The heart of the unit is a concept I thought of and actually is very simple. It is a bluetooth connection for CAT control, Audio in/out and GPS for time and location keeping. This is something that doesn't exist commercially as far as I know and I had to develop something myself.
I managed to get the GPS over bluetooth first with the help of a BT GPS module and BKTtimesync. After I did some experiments via a USB port and a Ublox7 GPS USB stick which didn't work at all. I also realized I could not simply split one USB port into multiple ones without problems even not with a USB hub, it would involve many cables which I wanted to avoid.
Bluetooth headset outside/inside
Second was the bluetooth audio connection. I bought a nice device with internal battery which could receive and transmit. However it didn't work because it could only receive or only transmit, you had to switch it with a external switch. I had to search for a full duplex unit to avoid switching. I bought a few 2 euro bluetooth in-ear headsets, the gold ones were the cheapest. Of course I tested them first before I dismantled them for the experiment. I really had no connection problems at all with these devices, they are real plug and play. However, they are only working in W10. In W7 I got it to receive audio but couldn't get any audio output for transmission. In W10 there was no problem at all. I mounted the BT module on a printboard and soldered in/outputs to connectors for the audiocables from my homemade digital modem, after some failures I finally managed to get it right with the third headset. To be shure I wouldn't get too much signal I mounted potmeters in both audio lines. I fitted the whole print in the same box as my GPS using the same (tablet)battery.
Third was the implementation of bluetooth CAT control. I bought one of those cheap ones from China. They cost about 10 euro including postage. First tests with connection via a Android app called pocketrxtx on a tablet are successful. But unfortunately connection on any computer with Windows failed. When I finally could get it paired, ham radio de luxe (or any other software) couldn't find the COM port connected to the bluetooth device although it was clearly there. I found a solution redirecting the port with serial splitter software, it worked, however this software isn't free and free versions (like for example VPSE) did not work. I didn't want to spend more money on software I spend on the whole device. Imagine it took me over a year to experiment, I couldn't find a good solution for this. And without CAT control the unit would not be ready. After a few tips I decided to try com0com again which is open source software and free. The problem with this software is that it is very basic and I couldn't get it to do what I wanted to. The hub4com package would solve my problems, but you almost guessed it.....it did simply not see the bluetooth assigned COM port. However, the strange thing is that ham radio de luxe does find the port now and I can finally connect to the radio via BT. Don't ask me why and how but com0com seems to install something so ham radio de luxe is able to find every COM port now.
Test of the prototype concept setup
I decided to test the device working on a dummyload with 1W this afternoon. My base station was configured as FT8 robot answering automatic CQ calls on 10m for the experiment. Here some video footage of the experiment:
Now, this is working but far from ideal. The best option would be one box with BT CAT/BT audio and BT GPS in it, voltage supplied from the radio like the BT CAT is now. That would be a technical challenge but not impossible. However, time is a issue as usual. I'm already glad it is finally working now after such a long time. Things would be so easy if this box was commercially available. Since the new Icom IC-705 has bluetooth I suspect you can CAT control and connect audio via BT like I do. But I'm not shure and time will tell. Would it be commercially interesting to fabricate such a BT device?
Total cost of the bluetooth devices: BT GPS bought in 2017 15 euro, BT in ear headphone (full duplex) 2 euro, BT CAT control unit 10 euro. 27 euro in total, the box and battery were given to me and free. Of course you need some device to connect the audio to your radio, I simply made it myself. It is capable to trigger transmit via VOX but if CAT control is available PTT via CAT is a better option.
There is another approach to wireless connect your portable station. OH8STN for example does use a Raspberry-Pi minicomputer with linux OS connected to his radio. Another computer, phone or tablet can connect the Raspberry-Pi over WiFi for wireless remote. I don't know what the costs are for such a setup but I think the bluetooth solution is cheaper. Both systems are difficult to configure without knowledge of computers and operating systems.
Since I had to remove the christmas LED star from the tower I had the idea to do some changes. First one is the removal of the single radial that is attached to the autotuner. Not that it is not working but I wanted to know how things behave when I use the complete tower as counterpoise. You cannot simulate everything and it is a fun experiment.
From the tests I did I can confirm it is working like it did with the radial. I do hardly notice any difference except for a bit more noise may be. I hoped that it would perform better on low bands but so far I'm not shure there is any difference. Time will tell... The antenna tunes well on all bands and everything in between.
And I did something I didn't thought of recently. Triggered by the success DX contacts others had. I installed the VHF/UHF beam in the mast. Not that I expect to make contacts with it...however I might try in the FT8 activity contest on 2m. I actually didn't try it yet...I'm planning to use the FT-817 with 5W only. It might be not enough for DX. On the other hand, if ES and or tropo is strong, it will be enough for digimodes like FT8. Of course you'll read about my efforts in future posts.
As long as I have the great 4 element LFA monoband in my tower I need to be active on the 10m band. Actually through the week I'm not really active except for some 60m in the evening. 10m however is my main band in the weekend. And although this band looks death it is not. So far I can make contacts every weekend. Today my FT8 robot managed to make a contact with S01WS. Yes, I was in my shack and didn't do unattended operation. I was repairing the shack seat at the same time. With the robot I don't have to click at every station for the contact, it will reply to every new CQ if a station has not been worked before, The only thing I do sometimes is rotate the antenna. That depends in which direction I suspect propagation,
