Batboard

Hello all! Quick question (I searched a bit and seems like old info) about vehicle repeaters. Small rural community is dispatched through a Sheriff's Office. VHF (155 mHz) no repeater. How can an in vehicle radio help boost a portables' signal? Repeater? Can it boost both ways, or just to transmit? Thanks!

If the sheriff is currently VHF, they could use UHF vehicular repeaters. However, those portables are only useful around a sheriff's car with the VR turned on. The portable can be a few hundred feet from the car, but the system range will be whatever range the car gets.

OR

They could attempt an in-band VHF repeater in the car. That could get messy.

bedforddawg wrote:Hello all! Quick question (I searched a bit and seems like old info) about vehicle repeaters. Small rural community is dispatched through a Sheriff's Office. VHF (155 mHz) no repeater. How can an in vehicle radio help boost a portables' signal? Repeater? Can it boost both ways, or just to transmit? Thanks!

The vehicle repeater works on a simplex channel between the VR and the portable with the mobile RX audio also being repeated out to the portable.

You can do in-band vehicle repeat, but you then need filtering. Unless you can get a M03 freq up in the 170's (good luck) you will need filters on both the mobile radio and the repeater. The repeater will need a pass filter, and the mobile a notch. With a notch filter on the mobile it will limit you on your frequency range, so lets say the VR is on 159.00 and your mobile is on 155.00. The mobile will now not be able to use anything above 157.00 or below 161.00 with the notch filter in line. If you need to TX around the VR's freq then you will need come up with a way to take the notch filter out of line when not needed.

Check out Pyramid Communication's web site http://www.pyramidcomm.com and the page on in band filters http://www.pyramidcomm.com/in-band-filters/. They work great when set up properly.


Jim

I think in band would be best so we wouldn't have to change the portables. Trying to do this on the cheap. Is there a way to do with some older MOT units that can be picked up cheap? Even off brands?

Did one of these years ago with a GE Mstr 2. One way repeat to help ht get into system. Cheap radio to find, & easy to modify. I used 2 antennas, so no duplexer. It worked great. GARY

Did one of these years ago with a GE Mstr 2. One way repeat to help ht get into system. Cheap radio to find, & easy to modify. I used 2 antennas, so no duplexer. It worked great. GARY

Gary, thanks for the reply. So how does one go about doing that?

http://www.repeater-builder.com/ge/mast ... ystep.html This is the site you want to see, but you can go to repeater-builder.com & go to the GE section, & there are several how to's. GARY

Unfortunately, those GE Mastr II cannot be narrow banded.

OTOH, the concept could be applied to several models. You just have to be able to DIY.

Depending on the type of mobile radio, you may be able to connect them directly to each other. In my vehicle, I have 2 CDM1550's connected to each other trough the rear accessory port. When I have them connected, the radio traffic on 1 is broadcast on the second and vice versa. One is VHF and 1 is UHF in my case, but I would think 2 VHF might work, especially if you can get the antennas separated. Keep the radio transmitting to the portable on a low power. The problem might come in when you are transmitting with the portable, and the high power mobile keys up and knocks out the signal from the portable.

You can find pre-made cables on Ebay. I found one by searching for duplex repeater interface cable. I 'think' it will work with any radios with the 16 pin connector, but I have not tried them on anything but CDM radios.

tdats wrote:Depending on the type of mobile radio, you may be able to connect them directly to each other. In my vehicle, I have 2 CDM1550's connected to each other trough the rear accessory port. When I have them connected, the radio traffic on 1 is broadcast on the second and vice versa. One is VHF and 1 is UHF in my case, but I would think 2 VHF might work, especially if you can get the antennas separated. Keep the radio transmitting to the portable on a low power. The problem might come in when you are transmitting with the portable, and the high power mobile keys up and knocks out the signal from the portable.

You can find pre-made cables on Ebay. I found one by searching for duplex repeater interface cable. I 'think' it will work with any radios with the 16 pin connector, but I have not tried them on anything but CDM radios.

The problem with this is that there is no priority hierarchy scheme in case two units get on the scene, both with VRS units active.

I would suggest the OP check into the Pyramid Communications equipment, specifically the SVR-200. I've run one in my truck for years without a hitch. Unfortunately mine is an older unit with an EFJ RF board, so ta-ta come January 1.

Pyramid will update the unit to narrow band (basically rebuilt it if needed) at a very low cost, I want to say $125.00, or 150.00 for the end user. They also give you a full year warranty on the unit after that.

d119 wrote:
I would suggest the OP check into the Pyramid Communications equipment, specifically the SVR-200. I've run one in my truck for years without a hitch. Unfortunately mine is an older unit with an EFJ RF board, so ta-ta come January 1.

n7maq wrote:Pyramid will update the unit to narrow band (basically rebuilt it if needed) at a very low cost, I want to say $125.00, or 150.00 for the end user. They also give you a full year warranty on the unit after that.

d119 wrote:
I would suggest the OP check into the Pyramid Communications equipment, specifically the SVR-200. I've run one in my truck for years without a hitch. Unfortunately mine is an older unit with an EFJ RF board, so ta-ta come January 1.

No :o? I'll call them tomorrow, or Monday if they take an extended holiday. Thanks for that!

A little more information on narrow-band options for the SVR200:

According to the manufacturer, units built prior to the year 2000 have a GREEN RF board in them. These units cannot be narrow-banded, and there's nothing you can do with them.

Units built in the year 2000 or after will have a BLUE RF board in them. These units can be converted to narrow-band operation with a kit that costs $100, or $150 if you have the manufacturer perform the operation, which I'm told includes return shipping.

Unfortunately, I have a green board unit. See my WTB post in the FSWT forum!