5-pin adapter for EF Johnson 5100 series (PRC-127A EFJ)

So yesterday I went ahead and made an adapter for the EF Johnson 5100 series (aka the PRC-127A EFJ) to be able to use 5/6 pin .mil connectors, such as my Liberator 2’s, H-250’s, and an old school single ear headset I can’t find any info on, but it’s all over ebay. Davies Selex summin such or other, so on and so forth. Best I’ve found is this:


It works, the U-94 PTT switch that came with it doesn’t like this thing, but it sorta works for the Lib2 headset. However, this thing works with the PTT that came with the Lib2. And a bigger bonus, It fits under my 3/4 motorcycle helmet with face shield! Now I just have to test it at highway speed to see how it does. Surprisingly, it’s pretty comfortable.

Now, as I was testing, things weren’t always reliable. I figured it was due to the length of wire (near full length of speaker mic’s wire + connector wire + full length head/handsets). That explains why the H-250 wouldn’t reliably key up(now it does). So, without further ado, here is the writeup!



I started with the speaker mic(I had 2, now just 1), and took the back off. It used a T-10 torx for the 4 corner screws, and a T-6 torx for the 2 inner screws holding down the circuit board.


Now, the circuit board isn’t too hard to read. But, I’ve done most of the hard part already. I traced it out, checked the continuity to what I needed, and wrote what color goes to what. Seems to work good.



Now, this cable goes to a PLGR/DAGR to fill comsec. What is nice about it is that it has the end we need on it to go to the various handsets/headsets I want to use. What’s even nicer is that even though I couldn’t check pinout with the plug on(kinda like a serial plug), after taking a risk and snipping the end, it had all the wires I needed, and then some. Plus some insane braided shielding. I would assume to help prevent leakage of comsec being transferred. Yes, you can pick up data running through lines. Voltage detection without having contact with wires. I would guess that is why data can jump from different Cat5 lines to other ones(from what I’ve been told).


Here is the jig I made to test various connections in my attempts to get it working right. Just some nails in a 2×4 and pieces of individual wires from Cat5 I had laying around to connect them. Alligator clips would work better.



Forgot to snap some pictures, but the gist is there. And yeah, my soldering skills are horrible. But some twist and solder action and some heat shrink over each set, and then bigger heat shrink and there we go.

So finding the pinout for the U-238 connector(.mil 5 pin) or 6 pin connector is pretty simple. A couple good sites out there. Both Cryptomuseum and prc68 have good pages:



NOTE: I am not affiliated to either. Just putting up what I used for reference.



Here is the pinout, in case there is any issues with the pictures I wrote it out below. The way I numbered them is probably different than how EFJ or anyone else does. Top down, odds on right, evens on left:

1 – Black – Ground

2 – Yellow/Red – Speaker

3 – White – Mic

5 – Brown – PTT

6 – Yellow/Red – Speaker

8 – Black – Ground

The pinout for the crypto cable is pretty simple:

A – Black – Ground

B – Dark Beige – Speaker

C – Red – PTT

D – Light Beige – Mic

E – Yellow – NOT USED

F – ??? – NOT USED

For some reason, the F pin isn’t connected to the last remaining wire…which I find odd. However, I don’t need it, so it’s a moot point. The connections go as follows:

Crypto Cable —-> Side Port Cable

Black                      Black

Dark Beige             Yellow (I had better luck with yellow than red)

Red                        Brown

Light Beige             White

And there you have it. Not sure what else this would work with, though I’ve read something about this particular variant of EFJ being compatible with a multitude of Motorola stuff, Jedi series from what it said. I dunno, don’t have a Motorola. Though I do have the wideband VHF antenna (136-174Mhz) on this thing, and it works nice.

I will try to edit a video I took during initial wire testing and upload it somewhere (probably the youtubes) so you can see it actually works before you hack up a speaker mic or other accessory.

Now, you may ask why I would want to do this. Or probably not. Either way, I like modularity and the ability to use the same things on multiple systems. As well as battlefield acquisitions. And standardization of stuff(like ammo). So, why not be able to use my Lib2’s? I like em, they work well, and they enhance normal sounds to make hearing things easier. It’s a win/win for me. My original plan when I got them a few years ago was to make a new PTT for my Yaesu, so I could just plug it in and go. Then I thought recently(probably after seeing someone’s youtube video about rewiring a H-250 for their Yaesu) why not just wire in the 5/6 pin plug on the radio to use any type of headset/handset? And there we have it.

I hope that this writeup helps you guys/gals out. I know this isn’t a really common radio to have around, but with my limited google-fu, I haven’t been able to find much other than aftermarket and OEM stuff to go with it, at a stupid high price. Don’t know about you guys, but I ain’t got that kind of money. Maybe next time I’ll have the adapter done for the 857D.


