HF/VHF/UHF Multicoupler


stevebwhite@btinternet.com
 

Hello Everyone,
I am thinking of purchasing a HF/VHF/UHF Multicoupler and wonder if having a pre-amp in line with it would 
be OK?
Thanks


Chris Moulding
 

It depends what you are trying to do.

If you place a wideband pre-amp in front of the Multicoupler then it is likely to overload the receivers connected to it with the high level of RF. At some point you will also overload the amplifier in the Multicoupler.

if you are using it for a specific band of frequencies then you can add a pre-amp and bandpass filter to select a few MHz wide band of frequencies.

As an example I'm tinkering in lockdown with a satellite APRS igate on 145.825 MHz. I'm using a simple 2 element yagi antenna directed straight up to the sky to receive satellite signals. I've built a low noise masthead preamp and filter with an overall gain of 12 dB. This narrowband amplifier doesn't overload the Multicoupler or attached receivers and I'm regularly receiving APRS packets on every pass from the satellite PSAT-1 (NO-84). PSAT-1 only transmits 300 mW and you would normally need a full blown multi-element yagi with azimuth and elevation tracking to receive packets.

So the answer is yes, you can use a pre-amp with a Multicoupler if the gain is below 15 dB and the pre-amp output is filtered.

Regards,

Chris


stevebwhite@btinternet.com
 

Chris,
Thank you for such an interesting and informative reply, much appreciated.
regards
Steve