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VIC 1 in the M37
- Thread starter ke6rwj
- Start date
here's the doc i mentioned in my post above..
http://www.roscommonequipmentcenter.com/projects/rec2.pdf
and
http://www.roscommonequipmentcenter.com/news_notes/nn9.pdf
did you get this going? I finally had time to hack on mine, here are the results...
LS-671 - RadioNerds
serial14
Member
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- Albuquerque, NM
Like all projects & tinkerers, yes I've done some work, but I haven't finished it. And of course since you asked the question then I'm not currently working on it, nor do I have access to my notes at this time. 
That being said though, I found some interesting results that I remember off the top of my head.
First was that I found a couple sources of information on the internet, and drug up tech manuals that had block diagrams, wiring pin outs, etc. And sadly none of them really agreed. What turned out to be most correct was a pinout/block diagram of the LS671 internals that I found in a tech manual. In the end, I traced everything and experimented with it on my own to validate the results. I never cracked open the unit, but what I observed matched the block diagram I was seeing.
The unit certainly runs best on 24V. It will run on 12V but it won't drive the speaker as hard compared to 24V. I didn't characterize the reduction in power however. I could have given the fact that the raw speaker pins are brought out to the main connector. I'm guessing there is probably a point between 12V and 24V where the loss starts to occur, which probably matches up to how they built their voltage regulators inside.
The volume knob/mute switch adjusts the volume on both the speaker and handset. When I first looked at the block diagram it looked like they might be independent which I thought would be cool. However, they are tied together. As it turns out though, they setup the gains correctly so that its works nicely switching from handset to ears only. The LS671 internal circuits also handles cutting off the radio feed back when you transmit so the speaker doesn't create a feed back loop. Note: this feed back is produced by Military radios as an indication that the radio is transmitting.
The main connector( J1 ) provides alot of nice signals. It appears that it observes some sort of "line level" behavior. However I recall that its version of Line level doesn't match up with the modern definition of Audio gear. It seamed to be alittle larger, maybe +-2V instead of the +-1V of modern gear. These results along with the block diagram indicate that there are active components inside the unit. The handset for instance uses a dynamic mic which only puts out something like +-10mV, yet the audio from J1 is +-2V.
I used both an Oscope and Signal generator to do some testing on my unit. Everything looks clean and sounds good. I did this sort of testing since I got my surplus and it was shipped AS-IS, UNTESTED. As it turns out I got lucky and the unit appears to be fully operational.
I made an adapter cable that would go from J1 to the DB9 pinout commonly used in ham radio for TNCs. With this I then used my existing TNC cables to connect the LS671 directly to a couple radios. I tested against the PRC119, a TMV7A, and an older Kenwood HT. For the quick test I was doing I simply used a POT to correct the voltage levels going in each direction. All of the radios gave me the same results. RX Audio( Speaker ) came through but there was always the same background tone in the audio. I never did debug it further. I did order some 600:600 transformers to insert some isolation to see if that was the problem, but they still sit on my work bench unopened. TX Audio worked fine. This is where I really had to knock down the voltage levels and insert a DC blocking cap. TX audio was shoved through a standard H250 handset and my voice. My lovely assistant and I took turns on each end of the radio link and the audio sounded fine.
I did find a document some where( I can't remember which one ) that did say that the J1 interfaces were all 600ohm busses.
I did try and test fit the LS671 in my daily driver and its a tad bigger than I was expecting... or perhaps my daily driver was a tad smaller than I thought. So I'm still working out how I want to mount the unit.
In another experiment I got a hold of some LS454 NOS speakers. After tweaking their U229 plug so that it'd work on the PRC119 directly I was surprised to see that the unamplified LS454 sounded just as loud as the LS671. Its not truly a fair comparison, just an interesting observation.
So that's where I stand. I still see the speaker sitting on my work bench and want to pursue the project further, but life gets in the way. Remaining items would be tracking down the background tone I'm seeing and then building a proper interface unit. At minimum I'm going to have to build a circuit that will adapt the various voltage levels between what my radios produce and what the LS671 expect. At the higher end... this adapting may happen in a larger multi radio system or intercom system. Though to be fair and realistic, I'll probably build the minimum at first to work out the bugs and then build something bigger.
