The AM Forum

Made a deal on a BC1T. I will be setting forth on the sojourn in a couple of weeks, pulling a U Haul trailer. If I'm lucky, I'll have it back up and running by the fall. It was retired from 1490 WWNB New Bern, NC, a year so ago as a working backup. The TX originally operated from 1590 WAWA Milwaukee, Wisconsin.

It was a tough decision. Another TX was available but the weight factor ended up being the deciding one. The TX is uncoverted.

Philip

Be sure to take pics when you arrive and load it! travel pics are always fun!

Photos sent by the seller...

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Wow, that's nice and it's going to be QUITE a project !!  We'll be watching your progress.

Was looking at replacement rectifiers. Of course, no way am I going to go with Mercury Vapor. See this link:

Pair of 833s modulated by a pair, 4000 watts peak @ 2500V B+ equates to 1.6A peak current.

Rule of 4x your working voltage for PIV = 10 KV. Get conservative and run with the 20 KV rated unit at 1A...

Since 1A is below the constant current rating of 1.6A, parallel two for each leg of the HV.

Am I on the right track here? The rectumfryers go for about 5-7 bux each. Need 4, so perhaps 30 dollars spent to replace the 8008s.

Philip

Why the MV prejudice? Internet myth?  Too lazy to preheat?

I offered you good ones for free...

That TX has personality one, silicon has none.

The Xenon tube is a 4B32, not a lot of good glow, true.

Of those I have not one.

73DG

Simply slipped my mind.

Thanks for the pron and the great nameplates! Mercury gives a homely warmth and glow, cozy like.

HV rectifier stacks are cheaper than a replacement fil.transformer for the MV toobs... easier to find also. With the tx. in another room with the front door closed, you'll never see 'em anyhow. On the other hand, MV rectifiers in an old buzzard HB rack setup; mighty FB OM! HI HI!! 

When I got started in broadcasting the transmitter was a BC-1T which wan't more than a few months old.  In fact, I was a janitor at the station and helped with re-wiring and remodeling the studio.  Went on the air for the first time on my 16 th. Birthday.  I worked for the station a couple of times over the years and was on the air in the mid-90's when the HV transformer shorted out and the Gates died.  I was there when it went on the air for the first time and was there when it died.  The rectumfryers had been replaced with with all solid-state National direct replacements.  A few years later, the transmitter was hauled out by the tower and covered with a tarp where it sat for a few years of Wisconsin winters.  I got permission to salvage it about 15 years ago which I did.

If you can score some of those solid-state jobs, I'd go with them rather than kludge together something equal.  They work great, no modifications are needed, and are direct replacements.  The driver boards look like they will need work.  That was a big problem with our's as well.  Components kept frying and unfortunately the engineer was a total lid who wasn't particular with replacement parts.

I still have some parts from the beast along with a manual.

Mike
W9ZSL

One thing I do not like about that transmitter and others is using circuit boards for power tubes. They are always black in the end.

The rectifier tubes provide some time delay on dumping the HV B+ to the plates - unless there is a contactor in the circuit (?), so watch out for that issue when going to solid state rectifier - that and inrush current when turning on the AC mains.

Looks sweet!

Where is it going to sit, in the living room? :D

                          _-_-

Bear

It's going to sit in the garage directly, and I mean DIRECTLY, below my shack. Cable runs will be less than 15'.

Road trip is this Friday to hook up with K2DX Fred.

PAN

So, then you will be installing a "chair lift" in the floor so you can push a button, and descend directly below into the netherlands in order to quickly tweak the tuning and return to the operating position??

                            _-_-bear

No, simpler than that.....

1. Pair of FRS Walkie talkies.
2. Video camera aimed at TX meters.
3. Adolescent minor.

Procedure:

1. Send whining adolescent to garage below.
2. Issue destructions via FRS radio.
3. Watch metering on CCTV display during implementation of destructions.

Perfect!

BC-1Ts have contactors in the HV.

Now K4SMN sez....."Why don't we build a little shed out back to locate the transmitter?"

