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5 MHz Split


Question

Posted (edited)

I am attempting to program a repeater that does not have the standard +5Mhz into my radios. The radios I  own, a Radioddity GM-30 and DB20G do not seem to allow this and the seeming lack of documentation is perplexing. I have been advised that this is a specific radio issue and it is also a FCC requirement for gmrs radios... Another internet and word of mouth conundrum ie: pain. Thanks for any clarification, information and or documentation🙂

 

BTW any thoughts on Wouxon KG805G radio's quality, durability and reception and transmissions. Hope that covers it all.....

Edited by Elbowmac
Additional info needed

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  • 2
Posted
13 hours ago, Elbowmac said:

Hello WRYS709, I am finally understanding your post. I did not know that there is a Sort by posts type thread. I was wondering about the crazy answer structure I was receiving. How do I go about reposting and finding the options on type of posts?

You posted in the correct area. Some don’t like the voting system but as it was a technical question and the voting system is designed to allow the most relevant answers to move to the top. It is unreasonable to expect you to make a double post just for one person’s preferences. If you had made a second post someone would give you a hard time for that. Don’t worry about your post you are doing fine. I say all this as someone that prefers to read post in order by date but I’m not going to give the poster a hard time about it.

Back to the original subject. If you tell us what the TX and RX frequencies are a determination of whether this is a GMRS repeater with an unconventional offset or if perhaps it’s an amateur band repeater could be made. Though it sounds like might have already determined that. 

  • 1
Posted
I am attempting to program a repeater that does not have the standard +5Mhz into my radios. The radios I  own, a Radioddity GM-30 and DB20G do not seem to allow this and the seeming lack of documentation is perplexing. I have been advised that this is a specific radio issue and it is also a FCC requirement for gmrs radios... Another internet and word of mouth conundrum ie: pain. Thanks for any clarification, information and or documentation
Is it a non gmrs repeater?

Why I ask? The gmrs repeater frequencies are set by the FCC. Set with a +5Mhz offset. Unlike amateur radio repeaters, you can not have a reverse offset and remain compliant.

Even then a way to "monitor" a repeater is simply listen to the output frequency. You just won't be able to transmit.

For the db20g, you can three finger salute the radio in "open it up". So you can bypass the firmware locking for GMRS. I don't condone it.

Sent from my SM-S901U using Tapatalk

  • 1
Posted
1 minute ago, WRXB215 said:

The GM-30 and the DB20G do have the +5 offset on the repeater channels. Just pick the correct channel and add the input tone for the repeater.

The interesting thing about the rules is it simply states that the repeater input frequencies and output frequencies have to be picked from the allowed list. Note the rules say nothing about any kind of required frequency shift.

https://www.ecfr.gov/current/title-47/chapter-I/subchapter-D/part-95/subpart-E/section-95.1763

There is no requirements the input and output frequencies must be 5MHz apart. While that is the usual case it's not required. One could really frustrate users of preprogrammed, firmware locked, GMRS radios by selecting a pair of frequencies, from the allowed list for repeaters, that are not using a 5MHz split. Any talk about how that would affect channel sharing is another topic.

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Posted
3 hours ago, Elbowmac said:

I did not explain myself well enough, thanks. I want to program a non-standard repeater split, not the +5 Mhz standard!!

The largest repeater in my area (462.575) has two receivers, primary on the standard +5 (467.575) and a secondary on 467.725. The repeater overlooks the port of Tampa and gets occasional interference on the primary input from ship traffic and they have shut it down. Unfortunately it confuses a lot of folks and a lot of radios (Midlands for example) don't support anything other than a +5MHz offset so they are unable to transmit to the repeater but receive it just fine. My Wouxun's (KG-1000 and KG-935) will allow for a different offset - as long as the TX offset is a GMRS frequency (including frequencies not assigned for repeater inputs like 467.6125) but a lot of radios don't.

If your radios have dual scan or priority watch, what you can try (as long as the TX frequency is a standard GMRS frequency) is setup TX on whatever you want and RX as a 2nd channel on the dual scan or your priority watch channel. 

  • 1
Posted
28 minutes ago, Socalgmrs said:

Loads of radios Atleast same quality for much less money. It’s just a radio like all other radios.  It will rx and tx exactly the same as a radio 1/5th the price 

Thanks for the feedback. It is what I am listening for!

  • 1
Posted
15 hours ago, Elbowmac said:

Hello WRYS709, I am finally understanding your post. I did not know that there is a Sort by posts type thread. I was wondering about the crazy answer structure I was receiving. How do I go about reposting and finding the options on type of posts?

