Avoiding interference building a repeater

[WSCV533]

Hello all, probably got a stupid question for y'all to make fun of. I am slightly new still to GMRS. I got my Callsign about 3 months ago now. I have a simple 20' flagpole antenna and get good (~15 miles) simplex range for my needs. I'm trying to figure out how to avoid causing any interference when choosing what channel to set on my new repeater. There's a lot of repeaters within my range and my thoughts were on RP22 or 462.725 . I have not received anything on this channel and on the map the closest repeater to me that's on the same channel is about 50 miles away. I have tried keying up using the ctcss tones and get nothing, which leads me to believe it is out of range. I want to avoid disruption as much as possible out of respect for other GMRS operators. What's a fool proof method of avoiding interference? Obviously I will use "privacy" tones but is there more I can do to keep the air waves clear. I am almost ready to turn on my repeater system, but just wanted to ask this before I do.

 

Edit: Thank you all for your input. I appreciate your experience and support.

While this repeater will likely be open to all who draw near its primary purpose will be family communications between Pasco and Hernando Counties.

Edited May 29 by WSCV533

[marcspaz]

With only 8 pairs, it can get crowded in some areas.  It sounds like you are on the right track with the steps you have taken. 

 

Nothing is fool proof, but if you are really concerned, along with the monitoring you are doing, I would recommend publishing your repeater info.  This way, if you end up causing interference with a previously existing repeater, the legacy repeater owner will have some way of contacting you.

 

For what its worth, there are several repeaters around me on the same frequencies and overlapping coverage.  The repeater owners have talked amongst themselves and agreed to leave every machine up, have their regular users operate with a custom tone, and all run 141.3 for travelers and emergencies.  It has been working out very well for several years, with very limited interference.  Just about everyone has been pretty happy with the coverage and availability.

[marcspaz]

3 hours ago, WSCV533 said:

I'm starting my repeater project now

 

Good deal.  Have you gotten to the point where you are considering a particular repeater?

 

[MarkInTampa]

On 6/4/2024 at 2:56 PM, WSCV533 said:

I'll be using an external controller, actually experimenting now with some stuff. If it doesn't work out then this will just be my mobile and I'll figure something else out. Also checking out the retevis ra87. Also, 725 is a no-go. Something between is causing interference. I'm not familiar with the sound, something between dial-up noise and a printer printing? Completely constant 24/7, must be lower power or far away.

Here's a quick rundown of repeaters I know of in the area. Is there something on 650 in your area? Pasco has a repeater node on that frequency but it's a really low powered station.

550 maybe? - Clearwater is on that frequency, not sure if you are far enough away though
575 forget it! - Tampa 575 will stomp it
600 maybe? Tampa 600 is on it, but not quite as powerful as the 575 and 675 repeaters are but still pretty strong
625 nope - Spring Hill and is somewhat local to you
650 probably you best choice. There is a monster repeater in Sarasota on this frequency but you are more than far enough away. There might be something else on this near you, I'm 35 miles south and don't know what is around you for sure
675 nope - The new Tampa Bayshore repeater is another monster repeater in the area
700 most likely nope - nothing GMRS is on here but there is an illegal encrypted DMR repeater running on this frequency that has drove anybody trying to do a GMRS repeater away to another frequency
725 maybe? - but you said something is causing interference on this frequency

Most of these repeaters except Sarasota sit right between me and you. I can even tell you the height of the antenna and what they are using for a repeater for the most part if you want to know.

[kidphc]

Simple way is to leave a radio on the input frequency that you have chosen then let it run for 12hours. Same on the output. If nothing heard. Of course with low to no squelch and no tones. Then you should be good to go, assured that you probably aren't interfering, but it is hard to say with so many private repeaters.

Just remeber enabling tones just has it so the repeater won't open unless the the tone matches.

Sent from my SM-S901U using Tapatalk

[GreggInFL]

8 minutes ago, marcspaz said:

The repeater owners have talked amongst themselves and agreed to leave every machine up, have their regular users operate with a custom tone, and all run 141.3 for travelers and emergencies.

