiful antennas for HF and higher bands. In his line-up Paul PA3EPS sells a double quad for 23cm. It’s a bit pricey in comparison with DIY. But then again, if you focus on construction, used materials and the fact that is weather proof as is…. anyway,it wasn’t a difficult choice. I prefer excellent quality antennas on my roof in order to avoid unnecessary presence there. That has something to do with a fear of heights.

Before I attach the EPS double quad for 23cm on its final position in the mast, it might interesting to see if there is a significant difference in performance between the DIY double quad (not yet tuned) and the EPS double quad. Unfortunately I don’t own much measuring equipment for 23cm so the only way to roughly compare the two is to check the signal of PI6NOS on my 23cm transceiver with both antennas in the same place, connected with the same cable.
The result you can see in this video.

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weather station PA1JIMThe new Peet Bros. weather station Ultimeter 2100 runs for a few weeks now. First results where very disappointing. All kind of weird data was logged on aprs.fi. Even data for rain (which the weather station has no sensor for). The weather station itself logs fine and readings are okay. So I figured it has to be the serial connection between the Ultimeter 2100 and my Kenwood TM-D710. I tried several things but nothing seems to work. Then PA1EDL informed me about the fact that this is a very common problem between two devices, connected via serial port, but with separate power supplies. It can result in “floating” serial signals which the devices can’t process. Solution for this problem is galvanic separation.
I ordered some 3N44 optocouplers and start building a galvanic separation. It wasn’t very successful, there was no connection at all. I removed the optocoupler and hit a dead end.
I looked around in my shack and suddenly realize I still have a solar powered battery! Maybe it would work when I connect the weather station to the battery. It would still be floating serial signals, but maybe less floating then with 2 AC power supplies.
After a few hours of running on battery the data on aprs.fi starts to make sense. The weather station uses a few hundred milli amps, the battery is around 12Ah so it should be able to run 24/7.
The big data collection starts now. I’m still thinking about buying the extra sensor combo with rain gauge and humidity meter some day.
And I still want to make the optocoupler work because thats the only guarantee for a proper operation regardless of what power supply is used.
Antenna with wind meter