The AM Forum

What can anyone tell me about this transmitter?

Found it covered in dirt and sawdust in the workshop of a SK yesterday. I was there to remove the 50 foot crank up tower, which I did.

I used to work on these transmitters when I worked for ARINC in the 60's.  They were used for HF air/ground communication.  I believe that we had them in groups of 4 RF decks that used a common power supply and modulator.  Do NOT trust the interlock on this transmsitter.

Ted, KC3OL
www.kc3ol.dynip.com

I used to have the RF cabinet for a 96C and believe it had a pair of 450TL's and rated at 2500 watts output. Inside the back portion of the cabinet on the rear bottom was the filament transformer and a blower.
Leo WA6MTZ

John, is this the single RF transmitter in a tall, narrow cabinet or the refrigerator-sized one with 4 separate RF decks? I have one of the latter stored atm but soon to hit the market. I believe they ran a 250TH smacked around by an 813. Supposedly able to transmit on 4 frequencies at once, has a telephone dial on the front panel and solid front door with a handle reminiscent of an old Frigidaire. 6+ feet tall, 3.5-4 feet across, easily weighs half a ton. As Ted mentioned, FAA and MIL ground stations IIRC, and while they don't look terribly user-friendly as far as tuning (more like a tune and forget set up), they are packed with excellent parts like large neutralizing caps, porcelain tube sockets, big iron, and a lot of tubes. Plently of interesting linkages inside, and the typical nice bank of meters across the top.

Keep in mind that this is the 4-deck version; the tall, skinny versions are probably a lot easier to adapt for ham use. I've only seen pictures of those, so I can't offer any real info. I'm sure they are built to the same standard though, and well-worth saving at least for parts rather than letting it get scrapped.

~ Todd  'KAQ

I hope this link might help.

http://members.aol.com/jcstott/chase/bw3rcn.html

Try sending an email to Skip, K7YOO. He owned one for awhile. Passed it to Robert W0VMC. I don't think they listen here.

I can't say weather the Wilcox Skip owned was exactly the same but he will be able to steer you in the right direction

Mike

OK The 96C photo shows a series of narrow RF units with meters at the top, beside the massive unit on the right which might be power supply/modulator. What I saw was one of the narrow units, in green trim. I'll bet the modulation transformer and the power choke are the ones that Bob Grinnell sells at $urplus $ales of Nebraska.

Thanks for the tips. I wonder if anyone can find a schematic?
73
John

I once parted out one of the modulators.  Looked like the one in the bottom photo.  It used a pair of 450TL's driven by a pair of 845's.  As I  recall the power supply was a separate unit.

The modulation transformer is an "autoformer".  That means it is one continuous winding, with a tap for +HV, two taps for modulator plates, and two taps for the modulated final (for a choice of two impedance ratios).  It is designed for using one common power supply  for modulator and final.  Separate power supplies could be used by incorporating a modulation reactor and coupling cap.

I used the autoformer as a modulation reactor until I found a real modulation reactor for my 304TL rig years ago.

John,

Here's a picture of the "internals" of the Wilcox 96D transmitter I had when I was in high school (c.1963).  While the quality of the photo is not the greatest, at least you'll have some idea as to what's inside the final of the beast. Still have the some of the iron from the power supplies and modulator- the rest of the transmitter is long gone.

Hope this helps.

Alan, W3BV

(http://img.villagephotos.com/p/2005-3/968590/Wilcox96DInternal2.jpg)

Thanks Alan and Don for your info. Yes, that looks like it. I will get back over there and pull the shrouds off sometime and peek inside to see whats left. Might be some useful BA parts at least.

I picked up this thing yesterday at SK's wood shed for $50. It had been sitting next to the ugly-painted BC610E, which recently went on EPAY.

The Wilcox 96D is < a foot wide, 6 feet tall, 300+ lb box. It "works in a drawer", in that it can be slid out on rails, for inspection inside. It was built in November of 1952. It has an RF exciter, crystal socket inside, and an 807 driving an 813 driving a PAIR of 450TLs. Only the 807 remained in the socket. Plate voltage on the final was 4100 and current was 0.6 - 0.9 Amps. It was a powerful transmitter in its day! The power supply was separate, and it isn't certain it made AM or not. Frequency range is ~ 2 - 12 MHz according to the dials. It has little doors which open to expose the turns counters for tuning, and one opens to get to the fuses and power relays. On top are a pair of balanced output studs. This funky looking transmitter (slim) needs the final plate tuning cap, but has most else.  It is loaded with some good parts, including the turns counter dials, two big slip stator caps, a can within a can neaturalizing cap. The PA inductor is tapped at numerous points, and has a second coil which can be slid into and out of the fixed inductor.

