Running two antennas to cover freq range

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danostuff
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Joined: Tue Feb 26, 2008 7:02 am

Running two antennas to cover freq range

Post by danostuff »

Is there any way to hook two antennas up to an XTL5000 radio to cover the frequency range of my current codeplug? I need the 136-174 Mhz range on Low profile antennas. I can buy two antennas to cover the entire range, but need a combiner or something. Any help would be appreciated.
Jim202
Posts: 3610
Joined: Sun Sep 09, 2001 4:00 pm

Re: Running two antennas to cover freq range

Post by Jim202 »

There are some wide band antennas on the market today. However, you probably need to examine the
specific frequencies that you need. I don't know of any agency that needs in real time the entire spread
for their operation. Being a ham and also needing a public safety or government channel at the 174 end
might just make it. To go lower on the lower end, you dreaming.

To drift the comment just a shade, I have done both 46 MHz and 33 MHz out of the same radio using 2
antennas in a mobile environment. Had one antenna on the 46 channel and the second on the 33 channel.
I then had to cut the coax cable feed lengths to a tuned 1/4 wave length. The 46 antenna got the cable
with the 33 cable length. The 33 antenna got the cable length for the 46 antenna. Put a coax T at the
radio and it all played fine per a reflected measurement from a watt meter and a 100 watt TX.

I guess you could do the same thing on VHF, but you might be limited in frequency due to the 1/4 or multiple
lengths of a 1/4 wave to separate the antennas. The tuned coax might give you fits over broad ranges
of frequencies.

Jim


danostuff wrote:Is there any way to hook two antennas up to an XTL5000 radio to cover the frequency range of my current codeplug? I need the 136-174 Mhz range on Low profile antennas. I can buy two antennas to cover the entire range, but need a combiner or something. Any help would be appreciated.
W8RW
Posts: 68
Joined: Thu May 06, 2004 9:08 am

Re: Running two antennas to cover freq range

Post by W8RW »

danostuff wrote: I need the 136-174 Mhz range on Low profile antennas. I can buy two antennas to cover the entire range, but need a combiner or something.
It depends on whether or not you want continuous frequency coverage. A combiner using filters (diplexer) will have a gap where neither port works (or works well). If you want continuous coverage you would have to use a broad band antenna. Here is one from Sti-Co that covers 150-174 MHz:

http://www.sti-co.com/antenna-products/ ... e-antenna/
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