GR1225 Repeater Question

[WQOC472]

Hey guys,

I have a question about my Motorola GR1225 Repeater. The repeater is set up on RX:467.5500 and TX:462.5500 (with a 114.8pl).

is there a way without reprogramming the repeater and duplexer to switch the frequencies to the standard RX:462.5500 TX:467.5500?

Help is appreicated, I have the programming software. But i heard somewhere that if i switch the coax from the radio to the duplexer around that would fix my problem??

 

[rfradioconsult]

What "problem" are you having? Your repeater is programmed correctly with Tx on 462 and Rx on 467.

 

[gatekeep]

For GMRS you have the correct split programmed into the repeater. For repeated operation the repeater is always programmed in reverse of the portables...

For instance if your portables are programmed for 462.550 Rx and 467.550 Tx, your repeater should be (and is) programmed as 467.550 Rx and 462.550 Tx.

On GMRS 462.550 is the repeater output [Tx] (portable input [Rx]) and 467.550 is the repeater input [Rx] (portable output [Tx]).

FRS/GMRS combined channel chart - The RadioReference Wiki

 

[WQOC472]

im not having any problems with it... i just had all my radios set up on 462.550Rx and 467.550Tx (i had this set from my previous repeater, then i bought this gr1225 and it was like this)

 

[cmdrwill]

all my radios set up on 462.550Rx and 467.550Tx (i had this set from my previous repeater, then i bought this gr1225 and it was like this)

The repeater is set up on RX:467.5500 and TX:462.5500 so it IS correct...

 

[fineshot1]

Hey guys,

I have a question about my Motorola GR1225 Repeater. The repeater is set up on RX:467.5500 and TX:462.5500 (with a 114.8pl).

is there a way without reprogramming the repeater and duplexer to switch the frequencies to the standard RX:462.5500 TX:467.5500?

Help is appreicated, I have the programming software. But i heard somewhere that if i switch the coax from the radio to the duplexer around that would fix my problem??

What problem? The repeater is programmed correctly. The portables and mobiles are always programmed
the reverse freq configuration of the repeater.

 

[WQOC472]

I am also having an issue with another repeater in the area. my repeater is 462/467.550 - 114.8pl, running 30 watts. Our Police dept. is running on 460/465.2000 with a 114.8pl, running 50 watts. Their repeater and tower site is less than 500 yards away from my repeater and tower site. my antenna is 40 feet high, and the police dept repeater site is about 75 feet high. When we communicate on the GMRS repeater and the Police dept is communicating on their repeater at the same time i hear some kind of "bleed over" from the Police dept repeater. I am good friends with the City's radio tech and he has told me he isn't having any problems with the GMRS repeater affecting any of the City's repeaters, so were good there. What should i do?

Should i just change the PL tone?

The repeater works just fine as long as the GMRS and Police Dept. repeater is not TXing at the same time.

 

[fineshot1]

I am also having an issue with another repeater in the area. my repeater is 462/467.550 - 114.8pl, running 30 watts. Our Police dept. is running on 460/465.2000 with a 114.8pl, running 50 watts. Their repeater and tower site is less than 500 yards away from my repeater and tower site. my antenna is 40 feet high, and the police dept repeater site is about 75 feet high. When we communicate on the GMRS repeater and the Police dept is communicating on their repeater at the same time i hear some kind of "bleed over" from the Police dept repeater. I am good friends with the City's radio tech and he has told me he isn't having any problems with the GMRS repeater affecting any of the City's repeaters, so were good there. What should i do?

Should i just change the PL tone?

The repeater works just fine as long as the GMRS and Police Dept. repeater is not TXing at the same time.

Best to attenuate the offending rf overload in your repeater receiver.

A notch filter tuned to the PD repeater output (460.200) and inserted inline of your repeater
antenna feedline should attenuate enough to cure that problem. Usually a Telewave, Celwave,
TX/RX, Wacom, etc filter can is a good enough quality product to do the job.

 

[Scannerhead1983]

I agree with the other guys, your repeaters frequency pairs are set up correctly. A UHF repeater is designed to RX 5 mhz higher and TX 5mhz lower, Same as your radios. Your radio is tx'ing 467 to the repeater, the repeater is rx'ing 467 and tx'ing out 462. As far as the issue with the repeaters being close together, re programming a new squelch tone may not be a bad idea. you will just have a little time in re programming your fleet of GMRS radios.

