Digital RF power reading over LAN?

[Basil]

What's the easiest way to view a power reading from the PA to the POTY co-ax over the LAN like I could PA voltage, current and temperature, for example? I have one of the cheap Chinese made 40dB 200W directional couplers on its way, I now neeed to consider how to interface it, can anyone help please? I use an Arduino for the other digital data.

Thanks. Chris 2E0ILY

[Pa3fbx]

Its implemented in the datv easy

including a ino for an arduino uno...

Benno

[Basil]

I was meaning getting the RF out from the directional coupler into a DC format to use as an input to the Arduino? I know roughly how to do it at HF, but at 2.4Ghz.... Not so much Thanks Benno.

[radiogareth]

Have a read of Daves article in CQ-TV 273 page27-28.
You will need to calibrate it somehow, although I go by the output waveform on a SA (as an upper limit) and look at the DC input to my amp at that point. If I'm on QO-100 I know the drive level to start at. If you are using a Polish derived PA many of them (well both my types) already have samling bridges in them. You WILL need a magnifier to trace them though...
Gareth

[Basil]

Thanks Gareth, I'll dig out my digital copy and have a read, appreciated!

[M0DQW]

I've just got mine working today.

I use node red and a RF8000 Chinese power meter. I have tried with AD8317 modules but could never get the calculations correct.

The RF8000 has a serial output, which contains the dBm value. So I have a separate Orange Pi Zero 2 running node red. The RF8000 connects to the OPi USB port to provide a Serial/USB channel.

The RF8000 is connected via RF to the sample output of a 40db coupler, with another 13db attenuator.

I then use node red on the OPi to send the dBm value over MQTT, to the broker that is already running on the Pluto 0303 firmware.

Then, on my main QO100 transceiver, within Node Red, I just subscribe to my dBm topic and show it on my dashboard. Ofcourse I also convert this dBm value to Watts.

Yes, I know its a long winded way of doing it, but it works lol...

Matt

Desktop Screenshot 2023.03.30 - 14.42.39.74.png (229.69 KiB) Viewed 3607 times

[g8gtz]

Hi Matt,

Sounds like that would make a very interesting CQ-TV article

73 Noel

[Jabi]

Good morning again:
What is your power out in one normal operation in DATV for work with the 53 dB of attenuation?
73,s de Jabi, ea2aru.

[Basil]

I bought a cheap Chinese 40dB directional coupler, that on unpacking rattled. I took the lid off to find an appalling build quality and the thing shattered in pieces. So I bit the bullet and paid £80 for a branded one with a full spec sheet. I can now use a Marconi 6460 meter and power head I bought at a rally years ago to test power to the POTY. A friend heavily into microwaves with a lab full of calibrated gear checked it was in spec and surprisingly it was bob on!

So today I put the meter at the dish, added (for peace of mind, I know how fragile power heads are) another 30dB of attenuation in line with the new 20dB coupler, for a total of 50dB attenuation, and increased my signal up to the overload level, then a tad down to a fraction under it. It looks like 13.2W is all I need into this big dish. Which correlates with how much drive I have to give the 20W SG Labs amp.

So I now have some references to calibrate a digital setup.