Duplexers for Two Radios

[caravanken]

I have a Yeasu FT-8900 2m/70cm and a BC346XT Scanner that I would like to connect to the same antenna which is a Comet GP3. I have used the antenna on both radios (one at a time) and the antenna works great on 2m and the scanner frequencies I want to scan. Has anyone ever tried a Duplexer like the MFJ 916B to connect two radios to one antenna? I want to use the same antenna due to its height at 40' and I am running out of places to hang another 6' antenna down lower.
Ken
W0KRD

 

[teufler]

Have not used a duplexer but do use a Diamond Coax Switch cx210a, because I do not want any rf feeding backj to the radio while I transmii on vhf or uhf. The duplexers I have used allow you to transmit on one radio at a time. I supposs they have had isolation but my scanners are less robust then some radios I have , so I use the antenna switch. Going to transmit, just rotate the switch. Gonna listen to the scannerf, just rotate.

 

[dsmiley]

They work great...We have a dual band repeater UHF/VHF, each with a cavity dulpexer, both feeding a UHF/VHF diplexer, then upto a GP6...no issues at all

 

[DickH]

... running out of places to hang another 6' antenna down lower.
Ken
W0KRD

A 6' antenna? That would work for about 38MHz, but not 2 meters.

 

[kayn1n32008]

A 6' antenna? That would work for about 38MHz, but not 2 meters.

Depends on the band it was made for. It could be a 2m 1/2 wave over 1/2 wave... Makes it 6 feet long...

Please do not assume.

EDIT: it's a GP-3... It's dualband and 6' long... And is resonant on both 2m and 70cm

Sent from my iPad using Tapatalk

 

[zz0468]

Has anyone ever tried a Duplexer like the MFJ 916B to connect two radios to one antenna?

It'll work, but be aware of the limitations. Those devices are actually diplexers, not duplexers, and they consist of a pair of filters. There's a high pass filter, and a low pass filter, connected together at the antenna port.

So, yes, you can hook your ham rig and a scanner, but you will only be able to use either one on the range of frequencies allowed by the high or low pass filters, respectively.

If that works for you, go for it. If not, you'll need to come up with a better scheme.

 

[caravanken]

Thanks to all for your input. If I get it to work I will post back here with the results.
73
W0KRD

 

[mancow]

I guess I'm confused. Wouldn't that render you band dependent per radio? Either Vhf or Uhf but not both.

 

[LesWurk]

I guess I'm confused. Wouldn't that render you band dependent per radio? Either Vhf or Uhf but not both.

It'll make you band dependent, I have used these with sucess, but more to make up for poor front end filtering in some scanners

 

[caravanken]

It will make me band dependent but I will use my BC346XT to scan Aviation and Rail frequencies which the 2m/70cm antenna picks up pretty good.
I appreciate your input.
Ken