Kenwood TM-V7A Remote Control
Last Updated: December 17, 2001
This document is meant to instruct owners of the Kenwood TM-V7A dual band radio in the use of the radio's remote capabilities. Kenwood has documents (AAN0020A.JPG and AAN0020B.JPG) available on their FTP site , but I felt there was a lot of information missing. So, here we go.
First, I want to talk about what you can accomplish using the remote programming feature. Basically, you can use one band as an input to listen for DTMF codes transmitted from another radio to control settings on the other band. These settings include:
Step 1 - Programming an Input Memory Channel
The first step is to select a frequency to use to communicate with your remote radio. This frequency must be programmed into a memory channel. This memory channel must also contain a DTSS code. This code will be your security code, which will allow only people knowing this code to set the TM-V7A in remote control mode from remote standby. You should also program this memory channel with CTCSS tone decode. This will prevent your cross banded radio from being used accidentally by other hams.
Note: If you are using the microphone control feature, turn it off. Microphone control is not compatible with remote control.
Accomplishing Step 1
We now have a memory channel that contains the frequency and DTSS code for the input side of our remote. Why did we have to store this into a memory channel? Because we will have to turn off the radio to enter the remote mode. Turning off the radio erases any DTSS code set only in VFO.
Step 2 - Selecting a Frequency on the Output Band.
The band that you plan to control can be set to any frequency or memory channel you wish, including the call channel. I will call this band the output band because I think calling it the controlled band may be confusing.
Step 3 - Determine Cross Band Mode, One Way or Full Two Way Cross Band
You are almost there. You must decide now whether you want one way or two way cross band. One way cross band will receive signals on the input band and retransmit them on the output band. Two way cross band will retransmit signals in either direction. In either case, only settings on the output band can be modified from the remote radio. The radio will not go into cross band operation until it receives a command to do so from the remote radio.
For one way cross band:
For two way cross band:
Step 4 - Entering Remote Standby Mode
The next steps will put the radio into remote standby mode.
Step 5 - Command Confirmation
You can decide here whether you want the TM-V7A to confirm your commands by sending back confirmation tones on the input frequency. I would recommend this feature be set on. The TM-V7A seems to ignore any commands that contain a long gap between DTMF tones. This feature will tell you that the TM-V7A did go into remote control mode and is accepting commands.
Step 6 - Controlling the Radio
Now we can start controlling the radio. First we need to put it into remote control mode (out of remote standby.)
CTCSS ENCODE ON
CTCSS ENCODE /DECODE ON
CROSS BAND REPEAT ON
CROSS BAND REPEAT OFF
Using the Commands
At the beginning of this document I told you what you could accomplish using the remote programming feature. Here I will go into detail with each item, giving the control codes necessary to carry out each task. I will assume in the following instruction that the TM-V7A has gotten the command to go into remote control mode (see step 6 above.) REMEMBER TO SEND THE D COMMAND TO DISABLE CROSS BAND REPEAT OR ALL OF YOUR COMMANDS WILL BE IGNORED. Also, remember to send the A# command to return the TM-V7A to standby remote after all commands are sent.
Setting the output band in VFO mode.
Direct entry of the VFO frequency.
Stepping the VFO frequency up or down.
Setting the output band in Memory Recall mode.
Direct entry of the memory channel.
Stepping the memory channel up or down.
Setting the output band to the Call channel.
Changing the output band power level.
Putting the output band in Reverse.
Turn on or off the CTCSS tone encode.
Turn on or off the CTCSS tone encode and decode together.
Setting the CTCSS tone frequency.
CTCSS Tone Designation Numbers
You can set the radio in and out of cross band repeat.
Step 7 - Leaving Remote Control Mode
Jane, get me off this crazy thing. OK, here's how to shut it down.
Tips and Tricks
Here are a few tricks I've learned to make all of this go smoother.
