medicmurf Posted March 11 Report Share Posted March 11 Greetings - the GMRS repeater frequencies are limited on these radios. Also most repeaters use a DPL code input/output, while these old Motorolas use “Interference Eliminator Codes”. Are these older radios incompatible with current repeater systems and therefore obsolete for purposes other than basic simplex, radio to radio use? Thank you! Quote Link to comment Share on other sites More sharing options...
OffRoaderX Posted March 11 Report Share Posted March 11 Many repeaters use DPL codes.. Many other repeaters use CTCSS codes, and that is exactly what the "interference Eliminator Codes" are. So the answer to your question is: NO Quote Link to comment Share on other sites More sharing options...
nokones Posted March 11 Report Share Posted March 11 There is no such thing as Interference eliminator codes that Motorola ever used. Anyways, DPL and PL do not eliminate the so called interference it just keeps you from hearing the audio/noise of the interference source not eliminate it. To answer your question regarding are the old Motorola radios compatible with GMRS repeaters? Maybe and maybe not. Depending on the model/series of the old Motorola radios, most likely the GMRS Repeater(s) is/are operating wideband than there would not be a problem, today. A small majority of the GMRS repeaters operate narrowband and depending on the model series of those old Motorola radios, they could pose a problem if they can not operate narrowband with a narrowband operated repeater. Although, you will still access the narrowband operated repeater with a wideband radio, the audio quality will not be optimum. What Motorola⁹ model/series radios are they? Quote Link to comment Share on other sites More sharing options...
SteveShannon Posted March 11 Report Share Posted March 11 Are these the radios your title mentions? 2 watts out, ten GMRS channels? https://www.wirelesspro.com/motadira.html Quote Link to comment Share on other sites More sharing options...
OffRoaderX Posted March 11 Report Share Posted March 11 51 minutes ago, nokones said: There is no such thing as Interference eliminator codes that Motorola ever used If they never used them why would they take all the time to mention them in the SX700, T5100, and several other user-manuals? Quote Link to comment Share on other sites More sharing options...
taco6513 Posted March 11 Report Share Posted March 11 Motorola invented CTCSS. This was called "Private line" PL tones. I believe there were 38 original tones. Older Motorola equipment only has access to the original 38 tones. "Private Line" is a trademark of Motorola. WRCW870 Quote Link to comment Share on other sites More sharing options...
medicmurf Posted March 11 Author Report Share Posted March 11 The photo kindly provided by Shannon, is the radio in question. None of the repeaters listed as being in my area, are available in the frequency list for this radio, which only has 10 channels. Additionally, 38 “Interference Eliminator Codes” are listed and I don’t know if this is entirely different from “DPL codes” that are associated with the repeaters. I guess what I’m asking is, is whether or not these specific radios are capable of communicating with my local repeaters. Sorry for me being so “obtuse”, but I’m brand new to all of this. Any and all help is much appreciated! Quote Link to comment Share on other sites More sharing options...
SteveShannon Posted March 11 Report Share Posted March 11 Those Interference Eliminator Codes are just marketing talk for CTCSS, which is an analog tone overlaid on the speech that is transmitted. Motorola also called that PL for Private Line. It truly does not make your calls private but it can reduce hearing other calls that don’t have a matching tone. Unfortunately none of the ten frequencies your radio transmits are those needed to activate a repeater. Repeaters listen on 467.xxx MHz and transmit on 462.xxx MHz. You should be able to hear repeaters though. Just leave the tone out. WRUU653 1 Quote Link to comment Share on other sites More sharing options...
nokones Posted March 11 Report Share Posted March 11 8 hours ago, OffRoaderX said: If they never used them why would they take all the time to mention them in the SX700, T5100, and several other user-manuals? Ah, that's my mistake. I misspoke. Not owning a consumer grade radio or have read an user's manual for one of those radios I would have never thought that Motorola would have used a term like that. I do get it why they would Quote Link to comment Share on other sites More sharing options...
WRUU653 Posted March 11 Report Share Posted March 11 Looking over the listed frequencies it looks like 1-7 is GMRS channels 1-7 and A=16, B=18, and C=20. As @Sshannon mentioned it looks like there are no frequencies/channels for TX to a repeater but hey you got @OffRoaderX’s favorite off road channel 16. SteveShannon 1 Quote Link to comment Share on other sites More sharing options...
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