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Guest Mike733

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Guest Mike733

Greetings Folks:

New to the GMRS world.  Just installed the MXT275 with 6DB Antenna.  I am trying to figure out Rp channels and trying to make first contact.  I have viewed the local repeaters and their pertinent information, i just believe i may be doing something simple wrong with the MXT275.  I can hear it clear as day, but TX is just not working.  I am thinking it's something to do with CTCSS, however like i said i am totally lost and looking for a bit of mentorship from anyone.



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Hi Mike / WRUZ733,

As in Mike's quote, you'll need a tone (CTCSS tone or DCS code) to open the repeater.  The reason for the tone is to prevent unwanted noise on frequency from activating the repeater. The tones / codes are listed in the mygmrs.com repeater database (more below).  Also be sure you're transmitting into the "repeater input" frequency, more on this after the CTCSS / DCS comment:

42 minutes ago, BoxCar said:


Your radio needs to transmit a tone to wake up the receiver on the repeater. In your configuration for that channel, set the transmit tone to the same value shown in the repeater's listing. You do not need a receive tone.

About the CTCSS tones:
If you're using the repeater database here on mygmrs.com ( https://www.mygmrs.com/repeaters) , you'll need to do a conversion between "the number used by Midland" and the actual "CTCSS tone in Hertz".  The conversion is found in the Midland owners manual on page 28:

Link to Midland Owners Manual search: https://midlandusa.com/pages/owners-manuals

direct link (may not work after some time): https://cdn.accentuate.io/81031332017/1623709894082/MXT275-Owners-Manual-11-16-20.pdf?v=0

About the DCS tones:
From a radio operator perspective, DCS configuration is similar to CTCSS configuration, select the proper DCS number/setting as listed in the repeater database; select the proper input frequency (or in Midland configuration the proper RPTxx channel) and you should be on the air.

In implementation, CTCSS is actually a tone in Hertz, where DCS is a digital ones and zeros string coming out of the transmitter.  For the radio operator, each implementation yields similar results, the repeater is able to reject unwanted transmissions (noise) and transmitting with the proper code allows the radio operator to open the repeater to repeat the transmitted input signal of the radio operator.

About the input frequency:
Also be sure the input frequency is properly set.  Nearly  all repeaters have an input frequency which is different from the listen frequency.  For GMRS +5 MHz higher than the listen frequency would be the standard. In the above manual links, this would be page 27, table "GMRS Repeater Channels".

The column labeled "TX Freq. (MHz)" would be the "input frequency" of the repeater.  Repeaters are usually listed by which frequency we hear them on, which would be the "output frequency" of the repeater.  In the midland example on page 27, a repeater listed as 462.5500Mhz would have an input frequency of 467.5500Mhz and would be on 15RP in the Midland MXT275 radio. (see above links and owners manual for the MXT275, pg 27).

Notes from Midland GMRS  Repeater Channels table:
Ch. Number    TX Freq. (MHz)    RX Freq. MHz)
15RP                 467.5500               462.5500


After configuring the proper CTCSS tone (or DCS code) and transmit input frequency into your radio, you should be able to transmit and receive on the local repeater.

Hope that helps, looking forward to hearing your success story when you get your radio working with the local repeater!

If you want to talk to other GMRS users and be sure your radio is working, talking on one of the GMRS nets is a good way to find out.

Net directory for GMRS: https://www.mygmrs.com/nets

*date of post: 2022-10-25 // later readers may see reference links out of date.



-Mark / WRTQ652

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Hi Mike/WRUZ733,


It looks like you're on the right track for configuring the WQPL257: Winchester, Frederick, VA repeater (https://www.mygmrs.com/repeater/4076) !

Great news that the +5MHz is already configured on the repeater channels for the Midland MXT275 radio, it sounds like that part is configured correctly. 

The next step would be to set what Midland calls the "tC - Transmit Privacy Tone/Code":

Setting the transmit tone / code:
On page 19 of the manual from the above post there's this item for the repeater channels:
"tC - Transmit Privacy Tone/Code - Use this option to set the transmitter privacy code on repeater channels." in that sub-menu selecting "Ct" should enable the CTCSS transmit tones for the repeater (if it was DCS codes the setting would be dC). Updating the "tC - Transmit Privacy Tone/Code" should transmit the code on the repeater input frequency and the repeater would be expected to open the squelch setting on the repeater, resulting in your transmission being heard on the repeater output frequency.

As Mike (BoxCar) mentioned, the receive code can be configured to off and that's likely the most desirable setting, especially during initial setup.

Setting the receive tone / code:
To configure the receive DCS code / receive CTCSS to off:

On page 19 of the manual from the above post there's an item for the repeater channels:
"rC - Receive Privacy Tone/Code - Use this option to set the receiver privacy code on repeater channels."

in that sub-menu selecting "OF" should disable the need to receive a tone on the Midland MXT275 radio, effectively this opens the receive signal on the Midland radio to hear everything on the repeater output frequency.  (In the event the repeater does not transmit a CTCSS tone/DCS code or transmits a different tone/code on the output frequency the Midland radio will be able to hear everyone on the output frequency of the repeater by configuring the receive code (rC) to off (OF)).

It might take a moment for the repeater to "hear" the tone or code, so try holding down transmit for a second or two (or a "one-thousand-one" count) before speaking.

It's possible the settings may need to be updated on the mygmrs page or have been updated on the repeater, and if that's the case it's often a bit of trial and error on the tone or code setting to get things working. 

You're almost there and are surely likely to have the radio working to full potential soon!  Reaching out to the repeater owner via the "request access" button on the mygmrs.com repeater page link might be a good place to ask if the repeater tone / code has changed recently once all the above settings have been tuned.

The only settings left to be tuned are the "tC Transmit Privacy Tone/Code" settings and opening the "rC Receive Privacy Tone/Code" settings on the radio.  Once that's done you should be on the air! 

Good luck! 

-Mark / WRTQ652



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