 

[petnrdx]

Unless I screwed up the math, the difference between your tx and the PD tx, AND the difference between the PD tx and your RX make a product of 5 mhz. ( 7.35 mhz T to R, and 2.35 T to T = 5 mhz)
I think it is pretty likely you have an intermod mix because of the mathematic relationship since the two systems are physically that close.
A couple posts above is the suggestion to notch out the PD tx.
That might fix it.
Or a better ( pass/ reject ) duplexer if yours is just a notch type.
Any other more technical types have a thot on the mix possibilities? ( I would like to hear, I am curious )
You might have to choose another GMRS channel if you can't fix it.
Changing PL tone will just hide the problem.
Problem will still be there, and may cover weak stations at some time.
I would take a stab at fixing or eliminating it.
If the mix is not that strong, it probably won't take much to reduce it to where it has no effect.

 

[WQOC472]

if i change the pl tone do i need to have the duplexer re-tuned? I have the programming software and cable (although i have never used it) Does it work like programming a normal radio? read the radio, make changes, and the write it back to the radio?

 

[gatekeep]

No you won't have to retune the duplexer when changing PL's (all though as others have been saying you should notch out the PD freq to really fix the problem). Yes programming the repeater works like programming a normal radio.

 

[WQOC472]

Which PL do you recommend? All the repeaters in my area use either 114.8 or 151.4

I am looking into a Notch filter, but i have not purchased one yet, and if changing the PL will help until i can get one then that's what ill do.

I have Kenwood Radios. (and we all know how easy they are to program

 

[WQOC472]

Okay guys, just to clarify, The Police dept. repeater is set up on RX: 460.2000 and TX: 465.2000 with a 114.8pl (That is also why i was asking earlier in my first post, All the other repeaters in my area are set-up with the receive frequency being the lower frequency and the transmit being the higher frequency.) Like i said my repeater site is across the alley from the Police dept. repeater site (and dispatch center) I was messing around with it today, and i determined that i only have the problem with the repeater feeding back when the dispatch center is transmitting, when the officers are talking between each other it works fine. It's only when the dispatch center transmits that i have a problem.

Where is a good AFFORDABLE place to get a notch filter, so i can eliminate the problem??

 

[davidgcet]

that is because the dispatch center is probably talking on a base, if it was the repeater they direct keyed then even the officers would cause you issues. UHF freqs all have repeater TX on the low freq, RX on the high.

you do realize that you may or may not be able to just plug and play with the notch. it usually will require a retune of the duplexer, at least a slight touchup. you probably have the regular small black duplexer, these are band pass and not very selective. this is why you hear the PD base since they are in your "band" sicne the duplexer is designed for a 5 meg split.

as far as an affordable notch, check out ham fests/swap meets. you may even get one of them to tune it for you.

 

[R8000]

Me thinks your in over you head here. Several folks have chimed in with a solution, but if your asking about having to re-tune your filters when changing pl tones, flipping the repeater pair and co-locating a GR1225 at a high RF site without additional filtering...it makes me wonder.

Just because you can buy a repeater on Ebay and program it, doesn't mean your qualified as a radio technician.

The GR1225 is a nifty little repeater. Best located on a farm silo. In a dense RF environment, they need additional filtering to help keep the "crap" out. If you install a GR1225 in a high RF environment with just the flat pack duplexers, your on your own.

Changing PL's is just a band aid to the real problem.

I am not trying to be disrespectful, but I think someone has to be upfront and honest with you here.

 

[KA9JYO]

gr1225

This is the problem when a person gets a license without any technical test or knowledge of radio equipment,
the FCC lets anyone put up a repeater on GMRS. Sorry, no offence, but if you buy junk from ebay don't expect "plug and play".

 

[quarterwave]

If you CAN reprogram it, why not try 462.600 and another PL just to see if it helps? Moving 50Khz won't hurt anything duplexer-wise, and if it resolves the issue, go with it and re-tune the duplexer if needed. Some of these mobile duplexers won't know the difference between .550 and .600. I have a Celwave on a small repeater centered on .650 and I use it on .650 or .700, works no better or worse on either. My MTR2000 however has a very good duplexer, and is tuned spot on.