In my youth, end of the 70ies, it was my dream to have such a radio. Today I know that it is one of the worst radios that existed. I love it now, to have one 🙂
I looked a very long time for one of that radios. I wished me a TS-788DXcc, but this one the TS-780DX is harder to get as the TS-788DX. I had the luck that in the Ham Radio exhibition, one was sales. I got it for 100€.
The mike was strong modified with a lot of holes in and broken. So I throw it away.
Its seem to be not possible to get one of the “service manuals” with alignment instructions.
So I find out all alignment points by my self in the circuit layout.
And here they are…
The interesting alignment points on the under side
The interesting alignment points on the upper side
AM modulation factor, at 60% the modulation
is clear with a 1kHz sine wave. More AM modulation will disturb the modulation
The TS-780DX can not use FM with modern radios together! Its an very old FM standard
what use the 1.5 KHz filter from SSB. That does not working very well.
FM frequency deviation, 1.5KHz. That’s the max what this filter can handle
If you adjust more, the the FM Mod is strong disturb.
FM modulation clearness. They are still spikes on the sine. And so it sounds.
But it works not better, without a big modification.
You can try to get the FM receiving clearer with the FM filter (see upper side alignment pictures at the left side).
The SSB ist very good, for that the radio was build
Two tone Test in SSB, looks very good so far. If this is not clear, see at the bias and the ALC.
The maximum power in SSB, 100W, on FM 45W and on AM 20W with upward modulation to 50W
The Frequency is drifting with the temperature of this radio very high. I measure a difference from 700 Hz! So you can try to get it better. But with the temperature in your room, the frequency is changing. We have in Germany a proverb: “Sie läuft wie ein Feldhase” Translation “It runs like a hare” 🙂
AM/FM Frequency, that 10 Hz to high. very good
The SSB frequency I check with a 1Khz test tone. So that frequency is the offset
USB Frequency is 30 Hz too low. Good enough.
LSB Frequency is 130 Hz too high. it will works. You will not often use LSB
upper side inside with the main board
under side inside with the VXO
Self made mike with volume control
With this crystals the frequencies are:
If I get the right color, I will paint the case new with Sommerkamp blue.
Hello, i have a Sommerkamp TS780DX, i don’t have a user manual.
Help me please !
thank you & best 73 from switzerland
albertino look here
Finns det någon här som vet hur man gör för att få sommerkamp 780 dx att passa med nyare fm-system
Is there anyone here who knows how to make summerkamp ts 780 dx fit with newer fm systems
Is there anyone here who knows how to make summerkamp 780 dx fit with newer fm systems
I would like to install an external frequency meter on my ts 780 dx. how can i do? thanks for the help.
Je recherche le scanner d’un 788Dx car le mien que je tourne à droite ou a gauche rien ce passe