This is a short revision to the last article on programing the Baofeng DM-1701 and working it into a small unit’s SOI. Also note the Baofeng DM-1701 programming guide by Captain Attilla. -NCS

Having acquired a set of DMR radios, and then others I know having done the same, I had to try to come up with an easier way to integrate new radios into our “Plan.” I had also noticed that a number of other groups – including a larger “organization” – had neither the knowledge or experience to assemble something that would meet their requirements. (Newer organizations seem not to realize where they might be lacking.) Given the current situation, I set out to provide a tool that might help. Here it is. Feel free to use or not use it. To change, edit, improve, (or ruin) it to your hearts content.

* ALWAYS test that operation of the radios are as desired following programming and before operational use. * YOU are responsible for the final product and anything that goes awry.

Developing an SOI (Signals Operating Instruction) can be a time consuming task. One of the more tedious parts of writing a SOI is the assigning of frequencies and even more so any associated parameters particularly for channels, especially if using digital radios. To make matters harder, good ComSec (Communications Security) practices would include compartmentalization (only those who need to know a particular piece of information are given that information,) obscuring the transmission (e.g., through use of directional antennas,) obscuring the message and frequent changing of the SOI.

The attached spreadsheet helps mitigate the problems of creatin g appropriate sections of the SOI, making it easier to change the SOI more frequently, compartmentalizing relevant parts of the SOI and obscuring the message when the radios are capable of encryption. While the spreadsheet is optimized for the Baofeng DM-1701, it can be adapted for nearly any radio(s). It is also designed to provide examples of many types of communications “networks.” As it is, it is likely more complicated than most will have need for. However, a small amount of analysis of it should lead the aspiring SOI writer to see how to expand its use fairly easily to an even larger “Command Structure.” 

“Command” Structure of the Radio Network as used in the SOI Spreadsheet:

X

/ | \

P Q R

/ | \

A B C

/ | \

A1 B1 C1

X Battalion Commander

P/Q/R Company Commanders

A/B/C Squad Leaders

A1/B1/C1 Assistant Squad Leaders (or #2 Team Leader) – These are not specifically listed in the spreadsheet, instead referred to indirectly on Sheet 1 Intra-Squad Channels (3 and 4, for Columns A, B, C.)

Not everything in the spreadsheet need be used. It is easier though, not to utilize unneeded portions than to add them in, so I included more than most would likely want. The ability to set up both analog and digital is present. Organizing encryption keys, color codes, CTCSS tones, separate transmit and receive frequencies are all present. Just place the desired parameter in the proper block of of the Variables Sheet and the parameter will be automatically populated into the proper positions of of the applicable Sheets. You can rename the variable names on any page to anything you like without affecting the spreadsheet’s operation if you want to make something more clear. However, if you re-arrange locations of the actual cells on the Variables sheet, things will run amok. (Adding or removing columns or rows does not seem to make a difference though.)

After a lot of testing trying to get separate Tx and Rx frequencies on DIGITAL channels to work, and a lot more reading, it seems that at the present time it will not work for direct radio-to-radio (in other words, no repeater,) at least on the DM-1701. Other DMR radios may have this functionality but I can’t say. The reason seems to be that when a digital channel has separate Tx and Rx frequencies set, the CPS (software) automatically sets the radio for repeater access mode. When in this mode, when you key the radio it sends a signal to whatever repeater may be out there listening on the radios Tx frequency and waits for the repeater to send a signal back, along with timing control information for the slot, and lets the radio know it can actually start transmitting – which is not happening when operating direct radio-to-radio as nothing sends back the “ok to transmit” signal. There is no way (that I have found so far) to turn off this requirement in the radio. Placing the radio into Talkaround mode just sets the radio’s Tx frequency to the Repeater’s output frequency and bypasses the Repeater altogether. DCDM is another mode whereby two sets of DMR radios can operate on the same single frequency, but on both timeslots – one set for TS1 and the other set for TS2. One radio in the set sets the time synchronization for all. This is available because DMR is commercial, not Ham, and was designed so that the end-user could operate the radios with fewer required frequencies, for which they pay to license. So, for the time being and until a firmware upgrade (along with a corresponding CPS) becomes available that will enable the user to turn off the requirement for the repeater acknowledgment, digital channels for radio-to-radio contact will have to be single-frequency (simplex.)

