Two Repeaters, 10 miles apart, will this work?

[WRPL657]

Can two repeaters with same input and output frequencies but with different transmit and receive tones for each repeater work without creating a feedback loop or some other problem? Our situation is we have two repeaters, one is in operation now. It does not cover a critical location in a mountainous area. We have a second repeater set-up that is identical in frequency and tones. If the second repeater's tones were changed to be different from the first repeater could they operate in close proximity (10 miles) with out creating a problem? Anyone out there with similar experience?

[marcspaz]

If the tones are the same, both repeaters would come up and 'repeat' your transmission at the same time.  No loop could be created.

If you set it to different tones, then the only issue to watch for is mistakenly causing interference.  The users of each repeater would probably need to just transmitting a tone, but not using tone squelch.  This way they can tell if the frequency is in use.  Either that or they would need to 'monitor before transmit' if they have a monitor button on their radio.

[WRXL702]

5 minutes ago, WRPL657 said:

Can two repeaters with same input and output frequencies but with different transmit and receive tones for each repeater work without creating a feedback loop or some other problem? Our situation is we have two repeaters, one is in operation now. It does not cover a critical location in a mountainous area. We have a second repeater set-up that is identical in frequency and tones. If the second repeater's tones were changed to be different from the first repeater could they operate in close proximity (10 miles) with out creating a problem? Anyone out there with similar experience?

Depends on the coverage area of both repeaters. If they overlap, you will have interference when both are transmitting at the same time.

Having different squelch tones is not the same thing as having different frequencies.

My suggestion - Set the second repeater at a different frequency to avoid potential problems.

[BoxCar]

3 hours ago, marcspaz said:

If the tones are the same, both repeaters would come up and 'repeat' your transmission at the same time.  No loop could be created.

You will still get some interference from the other repeater in overlap areas due to the phasing of the signals. Overall, it will work with the same frequency/tones.

[marcspaz]

14 minutes ago, BoxCar said:

You will still get some interference from the other repeater in overlap areas due to the phasing of the signals. Overall, it will work with the same frequency/tones.

 

Yeah, we have had that happen around here a few times when a new machine was stood up.  It sounds weird when its understandable. 

[gortex2]

I have done similar with our SAR repeaters. We use a different input PL on the repeaters but common transmit PL. That way ou can hear folks on both repeaters regardless which channel I have selected. In the old days this was considered poor man voting but worked well for many public safety agencies. 

 

[WRTC928]

I'm curious about why you want to do this. 

[BoxCar]

3 hours ago, WRTC928 said:

I'm curious about why you want to do this. 

 

On 5/22/2025 at 1:25 PM, WRPL657 said:

Can two repeaters with same input and output frequencies but with different transmit and receive tones for each repeater work without creating a feedback loop or some other problem? Our situation is we have two repeaters, one is in operation now. It does not cover a critical location in a mountainous area. We have a second repeater set-up that is identical in frequency and tones. If the second repeater's tones were changed to be different from the first repeater could they operate in close proximity (10 miles) with out creating a problem? Anyone out there with similar experience?

That's why.

[WRTC928]

5 hours ago, BoxCar said:

 

That's why.

How the heck did I read right past that? Of course, if I read it a couple of days ago, it's entirely possible I forgot it. I'm old. That happens.

[WRPL657]

On 5/23/2025 at 5:30 AM, gortex2 said:

I have done similar with our SAR repeaters. We use a different input PL on the repeaters but common transmit PL. That way ou can hear folks on both repeaters regardless which channel I have selected. In the old days this was considered poor man voting but worked well for many public safety agencies. 

 

Something like this is what I was wondering about setting up. Our area can not be covered with handhelds in the entire area (mountains/terrain) but the repeater now in use can be heard in all locations. We're using it for assisting EM/Storm Watches, etc. The current repeater is on top of a mountain 2,184 elevation. In one direction a handheld can work the repeater from 28 miles away without a problem, in another direction 7 miles away it is impossible to use a handheld.

[WRPL657]

On 5/23/2025 at 5:42 PM, WRTC928 said:

How the heck did I read right past that? Of course, if I read it a couple of days ago, it's entirely possible I forgot it. I'm old. That happens.

Welcome to the club, been there, done that... getting older is not what it is cracked up to be that's for sure.

[WRQI583]

Don't forget the barn door effect. If a conversation is going on on one repeater and someone keys up on the other repeater, it is highly likely that they will be close enough to hit both repeaters, and what will happen is that they will come across the other repeater as long as someone is talking which would cause the receive to be open. It would make it sound like someone was keying over the person talking.

PL tones only keep the receive from opening up unless someone with the proper tone keys up. Once that person with the proper tone keys up, it opens the receive allowing everything in, hence the "barn door effect, however, in normal circumstances, just the person using that repeater should be heard.

I have a repeater right down the road that is local. There is another repeater 35 miles from me that, when you are on the hill tops around here, you can get into it and definitely hear it well. I know there have probably been many times where I probably clobbered a person talking on the other repeater when I put my callsign out on the local repeater near me. The two repeaters? Same deal as what you are asking about. Same frequency, different tones.

[WRYZ926]

There are two other repeaters in Missouri using the same channel and PL tones as our repeater. One is in the Kansas City area and the other is just outside of St Louis. We are located towards the middle of the state. Here lately with the temperature inversions, one or both of those repeaters have been opening up our repeater. The closest one is 80 miles away.

And no we do not see anywhere near 100-200 miles of coverage on UHF here in Missouri.