2 Antenna's; their distance apart?

[bradjg25]

Hey Everyone,

Had a question that I was just pondering. I have a 50 watt VHF mobile radio in my car that is connected to a permanent mount antenna. I also have a Radio Shack Scanner PRO-2096 in the car that I want to hook to a permanent mount antenna.

The Question:

How far apart should these antennas be so that the scanner doesn't get fried?

Thanks for teh help!!

Brad

 

[RayK]

With that much power you will fry the scanner,best not to have scanner on,when xmiting
with your mobile.

 

[mikeATtleccdotnet]

If you can be a 1/2 wave on VHF away, about 36"s, it will limit the power coupling to the scanner. Even being a 1/4 wave away, 18"s, will still work and not fry the scanner. What will happen is that you will desense the receiver of the scanner and inturn, it will not receive as well when you have your two way keyed up. Chances are, you will not care about this situation as your talking and don't need the scanner at that moment.

-Mike

 

[SLWilson]

What I have...

Here's what I have on my car.

Haven't had a problam with it so far. Been using it for months.....The mobile is VHF Hi band. 45 Watts. The scanner is a Pro96....

I'm using the scanner mainly for Ohio's MARCS system...(800MHz trunked radio)...Almost everyone in our area is VHF Hi band, so I have them in the mobile & use it on scan to listen to.

The UHF that I do listen to is close enough to where I drive that I can hear it OK even on the 800MHz antenna.

Steve/KB8FAR

 

[mikeATtleccdotnet]

The only thing that I would change about your install is to terminate the coax to your scanner with a BNC connector, not a PL259 to BNC adapter... Otherwise, it looks good.

-Mike

 

[SLWilson]

Well...

The only thing that I would change about your install is to terminate the coax to your scanner with a BNC connector, not a PL259 to BNC adapter... Otherwise, it looks good.

-Mike

Sometimes I switch out the scanner for a UHF mobile that needs a PL259, so, that's why I've used the adapter for the Pro96. If I didn't use the UHF every once & a while, I'd change it....

Thanks for the thought!

Steve/KB8FAR

 

[kc8zdf]

Well here is a little story for you about tx with the scanner on..

When I had my pro-96 in the car with my 65watt ft-2800m not thinking when talking on the ham would hurt it. Well it fried the front end on high power. Worked great on 800mhz in fact so good that cell towers did not make it load the front end. However no more vhf or ufh...lol. Not only that but then two nmo mounted antennas were just 6 inches apart.

So now I have relocated. I have a 1/4 wave length between the two antennas. I use a comet sbb 5 for the ham radio and a maxrad low profile 800mhz for the scanner. Looks just like antenex but made by maxrad. I also now have a pro-2096 in the mobile now too instead of the pro-96. However I still tx in the car with the scanner on but I am only using 5 watts. Not high power of the radio. But with the radio you have I beleive you have to program it to do lower power or that is just it that it does all the time. I have not expericend any loss of front end performance by just using the 5 watts tx for local repeaters. Still loads up by cell towers on 800mhz. Although when I have to kick it up a notch I then shut the scanner off above 5 watts.