Retevis RT76P Glitch?

[atnbirdie]

This may be unique to this device, but maybe someone else has had a similar experience on another unit?  I'm new to GMRS so maybe I'm missing something obvious.

Every reference I find from FCC and many other sites lists the frequency of FRS/GMRS Channel 8 as 467.5625.  However, my Retevis RT76P (and its manual) list the channel 8 frequency as 467.5675.  When I use another radio (Midland T71VP3) set to Channel 8, and set the Retevis to Channel 8, I get static when I press the PTT button on the Midland which stops only after I talk for 1-3 seconds.  The Retevis communicates back to the Midland OK.

If I switch the RT76P to frequency mode and key in the Channel 8 frequency of 467.5625, it receives transmissions from the Midland set to Channel 8 perfectly with no static.  However, then Midland gets nothing from the Retevis on that frequency.

All other Channels work fine both ways as they all match the known GMRS frequencies.  Also note that I have all privacy codes turned off on both units and channel 8 is set up as simplex.  I tried a second T71VP3 with the same results.

Any ideas on what's going on?  How is the Midland receiving anything on Channel 8 from the Retevis when the frequencies don't match?  

Steve

WRMP836

[Ian]

The RT76P has some seriously dodgy firmware issues.  This one's new to me, normally it's getting config files to stick when programmed from the radio's control pad.  I highly recommend trying a firmware update and seeing if it resolves that.  I'll let you know if it works for me… once I figure out how to update the firmware!

 

Seriously, I'm considering giving up on my 76P and ordering the RB27 at this point.  If you have any insights, please share.

[Citizen]

5 hours ago, Ian said:

 I'll let you know if it works for me… once I figure out how to update the firmware!

Seriously, I'm considering giving up on my 76P and ordering the RB27 at this point.  If you have any insights, please share.

 

The RT76P firmware and instructions can be found here: https://www.retevis.com/Retevis-RT76P-GMRS-Radio-Portable-Walkie-Talkies/#A9180BX1-C9034AX1 .  Then click "Support", then click "Firmware/Software".

Once I did this firmware upgrade, programming was easy using a Windows PC.  I was able to set wideband, high/low power, and fix the Channel 8 bug as found by atnbirdie.

Before you give up on the radio, try this.  It's pretty decent once things are ironed out.

...

[Citizen]

15 hours ago, atnbirdie said:

This may be unique to this device, but maybe someone else has had a similar experience on another unit?

[snip]

 

You have found a bug I missed.  Thank you for that.

 

I went to my RT76P original program file and saw the error right there just as you said, so it must be coming pre-programmed new from Retevis with that frequency error on ch-8.

 

Thought it would be easily fixed.  Took me about 1 minute to run the programming software, load up my previously saved configuration file, change ch-8 TX and RX to correct the correct frequency (467.5625) and no tones, then save the file to disk, then write back to the radio.  But in testing, I got the same results you did, Midland to Retevis on ch-8 works, but Retevis to Midland on ch-8 does not.  Hmmm.

 

You may want to view this thread right here on myGMRS with more information on RT76P programming, it's a great thread that helped me a lot:

https://forums.mygmrs.com/topic/2305-retevis-rt76p-programming/

 

Good luck!

...

[Ian]

On 6/19/2021 at 10:23 AM, Citizen said:

 

The RT76P firmware and instructions can be found here: https://www.retevis.com/Retevis-RT76P-GMRS-Radio-Portable-Walkie-Talkies/#A9180BX1-C9034AX1 .  Then click "Support", then click "Firmware/Software".

Once I did this firmware upgrade, programming was easy using a Windows PC.  I was able to set wideband, high/low power, and fix the Channel 8 bug as found by atnbirdie.

Before you give up on the radio, try this.  It's pretty decent once things are ironed out.

...

They really don't want me to be able to download those files, though.  I didn't buy them at Retevis.com, so I keep getting

Quote

Users who purchased this product on www.retevis.com, please sign in your account and download the document. For other users, please contact us to obtain it.

 

[wayoverthere]

35 minutes ago, Ian said:

They really don't want me to be able to download those files, though.  I didn't buy them at Retevis.com, so I keep getting

 

shot in the dark, but did you try just signing up for an account?

i tried making one just now (never purchased anything direct from retevis), and it looks like it will let me download the files, though i cancelled the windows download dialog.

could it be some other browser issue preventing it?

[Ian]

I run a crapload of security software -- content blockers, adblock, script limitations -- because modern web technologies have made the Goodtimes Virus a practical reality.

[Citizen]

On 6/18/2021 at 6:38 PM, atnbirdie said:

This may be unique to this device, but maybe someone else has had a similar experience on another unit?  I'm new to GMRS so maybe I'm missing something obvious.

Every reference I find from FCC and many other sites lists the frequency of FRS/GMRS Channel 8 as 467.5625.  However, my Retevis RT76P (and its manual) list the channel 8 frequency as 467.5675.  When I use another radio (Midland T71VP3) set to Channel 8, and set the Retevis to Channel 8, I get static when I press the PTT button on the Midland which stops only after I talk for 1-3 seconds.  The Retevis communicates back to the Midland OK.

If I switch the RT76P to frequency mode and key in the Channel 8 frequency of 467.5625, it receives transmissions from the Midland set to Channel 8 perfectly with no static.  However, then Midland gets nothing from the Retevis on that frequency.

All other Channels work fine both ways as they all match the known GMRS frequencies.  Also note that I have all privacy codes turned off on both units and channel 8 is set up as simplex.  I tried a second T71VP3 with the same results.

Any ideas on what's going on?  How is the Midland receiving anything on Channel 8 from the Retevis when the frequencies don't match?  

Steve

WRMP836

By chance I stumbled on a legal opinion that states that the first GMRS 467 MHz interstitial channel is 467.5675, which is wrong.  As atnbirdie said, it should be 467.5625.

https://www.law.cornell.edu/cfr/text/47/95.1763  (see item [d]).

Didn't want to resurrect an old thread for nothing, but I thought maybe this is where Retevis got the idea that Channel-8 was that incorrect frequency, and used it to program/hard-code their radios.

...

[MichaelLAX]

Which raises a question in my mind:

Limited to only 1/2 watt; why would any GMRS operator want to use Channels 8-15; other than to talk to their kids on FRS, and even there have the kids switch to Channels 1-7, where they can use 2 watts?

[MichaelLAX]

3 hours ago, Citizen said:

By chance I stumbled on a legal opinion...

That's not even a legal opinion; it is supposed to be an accurate word for word retelling of the statute involved (47 CFR § 95.1763 - albeit unofficial)!

You should write them and tell them of their typo!

[kirk5056]

"Limited to only 1/2 watt; why would any GMRS operator want to use Channels 8-15"

I use those low power channels in high GMRS use environments such as NASCAR tracks, large camp grounds and amusement parks.  Even with "PL" filters other users on the same freq can cause distortion or interference.  But on those low power channels all LEGAL users are also limited to 1/2 watt so are less likely to over power my communications.  My group rarely gets very far from each other so range is not all that important.

For the same reason, most of my daily comms are on channels 1-7 to avoid the 50 watt units and repeaters.

[Citizen]

21 hours ago, MichaelLAX said:

That's not even a legal opinion; it is supposed to be an accurate word for word retelling of the statute involved (47 CFR § 95.1763 - albeit unofficial)!

You should write them and tell them of their typo!

Yes, very true... I just wasn't sure what word to use : )

This morning I emailed them and pointed out their typo.  I won't hold my breath for a correction or even a reply, but I tried.

T.

...

[MichaelLAX]

I suspect that they will be happy you pointed it out to them!