saved from the dumpster - the hamfest started early for Derb

[N3DRB The Derb]

this military version of the NC 100 XA (I think) was headed towards the dump because the guy trying to sell it at the flea market (same one where I got the 10 buck speakers last week)  had hauled it out too many times.

I gave him 20 bucks to make sure it did'nt wind up in the dumpster. tuning is busted on it, caps dont move when you spin the knob and the main dial pointer dont move either.

This thing must weigh 65 pounds, and it's freaking huge. The coil rack feels good. There's no military nameplate on it anywhere, excepting a tiny USN number stamped on the chassis. Pretty obvious it's a mil radio because of the tropical treatment. Tunes 500 KC to 30 MC.

I could'nt let him throw it, but I dont think it's for me. It would make a great rx to go with a black crackle HB derb rig though. But it's SO BIG. 

I have the tabletop cabinet with it. Did I mention it's freakin heavy? 

Anyone know what the Military nomenclature is for it? 

[w4bfs]

hi Tim ... glad about the good medico news ... I have the lf version of this guy ...its also very heavy ... next time I'm in the shop will look to see iffin it has mil nomenclature ...73 ... John

[N3DRB The Derb]

oh yeah, notice how good the wiring is with the tropical treatment? Stuff really worked.

Transformer has some drippies underneath of it. Hard to know if thats bad. Other interesting thing - it has a 1950's plastic line cord on it and a modern clear plastic speaker cable attached to it.

hmmmmmmm. 

[Tom WA3KLR]

Derb,

Check out this page. Lists 10 versions of the RAO/NC-120, one must be yours :

http://oak.cats.ohiou.edu/~postr/bapix/NC120RAO.htm

[Tom WA3KLR]

You have the additional r.f. stage = RAO-7.

[N3DRB The Derb]

tnx Tom. based on what I see there, it's a RAO 7 or a RAO 9. It has the panadapter output , the slide out case, no s-meter, etc. Beast of a receiver.

yah, I think U R rite.

I got something else in th FEd EX box today too. Let me see about that.

[w3jn]

I've got some spare tuning gearboxes for those bad boys, if you need one.

[N3DRB The Derb]

it feels pretty solid. detents seem to engage OK. Wont really know until I hit it wit da juice. Damn thing is built like a tank and is just as heavy.

I got mixed feelings about it right now, but I had to save it from the goof that had it. No matter what, it will be better than going into the Frederick County VA landfill.

[K5UJ]

it feels pretty solid. detents seem to engage OK. Wont really know until I hit it wit da juice. Damn thing is built like a tank and is just as heavy.

I got mixed feelings about it right now, but I had to save it from the harley riding maggot that had it. No matter what, it will be better than going into the Frederick County VA landfill.

no doubt about that.  I think the best way to deal with the weight is keep it off a table and put it in a heavy duty rack but then ur into even more $$ unless you already have one with space.  speaking of racks and such, did you see the thing on the ARRL webpage by this guy who built up a hb pair of 3-500 amp and seemed to do it right with no wimpy plate supply, whisper cooling and all that?  I'll see if I can find the url....oh ya here it is:  http://www.arrl.org/news/features/2009/06/12/10881/?nc=1
i think you will enjoy looking at it derb 73
rob / k5uj

[N3DRB The Derb]

I know exactly how he feels. 

[K5UJ]

I know exactly how he feels. 

you mean about the wimpyness of commercial gear?

[w3jn]

That's actually a pretty decent receiver.  Too bad it's the version without a guess meter.  Also it doesn't have the shove yank audio like the civilian NC-100.

Beware the power tranny.  They're prone to going bad, 'specially on 125V.  Recap is the watchword here.  Well worth the effort to resurrect it.

Those metal escutcheons are riveted on.  Drill out the rivets, pull 'em off, and you can repaint the cabinet and polish up/repaint the escutcheons.  Makes it look like new!

Those gearboxes are planetary... chances are the grease is all coagulated.  Douche it with WD-40 and re-grease with some of that teflon-based grease from Radio Shack.  You can spin the knob end to end when it's all lubed up.

[N3DRB The Derb]

any clues on the busted tuning? broken shaft coupler? it was dropped on its face at some point, the left rack handle is bowed in slightly in the middle. I'm betting that was it.

[WQ9E]

Tim,

Well worth saving.  I have one (RAO-7) produced by Wells Gardner of Chicago but using all National branded components.  It has been too long since I went through mine to guess at the gearbox problem but a physical exam will probably make the problem obvious.  Re-capping is pretty easy since the sliding coil catacomb slides out of your way to access the various caps.  The power supply caps are probably oil type and won't need replacing; take a look and see.

Warning, these moving coil catacomb receivers become addictive!  My RAO-7 came as a freebie with an HRO-60 I bought several years ago and since then I have added a pair of NC-100X, an NC-101X, and a couple of NC-240D along with a Pierson KP-81 which borrowed the moving coil catacomb idea from National.  You will want to lubricate the front gear rack on the coil to keep it sliding smoothly.  The rear slides on a pair of bushings and these sometimes disintegrate; I was fortunate to find someone who made me a couple for one of my NC-100's.  You can probably find a substitute and it would probably work OK without them.  The other thing you might need to adjust are the toggle switches controlled by the power/ receive-standby switch.  Sometimes they refuse to switch and they may just need their position adjusted slightly.  It is difficult to describe but you will see what I mean when you look at them behind the front panel. 

Once you get this one going keep an eye out for an NC-240D.  One of the neatest receivers made by National and features band switched general coverage and band spread ranges; it also has a very nice push/pull 6V6 output stage for plenty of audio.  And then you need an NC-101X; it covers only the ham bands from 160 thru 10 meters (no 15 meters of course).  It is probably the only ham band only receiver made complete with push-pull 6F6 output stage-perfect for listening to the ole buzzards in hi fi.

Rodger WQ9E

[Opcom]

its cousin?  from ham-com yesterday. Very much alike -- by Wells Gardner

detail image here:

http://www.bunkerofdoom.com/hamcom/2009/tailgate/index0013.html

Derb, if you don't want it..