Good news: Sheri has accepted the fact that this is the new home of WAWA 1590, Soul, RB, and Jazz.
Bad news (maybe): I have to formulate an engineering / economic analysis to say why we're better off with the TX in the garage directly below my feet in the shack.

just quote a lot of statistics .... you might even believe them urself after a while

Just suggest that the combination of concentrated RF power and high voltage components will take care of any rodent problem you may have in the garage.

Feelip
the transmitter did fine for many many years with the original design. Clean her up and see what happens after re-assembly; then look into design changes.

Fred

Remote control should be pretty easy. Many BC TX have a remote input for keying. Remote audio can be supplied via the standard line level input (as is done in every BC installation). You can have your VFO/exciter at your operating position, so smaller frequency changes can be done right there. When tuning is required, you need a line from the TX location to your exciter. This is just a longer PTT line. In your situation, this should be easy.

Once the TX is tuned up, there is no need to monitor the meters. The TX has overload protection. So if something goes wrong, it will shut down.

I had a very similar set up to yours in the past. My station/operating room was on the second floor of my house. The BC TX was in the basement. I used a FT-101 as the exciter. I used the amp keying output on the 101 to remotely key the BC TX. It worked FB.

Its gonna be a job, that's for sure.

Task List (Subject to change).

1. Clean unit.
2. Replace any defective components and wiring.
3. Run dedicated grounding conductor to a ground rod. Probably around #4 directly through conduit sleeve in adjacent exterior wall. Conductor run less than 10' long.
4. Provide dedicated 240V, 1 phase power to unit. Feed it with 50A ampacity No. 8 AWG from a new 30/2 breaker in house electrical panel (probably about 30' run - need to do a voltage drop calc).
5. Power up on original freek.
6. Mod to 160/80m.
7. Mod for PTT.
8. Run control lines and shielded balanced audio lines from operating position directly above.
9. Install audio rack in shack.......clipper, equalizer, compressor, mic preamp (not necessarily in that order).
10. Change antenna system if needed.

I may consider using the Valiant to drive the TX from above; eg. exciter and audio. Timtron recommended this.

I'll be lucky to have it on by the fall.

Connect your new ground rod to the service ground #6 or larger.

No need to do a voltage drop calc, probably today's line voltage is higher than what the xmtr was designed for.

Good luck with it.

Fred

Yep...another item. Check service ground. The original builder did a hotel alpha job on a lot of things. Need to borrow a meggar from my power company friend.

I don't see what a megger would do in terms of checking a ground system.. ???..you need a low-resistance Ohmmeter.

Meggers test insulation and such with high voltage.

73DG

Meggers have been used for decades to test ground rod/grounding systems; one method is the "fall of potential".

http://ecmweb.com/bonding-amp-grounding/ground-testing-techniques

Looks like there's some difference between the electronic test meter called a "megger" and the thing shown for testing the ground rods??

Btw, what's the book that this is from??

                       _-_-

Megger is actually a trade name, Bear, Google is your friend. Search for "megger fall of potential method". I don't remember the exact reference.

http://www.megger.com

In other news….

I have the 5x8 enclosed U Haul trailer affixed to the Tacoma. I plan on venturing out on the Great Transmitter Expedition (GTE) at 0500 EDT (0900 Z) tomorrow.

Best of luck!

Take some old blankets, quilts, or similar with you; as many as you can get. You'll probably have to lie it down and slide it in on it's side, so make it's transition to it's new home as comfy as you can.

2 el.

suggest adding 5a      have local fire dept on standby

Be sure to take GOBS of pictures on your recovery!
Its always fun to see other peoples adventures.
Good luck!!

FWIW,

A couple of old broom handles cut to a bit wider than the transmitter width. Tilt the load back, toss one or two under, roll forward, and repeat.  I moved cemetery  monuments around with this system. (I also used 2X8 planking on the dirt). You also may need a cooler. Put a few 807 inside, pack with ice and yer gud2go. The ice is used to sooth the aching muscles after manhandling this best around. Gud luck on yer mission.

This is what a Megger looks like.


KLC

Home safely. Will remove the behemoth tomorrow from the trailer. It's been a LONG day.

Glad y'all made in back safely. Time to pop the top on a cold 807 after that ride

Bad traffic, weather, wrong turn. 10 hours going home. Here is a link to photos!

https://flic.kr/s/aHskac24Kz

Nice place! I like the audio driver in the pictures.

