[Premium-Rx] Antenna Couplers

[Morris Odell]

Jim Garland wrote:

> Does anyone have a circuit diagram of an active multicoupler? 
> I'd like try 
> and homebrew one, and don't want to reinvent the wheel.
> Thanks,

I use an 8 channel one I built a few years back which is quite simple. It
uses a "Norton" transformer coupled feedback amp with a 2N5109, feeding a
simple resistive divider chain. The overall loss is about 3 dB. Ahead of it
I have a "QRN squasher" noise cancelling circuit which picks up the
(considerable) local crap here on a small wire antenna and allows me to
cancel it in the main signal chain.

There are lots of suitable chips around these days which make this even
easier. One of our local magazines published a video distribution amp design
last year using a single chip amplifier that would be ideal. It has a high
broadband gain and is designed to work into a 75 ohm load. When you think
about it, there are a lot of similarities between the requirements for video
distribution amps and HF multicouplers. 

Morris VK3DOC