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K7RPT
Digital Voice Modes

 by Marc Peterson, W7PM


ARRG currently owns and operates twenty VHF/UHF repeaters located at 10 different repeater sites around Oregon and SW Washington are mostly Analog (good old fashioned FM) repeaters. For our true Analog purists, don't worry, there is no discussion to change any of the existing Analog Repeaters over to Narrowband FM or Digital anytime soon.

ARRG now provides both System Fusion and DMR repeaters for use by our users and the general Amateur Radio Community.

ARRG currently operates several Yaesu System Fusion (YSF) repeaters, which are currently set up to favor regular Analog FM communications. Each YSF repeater is programmed to scan the incoming signal and switch voice modes from analog to C4FM, and back, within 15 ms.


K7RPT System Fusion Repeater System 
To learn more about how to operate the K7RPT Multimode FM and System Fusion Repeaters
please visit our System Fusion Page
here
Repeater Location  Repeater Callsign  RX Frequency  TX Frequency CTCSS  Comments/Talk Group
Sylvan Tower - Portland West Hills  K7RPT 442.2250 447.2250 100.0 In AMS mode. Linked to 443.750 (Analog) at Chehalem 
KPDX Tower Portland West Side  W7PM  442.2500 447.2500 100.0 In AMS Mode 
Event Repeater  K7RPT 442.3500 442.3500 100.0 AMS mode

New DMR Access

Through a partnership with the Pacific Northwest Digital Network of Oregon (PNWDNO) we are happy to announce that the group will be installing three
Digital Mobile Radio (DMR) repeaters at our highest, wide-area repeater sites. Beginning first with our Sylvan - Portland West Hills site, followed up in early 2020 with a Mount Hood site and finally out in the Coast Range on South Saddle Mountain.

Why DMR and Why Now?

ARRG was always working towards adding at least two interconnected DMR Tier 2 repeaters to the K7RPT repeater system, however, the cost to do so was high...especially when most of our repeater fund really needs to be going into upgrading and replacing our 30+ year old aging FM only system.


After months of research, including attending several talks and presentations, we are happy to announce that during our November 2019 board meeting, ARRG voted to partner with the Pacific Northwest Digital Network (Oregon) to help provide our users DMR services. The founders of the PNWDNO share ARRG's common value of providing free and unrestricted repeater access in an open and inclusive manner, for the good of the entire Amateur Radio Community.

Because DMR is much more band efficient and uses a TDMA (time-division multiple access) modulation coding scheme, it makes it possible for a single repeater to repeat two separate, but simultaneous QSO's.

DMR Gear

Although we are throwing out DMR models here, all these models do regular Analog FM bands as well as DMR

When considering a Dualband 144/440 MHz DMR radio, there are only a few FCC certified radios, like Motorola, Connect Systems and Anytone brand/models that are currently okay to use for use on the system.

We are openly testing several other models, like the FCC Part 90 approved Alinco DJ-MD5TGP and the under $100 non-FCC type accepted Retevis RT83 and Baofengs DM-1701B and cheaper DM-1801 models. All of the under $100 models listed lack many features including a mica audio adjustment, which causes them to sound very over modulated on DMR repeaters and tend to irk the DMR audio purists out there.


I personally like my $238 Anytone AT-D878UV Pro, which is a true Dualband walkie and includes a built-in GPS, Analog APRS and Bluetooth. One could also pick the much cheaper, almost identical copy $168 BTECH DMR-6X2 Dualband walkie which also has GPS but lacks Bluetooth.

The radios that have Bluetooth capability usually include a wireless Bluetooth PTT switch and when paired with the walkie and the walkie then paired with your car stereo, it allows you hands free communications. You can even use any of your old cell Bluetooth headsets.


For your car or in the shack, we like the Motorola and Connect Systems mobile rigs. I'm currently waiting for a new FCC Part 90 approved Anytone AT-D578UVPRO Dualband Commercial DMR Mobile, they run around $399. Anytone also makes a non-part 90 Tri-band mobile rig for Amateur use for the same cost.

Using the System

There is a steep learning curve to programming your radio and actually using the DMR system, all I can say is be patient. You need three items of programming to be correct, to make a DMR contact. 1- Frequencies 2- Color Code and 3- Talk Group number.

For example, make sure to check your programming software (CPS) for repeater tx/rx frequency typos. Also make sure the proper color code (repeater access code) is correct. Then, make sure the Talk Group is accurate.

In my own case, I accidentally put in 3142 for OREGON for an entire week before I found that OREGON is actually 3141.