A final note on how these units where originally used. The LS671 was always driven by the mounting plate/structure for the SINGARS radios when installed in vehicles. This was done for a couple reasons. 1, the switch on the LS671 controls the main power distribution within the vehicle mount. 2, most installs were in smaller vehicles that didn't have intercoms, as such the LS671 was the main interface to the radio system. It was also common to have a long cable on the LS671 so it could be removed from the vehicle and used at a remote location. This is actually the most common use I've seen for it. This being said... there will always be some sort of adapter/middle man component between the LS671 and radios when you're trying to use it in a custom application.
That being said though, I found some interesting results that I remember off the top of my head.
First was that I found a couple sources of information on the internet, and drug up tech manuals that had block diagrams, wiring pin outs, etc. And sadly none of them really agreed. What turned out to be most correct was a pinout/block diagram of the LS671 internals that I found in a tech manual. In the end, I traced everything and experimented with it on my own to validate the results. I never cracked open the unit, but what I observed matched the block diagram I was seeing.
The unit certainly runs best on 24V. It will run on 12V but it won't drive the speaker as hard compared to 24V. I didn't characterize the reduction in power however. I could have given the fact that the raw speaker pins are brought out to the main connector. I'm guessing there is probably a point between 12V and 24V where the loss starts to occur, which probably matches up to how they built their voltage regulators inside.
The volume knob/mute switch adjusts the volume on both the speaker and handset. When I first looked at the block diagram it looked like they might be independent which I thought would be cool. However, they are tied together. As it turns out though, they setup the gains correctly so that its works nicely switching from handset to ears only. The LS671 internal circuits also handles cutting off the radio feed back when you transmit so the speaker doesn't create a feed back loop. Note: this feed back is produced by Military radios as an indication that the radio is transmitting.
The main connector( J1 ) provides alot of nice signals. It appears that it observes some sort of "line level" behavior. However I recall that its version of Line level doesn't match up with the modern definition of Audio gear. It seamed to be alittle larger, maybe +-2V instead of the +-1V of modern gear. These results along with the block diagram indicate that there are active components inside the unit. The handset for instance uses a dynamic mic which only puts out something like +-10mV, yet the audio from J1 is +-2V.
I used both an Oscope and Signal generator to do some testing on my unit. Everything looks clean and sounds good. I did this sort of testing since I got my surplus and it was shipped AS-IS, UNTESTED. As it turns out I got lucky and the unit appears to be fully operational.
I made an adapter cable that would go from J1 to the DB9 pinout commonly used in ham radio for TNCs. With this I then used my existing TNC cables to connect the LS671 directly to a couple radios. I tested against the PRC119, a TMV7A, and an older Kenwood HT. For the quick test I was doing I simply used a POT to correct the voltage levels going in each direction. All of the radios gave me the same results. RX Audio( Speaker ) came through but there was always the same background tone in the audio. I never did debug it further. I did order some 600:600 transformers to insert some isolation to see if that was the problem, but they still sit on my work bench unopened. TX Audio worked fine. This is where I really had to knock down the voltage levels and insert a DC blocking cap. TX audio was shoved through a standard H250 handset and my voice. My lovely assistant and I took turns on each end of the radio link and the audio sounded fine.
I did find a document some where( I can't remember which one ) that did say that the J1 interfaces were all 600ohm busses.
I did try and test fit the LS671 in my daily driver and its a tad bigger than I was expecting... or perhaps my daily driver was a tad smaller than I thought. So I'm still working out how I want to mount the unit.
In another experiment I got a hold of some LS454 NOS speakers. After tweaking their U229 plug so that it'd work on the PRC119 directly I was surprised to see that the unamplified LS454 sounded just as loud as the LS671. Its not truly a fair comparison, just an interesting observation.
So that's where I stand. I still see the speaker sitting on my work bench and want to pursue the project further, but life gets in the way. Remaining items would be tracking down the background tone I'm seeing and then building a proper interface unit. At minimum I'm going to have to build a circuit that will adapt the various voltage levels between what my radios produce and what the LS671 expect. At the higher end... this adapting may happen in a larger multi radio system or intercom system. Though to be fair and realistic, I'll probably build the minimum at first to work out the bugs and then build something bigger.
