A Converter for the NB-Transponder to 28 MHz that really works fine

Hello Sat-Fans !

Based on a discussion, after I described my 739 to 144 MHz converters, whether it is possible to make a converter to 28 MHz, I did some experiments, and found out that it IS possible.

So came out a converter 739 to 28 MHz that really works fine.

I called it the "NB-Konverter tiny28 V1.0"

You can find the description at : https://elektronik-muenster.de…-0-739-mhz-auf-28-27-mhz/

I build up two versions, one for 28,5 MHz for use with regular shortwave receivers, and one for 27 MHz for use with CB-radios. The CB-version is nice for monitoring the beacons and for outdoor use for alignment of dishes and LNBs.

Sorry, the description is german language only, but there are many pictures, shematics and layouts so anyone might find it interesting. In other case "deepl" helps.

For me it was a very nice experiance to tune over the OSCAR100 with the old analog "flyheel" of my Trio JR599 and to tune the SSB-Signals with no digital steps.

If there is a lot of interest in this project I can offer some smiprofessional PCBs and a package of the "uncommon" components.

best 73 and stay healthy

Armin DF1QE

Yes, it's absolutely stable enough

Keep in mind : There's no multiplikation factor like with the TCXOs for LNBs.

In all converters I build with the SI590 the CW-Beacon stayed in the CW-Filter range for month

and usually one uses the converter indoor at constant temperature.

73s and stay healthy

Armin DF1QE

Very nice and professional PCB and case.

But what I miss is a filter for rejection of the imagefrequency.

This nearby doubles the noise.

And what's about the output matching of the mixer ?

73's

Armin DF1QE