Glad you made it back safely Philip, with the transmitter in tow.
Bet you can't wait to play with it!
Keep the pics coming, you can never have to much Transmitter Porn.  ;)

Beautiful scenery, the landscape looked pretty good too.
There's just something too sexy about a PP pair of 845's...oh me, ohhhhh my!  :)
Love the "Cool Breeze" cooling configuration design.
Looking Good Grant!

Got TX safely inside. Installed custom stable outrigger dolly. 2 x 3 x 3/16" steel, 1000 lb rated steel casters (each). Fellow in photo is longtime friend W4REQ. Dolly is secured to bottom of TX.

https://flic.kr/s/aHska7gcKA

Did u send the xyl on a shopping trip?

She was at work.

  looks good, you did a close measuring job for the height, just cleared your garage door from the look of it. Good pics, enjoy watching others projects.

  My T-368 only had to be transported a 150 miles and I worked out a deal, a friend sold two BC-610's to the guy who I got the T-368 from. He came up here to my place 40 miles from San Jose and then the 150 mile drive. A lot was on two lane mountain roads, we towed a motorcycle trailer, worked out well.

Original home of BC1T, 1590 WAWA, "The Giant Killer".

https://news.google.com/newspapers?nid=1368&dat=19740104&id=VotRAAAAIBAJ&sjid=exEEAAAAIBAJ&pg=5582,929102&hl=en

and full of soul with Dr. Bop…..

http://stepfatherofsoul.blogspot.com/2010/06/soul-on-air-15-dr-bop-1973.html

Interior higher rez photos...

https://flic.kr/s/aHskagtK3r

Philip,

Good luck with the project.  Looks like you have a lot of work ahead.

Fred

So basically this tx is haunted by some guy they buried with a giant fro wig?

Yep.

When you get the rig going it will be a treat to hear the signal up here.

Thanks for posting the pictures Fleep.

Haven't touched the Valiant all week. This trip really saturated my radio gland. Cleaned up the bottom chassis some last night. Wondering if I should hit it with a garden hose. My friends tell me this is a really clean one and obvious it was stored in a conditioned environment.

Big project. I may be at the point of running a power line in 2 or 3 weeks at the rate I'm going.

I also need to put some bumpers on those outriggers. Those suckers will kill your shins. You should see the bruise I already have!

Philip

Was busy today....

https://flic.kr/s/aHsk9KiE5K

Philip

Sarah shot this photo….

Better test that Pyramid cap.  Lucky if those things were good when new.

Fred

Roger.

Notice the ripple freq on the GE filter reactor, 360 hrz, rectified 3 phase.  Wonder how well it will work at 120 hrz.

Fred

They were using that piece of iron when taken out of service. Elaborate please.

10hy choke at 360 hrz is still a 10hy choke at 120 hrz.  The inductive reactance would be less at 120 hrz.  The higher ripple freq from a 3 phase supply is just easier to filter.  Was that xmtr running on 3 phase power or just single phase??  The building it was in probably had 3 phase but the xmtr may have been on one phase.  Is the plate xfmr 3 phase or single phase??

I wouldn't worry about the choke, just use it as it was being used.  You may need to add more capacitance in the filters.

Fred

That's a BC-1T. It's single phase.

And that's a coil not an inductor. Inductance only exists when there is current.  ;)

Unless I'm confused, a coil is also called an inductor

I'm assuming it will have some current running through it when he uses it.

Just yanking your chain. But it is improper use of terminology that has become standard. There is no inductance without current. In that photo, there was no current. Speaking of current, I often hear people speak about "current flow." Current doesn't flow.  ;)

Current is, if I'm not mistaken, the movement of electrons in a conductor from (-) to (+) as the result of a difference of voltage potential,  i.e. free valence electrons moving from atom to atom (3 or less in outer shell for a conductor). 1 coulomb of electrons (a big number) moving past a point per second is 1 ampere. So perhaps flow is a misnomer but used all the time to visualize the process. Of course, the electron holes move from (+) to (-).

Thanks Steve,  you had me going back to re-read some of this stuff along with all that math that I long since forgot.

Fred

Current flow? All very mysterious, using electron exchange among creatures inhabiting Bohr's atomic model as an approximation.