A final note on how these units where originally used. The LS671 was always driven by the mounting plate/structure for the SINGARS radios when installed in vehicles. This was done for a couple reasons. 1, the switch on the LS671 controls the main power distribution within the vehicle mount. 2, most installs were in smaller vehicles that didn't have intercoms, as such the LS671 was the main interface to the radio system. It was also common to have a long cable on the LS671 so it could be removed from the vehicle and used at a remote location. This is actually the most common use I've seen for it. This being said... there will always be some sort of adapter/middle man component between the LS671 and radios when you're trying to use it in a custom application.
Wow, this thread is amazing! I'm just reading it for the first time today and I must say, the two of you are going above and beyond!!
I'm now the proud owner of a M10-Oh'9 with, sadly empty radio trays. I'm in the process of purchasing an R-442 from a SS member and will follow this shortly with an RT-524. Then a VIC-1, CB and some sort of other 2-30MHz mil set up.
There are many fine choices in the frequency range, all of them not cheap, so I'm a little afraid of jumping in. (PRC 350, 351, 352 GRC106, SE-170, etc and VRC-176A my current favorite). I've only had my HAM license for about 2 years and have really only been on the club repeater. Any suggestions for this radio would be appreciated!
I'll be watching this thread!!opcorn:
Thanks and know youre work is appreciated by others!!
73
I'm now the proud owner of a M10-Oh'9 with, sadly empty radio trays. I'm in the process of purchasing an R-442 from a SS member and will follow this shortly with an RT-524. Then a VIC-1, CB and some sort of other 2-30MHz mil set up.
There are many fine choices in the frequency range, all of them not cheap, so I'm a little afraid of jumping in. (PRC 350, 351, 352 GRC106, SE-170, etc and VRC-176A my current favorite). I've only had my HAM license for about 2 years and have really only been on the club repeater. Any suggestions for this radio would be appreciated!
I'll be watching this thread!!
opcorn:Thanks and know youre work is appreciated by others!!
73
serial14
Member
- 104
- 13
- 18
- Location
- Albuquerque, NM
762Luver,
Congrats on the project truck and the future radios.
On the HAM radio side of things do you just have a tech license or do you have something higher. If you want to talk in the 2-30MHz range you'll need a general class or higher.
I my self have a pile of ham radios that I play with, a PRC77 and a PRC119. I don't yet have a military radio that does the 2-30MHz range and keep looking for something that catches my eye. Instead I generally turn to my Yaesu FT897 which is an All band all mode radio. Its been a pretty nice goto radio for anything mobile, remote, etc. Antenna wise, I do have a AT1011 setup that is really impressive. I got the antenna its self at a ham fest and the base I got from Murphy's Surplus. The base I got is one of the slick Harris ones that can lock stationary or be unlocked.
The main problem I see with military HF sets is that they are channelized, meaning you can't freely tune them up and down the bands with what ever resolution you like. Instead you have to turn channel knobs or enter freqs through a key pad. This kind of makes finding contacts on the HF ham bands difficult since most people just tune around till they find a clear spot to call CQ or find somebody to answer their CQ/QRZ. Unless you happen to get lucky or prearrange things, it seems like a more difficult operation with the military gear.
Then again, I do know that there are established freqs in the HF band for 'green radios' which line up to the military channelization so that can offset the problems if you're looking to chat with fellow collectors.
I haven't done too much yet with my AT1011, but when I have used it its been great and has alot of potential for ground path and 1 hop contacts as well as NVIS contacts. I frequently will make contacts in the 0 to 500 mile range while out in nature. When life settles down for me and a couple friends we'll probably try and get more into the NVIS side of things which the military does quite a bit with. Its a pretty interesting mode that has excellent performance in the mobile HF environment.
What I do highly recommend is that you have some sort of VHF/UHF/FRS/GMRS capability. Nothing beats it for crystal clear comms when you're in a convoy or working over line of sight ranges. Its also especially useful if you have access to a repeater with auto patch functionality in your area.
I guess the best advice is to simply have fun, explore, and see what works best for you.