Dial up your closest repeater and select the Talk Group (TG) adn your timeslot (TS) if needed.
For example, if your are located in SE Portland, select the Mt. Scott repeater frequency pair and select the Talkgroup you wish to connect the system to, in this case OREGON 1 (or time slot 1). Key up and wait a second, then say something like "KJ7BRE, this is W7PM on Oregon 1."

Many people like to listen to both timeslots (much like having two frequencies up at one time). By saying the timeslot, in this case 1 after Oregon, it tells those listening on dual timeslot monitor mode, which TS to come back to you on.  Also, please try to limit kerchunks, as they don't actually do much, because you won't actually hear a repeater squelch tail come back like on FM.

Got Questions? We Got Answers! Email me here.


  Pacific Northwest Digital Network of Oregon 
DMR Repeater System
 
Repeaters  Repeater Callsign  RX Frequency  TX Frequency Color Code  Comments/Talk Group
Mount Scott - Portland Metro  N7LF 441.3250  446.3250  7 Open- see TG list below
Providence Hospital Portland  N7LF 444.8375  449.8375 7 Open - see TG list below
Mount Hood Medical Center - Gresham  N7LF 443.1000  448.1000 1 Open- see TG list below
Lookout Point - Corbet  N7LF 444.1500  449.1500 1 Open- see TG list below
Coming Soon
Sylvan - Portland West Hills  
K7RPT 440.5125 445.5125 1 Currently Off Air
ARRG TG 31418 TS 2
Coming Spring 2020
Mount Hood
N7LF 440.XXXX 445.XXXX TBA Currently Off Air
ARRG TG 31418 TS 2
Coming Summer 2020
South Saddle Mountain 
K7RPT 440.8125 445.8125 TBA Currently Off Air
ARRG TG 31418 TS 2
Coming late 2020
Astoria - North Coast 
 K7RPT 440.XXXX 445.XXXX TBA Currently Off Air
ARRG TG 31418 TS 2
Talk Groups Slot One Slot Two TG is open Fulltime TG opens by first PTT Comments
ARRG   31418     Sylvan Talk Group
PNWDNO Local One 3181       Local Tech Group
PNWDNO Local Two   3166     Local Tech Group
Oregon Wide 3141 Yes, In State PTT - Out of State Full time in-state, PTT out-of-state. QSO's are generally restricted to 10 minutes, use Oregon Local 1 or 2
PARROT 9998   n/a PTT Select closest repeater and select TG 9998, key down and say your callsign, unkey and about 1.5 seconds laters, the computer will reply with your voice saying your callsign. Great for checking signal/audio levels.
North America Nets One 31001     PTT Various Nets/Topics from around the US and Canada
North America Nets Two   31002   PTT Various Nets/Topics from around the US and Canada
PNW ALL CALL 3187   FT   NW Main All Repeaters; Calling or Standby use ONLY
No QSO's, NOTE: this TG lights up EVERY repeater on PNW


Modes, Modes Everywhere!

There several different modes of communication available to Amateur Radio, they can be summed up in three basic modulation groups. 

1-    Analog – which includes regular 144, 220 and 440 FM local simplex and repeater use. For longer range communications utilizing HF through 6-meter bands, the preferred analog mode is SSB or Single Sideband using LSB or lower sideband below the 20 M band or USB which is upper sideband and used on the 20M band and above. Even AM use also fits into this section.

2-    Digital Voice – which also includes using the 144, 220 and 440 local simplex and repeater frequencies. There are also some long-range DX experimental uses of sending digital HF Voice using special modems. In fact, System Fusion users who own a Yaesu FT-991 or 991a HF rig, can even use DN (digital narrow) voice to legally operate DX on both the 6 and 10-meter bands.

3-    Digital Modes by use of a Computer or TNC Modem – these modes include PSK31, FT8, RTTY, Fastscan TV, WEFAX, the list goes on and on, best to say that whatever digital mode you can send through an attached computer is allowed on most portions of every Amateur Radio band from HF to Microwave. 

Different types of Digital Voice Modes

There are also different types of Digital Voice coding methods used by different manufacture's. Most modes ARE NOT compatible with each other, which really blows for the common Amateur Radio operator, mostly because you will be forced to own several different radios to cover everything 'digital' out there.

D-STAR by ICOM (and now offered on some Kenwood models) is a combination voice and data mode. It is commonly used simplex or through the thousands of DSTAR repeaters in operation around the Country. Here is a quick breakdown of the three top Amateur Digital modes:

1- DSTAR by ICOM (and now Kenwood) is a combination voice and data mode. It is commonly used simplex or through the thousands of DSTAR repeaters in operation around the Country. DTSAR allows a data backbone connection, like a slow wireless internet at 128KBS, between computers for groups that have created their own mesh internet system and runs independently from the regular WWW. D-STAR users can remotely  can access the internet, communicate with other Ham's anywhere in the world, look up a call sign of someone currently on air and even send a simple text message using a D-STAR capable Ham Radio.

