I have a 110 watt A9 Spectra on VHF and I'm looking at putting in a VRS unit. Is it recommended to put in a VHF VRS but have about 1-5 MHZ seperation between the Spectra and VRS unit without filters or duplexors? Or will they cancel out each other? The space is about 5-7 foot between the Spectra 5/8 wave antenna and the 1/4 wave VHF VRS antenna. I know it would work on crossband VHF Spectra to UHF VRS I'm just curious about in band.
Thanks in advance
VHF VRS Question
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VHF VRS Question
Stu
If you are going to try to run an in-band VRS you really need to install some fairly serious filtering to keep it from having major desense problems (Notch filter on your high-powered mobile, and a pass filter on the VRS).
One trick that will help, although it will not eliminate the problem entirely, is to mount the VRS antenna underneath the body of the vehicle. This lets you get the antennas more or less into each other's nulls, and the vehicle body will provide some shielding.
With VHF that would require some pretty serious ground clearance, unless you use one of the low-profile "can" or transit antennas. Even then, I don't know how waterproof any of those would be, and you might still manage to tear it off.
One trick that will help, although it will not eliminate the problem entirely, is to mount the VRS antenna underneath the body of the vehicle. This lets you get the antennas more or less into each other's nulls, and the vehicle body will provide some shielding.
With VHF that would require some pretty serious ground clearance, unless you use one of the low-profile "can" or transit antennas. Even then, I don't know how waterproof any of those would be, and you might still manage to tear it off.
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007
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Humhead is right on the money...here is a picture of our in-band VHF setup:
We run 110w M/A-Com Orion mobiles with OE-approved Pyramid VHF vehicle repeaters. You can see the tuned cavities for the Orion strapped to the outside of the mounting board, and the VR notch filter is mounted on the reverse side behind it. Because of the filtering, we are running a four foot gap between antennas at the rear of the car.
There is a second box strapped to the VR with a rubber duck antenna, which I am assuming is a mobile monitor of some kind.
It doesn't look like much, but that setup takes up the whole left side of the trunk in our Crown Vic's, and most of the radio tray in the 9C1's. All the filtering is factory-tuned by Pyramid, with final issues taken care of by our techs at the time of installation. I don't know the price tag is per car, but it isn't cheap.
It sounds fantastic, however. You can tell they are out of their car on the portable, but the system works very well.
We run 110w M/A-Com Orion mobiles with OE-approved Pyramid VHF vehicle repeaters. You can see the tuned cavities for the Orion strapped to the outside of the mounting board, and the VR notch filter is mounted on the reverse side behind it. Because of the filtering, we are running a four foot gap between antennas at the rear of the car.
There is a second box strapped to the VR with a rubber duck antenna, which I am assuming is a mobile monitor of some kind.
It doesn't look like much, but that setup takes up the whole left side of the trunk in our Crown Vic's, and most of the radio tray in the 9C1's. All the filtering is factory-tuned by Pyramid, with final issues taken care of by our techs at the time of installation. I don't know the price tag is per car, but it isn't cheap.
It sounds fantastic, however. You can tell they are out of their car on the portable, but the system works very well.
Do not make Sig angry...he'll just keep ringing the bell.