Congrats on the project truck and the future radios.
On the HAM radio side of things do you just have a tech license or do you have something higher. If you want to talk in the 2-30MHz range you'll need a general class or higher.
I my self have a pile of ham radios that I play with, a PRC77 and a PRC119. I don't yet have a military radio that does the 2-30MHz range and keep looking for something that catches my eye. Instead I generally turn to my Yaesu FT897 which is an All band all mode radio. Its been a pretty nice goto radio for anything mobile, remote, etc. Antenna wise, I do have a AT1011 setup that is really impressive. I got the antenna its self at a ham fest and the base I got from Murphy's Surplus. The base I got is one of the slick Harris ones that can lock stationary or be unlocked.
The main problem I see with military HF sets is that they are channelized, meaning you can't freely tune them up and down the bands with what ever resolution you like. Instead you have to turn channel knobs or enter freqs through a key pad. This kind of makes finding contacts on the HF ham bands difficult since most people just tune around till they find a clear spot to call CQ or find somebody to answer their CQ/QRZ. Unless you happen to get lucky or prearrange things, it seems like a more difficult operation with the military gear.
Then again, I do know that there are established freqs in the HF band for 'green radios' which line up to the military channelization so that can offset the problems if you're looking to chat with fellow collectors.
I haven't done too much yet with my AT1011, but when I have used it its been great and has alot of potential for ground path and 1 hop contacts as well as NVIS contacts. I frequently will make contacts in the 0 to 500 mile range while out in nature. When life settles down for me and a couple friends we'll probably try and get more into the NVIS side of things which the military does quite a bit with. Its a pretty interesting mode that has excellent performance in the mobile HF environment.
What I do highly recommend is that you have some sort of VHF/UHF/FRS/GMRS capability. Nothing beats it for crystal clear comms when you're in a convoy or working over line of sight ranges. Its also especially useful if you have access to a repeater with auto patch functionality in your area.
I guess the best advice is to simply have fun, explore, and see what works best for you.
deuceaid
Banned
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- Location
- Yucaipa CA
subscribed
Thanks for the feedback!!Wow, this thread is amazing! I'm just reading it for the first time today and I must say, the two of you are going above and beyond!!
I'm now the proud owner of a M10-Oh'9 with, sadly empty radio trays. I'm in the process of purchasing an R-442 from a SS member and will follow this shortly with an RT-524. Then a VIC-1, CB and some sort of other 2-30MHz mil set up.
There are many fine choices in the frequency range, all of them not cheap, so I'm a little afraid of jumping in. (PRC 350, 351, 352 GRC106, SE-170, etc and VRC-176A my current favorite). I've only had my HAM license for about 2 years and have really only been on the club repeater. Any suggestions for this radio would be appreciated!
I'll be watching this thread!!
Thanks and know youre work is appreciated by others!!
73
I will say that you *need* to have at least a Family Radio Service (FRS) radio in there. (as i see a later post has mentioned) even the handheld (which are the only legal FRS radios, although many people will dial in the freq on a general 440 rig) are capable of working fine with the intercom.. I recently built a cable to connect the VIC-1 C-Radio to the handhelds Headset/Mic jack and velcro'd the radio to the windshield.. (for clearer line of sight) one guy put his on the roof outside the truck..
anyway the point is, not all are hams, not all have (good enough) military gear on convoy, and you need comms that *work* not that just look coolAn RT-524 will go under that seat, but be aware that most of this military gear is wide banded compared to ham gear, that is it uses about 2x the deviation, and hams will complain about your signal, although its perfectly readable. the newer SINCGARS gear is more compatible with the deviation used by current ham gear. Most of the Military gear is simplex, so repeaters are out, although i often will put the R442 on the output and tx with the RT-524 to the input. Again though the deviation is an issue, as the pass band of most repeaters is so narrow that your signal wont be strong enough to key it... thats if there is no PL tone. If there is, your out of luck..
What i did was to buy a lot of old business band radios, and program them up to the FRS / GMRS (I have a GMRS license also ) and another that has the common ham stuff.. this has lots of advantages...