This affects several digital channels of the spreadsheet. The solution for now is to make sure to set Rx=Tx for all of those affected channels. This may just be easier to do manually for some. On the Variables sheet, those cells that are associated with digital channels all have “dig” as part of the name, with a suffix of 1 or 2. Make the values for “XXX dig 1” the same as “XXX dig 2” and the output should be fine. This can also make some channels redundant. For instance, channel 3 for squads is also covered by channel 11. However, this could be incorporated as part of your PACE plan.  

You can mix and match parts of the SOI Helper depending on your circumstances and hardware. For instance, you are Platoon Leader. You have 1 Squad of two Fire Teams and an Overwatch. The Squad has two UV-5r radios (1 per team, Squad Leader and Assistant SL.) Platoon Leader and Overwatch each have a DM-1701. You can count the Overwatch as a separate squad OR as part of the squad. Given that he has a DM-1701, it would likely be better to count the Overwatch as a separate squad. PL and Overwatch would then talk on digital, but the rest of the squad would be limited to analog. PL and SL would talk on analog. SL and ASL would talk on analog. If each of these communication links is limited to only two parties total, then each link could have separate Tx (transmission) and Rx (Receive) frequencies for analog. Overwatch could monitor (or even talk to) the SL/ASL also, but that would require a small bit of adjustment or “adapting” a different channel on the spreadsheet to fit this arrangement.

(It would be good to know how scanning on your radio works, so that you are not necessarily limited to only monitoring two VFOs, depending on your circumstances.)

The only items to enter directly into the Output Sheets are for Channel Name (if you choose to, but it’s not needed.) This is left for the individual users/radio-programmers to set up however seems fitting to them. Likewise, Channel Numbers are arbitrary and can be changed. They are only here to make it easier to find a section and to correlate between sections. (e.g., Channel 25 for the Platoon Leader has all the same information on each of the two Sheets.) Many radios do not allow the user to set a channel to a specific number without lots of handwaving and incantations. Be forewarned.

You can change the notes to whatever you like without repercussion. A lot of them may appear esoteric as they are. They are there for me.

For the mere minimal squad (two fire teams of two) the Platoon Output Sheet is overkill (let alone using The PL Sheet.)  Adding a second squad to the mix can complicate things quite a bit especially if you want to maximize ComSec risks. Adding a third squad (and the necessary Platoon Leader) make the requirements even more complicated. That’s where the Platoon Sheet really helps. Expand to two platoons and you just use the Platoon Sheets twice (and also the PL Sheet.) Ditto for another platoon. A second company requires two PL Sheets. Just make appropriate changes to the additional sheets used as applicable. You get the drift. I have tried to make it a little easier by color coding the relevant cells on the Variables Sheet if you are having to add squads for a second (or third) Platoon. If it’s green then you will need to *transfer* the appropriate information. If it’s red, do NOT change it. If it’s not colored, then change it. There are only a few items marked yellow – that’s for Company level. If you’re at that point, you’ll know what to do.

Don’t get hung up on the values I have entered into the sample spreadsheet – they are there for testing, and so that you can easily see what parameters in one radio correlate to parameters in another radio. You may not like the order or arrangement that I have the variables in on the Variables Sheet. Too bad. It annoys me too, but I can live with it. See my warning above regarding changes.

This does not include anything for repeaters (tactical or otherwise.) That’s up to you if you feel the need.

I am NOT advocating using parameters that might be contrary to the laws of your jurisdiction.

Note that this is not an instruction on how to program your radios or detail the use of the CPS (Code Plug Software, or Customer Programming Software, depending on who you talk to.) This helps organize information for you to enable easier programming of your radios with whatever software you use or from the radio face if possible. YOU have to know how to set up a contact list, group list, etc. for better utilization of text messaging or any other features your radios may have.