Hustler 5 BTV

So I got the 5BTV working. Not in the most optimal place, mainly due to lack of length on feed line, as well as where I can put it. It sits a little too close to the power line coming into the house, but I have it guyed pretty well so I shouldn’t have to worry about it.

So here’s how it all went down. Pulled out the antenna and the original mounting poles(galvanized pipe). In order to break it down, we(the guy I got it from and myself) had to cut through the coupler. That left 3 more manageable poles(the reducer came out easy). So I had to take the dremel and cut the coupler off.


2 cuts, ~180 degrees from each other and a little hammering made this come off. Did it twice to get each side of this former coupler.

So I managed to get that done, but the new coupler didn’t quite fit…


So I cut a slit in both pipes at ~90 degrees each(4 per pipe) and cranked it down. It works.

So, after that mess is done, I take a 2×4 block ad hammer the smaller pipe with the reducer into the ground using my 2.5lb cross peen. Sometimes I do it without the block, but then I notice deformation of the reducer. Not good. After that’s in I attach the pipe to the reducer and go back in. Help HH6 to bed and go to bed myself. At this point it’s like midnight local time.

The next day I put the antenna together, tighten everything down, and lean the thing against the roof. I used some 550 cord I had on some old 5 ft PVC sections to use as a small mast for guy lines(they were too short, but I made it work). I climb on the roof, pull it up, and put it in it’s spot.

But now, it doesn’t seat….So I stop, I bake in the sun, and then it hit me. I forgot to take the screw out of the bottom. So I pull it out, then pull the screw. Putting it back into the mount the second time was a little harder than the first. A slightly higher wind was hampering my efforts to not drop the thing and take out my house power. But I got it, and since I didn’t have the right size bolts to bolt the antenna to the mount, I just took and cut 3 strands of tie wire(about 2ft each), folded it in quarters, then used some vise grips and channel locks to twist them. So I used those instead of bolts. Just ran it through and twisted them. So far so good. Nice and solid.

Then got the feed line connected.

So the feed line….you take your coax, cut one end off, and crimp some connectors to them so you can use screws to attach to the antenna. Luckily I had one that had this done already. So I used that. Connect one end to the bottom of the antenna, and the other to the mount, and there you have it. Now, the manual says that you need some ground radials. I don’t have the room, especially for a pair of 32 ft radials that it said it needed for the 40m band.

However, SWR is about 1.2-2ish on each band it covers, and doesn’t get higher than 3 on the extreme. Totally acceptable performance.

Tomorrow I will try to have a few more pics up. Until then, have fun with this:


So, this is the VDET, the Video Display Electronic Terminal (Formerly known as the VDT – Video Display Terminal, and they both looked the same to me). My guess is that the onboard computer overheated(I’ve never seen that before, because our Strykers in Iraq and Afghanistan got waaaay hotter than these did). So yeah, Strykers run Winblows. My desktop does too, only because the hard drive with linux on it keeps overheating and corrupting the OS partition on it…

So yeah, figured someone would get a kick out of it.

So yeah, about that…

So I’ve been offline for the most part the last bit of time, dealing with other projects, work related stuff(I hate being in a S6 shop), and dealing with a broken heart(my first line talked the SIGO out of sending me down to the line as a rep. Told me this as we were starting PT. Talk about killing motivation).

Also managed to get ahold of some goodies. Such as a little gem of an HT. I will try to do a writeup on it this weekend. Got that BTV put up, sorta. Still working the kinks out(needs some tuning BAD. but trying to take it down to tune is scary. However, it might just be a craptacular connection and I may have to find a work around. Would suck if I broke it.

Found some more goodies so instead of wiring the H250 to the radio, I’ll just make a plugin for the radio so I can use my Liberator 2’s with it as well(good for nanpack setup, or TOC setup if I really need to hear it over background noise.

Just got done typing a response to someone’s question about Thermals vs. NODs on Dan Morgan’s blog. Waiting on him to see it and tell me I’m stupid(doubt it, but if he does I completely understand and will take my beating like a man). So now I’m trying to figure out how to set the interwebs ablaze with a Thermal vs. NOD debate(like the AR vs AK debate, or 9mm/40/45 debate), and if it’s even worth it to try(Really, I think it’s pointless. So probably not). However, maybe I’ll some day write an article on my experiences with them. Who knows.

So I guess it’s time to appease HH6, she thinks I have to work tomorrow and it’s after midnight local. Little does she know I not only don’t have to be up in 4 hours, I have a 3 day this weekend. “Training Holiday”. It’s kinda like snow days at school. Sorta. Ok, not really.

Please excuse my ramblings.

Postscript: Oh snap, I still owe yall a writeup on the soundcard cable. I’ll try to get that done and out soon(tm) too.

Back on the interwebs, and other tidbits.