1) Ham gear is expensive, and army trucks have no locks, no-one wants to steal these
2) Ham gear is not durable (unless you get millspec, but see #1 above) ive destroyed by share of ham gear
3) Used surplus Commerical gear is cheap, and easy to replace.
4) you can hard mount this stuff, and keep the ham gear for your regular car (bmw, porsche, mercedes)
I bought a *box* of EF johnson Challenger radios for 10 bucks... there were 25 radios, ive burned up 4, parted 2, had one stolen (ok i know i said #1, but crackheads will steal anything), i have plenty and i carry hot spares..
just my
...
ke6rwj,
I followed the link you provided. Basically it is this:
I followed the link you provided. Basically it is this:
Code:
Properly interfacing this speaker into 12volt radio, will require the use of an isolation circuit to prevent the 24volt system from harming the 12volt radios. example interfaces can be seen in [URL="http://www.radionerds.com/index.php/Integrating_with_other_equipment"] integrating with other equipment[/URL]
Below is a simple diagram to hook up receive audio only to server as an external speaker. Note the use of the transformer to isolate the 24volt speaker from the 12volt audio source.
If you choose to use 12Volt for the power to the speaker the transformer is not required
[COLOR=SandyBrown]THIS NEEDS TO BE UPDATED, THE POWER HOOKUP IS ON THE WRONG PIN [/COLOR]
[ATTACH]312498._xfImport[/ATTACH]
I wanted to try modding the cable to affect only the pins/wires below... if this will work. What do you think? Again this is receive only for a 12v CB or Scanner.
SORRY about the extra floating line in the drawing.
[ATTACH]312499._xfImport[/ATTACH]ke6rwj,
Thanks for the help. I'll go ahead and doctor up a cable to fit the other end of the CX-13292/VRC cable (I'd like the speaker to have an authentic look even though it terminates to only a VHF scanner).
Can you verify what I can use for the +12volt/-12volt inputs. I was going to just ground the 12volt(-) to chassis but under the dash. The 12volt (+) was going to run from the AUX Fuse Block that I added- it's HOT in Key "ACC" position. Would this be ok?
ps. thanks for the heads-up on your open WIKI; but as you can tell, my electronics knowledge is basic, and I hate to post anything that might get someone's components fried
.
Thanks for the help. I'll go ahead and doctor up a cable to fit the other end of the CX-13292/VRC cable (I'd like the speaker to have an authentic look even though it terminates to only a VHF scanner).
Can you verify what I can use for the +12volt/-12volt inputs. I was going to just ground the 12volt(-) to chassis but under the dash. The 12volt (+) was going to run from the AUX Fuse Block that I added- it's HOT in Key "ACC" position. Would this be ok?
ps. thanks for the heads-up on your open WIKI; but as you can tell, my electronics knowledge is basic, and I hate to post anything that might get someone's components fried
.yea thats fine.. you might get some engine hum, but thats a larger issue...
there is no basic criteria to participate in a wiki, your observations are enough, and as far as frying someones stuff, i would say they need to learn to filter themselves.. reader beware regardless where it comes from..ps. thanks for the heads-up on your open WIKI; but as you can tell, my electronics knowledge is basic, and I hate to post anything that might get someone's components fried
BIG UPDATE! Prototype boards for the any radio to VIC1 Interface
Hey all, wanted to give an update to my progress on this project.
if you recall im integrating the VIC1 with regular civilian radio for both transmit and receive via the VIC1 headset.. with a clean and clear signal..
I designed some printed circuit boards for this interface and they are ready!
Sneak Peek!
View attachment 317898
the two boards on the bottom are the interfaces to the radios.
the top white plug goes to the vic1 and the bottom red one to the civi radio..
now the very top board is a link board to allow you to run multiple radios into one vic1.
more details on this on my wiki at
Integrating with other equipment - RadioNerds
to the moderator, if you dont like the link outside, feel free to delete it, but this is such an edge topic i didnt want to hyjack your forum...
Hey all, wanted to give an update to my progress on this project.
if you recall im integrating the VIC1 with regular civilian radio for both transmit and receive via the VIC1 headset.. with a clean and clear signal..
I designed some printed circuit boards for this interface and they are ready!