All will become clear once we've cracked the quantum world's "sound barrier," that which lies beneath the Plank realm.  This may never occur since those exceedingly small dimensions approach absurdity. In other words, our limited laws descriptively break down at that which we can only surmise.

One thing we do know in the macro world is that it takes work to establish a voltage difference. We know you can't get something for nothing in any real, measurable time interval... But for very short periods you can fool the measurers, be they glass, metal or human, hence negative vibe promotional theory which we've all experienced especially on Christmas morn as children and daily in the political promise realm as "adults." ;)
The promise of that "Red Ryder" far exceeds the reality.

Did that electron really flow? Did its passing destructively produce heat in impeding material?  Was that heat a photon?  How did that electron excite the material to produce the photon? ...and just what is that photon, wave or particle or both?
Got the breakfast call, gotta go.

I prefer the "Row Row Row your Boat" explanation.....Life is but a dream anyway.

The power requirements for the BC-1T are 230 volts, 3 wire, solid neutral, single phase, 50 or 60 cycles.  Approx 4,000 watts consumed at 100% modulation at 1KC.  Since our station had 240 volts, the xtr had provision for a "variac" to drop the voltage.

Straight out of the manual.

It's not really a manual until someone reads it.

They always looked like a book to me.

Manuel was the guy turns no wrenches.   He was performing manual labor.

Lol


--Shane
KD6VXI

"if you're living right, throw the HV plate contactor switch."

Love the Gates BC1T manual/book/pamphlet/religious tract. It's full of humor.

If a transmitter is keyed in the forest.....

Just a while back, I saw a petition to Repeal Ohm's Law.   That would be borderline  political, so we must refrain from discussing it on this forum.  Resistance is Futile. 

Does anyone recall the short story about Millie Henry and Micro Mho?

aha!  Feelip with his aqueous AK47 .... death to slime devils

Right out of the book / manual!

Don't own an AK47 as I refuse to practice "spray and pray".

Apparently you do, if you are going to use that pressure washer on your TX. :D

One has to have good aim and know where to put stuff downrange. You don't think I washed the ENTIRE TX do you??? Egads…perish the thought. How stupid do I look…..wait, don't answer that.

 ;D

   STBY:

        I think my CONELRAD Just went off...

 

I've washed entire transmitters (minus big iron) but not with a power washer.

I'm painting now.....meter cover, ankle destroyer, and bottom shelf for the iron. Looking good.

I just washed my car by hand.

Good for you Pete. Whacha got, a Vette?
--did you hear about the woman in California who washed hers in the garage with one bucket of soapy water and one bucket of rinse water. A lot of water trolls hanging out in "New Desert." 

 Infra red pix from drones seeing if water running out from under the garage door at night is suspect.  --At HQ,   "ooh boy sarge, lookee that, another Perp!"

Reinstalling iron. I'll take some more photos for the group here. It's looking really nice. Pete; which hand did you use to wash your car?

Reinstalled Iron. See photos at link

https://flic.kr/s/aHsk6ZP2PT

PAN

the good hand.

As first said in Space 1999.

What episode Patrick?
I have both seasons in entirety.

Nice Pics Philip, keep em coming!!

I believe it was the one where the Dorcons tried to take the shape shifting woman away from the base, in order to steal part of her brain to make their old king immortal. After a short and one-sided 'demosntration' of the Dorcons weapons, they reiterated the demand and said those words.

Yup, sure enough!
That was the last episode ever made too, "The Dorcons".

Update…see link…

https://flic.kr/s/aHskaakH6s

Looking super, Philip. Keep the photos coming!

73
Jack
WA2OLZ

The plate transformer leads to the rectifiers will have to be replaced. Skinned insulation and just because.

Have you no sense of adventure, sir?

One can spit in the eyes of the Fates just so many times before the hammer is dropped......

The hammer will be dropped when you light that thing up on the air for the first time.

One has to look Murphy directly in the eye.........

Com'on, Phil. 

It's just a skinny kilowatt. ;)

Pushing the "Plate ON" on a resurrected 50kW is palpable... :o.

73DG

We'll, I've got to get all the gazintas and gozoutas fixed up first.

Not anymore.....said "I do" in front of a preacher. That's enough for one lifetime.