Is it possible to use multiple tones on a repeater, or am I reading that wrong?

[nokones]

10 minutes ago, GreggInFL said:

Is it possible to use multiple tones on a repeater, or am I reading that wrong?

Yes, but the repeater can only have one conversation on the air at the same time.

[GreggInFL]

3 minutes ago, nokones said:

Yes, but the repeater can only have one conversation on the air at the same time.

This place is a gold mine.

[kidphc]

This place is a gold mine.

It is and you will learn just how good of a site it is.

Sent from my SM-S901U using Tapatalk

[GreggInFL]

Oh, I'm learnin' all right.

[marcspaz]

2 hours ago, GreggInFL said:

Is it possible to use multiple tones on a repeater, or am I reading that wrong?

 

Yes. Many repeaters can have 2 or more tones. Many can have a receive tone that is CTCSS and transmit a DCS tone (a type of split tone configuration). Still more, some repeaters can also use a paging system where they only open the receiver if they hear two tones simultaneously, and transmit either the same two tones or two entirely different tones.

[kidphc]

Not sure if Marc answered the question that you were asking. He did but the question might have been different. Marc mentioned multiple tones earlier


Many of the repeaters in this area have multiple tones. One is kinda a psedu repeater owner tone. That if you have enabled the tone he always listens to, it's his private tone.

In our area, you really need to receive with no tone, or be at least able to turn the tone off (monitor). There are multiple repeaters across the area that are on the same pair. By listening for the squelch tail turning off and the recieve tones off/monitor, we are effectively able to cross repeater talk.

Sent from my SM-S901U using Tapatalk

[marcspaz]

11 minutes ago, kidphc said:

Not sure if Marc answered the question that you were asking. He did but the question might have been different. Marc mentioned multiple tones earlier


Many of the repeaters in this area have multiple tones. One is kinda a psedu repeater owner tone. That if you have enabled the tone he always listens to, it's his private tone.

In our area, you really need to receive with no tone, or be at least able to turn the tone off (monitor). There are multiple repeaters across the area that are on the same pair. By listening for the squelch tail turning off and the recieve tones off/monitor, we are effectively able to cross repeater talk.

Sent from my SM-S901U using Tapatalk
 

 

Much better response. After reading the question again, I'm thinking you are right.

 

To use literal examples, a repeater can be configured to operate if it receives a 141.3 tone or a 127.3 tone (just random tones I picked for the examples).

[gortex2]

If there are multiple repeaters in your area what is then eed to add another ? It seems most think they need a repeater but if there are useable ones in the area ues them. 

[MarkInTampa]

16 hours ago, WSCV533 said:

Hello all, probably got a stupid question for y'all to make fun of. I am slightly new still to GMRS. I got my Callsign about 3 months ago now. I have a simple 20' flagpole antenna and get good (~15 miles) simplex range for my needs. I'm trying to figure out how to avoid causing any interference when choosing what channel to set on my new repeater. There's a lot of repeaters within my range and my thoughts were on RP22 or 462.725 . I have not received anything on this channel and on the map the closest repeater to me that's on the same channel is about 50 miles away. I have tried keying up using the ctcss tones and get nothing, which leads me to believe it is out of range. I want to avoid disruption as much as possible out of respect for other GMRS operators. What's a fool proof method of avoiding interference? Obviously I will use "privacy" tones but is there more I can do to keep the air waves clear. I am almost ready to turn on my repeater system, but just wanted to ask this before I do.

