DMR/TGIF Audio Offset

Hotspot Offset Calibration

People using DMR/TGIF please take a few minutes and setup your hotspot-offset-calibration. On the analog side of the system, many of you are unintelligible. Below is K9NPX procedure on doing this with Pi-Star. For OpenSpots and other products, there are similar processes.

on February 05, 2019Most of the boards I’ve been getting lately have required adjusting the offset to function properly on DMR. Many boards are shipped with a sticker on the bottom with the required offset. These are usually pretty close. There is however a way to get this more exact and specific to your radio.

MMDVMcal

Luckily there is a utility built in to Pi Star that enables you to tune your offset. All it requires is pen and paper, a calculator and a little time.
Step one is to gain ssh access to your Pi. The easiest way to do this is go to “Configuration” then click “Expert” then “SSH Access” and log in with pi-star and your password.
Next set your radio to VFO Digital mode at 433.000mHz TS1 TG9
Then go back to SSH and type “sudo pistar-mmdvmcal” this will start the calibration program. Type “m” this sets a 1031 Hz test tone. Next press the “space bar” to start transmitting. You should hear the test tone on your radio at this point. Next press the “f” key repeatedly until the radio goes silent. After that press the “F” key multiple times until the tone comes back. Write down the frequency at which the tone comes back. Now you have to go the opposite way. Press “F” until the tone stops followed by “f” and write down the frequency where the tone comes back again. Next subtract the lower frequency from the higher frequency of the two you just wrote down. Divide that number by 2 and add the result to the lower frequency. Now the difference you get from 433mHz is your offset.  To sum up

  • sudo pistar-mmdvmcal
  • m
  • space bar
  • f (repeatedly until you lose the tone)
  • F (repeatedly until the tone comes back)
  • F (repeatedly until you lose the tone)
  • f (repeatedly until the tone comes back)
  • subtract lower frequency from higher frequency
  • divide that number by 2
  • add the result to lower frequency
  • find difference between result and 433mHz

Once you have your offset you have to set it in Pi Star.

You’ll need to go to your pi-star dashboard, then “Configure” and “Expert” Now click on “MMDVMHost” Scroll down to “Modem” and enter your offset in RXOffset and TXOffset. Don’t forget to click “Apply Changes”

Still having trouble talking to your hotspot?

The above method will usually get you close enough but if it doesn’t there is a method to tune your hotspot for a minimal BER.
First, set your radio to 433.000mHz Talk Group 1 and Color Code 1.
Next, use the same command in SSH to start mmdvmcal “sudo pistar-mmdvmcal” then press “b” to start the BER tuning program. While pressing the PTT on your radio press the “f” key or “F” key to adjust the frequency until you get the smallest BER you can achieve. However far off you are from the starting frequency of 433mHz is what your RXOffset should be set to.
Tip: These are the instructions for DMR. When you start the mmdvmcal program it displays a list of codes for other tests and other modes you can test.

By K9NPX

Emory Allstar

As of 02/16/2019 the Emory repeater system has been removed from NCTC Allstar Network by Emory. Instead of being direct into Arlington is now running on a 3 link RF hop. Noticeable audio degradation has occurred, but is normal for the three hops.

Brandmeister Disconnected From NCTC

Per the request of the Brandmeister (BM) National Coordinator, the BM DMR link to NCTC has been disconnected. They do not want any cross linking to TGIF DMR. I kept TGIF Network over Brandmeister because of the openness of TGIF, friendly nature of the system, and there willingness to give us our own Talkgroup 189. I will keep the Brandmeister node disconnect, but running for Backup

For information on how to connect goto: https://tgifnetwork.createaforum.com/index.php

David KG5RDF

Paris

Paris on a East Texas run today with KG5RDF.. N5REL, and W5KJC.. and help from Tom and David. And Jon Moon. thx crew!!

David KB5WB

Talco

Talco has been resuscitated, however it’s temporarily on 442.125 / PL 151.4 while the primary repeater is sent off for repairs PA was cooked on the primary repeater. For reasons only known by Yaesu, we couldn’t get the temporary DR1X to move off of 442.125. Sometimes you have to improvise and adapt. Thanks to KB5EDB, KB5WB, KG5RDF and WA5TXI for the teamwork to get this back on the air. When the primary repeater comes back from warranty repairs at Yaesu, Talco will go back on its designated frequency of 442.200 / 151.4.

Nathan N5REL

NCTC Net 01/03/2019


Thanks to the 53 stations who checked into the net tonight. We learned a few new things:
– The government shutdown has caused the FCC to suspend operations including issuing and renewal of licenses. https://www.theverge.com/…/fcc-suspension-partial-federal-g…
– If the government is not fully funded before SKYWARN school then those sessions that are scheduled will be canceled.https://www.weather.gov/psr/ShutdownImpacts
– NCTC is available on the TGIF DMR TalkGroup 189. For instructions on the use of the TGIF DMR system on your hotspot, send an email to K4WZV Robert https://www.qrz.com/db/K4WZV and he can provide you with instructions. TGIF is not interoperable with the Brandmeister or DMR MARC systems.
– KB5WB said that there are plans to work on the Paris and Talco repeaters on the air Saturday/

Calvin Gluck W7KYG