Tip 1 - When sending the code to put the TM-V7A into remote control mode, add the D command to the end of the string. This has two benefits. First, it will make the radio send a confirmation tone, which indicates it got the remote control mode command. Second, it takes the radio out of cross band mode, which will allow it to accept other commands. Example, send DTMF AXXX#D where XXX represents the three digit DTSS code entered into the TM-V7A's input memory channel.
Tip 2 - If your remote radio will store DTMF sequences, you can store a single string of characters to put the TM-V7A into remote control mode and carry out a set of functions. For example, lets change from a VFO frequency to memory channel 5. Let's assume your DTSS code is 123. This string would start with A123#, then add D to take it out of cross band mode, then 9 to select memory channels, then A05 to select memory channel 5, then C to put in back into cross band mode, then A# to return to standby remote. The DTMF string would be A123#D9A05CA#.
Tip 3 - If you have the input band protected by CTCSS decode, you can silently send the remote control mode command to your TM-V7A by turning off the CTCSS tone encode on the remote radio. If you are cross banding to a repeater, this will allow you to enter the control mode without repeating the code to the repeater. This will increase the security of your DTSS code and make you less annoying to your ham community.
Tip 4 - If your off in the woods hiking and you are remote controlled cross banding to your car, make sure you do not run out of power on your remote radio. Without the remote radio, you cannot disable cross band mode on the TM-V7A. Unless you are able to disable cross band mode, you cannot take the radio out of remote mode (Power on + Control.) This will leave you without a radio on your way home. Updated info: See tip 8 and tip 11 for work arounds.
Tip 5 is from Joe Ruby, KC7GHT - When you update your RC stuff, you might explain that the Kenwood TH-79A HandyTalkie has all of the codes built in for the TM-733A (and maybe for the your new V7 radio too) and when you push one of the keypads it not only sends out the complete required code sequence but also displays on the face of the HT what it is doing. For example if I push 2 on the keypad of the TH-79A the display will indicate "TONE ON" while it is sending out the complete DTMF tone sequence required to turn the tone to on. Another example is the D key. When the D key is pushed the HT displays "REP OFF" while it sends the complete tone sequence. Its really neat. The next time you are in HRO pick up a TH-79A Kenwood HT and with the power off, hold down the MR button and the PTT switch, and while holding both of these turn on the power. The HT will come up in the remote control mode with the display indication "RC" on one band and the normal display on the other band. Then try pushing the keypad buttons and watch what happens! To get the HT out of the "RC" mode just repeat the MR+PTT+Poweron sequence. Don't forget to tell them that even the latest production Kenwood TM-733A has software problems with the remote control system. They fixed everything else though.
Don Putnick, KK6DP wrote - The TH-G71A works like the TH-79A. Just follow the one page addendum to the instruction manual (available from the Kenwood ftp site as AAN0023A.JPG and AAN0023B.JPG) to enter the three-digit DTSS code into the G71A's memory. The G71A goes into and out of its REMOTE CONTROL mode the same way the TH-79A does. You don't need to send the AXXX# or A# commands to the V7A; the G71A does that for you with EACH command; the side effect is that the V7A appears to stay in its remote standby mode. Of course, you can also use the G71A (or any DTMF-capable handheld) in its NORMAL mode to put the V7A into remote control mode per Step 6 by sending AXXX#, send individual commands from the keypad, then return the V7A to remote standby mode by sending A#.
Tip 6 is from Joe Ruby, KC7GHT - One thing I always do to verify that my remote radio is really following all of my commands is to return the output to a simplex frequency and put it into crossband by remote control. When I key my HT on one band the remote radio radio will transmit on the other band and my dual band HT can hear the remote transmitting on the correct simplexfrequency. Once I get this confirmation I know it followed all of my commands up to this point. Then I am free to control it to a new repeater frequency or memory channel and talk over a repeater. If the repeater comes back to me thru the remote, I know it worked this far. When I am finished with the repeater, I change the remote back to the simplex frequency and listen to see if I can hear the remote go back to the simplex memory channel. This really gives me confidence that the remote is following my commands. Without this kind of feedback, you can't be sure your remote radio is following your commands, and may in fact be causing interference. Be carful with your remote operation, be in control of your remote radio at all times, and set the transmitter time-out-timer (TOT) as a fail safe. I have successfully controlled my remote radio from as far away as 40 miles, but you don't want your operation to go off onto a stray frequency and cause interference problems. With the tip I have just described, you will be sure what your remote radio is actually doing.
