Gates BC-500T has followed me home

[K1HH]

Yup, I couldn't leave well enough alone, just the T-368 and me. I've been looking for a broadcast box close by, and sure enough, one appeared and it followed me home thanks to the efforts of KI4RUS, KC3CH, and W3HPW, who at one point was holding the entire weight of the box.

I've started cleanup and know there are others who have ventured down this path before.

Any advice on conversion to the ham bands would be appreciated. Looking to go to 160, 80, and maybe 40. Don't have room for a real 160 antenna, spend most of my AM time with the FL AM GROUP of 3675 and 3655.

This group gave me lots of good help with my T-368; I'm a willing listener again.

I first worked on a BC-1T in about 1964.

Thanks,

Rodger

K1HH

[DMOD]

Congrats!

I once worked on a BC-500T for a station in El Dorado, Ks. The Gates BC-500 is a hearty litlle critter requiring retubing only about every three to five years. It is capable of good modulation after an audio sweep to locate audio chain anamolies.

The only problems we had were due to some passive components in the Class-B modulator section and the blowers.

I would be glad to help you with your project via the internet or phone. A set of schematics to refresh my memory would help as well.

Phil - AC0OB

[Opcom]

Please post some pictures inside and out!

[WBear2GCR]

Ya... musta been kinda scary, like a bizzare horror/sci-fi movie gone bad, seeing that big thing following you on the highway in the rear view mirror! Then trying to shake it by making some quick turns, and then looking back, and... it's still there!!! My advice, be very very scared if that thing found its way into the house - no telling what its intentions really are. Word to the wise, eh?

                   _-_-WBear2GCR

[John K5PRO]

Wasn't one of the old Gates transmitters on Outer Limits (the original shows)? The episode where the alien lifeform uses the broadcasters signal to get to earth? I think we talked about this on AM Forum before.

[WA3VJB]

It will be good to hear another strapping signal from Florida, Rodger, best wishes and good luck in the restoration/re-tune.

There's a guy in Michigan who does not get on very often and he has made a tri-bander out of a BC-1T.  I think it's pretty much the same tank as the 500T. Gates sold an upgrade kit when stations got a higher power authorization, and there wasn't much to do in the tank area.

Let me check my card file for him next chance, in addition to the help you've already been offered.

Also, I'd like to point out an email reflector that might be of interest.

http://groups.yahoo.com/group/bcast_xmtr_4ham/

Right now there's an interesting discussion underway about converting a Bauer 707. Fellow has it up and running on its original frequency, and this quote made me grin when someone asked him the status.

Yes, I left it key down for over an hour and when my wife came out to the shop, she asked what was burning?

[W2XR]

Wasn't one of the old Gates transmitters on Outer Limits (the original shows)? The episode where the alien lifeform uses the broadcasters signal to get to earth? I think we talked about this on AM Forum before.

That episode was named "The Galaxy Being", and starred Cliff Robertson as the station engineer. It was the first Outer Limits show to have aired, in September of 1963.

No, there was no Gates rig in that episode; the transmitter was a prop with a variac and Simpson meter on the front panel!

It was my favorite episode of the entire Outer Limits series.

73,

Bruce

[K1HH]

You are right, no matter which way I turned, it followed me. Today, some 6 big ole 7 foot tall racks followed me into the shop. What am I doing wrong?

Rodger
K1HH

[WQ9E]

Rodger,

Nice find!  I have your transmitter's smaller and older brother (BC-250GY).

Rodger WQ9E

[K1HH]

The Gates achieved vertical polarization again today on new casters. The only visable damage noted in its trip home was that two screws that hold the insulators on the air/dummy load switch had vibrated out. Not a difficult fix but the whole dummy load assembly had to come out. There were 50 years of dustbunnies and dirt trapped underneath that panel too. I wish I had taken photos of the fans befrore I cleaned them. Yecchhhh!  Gates used two 120v fans in series across 240 volts. Medium noise level. I tried them in series across 120v; low noise level, but I don't know if its enough air flow.

I've started cleanup, removing that "yellow" preservative known to accumulate in broadcast facilities of yore.

More photos attached.

Rodger
K1HH
k1hh@naples.net

[k4kyv]

The BC500T is basically a BC1-T with one of the 833A's missing.

What I wonder about is the  mismatch with the modulation transformer and reactor, since the modulating impedance is doubled but the transformer and reactor impedances are the same, it should result in a slight reduction in low frequency response.  It would undoubtedly be inaudible to the listener, but I wonder how it would affect the proof of performance.

Did Gates just let it go as inconsequential, or is there some difference between the mod iron in the 500 watt and 1 kw versions?

Also, since the PA is running at the same voltage but half the current, it would seem that there would be some differences in the rf output network for optimum matching between the final tubes and the antenna feedline.

[flintstone mop]

  Gates used two 120v fans in series across 240 volts. Medium noise level. I tried them in series across 120v; low noise level, but I don't know if its enough air flow.

I've started cleanup, removing that "yellow" preservative known to accumulate in broadcast facilities of yore.

More photos attached.

Rodger
K1HH
k1hh@naples.net

YUP a lot of smoking of all types of materials during those dayz.
The slower fans will be fine for Ham use, unless you will be broadcasting more Amateur radio news.
And the YouTube vid would have been nicer with comments and activity in the studio
Fred

[K1HH]

Don and Fred:

I don't have the answer to your questions. I don't have a manual or a

schematic for the BC-500T.  I have the downloaded version of a BC-1T

manual, but on first perusal do not see a separate parts list for the BC

-500. Here is what is actually in the unit.

Modulation Transformer T3, part number AM30469E

Modulation Reactor L3, part number AC-10650

High Voltage Transformer, Gates 47200624-000
manufactured by Basler Electric Company BE-10107-001

This transformer has a tapped primary so that secondary voltages can be

either 3100 or 2335 volts. Current rating is 710 mils either side of

center tap. It appears the transmitter was using the low voltage taps.

An earlier Gates 500 watt transmitter, the BC-500GY used a single 833 in

the final and was modulated by 2-810s. I think it only used 2kv for the

plate supply.

Not knowing what the 500-T is supposed to have for Plate voltage/current
as compared to the BC-1T is a question that I would like the answer to.

I also believe their were adjustments on the audio driver assembly for

some low frequency (30 cycle?) distortion minimization at low power too.


Fred: I agree wholeheartedly, I did not see the video before it was

released. I spent a lot of years in the film and teleproduction industry

but I did nothing to discourage the efforts of others who wanted a

learning experience. I appreciate someone wanting to share our

transmitter recovery.

Rodger
K1hh

[Opcom]

You are right, no matter which way I turned, it followed me. Today, some 6 big ole 7 foot tall racks followed me into the shop. What am I doing wrong?

Rodger
K1HH

I'm amazed you towed that with that.  Otherwise, I don't see nuthin wrong! Good find, pls keep the pics coming as you work on it!

[K1HH]

Actually the PT has a rated towing capacity of 1000 pounds and a wind load rating of 25 square feet, I think. Meaning the front of a trailer shouldn't be more than 5 by 5. I towed my T-368 home upright on a pallet from Charlot to Naples, on this trailer. It weighs about 750 and the Gates is a little less than a thousand. Towed fine. On the other hand, I recently brought 6 7 foot tall racks home on a trailer behind the PT and I could definately feel the wind load.

Rodger

[KA8WTK]

Today, some 6 big ole 7 foot tall racks followed me into the shop. What am I doing wrong?

Not a thing!