2- SYSTEM FUSION or C4FM is the flagship digital voice/data mode used by Yaesu.  YSF has three modes, regular analog FM, VM or Voice Wide mode, which runs in a 12.5 KHz wide channel and includes embedded data that shows a caller’s name and callsign on your radio display. There’s also even a narrower mode, called DN or Digital Narrow, which operates in a 6.25 KHz channel and includes embedded data that shows the other persons callsign, name and even current location. On the plus side, the VW and DN YSF digital mode uses a store, error correct and send codec that cleans up the signal, even when a comparable FM signal would be quite noisy into the repeater. There are also hundreds of YSF repeaters operating in the Pacific Northwest. ARRG has three such repeaters in operation.

3- Digital Mobile Radio (DMR)  is an international standard for digital radios that has been in use since 2005. With nearly 1,090 amateur repeaters already on the air in North America, DMR infrastructure is well established and is on pace to surpass D-STAR and System Fusion in 2019. Digital Mobile Radio (DMR) was developed by the European Telecommunications Standards Institute (ETSI) and is used worldwide by professional mobile radio users. [http://www.dmrassociation.org] .

DMR is divided into three tiers. Tier I is a single channel specification originally for the European unlicensed dPMR446 service. It is a single channel FDMA 6.25 kHz  bandwidth; the standard supports peer-to-peer (mode 1), repeater (mode 2) and linked repeater (mode 3) configurations.

Tier II is 2-slot TDMA 12.5 kHz wide peer-to-peer and repeater mode specification, resulting in a spectrum efficiency of 6.25 kHz per channel. Each time slot can be either voice and/or data depending upon system needs. IP Site Connect (IPSC) for interconnecting repeaters over the Internet is vendor specific and is not part of the ETSI standards at this time. All ARRG supported DMR Repeaters operate in TIER ll, using voice on both time slots.

Using Tier ll on our repeaters means that two simultaneous QSO's can be occurring on the same repeater at the same time, all without interfering one with the other.

Unlike Echolink and IRLP nodes, which require solely on the internet (which we know can and will fail during a disaster) DMR can be interconnected through either RF or Internet based linking, including the new wireless Amateur HSMM or Ham Wan.

Experimental Note: Some of our Yaesu System Fusion repeaters can be hacked to accept a new MMVDM Multi-mode voice modem. For example, repeater owners are adding the modem to YSF repeaters which opens them up to receiving and transmitting FM, Fusion, D-STAR, P-25 and even Tier One DMR.

Why DMR?

I've only been on DMR officially for about 1 week and I've listened to multiple QSO's thus far, including two different nightly nets and so far when asked about my experience thus far, DMR can be summed up with one word, professional. I don't know if it is because one's registered Radio ID, Callsign and name pops up on each transmission or not, but operators are much more professional sounding and courteous than what I hear on our local analog repeaters. Many ARRG members have told me the DMR system was a breath of fresh air to listen to, notwithstanding some fairly nasally audio, it's crystal 'quiet' not crystal clear.

 What's a good starter DMR Radio?

Motorola makes great single band UHF mobiles and portables, Connect Systems and Alinco makes a great Dualband DMR portable, but most the local DMR guys recommend the Anytone AT-D868 or the 878UV PLUS Bluetooth W/GPS Dualband Analog FM/DMR Walkie or the new Anytone AT-D578UVIII Pro Tri-band DMR mobile radio. They are both FCC Certified Part 90, which means your rig is legal to use on Amateur, Public Safety, Business and GMRS. I'm sure any FCC certified DMR radio would work fine, however, non-FCC certified sub $100 Baofengs, Retivis, etc. are said to have some audio issues. However, nobody wants to restrict your use of the system so if a $50 DMR rig is all you come up with to dip your toes into the DMR waters, it's all good.



When it comes to programming up your new DMR Radio, start by programming in the PNWDNO frequencies listed above. You'll need to add the proper Color Code and throw some TG (Talk groups) in so you can start to make QSO's. The Oregon TG of 3141 is a great place to start. Also, we'll have a more private ARRG TG (TBA) and available where you'll find most of the ARRG members hanging out.

Much more to come, but in the meantime, there are already volumes of FAQs and programming guides which are directed to users in the Pacific Northwest, including frequency lists, please visit the following PNW DMR site listed below to read their published information:

http://pnwdigital.net/   

https://www.raqi.ca/~ve2rae/dmr/Amateur_Radio_Guide_to_DMR.pdf

 
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