Tip 7 is from Joe Ruby, KC7GHT - If I position the HT antenna for a weak received signal from the remote simplex frequency - ie horizontal position, I can change the power setting on the remote and tell what power setting I am really at - low, med, high by looking at the strength of the received signal on my HT display.
Tip 8 - Use your programmable memory (PM) to make it easier to go into remote control mode. When your radio is all set up and ready, save the settings to a PM before activating remote control mode (Power on/Control button.) Be sure to turn off PM Autostore for this PM so you don't accidentally change it later. When your ready to go remote, recall the PM and activate remote control. An added benefit to this set-up is that you can leave remote control even if cross band repeat is enabled. If you run this PM with PM Autostore set to off, remember to manually store changes you want to keep. To manually store the current settings to a PM press F+PM+(pm number.) I recommend you set the Time Out Timer (TOT) to a reasonable value in this PM and also set the Program VFO to 144-148 MHz.
Don Putnick, KK6DP wrote - A clarification re tip 8. If cross band repeat is enabled, the Time Out Timer is automatically set to 3 minutes.
Tip 9 is from John Seng, KC7ZNS - You can set the TM-V7A for two way cross band remote and use this trick to switch between one way and two way crossband from your remote radio. Turn the CTCSS encode/decode feature (CT) on for one way cross band and either off or encode only (T) for two way crossband. Most repeaters strip the tone from their output. so if you decode CTCSS, the repeater (or simplex signal) will not break squelch on the output side of your cross bander.
Tip 10 is from John Pahl N0YZH - John contributed some information as well as a great idea to keep people from sending unauthorized codes to your remote controlled radio. First, the information. In the instructions above, I talk about using menu item 18 to setup the radio to send confirmation tones. The TM-V7A sends these tones in response to receiving a command from the remote radio. John says that these tones are your three digit DTMF code. According to John, many radios, like his Yeasu FT-50, can be set up to read and display the code. So much for keeping your code a secret! I'm not sure why Kenwood set it up this way, but there you are. Of course, anyone close enough to hear your remote radio send the codes to the TM-V7A could get the code anyway, but having the TM-V7A repeat them sure extends the range. But, never fear, John has a great solution! Set the TM-V7A input band for an odd split. This way, the TM-V7A will be talking on one frequency and listening on another.
For example; Set the UHF side of the TM-V7A as the remote control input with a transmit frequency of 445 MHZ and a receive frequency of 442 MHz. Your remote radio will need the same, but opposite split. People will hear your cross band radio on 445 MHz, but unless they are within range of your remote radio, they will not know what frequency you are using to access it.
Great tip, other John!
Tip 11 is from Bob Mueller KD7HLL - When stuck without a remote radio to take the TM-V7A out of remote controlled crossband, use the VFO Reset feature to shut down crossband operation and leave remote control at the same time. To do this, turn off the TM-V7A and then turn it back on while holding the VFO button. Answer yes to the RESET VFO? prompt and you're out. The only penalty you pay for this method is the loss of the frequencies that were set in VFO. All of your memories and PMs are still available.
Well, this is about all I know on the subject at this point. If you have anything to add, please let me know. Also let me know if I can give you credit and link your e-mail address or web site. I would really like to know how to store the remote control mode in a programmable memory. Good luck with your remote controlled cross band radio. I will update this article if I learn anything new on the subject.
73 Keith Casey KC7KC
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