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Repeater Question


Emsflyer84

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Hey all, I’m new to GMRS but been in the Ham game for a bit. Recently some of my buddies took an interest in GMRS and are getting licensed. I’m thinking of putting up a repeater at my house since I already have an antenna mount and coax cable up on my roof, where my current Ham antenna is. I’m looking for the most simple way to set up a simple repeater using one additional antenna on my roof. At the same time I can’t justify spending thousands just so my friends and I can chat. Looking at a few options. First is the Midland repeater-in-a-box:

https://midlandusa.com/products/midland-mxr10-repeater

Second is this gadget which I came across by accident, can’t find much info on it:

https://kleinelectronics.com/flex-professional-repeater/
 

Third is this unit consisting of a couple Mororola radios. But I’m not sure if it has a duplexer or if I’d need two antennas. 
 

https://www.ebay.com/itm/285485485142?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=ZIH74GuxSLC&sssrc=4429486&ssuid=GJxbJs7qTe-&var=&widget_ver=artemis&media=COPY

 

Any advice here or other suggestions would be idea. Simple and compact is what I’m going for here. The more “plug and play” the better. Thanks! 

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Those Midland/Retevis repeaters have a very small internal duplexer that can barely create any decent isolation when the repeater is cranking more than 5 watts.

There is no magic bullet. You are never going to find a good, cheap, compact duplexer that passes 95% of your transmitter power and still gives you 90+ dB of isolation. It doesn't exist.

Every rookie with a wattmeter wants to get the MAXIMUM possible output power out of their repeater. I mean, 50 has to be better than 5, right?  In my opinion, the MOST important spec in a repeater system is the isolation between transmit and receive. Especially if you're using portable radios out in the field that can talk back in with 4 or 5 watts of transmit power. 

What good is it to key up your repeater with 10 or 15 watts of power when you introduce 3 or 4 dB of desense into the system? 3dB of desense on the receiver just made your 4 watt portable into a 2 watt portable, and how well is that going to work?

Better isolation = a better repeater.

Want to have a cheap repeater? You will get what you paid for. Cheap is rarely good.

 

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1 hour ago, Radioguy7268 said:

Those Midland/Retevis repeaters have a very small internal duplexer that can barely create any decent isolation when the repeater is cranking more than 5 watts.

There is no magic bullet. You are never going to find a good, cheap, compact duplexer that passes 95% of your transmitter power and still gives you 90+ dB of isolation. It doesn't exist.

Every rookie with a wattmeter wants to get the MAXIMUM possible output power out of their repeater. I mean, 50 has to be better than 5, right?  In my opinion, the MOST important spec in a repeater system is the isolation between transmit and receive. Especially if you're using portable radios out in the field that can talk back in with 4 or 5 watts of transmit power. 

What good is it to key up your repeater with 10 or 15 watts of power when you introduce 3 or 4 dB of desense into the system? 3dB of desense on the receiver just made your 4 watt portable into a 2 watt portable, and how well is that going to work?

Better isolation = a better repeater.

Want to have a cheap repeater? You will get what you paid for. Cheap is rarely good.

 

VERY TRUE WORDS!!!

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Well said @Radioguy7268

When my local amateur radio club decided on getting a GMRS repeater, we went with a Bridgecom BCR-40U repeater and we are using a separate duplexer that has been tuned for GMRS frequencies.

Hopefully we will have the repeater installed at the tower and running in the next week or two. The GMRS antennas are around 400 feet up on the radio station tower.

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17 minutes ago, hmurmur said:

I am new to GMRS

I subscribed to a GMRS repeater but having trouble programming into my new BaoFend UV5G

I have input and output channels

are the Input channels RX or Tx

I know this is simple. thank you for the help

The repeater Input is the TX channel for your radio. It should be a 467.xxx MHz frequency. 

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Have you looked into the older Motorola GR500/GR1225 repeaters? Can usually be found for a few hundred dollars with duplexer so all you need is a GOOD antenna and elevation. 

I actually have a few of them, with one set up in my area. It works good, but gmrs is kind of dead here. I also have a Retevis RT97 that I tried out for a week or so. I tried selling a complete, tuned (.650) lower power GR1225 locally but no one was even interested

 

20231015_141344.jpg

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