Now the dilema. Its certainly a different rig, but it needs to be tubed with pair of paralleled 450TLs and needs the cap along with a few small parts. Should I part it out, for something homebrew, like a balanced antenna Tuner? Or try and restore 'er? I'd be curious about others experience and opinions. BTW, I have three other transmitter projects needing my attention right now. I got the Wilcox out of the truck bed and plopped it out under a roof next to my shed this afternoon. Inside one of the front doors there is a complete parts list and schematic!

John, I believe I have the modulator deck out of one of these - pair 807s driving a pair of 813s.  The mod deck has all the filament xformers as well as low level audio.  I also have the front panel with the turns counters, etc.  They aren't too useful as most are right angle drive and you need the bevel gear that goes with them (which you probably have though).

Were it mine, I'd restore it.  Not too many of them around, and antenna tuner parts are easy to come by - but complete vintage xmitters like this are not.  It's yours, though, to do wish as you like  :)

73 John

John:

I agree with Johnny Novice....restore it, fer shure!  Like he said, you can always get antenna tuner
parts, but a rig like the one you have in that condition....you gotta do it!  Just hold on to it until you
finish the other projects.  I'm envious! 

73,
Ken

OK several hams have recommended that i NOT part out the Wilcox. Believe me, I have a hard time justifying destroying whats left of it, too. The XYL caught me unloading it yesterday with help from a neighbor, and said "Whats THAT?" "nothing really, just 400 bs of junk, i was going to strip out for parts and haul the carcass to the landfill.....". By the way, she is all for my idea to build an external 2 car garage out back, with area for my large junk. The shack can't hold anymore.

Anyway, it is a slim package, so it is easy to stash out under the roof next to the shed. I think it needs the following parts to make it play again: Pair 450TL or smaller that fit the Johnson 211 socket, (7.5 VAC @ 12 amp filament). Plate Choke, 813, one insulating linkage, one turns counter and spinner handle knob, and a vacuum variable 50-250 pF, probably 12-15 kV rating if it was to run high level AM. Oh, and a blower in the bottom. I thinik I could come up with most of this, but the tubes are gonna hurt$. Also, the turns counter and insulator might have to be cobbled in. Anyone who has such and would like to part with them, let me know and I will certainly be grateful.

Then it needs a HV power supply of 3000-4000 VDC, a medium HV (2 kV for 813) and a low HV (550 VDC or so) as well as a plate modulator with transformer.I believe that the Wilcox 813 modulator wasn't very big on fidelity, and I see the mod transformers at Bob Grinnells Suplus Sales of Nebraska. Probably better to find something out of a BC transmitter (6000-8000 ohms on the secondary). With a built in exciter module at the bottom, the 96D is almost a complete transmitter instead of just a PA. Of course it would need VFO too.







I see AES has them for $195 and one is on ebay right now. I suppose could run just one tube, and back off the plate voltage to get the same plate impedance for the output network.

To clear confusion between the Wilcox 96-200, the 99, and the various 96 models (A-D), here is a photo of the transmitter RF module that I have. AA9TT website has a photo, although he is a bit conservative on his estimate on the power rating.

http://www.aa9tt.com/Fun_Stuff/Amplifiers/Wilcox/wilcox.html

There was a place in a New Jersey armory that sold radio surplus equipment. For the longest time, they had the modulator, (813's driven by 807's) for sale and I believe the price was fairly resonable. I had the site bookmarked but it was in my old computer. Seems to me that it had something to do with a compass?? If someone know what site I'm talking about, post the URL and maybe they still have the mod deck for sale.

John, I'm happy to help you out with a turns counter and spinner knob - if I can find the panel I have, you can have the whole frigging thing.

73 John

Thanks John. I only need the PA tuning knob, counter, and shaft/linkage to the vacuum variable.
My panel is FB. Now if i can find some 450TLs... and a BIG power supply that runs on 220 single phase.

