Placing a Repeater on a Frequency that is being occupied by another Repeater

[MrCoffee]

Okay here's the issue.  I am wanting to place a repeater on a pair of frequencies.

However, when searching for a Frequency to park on, there aren't any that aren't being occupied.

So I have searched and I have been listening through the frequencies for the weakest repeater signals near me.  So far I may have a 

place to park a repeater on a pair, as the repeater that has already perhaps been established but doesn't seem to be registered in no way that I can find is very weak on my receive.

With that being said, my thoughts are maybe install an antenna at a given height that may in no way interfere with the said repeater.  I am only looking to cover an area 

for some local folks within maybe a 10 miles or less radius.  I even thought of using two antennas.  Of course one for Rx at a higher height and the TX antenna at a much lower height which is practical for a repeater anyway and lowering the TX power as much as possible. (At Least this is what I have been learning anyway)

I have posted about placing a repeater on the air and discussing antennas along with gain so to speak, but I just 

realized my situation that I am coming up against, in which is throwing a wrench in the equation.

Any commits are appreciated either toward a solution using the same given frequency or even a reason to be against using the same frequency along with your opinion why.

I only ask to be open to the idea that there aren't any unused frequency pairs available and having the idea of helping a small group of people in a small foot print.

Thank you.

 

[WRXP381]

Just go for it.  If it’s weak already and you both have tones it’s going to be very rare you both are transmitting at the exact same time   Just make sure its different tones.  

[marcspaz]

There is lots of overlap around the DC metro area and it works out fairly well.  Just use a different tone and you should be fine, regardless of your coverage area.

[SteveShannon]

So can the small group of people not simply use one of the eight existing repeaters?

[nokones]

I wouldn't use two antennae unless you have a sufficient spacing vertically and/or horizontally. Buy and use a quality duplexer like a Celwave or EMR Corp.  If you are trying to keep the coverage foot print small in order to not interfere or be interfered, I would keep the antenna low and use a quality grade unity gain antenna like a Laird Base Station antenna.

Also, purchase your quality LMR400 cabling and connectors from a reputable radio product supplier and not from a source that sell cheap and is not their specialty.

[TrikeRadio]

If you can contact the repeater owner, or users on the other repeater, and get in touch with the owner - it is always good to contact them and tell them what you are thinking so you can coordinate CTCSS  tones that will not interfere with each other. Just good to be good with neighbors to start.

But also... of course no one owns a frequency so they can't tell you not to setup on that channel. but still try to make sure the tones don't conflict.

You might even find that their repeater could serve your needs and you would not need to set one up... or coordinate to make one that serves both groups and covers more area.

just a few thoughts

[MrCoffee]

On 8/7/2024 at 2:57 PM, WRXP381 said:

Just go for it.  If it’s weak already and you both have tones it’s going to be very rare you both are transmitting at the exact same time   Just make sure its different tones.  

Thank you for the reply.  

Being new to GMRS I just didn't want to rock the boat if its something thats not etiquette. 

[MrCoffee]

On 8/7/2024 at 3:37 PM, marcspaz said:

There is lots of overlap around the DC metro area and it works out fairly well.  Just use a different tone and you should be fine, regardless of your coverage area.

I appreciate the reply as I do from all, thank you.

I sense a sign of hope!  

 

[MrCoffee]

On 8/7/2024 at 1:14 PM, SteveShannon said:

So can the small group of people not simply use one of the eight existing repeaters?

Hello Steve,

Perhaps?  Just not at the moment.  The group are mostly retired and doesn't have much or any experience using UHF frequencies.  At the moment 

two are trying to communicate simplex.  One using a HT only and the other did install a J-pole at maybe 20 feet.  The one one with the HT is at lower 

elavation and the separation is a bit to far, well with only a HT.

The group would rather talk simplex or on a private repeater with no one listening in except for the group.

Two others can hit one of the repeaters that might be 30 to 45 minutes away. Maybe 30 minutes the way the crow flies.

We are all generally close to one another.  The one with the HT happens to the fartherest away.  He does have a 20 or 30 foot tower that might help aid in getting 

signal across the way later on.  I have purchased the Retevis RA87s and I am planning to installed them together for repeater usage.  I figure they may be worth experimenting

with as I have mentioned before due to their low price.  I have my eye on a couple of DB Duplexers that may cost me $300.00 to $450.00 depending what one I might be able to buy.

Anyway thats where I am coming from other then I also think it will be a good experience for me and hopefully for the others as well.

Thank you Steve, I do appreciate your replies.

 

 

 

 

[SteveShannon]

5 minutes ago, MrCoffee said:

Hello Steve,

Perhaps?  Just not at the moment.  The group are mostly retired and doesn't have much or any experience using UHF frequencies.  At the moment two are trying to communicate simplex.  One using a HT only and the other did install a J-pole at maybe 20 feet.  The one one with the HT is at lower elavation and the separation is a bit to far, well with only a HT.