I'm around 35 miles south of you - far enough to not get quite the same GMRS traffic as you but close enough to have a feel for the area. 725 would but a decent channel for your area but make sure you are NOT using 141.3 as a tone. I sit between two of the area 725 repeaters, the Bartow repeater - Polk Co's strongest repeater up 400ft around 35 miles east of me (and 60 miles south of you) and the Seminole repeater up around 60ft last I heard around 35 miles west of me (the one 45 miles south of you, since the antenna isn't up very high it's probably why you can't hit it). The two repeaters are 60 miles from each other and both run 141.3 as a tone. Normally the two repeaters don't interfere with each other unless someone like me forgets to turn off high power that sits between the two and key both up at the same time. Bartow hits me full scale, Seminole is just above the noise floor (height is might!) so if I run low power I "usually" don't key the Seminole repeater and cause interference. The same can be said of Bartow, if somebody in Manatee Co is using the Seminole repeater they also key the Bartow repeater with noise and everybody get upset on that repeater thinking somebody is causing intentional interference. This happens a few times a month and usually with just a handful of users that sit in-between the two repeaters. If there is a decent band opening, the Perry 725 repeater (also on the same tone and up 400ft) can also be added to the mix and is a really strong repeater. If the repeaters were on a different tones it probably would not be a issue. Also, the Tampa 575 repeater (the strongest repeater in the Tampa area) has an alternate input of 467.725 with a DCS tone but I don't think that will give you any problems as long as you are not using a DCS tone of 546.

[WSCV533]

On 5/27/2024 at 6:24 AM, gortex2 said:

If there are multiple repeaters in your area what is then eed to add another ? It seems most think they need a repeater but if there are useable ones in the area ues them. 

Because they don't cover the areas I need to have signal in. I am going between hills at a certain angle that my house has signal to the points I need, but not the repeaters.

On 5/27/2024 at 8:41 AM, MarkInTampa said:

I'm around 35 miles south of you - far enough to not get quite the same GMRS traffic as you but close enough to have a feel for the area. 725 would but a decent channel for your area but make sure you are NOT using 141.3 as a tone. I sit between two of the area 725 repeaters, the Bartow repeater - Polk Co's strongest repeater up 400ft around 35 miles east of me (and 60 miles south of you) and the Seminole repeater up around 60ft last I heard around 35 miles west of me (the one 45 miles south of you, since the antenna isn't up very high it's probably why you can't hit it). The two repeaters are 60 miles from each other and both run 141.3 as a tone. Normally the two repeaters don't interfere with each other unless someone like me forgets to turn off high power that sits between the two and key both up at the same time. Bartow hits me full scale, Seminole is just above the noise floor (height is might!) so if I run low power I "usually" don't key the Seminole repeater and cause interference. The same can be said of Bartow, if somebody in Manatee Co is using the Seminole repeater they also key the Bartow repeater with noise and everybody get upset on that repeater thinking somebody is causing intentional interference. This happens a few times a month and usually with just a handful of users that sit in-between the two repeaters. If there is a decent band opening, the Perry 725 repeater (also on the same tone and up 400ft) can also be added to the mix and is a really strong repeater. If the repeaters were on a different tones it probably would not be a issue. Also, the Tampa 575 repeater (the strongest repeater in the Tampa area) has an alternate input of 467.725 with a DCS tone but I don't think that will give you any problems as long as you are not using a DCS tone of 546.

Thank you, glad to hear from somebody nearby that understands the situation. Lots of repeaters in the area, most don't quite hit the areas I need to have signal. I have driven south to see when I hit the 725 repeaters. I've hit the bartow, possibly the perry 725 too, but honestly I must've missed that one on the map lol.

Edited June 4 by WSCV533

[MarkInTampa]

1 hour ago, WSCV533 said:

Because they don't cover the areas I need to have signal in. Honestly, why even post an "answer" to my question if all you're doing is criticizing me when you clearly don't know what I need and why I'm doing it.

Thank you, glad to hear from somebody nearby that understands the situation. Lots of repeaters in the area, most don't quite hit the areas I need to have signal. I have driven south to see when I hit the 725 repeaters. I've hit the bartow, possibly the perry 725 too, but honestly I must've missed that one on the map lol.