I agree with Gil (@WRUU653). Please don’t start a new thread because one person cannot adapt to the up/down voting. This is the technical forum. People have the ability to very easily choose “sort by date”. 
Unfortunately someone went through the responses here and downvoted almost every post, including your very reasonable questions.  That was petty and shows an utter lack of respect to those who honestly try to answer technical questions.

Back to your original question, although the typical GMRS repeater will use exactly 5.000 MHz as the offset, the regulations do not require it.  The regulations do require that transmitting to a repeater be done using one of the eight established 467 MHz main channels and that the repeater transmit on one of the 462 MHz main channels. https://www.ecfr.gov/current/title-47/section-95.1763

But choosing an offset that is different than 5.000 MHz will result in many (perhaps all) certified GMRS radios being unable to use your repeater.  All certified GMRS radios that I know of uses 5.000 MHz as the offset.  So that means that people will be forced to unlock ham radios or repurpose commercial radios in order to use your repeater transmit. Whether that’s a problem, only you can determine.  One way to get around that is to use a radio that can be programmed using Chirp and which supports non-standard offsets or separate receiver and transmit frequencies. The cheap Baofeng UV5R radios did this easily.  Many ham radios use “Automatic Repeater Shift” which assumes exactly 5.000 MHz offset for UHF frequencies. Commercial radios, found on the used market, like the ones @Lscott refers to would be absolutely excellent for this purpose.

Best wishes!

  • 0
Posted
1 minute ago, WRXB215 said:

The GM-30 and the DB20G do have the +5 offset on the repeater channels. Just pick the correct channel and add the input tone for the repeater.

I did not explain myself well enough, thanks. I want to program a non-standard repeater split, not the +5 Mhz standard!!

  • 0
Posted
3 minutes ago, kidphc said:

Is it a non gmrs repeater?

Why I ask? The gmrs repeater frequencies are set by the FCC. Set with a +5Mhz offset. Unlike amateur radio repeaters, you can not have a reverse offset and remain compliant.

Even then a way to "monitor" a repeater is simply listen to the output frequency. You just won't be able to transmit.

For the db20g, you can three finger salute the radio in "open it up". So you can bypass the firmware locking for GMRS. I don't condone it. emoji6.png

Sent from my SM-S901U using Tapatalk
 

Okay that ties in with the info on it being a requirement for gmrs. Being newbie I needed more than one confirmation of the reality! Thank you! It is possible that it is a non gmrs repeater, it did not specifiy. I have listened to several informative in depth communications on the repeater. I am having enough .... difficulty with the radio, lack of documentation and repeater etiquette that I am currently full up. Will wait to venture forth, but again thanks for the possibilities.

  • 0
Posted
Okay that ties in with the info on it being a requirement for gmrs. Being newbie I needed more than one confirmation of the reality! Thank you! It is possible that it is a non gmrs repeater, it did not specifiy. I have listened to several informative in depth communications on the repeater. I am having enough .... difficulty with the radio, lack of documentation and repeater etiquette that I am currently full up. Will wait to venture forth, but again thanks for the possibilities.
Glad you are getting it.

I should rephrase the part about listening to the output. You "can" transmit it just will go over simplex not be heard by the repeater.


Sent from my SM-S901U using Tapatalk

  • 0
Posted
4 minutes ago, kidphc said:

Glad you are getting it.

I should rephrase the part about listening to the output. You "can" transmit it just will go over simplex not be heard by the repeater.


Sent from my SM-S901U using Tapatalk
 

A distinction that I would not notice, if you hadn't pointed it out. Fishing for knowledge in the wrong creeks 🙂. Getting some strong bites now!!

  • 0
Posted
9 minutes ago, Lscott said:

The interesting thing about the rules is it simply states that the repeater input frequencies and output frequencies have to be picked from the allowed list. Note the rules say nothing about any kind of required frequency shift.

https://www.ecfr.gov/current/title-47/chapter-I/subchapter-D/part-95/subpart-E/section-95.1763

There is no requirements the input and output frequencies must be 5MHz apart. While that is the usual case it's not required. One could really frustrate users of preprogrammed, firmware locked, GMRS radios by selecting a pair of frequencies, from the allowed list for repeaters, that are not using a 5MHz split. Any talk about how that would affect channel sharing is another topic.

Thanks? 🙂 Maybe the license should require a test......................

  • 0
Posted

If it is a GMRS only radio, and there is no way to "unlock" it ( look it up ) then it will only offer the 5MHz split, since that is what is used on the GMRS band.

