LNB downstream and LO upstream over 1 coax
Can you provide the link of the ON4CJQ solution? Also keep us informed about your progress. I use 25 MHz+740+bias and 430 for the other cable. I run about 60 meters. A Lab testing can be personal run from September. Also I use a second cable for H. Maybe a combiner can be used also to use a single cable for NB and WB signals. One question to the designers of QO100 is why NB and WB use different polarization?
many people are using the cable from the LNB to the receiver to send 3 "signals" over the single cable:
- the receive IF signal e.g. 740 MHz
- the supply voltage for the LNB including the information to switch between V and H polarization (14v / 18V)
- the reference frequency signal for the LNB (typ. 24, 25 or 27 MHz)
Sending the local oscillator signal for the LNB upstream will be very difficult as it is a rather high frequency
and the attenuation of the cable will be very high.
Triplexers for the above mentioned 3 signals are built into the AMSAT-DL downconverters and can be bought
stand alone for instance in the BATC shop in UK (design by Mike Willis G0MJW). Here is a descrition of my built:
Maybe I am not understud. The proposal is to send also 430 MHz, not LO. Also my proposal is to combine also Rx NB&WB signals. Now I use one for 25+739+13V , one for 740-750+18V and one for 430 MHz. The proposal is 3 to 1 cables.
I am also not sure whether I understood what Johan wants to accomplish. So we need his response.
In any case I think there are 2 "links" where multiple signals can be combined.
1.) One is the receive path as I had described above,
2.) The other is the path from the transverter to the transceiver where the RX-IF-signal, the TX-IF-signal and the reference signal can be combined. For the second topic I am using a triplexer from Diamond.
You can find a description of ma portable setup (where both "links" are using multiplexing) here:
Looks like DD1US Matthias has the solution already.