I don't have good luck with GMRS repeaters north of Tampa for the most part due to the terrain between me (in Brandon area) and to the north. I can hit the Spring Hill 625 machine (37 miles north) but it hits me noisy around S-2. The Cortez (Bradenton, around 39 miles south) on the same frequency but different tone hits me around S-5 and I've never heard interference between the two and can operate both since they are on different tones. The 725 machines not so much since they are on the same tone. It seems like folks around here really like using 141.3 tone if its a open public repeater and I get that - it's just kinda overused and prone to interference of other repeaters. That's the main reason I'd suggest something other than 141.3 or DCS 546.

Bartow has a really strong machine and covers most of Polk county. It doesn't make it much past Brandon unless your on a rooftop in downtown Tampa (I've heard it!). You are far enough away that I don't think it would be a issue. Funny story on 725 - A few months ago there was a decent band opening, nobody was using the Seminole or Bartow repeaters and I was getting Perry full scale 165 miles away and checked into their net. Of course I heard at least 3 repeaters on the same frequency and tone I was keying up at the same time so I kept it short.

[marcspaz]

4 hours ago, WSCV533 said:

Because they don't cover the areas I need to have signal in. Honestly, why even post an "answer" to my question if all you're doing is criticizing me when you clearly don't know what I need and why I'm doing it.

 

 

Your response seems unusually harsh, especially considering you have asked such a novice question. Maybe I'm misreading it.

 

That said, there is an overwhelming amount of new people that come here convinced they need a repeater, when the know nothing about radio and have only had a license for a few weeks to a few months. 

 

Given how long some of us have been around and seeing the trend of unnecessary repeater build ideas that never come to light, it's not an unreasonable question to ask why someone new thinks they "need" a repeater. Especially if there are some already in the area or possibly another solution. 

 

Also, not everyone can afford putting a repeater up, not realizing putting a quality and reliable repeater on the air cost anywhere between $15,000-$20,000 when you include the mast and antenna system. On the high-end I have a friend who spent over $1.8m to get a 300' tower built to install his repeater system. Even on the low side, if you have access to free tower space, you're going to spend $5,000-$7,000.

 

If there is another option available and someone can help me find a better or alternative solution that doesn't cost me a fortune, I would want the feedback. If someone just wants to understand "why", I wouldn't be mad that they asked.

 

 

[WSCV533]

On 5/27/2024 at 6:26 PM, marcspaz said:

 

 

Your response seems unusually harsh, especially considering you have asked such a novice question. Maybe I'm misreading it.

 

That said, there is an overwhelming amount of new people that come here convinced they need a repeater, when the know nothing about radio and have only had a license for a few weeks to a few months. 

 

Given how long some of us have been around and seeing the trend of unnecessary repeater build ideas that never come to light, it's not an unreasonable question to ask why someone new thinks they "need" a repeater. Especially if there are some already in the area or possibly another solution. 

 

Also, not everyone can afford putting a repeater up, not realizing putting a quality and reliable repeater on the air cost anywhere between $15,000-$20,000 when you include the mast and antenna system. On the high-end I have a friend who spent over $1.8m to get a 300' tower built to install his repeater system. Even on the low side, if you have access to free tower space, you're going to spend $5,000-$7,000.

 

If there is another option available and someone can help me find a better or alternative solution that doesn't cost me a fortune, I would want the feedback. If someone just wants to understand "why", I wouldn't be mad that they asked.

 

 

Fair nuff, yeah looking back I definitely reacted poorly and I apologize.

Edited June 4 by WSCV533
He's right

[WSCV533]

On 5/27/2024 at 3:16 PM, MarkInTampa said:

I don't have good luck with GMRS repeaters north of Tampa for the most part due to the terrain between me (in Brandon area) and to the north. I can hit the Spring Hill 625 machine (37 miles north) but it hits me noisy around S-2. The Cortez (Bradenton, around 39 miles south) on the same frequency but different tone hits me around S-5 and I've never heard interference between the two and can operate both since they are on different tones. The 725 machines not so much since they are on the same tone. It seems like folks around here really like using 141.3 tone if its a open public repeater and I get that - it's just kinda overused and prone to interference of other repeaters. That's the main reason I'd suggest something other than 141.3 or DCS 546.