The group would rather talk simplex or on a private repeater with no one listening in except for the group.

Two others can hit one of the repeaters that might be 30 to 45 minutes away. Maybe 30 minutes the way the crow flies.

We are all generally close to one another.  The one with the HT happens to the fartherest away.  He does have a 20 or 30 foot tower that might help aid in getting signal across the way later on.  I have purchased the Retevis RA87s and I am planning to installed them together for repeater usage.  I figure they may be worth experimenting with as I have mentioned before due to their low price.  I have my eye on a couple of DB Duplexers that may cost me $300.00 to $450.00 depending what one I might be able to buy.

Anyway thats where I am coming from other then I also think it will be a good experience for me and hopefully for the others as well.

Thank you Steve, I do appreciate your replies.

Thanks for the additional information. Good luck with your project.  I’ll be interested in your progress. 

[MrCoffee]

On 8/7/2024 at 6:00 PM, nokones said:

I wouldn't use two antennae unless you have a sufficient spacing vertically and/or horizontally. Buy and use a quality duplexer like a Celwave or EMR Corp.  If you are trying to keep the coverage foot print small in order to not interfere or be interfered, I would keep the antenna low and use a quality grade unity gain antenna like a Laird Base Station antenna.

Also, purchase your quality LMR400 cabling and connectors from a reputable radio product supplier and not from a source that sell cheap and is not their specialty.

Thank you for your reply and for your help on the antenna and the cabling.

I have posted about what antenna to use so to speak or at least an idea of an antenna.  I will look up the Laird Base Station antenna.  I have several towers

that I can employ for height purposes and maybe horizontal separation.  However I think I want to keep it as simple as possible in the beginning. (KISS)

So I probably will just use one antenna and a duplexer.  As for cabling, I have some runs of LDF4, LDF5, and even some LDF7.  

Maybe even some LDF6, not sure how much though, but cabling I do happen to have.

Thank you for your insight and as mentioned I will look up the Laird Base Station antenna.

 

[MrCoffee]

On 8/7/2024 at 6:59 PM, TrikeRadio said:

If you can contact the repeater owner, or users on the other repeater, and get in touch with the owner - it is always good to contact them and tell them what you are thinking so you can coordinate CTCSS  tones that will not interfere with each other. Just good to be good with neighbors to start.

But also... of course no one owns a frequency so they can't tell you not to setup on that channel. but still try to make sure the tones don't conflict.

You might even find that their repeater could serve your needs and you would not need to set one up... or coordinate to make one that serves both groups and covers more area.

just a few thoughts

I never thought of that idea.  I would first have to find who they are.  I can't seem to access their repeater.  Not sure what tone they may be using either.  I have tried

all of them!  They may have some other coding/tones that I was not trying to use too.  It seem that they may not be listed either, but I am not

totally sure on that either.  I am still searching.

Thank you for that "Food for Thought"!  In my opinion, that is a very wise thought. 

[MrCoffee]

8 minutes ago, SteveShannon said:

Thanks for the additional information. Good luck with your project.  I’ll be interested in your progress. 

Thank you Steve.  I will be glad to post back when it happens!  Everyone has been very helpful.

[WRYZ926]

13 hours ago, MrCoffee said:

I have my eye on a couple of DB Duplexers that may cost me $300.00 to $450.00 depending what one I might be able to buy.

Makes sure that whoever you buy the duplexer from can tune them for the correct frequencies that you are going to use. Tuning duplexers is not something an average person can do at home since it requires specialized equipment to tune them.

[nokones]

How long is your cable run end to end? If your cable run is less than 50 feet are you really serious in using heliax? The connectors are not cheap.

[WRKC935]

OK, from a legal / FCC regulation standpoint.  You are NOT allowed to purposefully interfere with the communications of another.

You did your due diligence and picked the pair with the lowest signal level at your repeater site.  You monitored all the pairs and found that one to at least seem to create the least interference with the co-channel user.  You are obviously NOT going to use the PL / DPL code of the other repeater.  So that puts you in the clear from doing it wrong.  I am not saying that you will not get a letter from the FCC.  It could happen, but it's not likely.  And as long as you tell them it was the pair with the lowest signal and was the least used of all of them and you used a PL / DPL that was away from theirs, they are gonna look at it and tell you you're fine with what you did.

 

[MrCoffee]

On 8/10/2024 at 9:34 AM, WRYZ926 said:

Makes sure that whoever you buy the duplexer from can tune them for the correct frequencies that you are going to use. Tuning duplexers is not something an average person can do at home since it requires specialized equipment to tune them.

Yeah that is an issue isn't!  One guy says he will tune it on my frequency. ($450.00). The other guy buy as is...(300.00)

[MrCoffee]

On 8/10/2024 at 9:45 AM, nokones said:

How long is your cable run end to end? If your cable run is less than 50 feet are you really serious in using heliax? The connectors are not cheap.