If it can be unlocked, then you might be able to enter the needed offset, but make sure you would be welcomed on the repeater, since it does not sound like a typical GMRS repeater, and if it is, then it should be using the standard GMRS repeater offset.

  • 0
Posted
21 minutes ago, Lscott said:

The interesting thing about the rules is it simply states that the repeater input frequencies and output frequencies have to be picked from the allowed list. Note the rules say nothing about any kind of required frequency shift.

https://www.ecfr.gov/current/title-47/chapter-I/subchapter-D/part-95/subpart-E/section-95.1763

There is no requirements the input and output frequencies must be 5MHz apart. While that is the usual case it's not required. One could really frustrate users of preprogrammed, firmware locked, GMRS radios by selecting a pair of frequencies, from the allowed list for repeaters, that are not using a 5MHz split. Any talk about how that would affect channel sharing is another topic.

No I guess not...... !!!!!!!!!!!!!!!!

  • 0
Posted
8 minutes ago, WSAM454 said:

If it is a GMRS only radio, and there is no way to "unlock" it ( look it up ) then it will only offer the 5MHz split, since that is what is used on the GMRS band.

If it can be unlocked, then you might be able to enter the needed offset, but make sure you would be welcomed on the repeater, since it does not sound like a typical GMRS repeater, and if it is, then it should be using the standard GMRS repeater offset.

That is what I was piecing together. Thanks for the confirmation!

  • 0
Posted (edited)
3 hours ago, Elbowmac said:


BTW any thoughts on Wouxon KG805G radio's quality, durability and reception and transmissions. Hope that covers it all.....

I'll have to double check the software; with the 805g, the software is the barrier that keeps you in bounds for gmrs. If I remember right, it will let you enter whatever you want for receive frequecies, but transmit was limited to the gmrs simplex and repeater frequencies.

Quality wise, it's a definite step up from the average baofeng, and less susceptible to desense/interference in my experience. Also handled a few drops just fine. My only complaint is the battery drain when not in use, common with some other wouxun handhelds as well

Edited by wayoverthere
clarifying
  • 0
Posted
1 hour ago, wayoverthere said:

I'll have to double check the software; with the 805g, the software is the barrier that keeps you in bounds for gmrs. If I remember right, it will let you enter whatever you want for receive frequecies, but transmit was limited to the gmrs simplex and repeater frequencies.

Quality wise, it's a definite step up from the average baofeng, and less susceptible to desense/interference in my experience. Also handled a few drops just fine. My only complaint is the battery drain when not in use, common with some other wouxun handhelds as well

It is then similar to the db20g in that it will allow like 500 channels, but can only transmit on gmrs preset channels. Want a quality ht that isn't dire in it's cost and will give good listening and talking.

Thanx

  • 0
Posted
4 hours ago, WSAM454 said:

If it is a GMRS only radio, and there is no way to "unlock" it ( look it up ) then it will only offer the 5MHz split, since that is what is used on the GMRS band.

If it can be unlocked, then you might be able to enter the needed offset, but make sure you would be welcomed on the repeater, since it does not sound like a typical GMRS repeater, and if it is, then it should be using the standard GMRS repeater offset.

Learning that it was a gmrs repeater thing explained enough to me for now. Want to of course get me a technician's license, eventually..

  • 0
Posted
1 hour ago, MarkInTampa said:

The largest repeater in my area (462.575) has two receivers, primary on the standard +5 (467.575) and a secondary on 467.725. The repeater overlooks the port of Tampa and gets occasional interference on the primary input from ship traffic and they have shut it down. Unfortunately it confuses a lot of folks and a lot of radios (Midlands for example) don't support anything other than a +5MHz offset so they are unable to transmit to the repeater but receive it just fine. My Wouxun's (KG-1000 and KG-935) will allow for a different offset - as long as the TX offset is a GMRS frequency (including frequencies not assigned for repeater inputs like 467.6125) but a lot of radios don't.

If your radios have dual scan or priority watch, what you can try (as long as the TX frequency is a standard GMRS frequency) is setup TX on whatever you want and RX as a 2nd channel on the dual scan or your priority watch channel. 

Will have to digest the procedure you have described, but I am not particularly concerned any longer. I have a lot to learn and I am doing it intermittently. Thanks for the response and idea!

  • 0
Posted
19 minutes ago, AdmiralCochrane said:

But it is more likely to apply more of its radiated power on receivable center frequency and less wasted on harmonics that no one hears.  Your money is not wasted.

Cool, thanks!

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