Connecting 2 Ant's Together Question ?

[BOBRR]

Hello,

I have an Airspy HF+ Discovery, and for reasons I'll never understand, it has only a single
ant. input.
So, when going from the HF bands <30 MHz to perhaps the Aero. "stuff" at 118 MHz, you have to either switch
the spigot cables manually, or use a switch box. Another annoyance and complication.

Was wondering:

I have a Scantenna ST-2 in the attic, and outside a long 70 foot or so simple
end fed wire ant. (and Balun) for receiving (only) below <30 MHz.

What would happen if I connected both together at the Airspy ant. input connector ? I do only receiving.

Would they "interact" ? How ?

Thanks,
Bob

 

[popnokick]

You can do this with a duplexer such as the Comet CF-360A or CF-360B (difference is only in the connectors). One port will handle 1.3-30 mHz low pass (your end-fed wire) and the other 49-470 mHz high pass (your ST-2). This type of duplexer works best with a match in the 50 ohm range which your ST-2 has, but you should consider a matching device / tuner for your end-fed wire (unless you already have a 49:1 or other balun for the wire antenna). You will probably have slightly more signal loss than you would experience if you instead used and A - B antenna switch. Don't use a simple "T" connector - you'll lose half the signal from each antenna and since there is no isolation between the two antennas, you will have unexpected interactions and phase differences between the antennas that will likely produce poor results. There are many places you can get duplexers... here's one

Comet Antennas CF-360B Comet Duplexers | DX Engineering

Free Shipping - Comet Duplexers with qualifying orders of $99. Shop Duplexers and Triplexers at DX Engineering.

www.dxengineering.com

 

[jonwienke]

A duplexer/diplexer is the best option. Just get one whose frequency split best matches the antennas you want to combine.

 

[BOBRR]

Hi,

Thanks for suggestions and thoughts.
Appreciated.

Bob