20 august 2022

Home made HF PWR/SWR-meter - revisited

Three years ago I played with a Stockton Bridge and made (just because I had it on my shelf) a nice portable HF power meter and SWR meter with cross-needles.

In the first iteration, it was meant to work with QRP radios; it has an impressive 5-600 mW range but on a second thought, I though what if I can use it for a broader range.

And I put a double potentiometer to change the range. 

But that was not a reliable solution because the range was somehow too "variable" and I never knew the real power.

So, a new iteration was born.

The PWR and the SWR voltage came from the Stockton bridge to a set of 2 x 4 * 1 MOhm potentiometers that will set the range for each position on the switch.

The switch is a dual pole-4 position and the ranges will be 10 W, 50 W, 100W and 200 W.

The calibration was made with a NRP-Z11 power sensor. While it is not a very reliable measurement tool, it helps to see the approximative value of the average or CW power. The 10W scale is pretty precise but the others are not so good.
The values are consistent through 1.5 MHz - 80 MHz.

04 august 2022

ADSB on RaspberryPi

 Playing with Raspi and ADSB.

I made a little box to put it on a pole at my second location.

The antenna is a double helix, housed into a PVC pipe.

Testing in Bucharest on the balcony, it looks well!

50-100-150 km range circles.

Note to myself:

25 mai 2022

ICOM IC-7100 E Extended frequency Mod

Our EmComm group ( RVSU ) is using  the IC-7100 from ICOM as primary HF Radio.

We therefore must be able to use it on the full range of frequency so we "mod" it. 

Actually, we modified the configuration diode matrix so the radio will TX from 

0.1 MHz - 199.999 MHz and

400 - 470 MHz.

It will still not transmitt AM on the VHF and UHF.


-The modification cand damage your radio!

-Do not transmitt out of the authorisation privileges!

-I have no responsibility for what are YOU doing with YOUR radio.

Pictures are said to worth thousand words, so I give you two thousand:



The removed diodes are soldered on one side of the pads just to have them handy when the mod will be reversed (if needed).

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