Bartow has a really strong machine and covers most of Polk county. It doesn't make it much past Brandon unless your on a rooftop in downtown Tampa (I've heard it!). You are far enough away that I don't think it would be a issue. Funny story on 725 - A few months ago there was a decent band opening, nobody was using the Seminole or Bartow repeaters and I was getting Perry full scale 165 miles away and checked into their net. Of course I heard at least 3 repeaters on the same frequency and tone I was keying up at the same time so I kept it short.

I got a Nagoya NMO200c antenna I think it's called, for my car. Put it in my mobile, so far it's been impressing me. I've hit the Tampa 575 repeater from my driveway which is slightly out of the repeater's estimated range. It's pre tuned for gmrs (and MURS, never used it other than to test) swr on a mag mount was 1.01 . I'm starting my repeater project now. Thank you for your help, wish me luck!

[SteveShannon]

39 minutes ago, WSCV533 said:

I got a Nagoya NMO200c antenna I think it's called, for my car. Put it in my mobile, so far it's been impressing me. I've hit the Tampa 575 repeater from my driveway which is slightly out of the repeater's estimated range. It's pre tuned for gmrs (and MURS, never used it other than to test) swr on a mag mount was 1.01 . I'm starting my repeater project now. Thank you for your help, wish me luck!

Good luck!

[WSCV533]

On 5/30/2024 at 4:26 PM, marcspaz said:

 

Good deal.  Have you gotten to the point where you are considering a particular repeater?

 

Yeah I'm pretty much set on building a Radioditty DB-40G repeater. Got a duplexer on the way straight from Chinaland. Already have one of these Radioditty radios and it's quite fantastic.

[marcspaz]

29 minutes ago, WSCV533 said:

Yeah I'm pretty much set on building a Radioditty DB-40G repeater. Got a duplexer on the way straight from Chinaland. Already have one of these Radioditty radios and it's quite fantastic.

 

That's cool.  I had no idea you could pair a couple of DB-40G's together.  Is that a native feature or are you using some kind of external controller?

[WSCV533]

10 minutes ago, marcspaz said:

 

That's cool.  I had no idea you could pair a couple of DB-40G's together.  Is that a native feature or are you using some kind of external controller?

I'll be using an external controller, actually experimenting now with some stuff. If it doesn't work out then this will just be my mobile and I'll figure something else out. Also checking out the retevis ra87. Also, 725 is a no-go. Something between is causing interference. I'm not familiar with the sound, something between dial-up noise and a printer printing? Completely constant 24/7, must be lower power or far away.

[marcspaz]

11 minutes ago, WSCV533 said:

something between dial-up noise and a printer printing? Completely constant 24/7,

 

There is a fire department near me that has a digital RF link between two locations on exactly 462 MHz.  They had a really dirty transmitter for months, causing interference with GMRS for about 6 miles around.  I was able to find out it was from them and got them to fix it.  At first, they swore I didn't know what I was talking about... but a few days later, it was resolved. 

 

You may have something similar going on there.  I would ask around to see if anyone local to you has a Kraken SDR or is familiar with RF triangulation, to see if you can find it.  It may be a matter of just having a convo with the right person to get it resolved.

[WSCV533]

21 hours ago, WSCV533 said:

I'll be using an external controller, actually experimenting now with some stuff. If it doesn't work out then this will just be my mobile and I'll figure something else out. Also checking out the retevis ra87. Also, 725 is a no-go. Something between is causing interference. I'm not familiar with the sound, something between dial-up noise and a printer printing? Completely constant 24/7, must be lower power or far away.

Decided I'm gonna get 2 Retevis ra87 radios, so much simpler. I'll just keep my Radioditty in my car for now.