John

W3SLK, were you talking about CompassNJ? I see links to them online, but they are broke. Did they go out of business?

I wonder what sort of power output in AM the 96D would be capable of. Mine has some notation on the front panel for tuning for 0.6-0.9 amps of Ip, and the Ep was ~4 kV. That alone would lead to 2.4 kW of minimum DC input to the final. Based on that, wouldn't a pair of 813s in a modulator be a bit weak to get anywhere near 100%. I would think it needs something stronger like a pair of 450TL or 833s.

I am looking for a manual for the Wilcox 96D, I understand that there was a military copy for it. Anyone got anything on this? Thanks.

John said:
That sounds like it. I don't know if it was the matching modulator that they had but it was to a Wilcox and it was pretty stout. Now thinking about it, it may have been 4 813's. That would put in the ball park of your 450's. A memory is a terrible thing to waste on a mind.

The 813 modulator is for the 99 transmitter that used a similar concept of construction to the 96. The 99 had 4 decks with 250TL's modulated by a pair of triode connected 813's. There was even a LF deck that ran a 4-400 and a linear deck with 4CX1000 as well as a VHF deck. Each deck was about the size of a large computer tower. The 96 was similar except each of the 4 towers was a large floor model cabinet. The power supply modulator was a separate unit (3 phase only) and sported a pair of 450's to modulate the 450's in the individual RF decks. Typically  the power supply was set up so that any 3 decks could be on the air simultaneously. One on AM and the other 2 on RTTY or CW. The 99 transmitter was similar and had the option of 2 modulators so that 2 voice channels and 1 "data" channel could operate at the same time. A real relay & switching nightmare!!!!!
PART IT OUT

John,
       It may be tempting to scrap out the Wilcox for parts, but it sounds like all you really need for it are tubes and probably a few incidentals. I think they used plug in coils for the exciter, and I may have access to the coil data if you need it.

I'm not a purist or someone who is anal retentive about what other people do with their vintage rigs, but to bring it back to life and see it in operation would probably give you more joy and personal satisfaction that anything you could build from it's parts.

Man, it would STRAP with a Capital "S"!

The best of luck with whatever you decide.
                                                            Joe Cro N3IBX

It shall be restored, that is the decision. I now have two 450TLs via EPAY, and a vacuum capacitor the same way. I still need the PA tuning control/counter and linkage, will have to cobble that to my variable. A blower is needed, I can find that. And some cleaning up and checking for loose stuff. It had a wierd HV fuse that I will probably have to do without. Now for the docs and the power supply. Not having the power supply is probably a blessing, as it was 3phase and sounded to be a switching nightmare. The RF box is fairly simple, full exciter up to PA. If anywone has a manual for one I would be grateful for a copy. Also, i am now looking for a 4 kV 0.8 Amp power transformer, 1 phase! Thanks for the advice.

JOhn, I haven't had a chance to look for the front panel for that thing yet, when I find it I'll shoot it off to you.  I know generally where it is (that's the hazard of having too much crap).

73 John

Thanks John, that would be great to have the tuning knob/counter for plate, to finish resto of this amplifier. Whenever, let me know.
73
John L.

John, I found the front panel, it has all of the turns counters plus 2 drive mechanisms (final plate and another one that's a right angle job), knobs, switches, rheostats, etc.  I'll ship it out fedex ground today.

73 John

I received the TM for this thing yesterday from a very nice ham, it officially the T-158/FRT transmitter, and there is the PP-219A/FRT power supply and the MD-69A/FRT modulator cabinet. The power supply would power at least 3 of the RF decks simultaneously at 2.5 kW output each, so it weighs 1800 lbs! Quite the Maul. Yikes - no wonder people have parted out the T-158s in the past. The control circuits are very complex, having a telephone dial that is used to dial up different modes remotely. There are big telco style stepping relays that went along with that. I haven't lost my resolve but certainly this beast is going to have to wait for my new garage/workshop addition this summer. Just tracing out the circuit diagram to build a simple turnon/off control scheme looks to be nightmarish.

I received the spare front panel with the exact tuning counter, knob that i needed for the Wilcox 96D, Thanks John (W3JN)! Also got a big mutha vacuum variable cap to fit it with a bit of mechanical shaft work.