Sneak Peek!
View attachment 317898
the two boards on the bottom are the interfaces to the radios.
the top white plug goes to the vic1 and the bottom red one to the civi radio..
now the very top board is a link board to allow you to run multiple radios into one vic1.
more details on this on my wiki at
Integrating with other equipment - RadioNerds
to the moderator, if you dont like the link outside, feel free to delete it, but this is such an edge topic i didnt want to hyjack your forum...
I went thru the schematic and built a test cable. Sorry to say this will not work.
I am supplying the 12volts to the A/B and trying to get the speaker to work per the second diagram. No good. I have tried other combination; but no speaker sounds. Perhaps only 24volts can be used.
I am supplying the 12volts to the A/B and trying to get the speaker to work per the second diagram. No good. I have tried other combination; but no speaker sounds. Perhaps only 24volts can be used.
I followed the link you provided. Basically it is this:
Code:
Properly interfacing this speaker into 12volt radio, will require the use of an isolation circuit to prevent the 24volt system from harming the 12volt radios. example interfaces can be seen in [URL="http://www.radionerds.com/index.php/Integrating_with_other_equipment"] integrating with other equipment[/URL]
Below is a simple diagram to hook up receive audio only to server as an external speaker. Note the use of the transformer to isolate the 24volt speaker from the 12volt audio source.
If you choose to use 12Volt for the power to the speaker the transformer is not required
[COLOR=SandyBrown]THIS NEEDS TO BE UPDATED, THE POWER HOOKUP IS ON THE WRONG PIN [/COLOR]
[URL="http://www.steelsoldiers.com/attachments/m37/312498d1330476658-vic-1-m37-ls-671_rx_only-orig.png"][IMG]http://www.steelsoldiers.com/attachments/m37/312498d1330476658t-vic-1-m37-ls-671_rx_only-orig.png[/IMG][/URL]:-(
I wanted to try modding the cable to affect only the pins/wires below... if this will work. What do you think? Again this is receive only for a 12v CB or Scanner.
SORRY about the extra floating line in the drawing.
[URL="http://www.steelsoldiers.com/attachments/m37/312499d1330476658-vic-1-m37-ls-671_2ndb.jpg"][IMG]http://www.steelsoldiers.com/attachments/m37/312499d1330476658t-vic-1-m37-ls-671_2ndb.jpg[/IMG][/URL][/INDENT]I re-drew the schematics for this, and confirmed that they worked..
there should be no issues...
LS-671 - RadioNerds
- 12Volt radio in a 24 volt vehicle (amplified)
- 12 volt radio in a 12 volt vehicle (amplified)
- any radio in any vehicle (unamplified)
there should be no issues...
LS-671 - RadioNerds
- 12Volt radio in a 24 volt vehicle (amplified)
- 12 volt radio in a 12 volt vehicle (amplified)
- any radio in any vehicle (unamplified)
i guess 1 amp i need to measure to be sure, but start with that...
serial14
Member
- 104
- 13
- 18
- Location
- Albuquerque, NM
When I was playing around with my LS-671 a while ago I also had a problem with a tone being on both the RX and TX audio. I haven't traced it down as much as I'd like, but I did try putting in isolation transformers and that DID NOT help. I was starting to think that there was something wrong with my LS671, but now that I've heard that other people have the same issue I wonder if there is simply an issue with the way we are talking to these things.
If you figure out the issue I'd be very curious to know the answer.
If you figure out the issue I'd be very curious to know the answer.
Yea i did some tests last night on that, i posted the basic diagram on my wiki, not a solution though.. it seems that the mute circuit isn't being activated, not sure if its due to low voltage (12 instead of 24) but i cant really test that just now.. ill have to integrate one of my isolation modules to do that.
but i noticed that even with the RX audio line disconnected it did the same thing. the only thing that stopped the feedback is disconnecting Pin S (TX Return line) from the setup, but that provided low audio with a noticeable "buzz".
It was noted that this outputs low tx audio no matter what, so it just maybe that the solution is to disco S, and fix the buzz..
if i find a solution ill post i here as well as the wiki.
BTW NM gives me flashbacks, went to school in Roswell... AAHHHHH!!!