Here are some additional notes that you might find helpful:

General note regarding DMR:

For a simplex radio in a normal DMR mode, the radio will receive calls from either timeslot. The transmitting radio can change which slot it transmits on, there is no need for ‘sync’ as there is only one data stream. The radios normally lock into whatever slot they hear as active, if there is an irrelevant call coming in on slot 2 then the radio will not hear a relevant call on slot 1 while both are happening. You can even see this in the CPS software, you can always select the slot in simplex. This can obviously cause some annoyances. This could probably be prevented by using DCDM.

Uniden’s Close Call doesn’t pick up the transmission, because Close Call requires a continuous TX for more than 30ms to trigger a hit. DMR transmissions are 27.5ms out of every 60ms.

However, transmissions CAN be picked up IF the frequency is programmed into the scanner as part of a scan list. The scanner will display a lot of useful info for the listener. Because the above information can be scanned, it is IMPERATIVE that the radio ID and “custom” Talk Group IDs be changed EVERY Mission/Op, or else a partially competent SigInt guy will be able to correlate personnel/teams/you-have-its from op-to-op. My testing so far has shown that a custom talk group number is not required – that is, they can be different from one radio to the next when using the parameters provided by the SOI Helper. Also, an operator should NEVER utilize one of these as a “typical” DMR radio attached to the net with their personal 7-digit radio ID as this would positively correlate the radio with the operator through their FCC call sign. That would be…bad juju. Don’t be that guy.

 

Notes Specific to DM-1701:

  • Avoid having the same channel selected on both VFOs – seems to get goofy/inconsistent on whether the signal comes in on A or B, and sometimes results in funky non-transmission/receipt of messages.
  • Of course I recommend enabling the “power on password,” “radio program password,” and “PC programming password.” For the PC programming password, I noticed that it is *not exactly* case sensitive, but kind of. If you try to set it using capital letters, the CPS will convert the capitals to lower case (but not tell you.) Later, if you enter the password as you typed it, you will be very “disappointed” as it tells you it is incorrect. Don’t use capitals. I have no idea if it will accept anything other than numbers and (lowercase) letters, and I don’t feel like trying it out. The manufacturer’s documentation is keeping that a mystery. My research (for what that’s worth) is that there is no known (publicly anyway) way to get into your radio if you’ve lost the password sent to it originally. I’d expect there is, but don’t know it.
  • DO NOT enable *Privacy On/Off* key – will default to [Basic 1 Key] upon re-enabling. Just set to On in menu for channel. (Unless, of course, you want it to just use Basic 1 encryption.)
  • Text Messaging DOES NOT utilize encryption! I have tested this with the latest CPS and Firmware with my set of 4 radios, setting all radios equally with the exception of 1 having encryption not enabled on the channel. Voice transmitting encrypted only is decrypted on the radios with encryption enabled. SMS transmitted from encryption-enabled radio IS STILL successfully received on the radio without encryption enabled. In support of my findings I note the following:
  • [From Radioddity.com (the primary supplier of the DM-1701 for Baofeng) and repeated at the Top-10 evaluation at https://www.myaudioplanet.com/the-best-dmr-radios/
  • “Strong Digital Function – …encryption only supports calling between the DM-1701 devices…”]
  • Enable/Kill works without encryption – if Color Code matches (or None if CC# is set to None) then can be killed. Attacker must know Radio ID and CC#. CAN BE DETERMINED via scanning (e.g., DSD on Linux w/RTL-SDR, or Bearcat 436/536.) Have not fiddled with the analog DTMF option for it, as would require receiving radio to be on an analog channel which would probably be rare, especially if radio was “compromised.” Summary: don’t enable the Kill function. Was neat, but a partially competent SigInt guy will screw the team over by trying to kill the radios, so don’t tempt him.
  • Battery Release needs a block/stop of some kind to prevent accidentally dumping power to the radio when grabbing it. Easy fix.
  • Sometimes the volume knob seems to stop really low. It’s the bumps on the volume knob stopping against the left (selector) knob bumps. Turn harder.

Link to Spreadsheet:  https://www.dropbox.com/s/aswg02174sv1i8q/DMR-Analog-SOI-Helper.xlsx?dl=0

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