So, instead of going through the attic(Reminded me of Kuwait…yuck), and rerouting a Cat5 cable I had routed in the winter from the previous location of the modem and my desktop to my TOC(aka my garage), and the new location of the modem, I had a stroke of genius(well, HH6 did) and decided to pull the wifi card out of her old broke laptop and put it in mine. After booting and it telling me that it was incompatible(BIOS, so retarded sometimes), Lubuntu booted up and told me wifi networks were available. Yay! So here I am.

Fleas. Been fighting those awhile now. Apparently all the rain has made them hit everyone around pretty hard. HUMINT collected from the dog groomer and an exterminator shows that it’s pretty bad. Like, dog gets professionally flea dipped, then we put a couple different flea killing chemicals and apparatus’ on him, and he’s still getting mauled. Like that exterminator just got done with a job that paid him 500 bucks over the course of a few weeks to get rid of fleas in someones house. Cheaper to keep fighting them myself. And yeah, he’s pretty booked. Talk about making bank. Honestly, fleas make me want to set a large wildfire off just to burn them out. Too bad I can’t get away with it.

So a couple of weeks ago HH6 and I went to go pick up a pig. Potbelly mix of some kind, he’s a big boy for a potbelly. Anyway, taking 2 vehicles so my wife’s van doesn’t have to smell like fresh pork. Not a bad deal considering her van brought home our initial 4 goats.Well, lets just say it took awhile to get the smell out of my car.

Anyway, onto the story. Yes, so we’re going down the roads, got some FRS/GMRS radio’s so we can keep in contact(still fresh from the tornadoes we had previously), and as we’re going through one of the city’s, my radio comes to like. Not sure what they were going on about, and wasn’t able to write down anything they were saying, all I know is that they were talking about some kind of model numbers. Not sure. Granted, we were near post, and could have been a soldier in the motorpool an another in an office, not sure. It was Saturday though, so I doubt it. Moral of the story, lots of radio waves to listen in on.

Got the bench grinder set up, an sharpening a hatchet is a PITA when you’ve got 2 grinding wheels on it. Gotta be careful about letting the handle get too close to the other one. Need to replace the coarser wheel with the wire wheel I bought at Harbor Freight awhile back. Now I just need to do one of the other million projects I want to get done. Fun fun.

More to come in the next few days when I actually get a few minutes from the honey-do’s and get to do some cool stuff.

Well now, this sucks…

So it seems that the wifi in my laptop has finally died. Now I have to run a line from the modem to my garage. Not looking forward to HH6’s reaction to that.

Booted to multiple known good distros of linux, both on my hard drive and live usb, and nothing. Kinda puts a damper on me doing anything on it. Cant even print without a network connection. One more thing to try to get done over the next couple of weeks. Between this and the boxes on my bike having an almost catastrophic failure (60mph with a zip tie and nail clippers being the only thing from the home brew hard bag setup from falling off), and by leave form not being at staff duty last night (in one of the s1 guys’ desk with a bunch of others apparently), the gremlins are really out to get me. Either that or a .gov conspiracy…. nah. Gremlins.

So with any luck HH6 wont have too many issues with me poking more holes in the ceiling.

The Digital Audio Cable

So, managed to get the digital audio cable built and tested out over the weekend. I can’t get it to reliably trigger the VOX, but I managed to figure out where to put it to keep the ALC from spiking, and everything looks good so far. Tore down the station to bring it with me to CQ duty on Friday. Here are some notes:

Originally intended to use one of those USB to PS2 adapters I had laying around in a box with random cables and computer stuff. Underneath the rubbery shell the wires are encased in a waxy, plasticy substance. Managed to pull the 6 pin portion off, but after messing with it realized that it wasn’t suitable for me to solder on(I am still learning how to do that, by the way).

So at one of the local thrift stores, I managed to snag for a whopping 50 cents an old microsoft ball mouse. Works like a champ. Well, after some snipping of some wire, and checking for which wire went where, I jotted it all down and cut my 6 ft mono cable in half(had that running from my rig to my aux in port in my car, had to use some ferrite chokes to cut down on the engine noise on the highway), and checked the wires on that. After that, just needed to solder it all together. And it’s a rough, but serviceable, solder job. After a few strips of electrical tape to help insulate the wires and some heat shrink tubing to seal it all up, it works. Not exactly awesomely or anything, but it works. For a mix of what I had on hand and 50 cents at a thrift store(which I need to go back on payday and snag the few sets of BDUs they have for cheap), I have a working cable.

Hopefully this week(or weekend) I can test it out and see how it does.

In other news, I hope everyone was able to stop for a moment and remember those who have served before, and what they sacrificed. HH6 had the idea of doing this paper garland with the names of soldiers, sailors, and airmen(where do the marines fit into this?) who have fought and died. I think the names she got went back to WW2 (She asked people on facebook for names and dates, plus some of my friends I’ve lost). When she brought up the idea, I thought it was awesome. Apparently so did some older vets she’s talked to. Teach the real meaning behind Memorial Day. I think we did ok.