Thank you, but I have had the cables and the connectors for a long time, its about time I start using them!

My tower may be anywhere from 30 feet to 125 without counting the run to the house.  More than likely though, I will probably place the tower height at 40 or 50 feet.

I been around cells sights and other communications for a long time.  However I need to learn the in and outs of GMRS.  Connections, type of cables, how to seal the connectors, radius of the hardline, grounding, SWR, pointing Yagi antennas, tuning antennas...I have that covered.  I just need to know the ins and outs basically.

Meaning a good Repeater antenna, a good duplexer, and later down the road a good solid GMRS repeater instead of two mobiles connected for RX/TX.

I can make all the connections, climb towers, install towers along with guy wires, and so on, as I have been learning all of this since I started in radio communications at the age of 10.  I enjoy the installation experience more then anything!

Thanks for the reply.

[MrCoffee]

On 8/10/2024 at 8:05 PM, WRKC935 said:

OK, from a legal / FCC regulation standpoint.  You are NOT allowed to purposefully interfere with the communications of another.

You did your due diligence and picked the pair with the lowest signal level at your repeater site.  You monitored all the pairs and found that one to at least seem to create the least interference with the co-channel user.  You are obviously NOT going to use the PL / DPL code of the other repeater.  So that puts you in the clear from doing it wrong.  I am not saying that you will not get a letter from the FCC.  It could happen, but it's not likely.  And as long as you tell them it was the pair with the lowest signal and was the least used of all of them and you used a PL / DPL that was away from theirs, they are gonna look at it and tell you you're fine with what you did.

 

I try to be considerate, I don't like confrontation.  That doesn't mean I will be quiet, but I will try to void any issues if possible, for the reason for this post.

Life is to short, time flies by and later you are ask, where did it go?

Thanks for chiming in.  

 

[WRKC935]

6 hours ago, MrCoffee said:

I try to be considerate, I don't like confrontation.  That doesn't mean I will be quiet, but I will try to void any issues if possible, for the reason for this post.

Life is to short, time flies by and later you are ask, where did it go?

Thanks for chiming in.  

 

Go back and read what I said.

Short version.  You did your best to NOT interfere.  Which is what's expected.  So you are good. 

The other repeater owner may complain, because that's what people do.  But there is no coordination on GMRS.  We need to work it out between ourselves.  You did that.

And that is what I was trying to convey. 

[MrCoffee]

3 hours ago, WRKC935 said:

Go back and read what I said.

Short version.  You did your best to NOT interfere.  Which is what's expected.  So you are good. 

The other repeater owner may complain, because that's what people do.  But there is no coordination on GMRS.  We need to work it out between ourselves.  You did that.

And that is what I was trying to convey. 

Hello WRKC935,

I'm sorry if in my reply sounded as I was maybe angry or disturb or...  

I guess I was just explaining who I am relating to your reply.  Something like that anyway!   Also I had worked on installing a new antenna for a friend all day yesterday and the heat from the sun worn me out!   

I did not take your reply in a harsh way, at least as far as I recall !  Just the same, I'm sorry if I did. 

Thank you for bringing this to my attention. 

[WRKC935]

9 hours ago, MrCoffee said:

Hello WRKC935,

I'm sorry if in my reply sounded as I was maybe angry or disturb or...  

I guess I was just explaining who I am relating to your reply.  Something like that anyway!   Also I had worked on installing a new antenna for a friend all day yesterday and the heat from the sun worn me out!   

I did not take your reply in a harsh way, at least as far as I recall !  Just the same, I'm sorry if I did. 

Thank you for bringing this to my attention. 

OK, and please don't take offense to what I said either.  As mentioned, you did your level best to NOT cause a problem.  And the other guy should recognize that

Good luck with getting your repeater on the air and let us know if you have any questions

 

[steved28]

Just my $.02 regarding a repeater setup. I ran a GMRS repeater for about 5 years. That was about 20 years ago. I would absolutely recommend a good duplexer, and a friend with a frequency analyzer who can tune the cans. Otherwise, your sensitivity will be junk IMO. No matter your antenna spacing.  I still have 2 sets of Decibel duplexers hanging around, one 4 can and one 3 can. Let me know if your interested.

[MrCoffee]

On 8/14/2024 at 12:55 PM, steved28 said:

Just my $.02 regarding a repeater setup. I ran a GMRS repeater for about 5 years. That was about 20 years ago. I would absolutely recommend a good duplexer, and a friend with a frequency analyzer who can tune the cans. Otherwise, your sensitivity will be junk IMO. No matter your antenna spacing.  I still have 2 sets of Decibel duplexers hanging around, one 4 can and one 3 can. Let me know if your interested.

Sorry I don't get a chance to get in here as often as I would like.  Understood on a good duplexer and to have it correctly tuned.

On your duplexer, roughly where are you located?

Thank you for your reply.