INCOMING! Soon to Pick-up My BTA-1R1

[KU8L]

GM List:

I have committed (or...perhaps I SHOULD be committed..according to XYL) to acquire a nice BTA-1R1.  I have been looking at these for quite some time, waiting for the right location and circumstance to make it doable.  Anyway, the plan is, after arrival, to do the following:

Clean and perhaps paint before re-install of Iron.
Put into position in garage( attached to house) and power-up on original frequency for evaluation.
Then:  Look at options for putting it on 160-40M. 

I am not sure it can live in the house so will include the remote systems in the plans.  I currently do not have any 160M capability due to a rather small suburban lot but figiured I might want 160 even with a compact antenna at some point.  I would really like to be able to run it on 80 and 40 so am looking for info on options for a tunable output system.  I have a parts donor KW+ 4-400 amp available and am wondering about simply adding its pi out system to the BTA and using motor controlled elements. 

Anyway, any input regarding the plan or links to examples is appreciated.  Would love to have it going for next years' Heavy Iron Rally but that might be wishful thinking.

Curt
KU8L

[Todd, KA1KAQ]

Good luck with it, Curt. There are a lot of folks here with RCA-specific experience once you get it on site.

[ka4koe]

If you've got a couple of trees maybe you can do an inverted L?

[VE3AJM]

GM List:

I have committed (or...perhaps I SHOULD be committed..according to XYL) to acquire a nice BTA-1R1.  I have been looking at these for quite some time, waiting for the right location and circumstance to make it doable.  Anyway, the plan is, after arrival, to do the following:

Clean and perhaps paint before re-install of Iron.
Put into position in garage( attached to house) and power-up on original frequency for evaluation.
Then:  Look at options for putting it on 160-40M.  

I am not sure it can live in the house so will include the remote systems in the plans.  I currently do not have any 160M capability due to a rather small suburban lot but figiured I might want 160 even with a compact antenna at some point.  I would really like to be able to run it on 80 and 40 so am looking for info on options for a tunable output system.  I have a parts donor KW+ 4-400 amp available and am wondering about simply adding its pi out system to the BTA and using motor controlled elements.  

Anyway, any input regarding the plan or links to examples is appreciated.  Would love to have it going for next years' Heavy Iron Rally but that might be wishful thinking.

Curt
KU8L

Hi Curt

Check your email. I will send you some of the ER articles on converting the BTA 1R1 for multiband operation, that I had send to Ed VA3ES. It should give you some good ideas. It is a large file. Compiled/scanned info from 3 or 4 ER Magazine articles.

Sounds like a great project for you.

Al VE3AJM

[W7TFO]

Be careful around the lever switches on these.  I've seen many with them broken off, mainly from moves.

73DG

[VE3AJM]

Yes, I managed to break off the knob for the filament rheostat control during the move of my 1R1. It was a 23 hr. round trip drive from home here in southern Ontario to the suburbs of north Philadelphia PA and back.

When I arrived back at Canadian customs at the border crossing at Kingston ON from US 81, they were thinking of making me slide the tx back out of my GM van to have a look at what I was hauling. Luckliy they did let me pass through with no problems. I'll never forget that trip all the way around. Before the days of 9 11 and aftermath, and the Homeland security stuff at the border.

It was not quite as nerve wracking/wrecking as crossing the border after the Rochester hamfest with Dale AAM, who had been 807'ing in the passenger seat of my van, and tossing empty beer bottles out the window before we got to the border and customs. It was Canadian beer though...

Al VE3AJM

[KL7OF]

Is the final on that 1R1 a slug tuned coil???  Are the audio and RF drivers solid state?...I have a highly modified Bt1A on 160 meters...It came from a mom and pop in Montana and the slug tuned coil had got so hot that the fiberglas spreaders caught fire...The audio driver was toasted as well as the RF driver.....It has now been converted to 813 modulators (still has the 4-400 finals)  and a pi output with a 2x 2a3 speech amp and a 2E26 rf driver driven by a HB VFO  All the iron in mine is stock and working fine....The conversion done with help from KF7EH......Good luck...Steve KL7OF

[KL7OF]

pictures  It is a BTA1-S

[VE3AJM]

Is the final on that 1R1 a slug tuned coil???  Are the audio and RF drivers solid state?...I have a highly modified Bt1A on 160 meters...It came from a mom and pop in Montana and the slug tuned coil had got so hot that the fiberglas spreaders caught fire...The audio driver was toasted as well as the RF driver.....It has now been converted to 813 modulators (still has the 4-400 finals)  and a pi output with a 2x 2a3 speech amp and a 2E26 rf driver driven by a HB VFO  All the iron in mine is stock and working fine....The conversion done with help from KF7EH......Good luck...Steve KL7OF

My 1R1 uses 2 2E26s as the audio drivers, 6AK5 5763 and 6146 tube lineup in the RF, although I now use a Ranger as the RF driver. Originally used the slug tuned coil for the finals, now a pi network.

Al VE3AJM

[KA3EKH]

Cool, my 1M X uses 833 and 807 for everything being more primitive but that was a fun project. Ended up striping everything out and washing the cabinet outside with a bucket full of car wash detergent and a garden hose. Know what everyone says about get it running firs on original frequency but sometimes things are so dirty it’s better to strip and clean everything first, at least for me it was.

[KU8L]

OK..thanks for the replies so far.  I expect I will have many questions once I get it home.  I believe this one is stock without mods but have not inspected it yet except via Inet. 

I suspect that trying to simply use the output coil slug to get the match proper will produce a lot of heat via circulating currents in the tank.  I am thinking relay powered taps on the tank coil and motorized caps/relay switched caps all optimized for the proper loading and match on respective frequencies.

THinking driving the RF input with a simple HF rig direct to the finals via a 50 ohm swamping resistor...something like that.

I will be very careful of all the controls and switches.  I have experience moving large, heavy industrial electrical enclosures and drives and will be using a tandem equipment trailer.

THis one is already partly dis-assembled--at least iron is out, so will clean prior to re-sasembly and test on original frequency.

Thanks

Curt

[WA3VJB]

Curt I will be among the many looking forward to hearing that RCA on the air.
4-400A are a lot easier to multiband than triodes, and I know of several that have been successfully tribanded.

To Steve KL7OF -- wow, a 1S !  Yah don't see them very often anywhere.

I found one at a Baltimore AM station, date code 1971.  There was some thermal damage around the integral sockets for the modulator and final tubes, but the aluminum rack was considerably smaller than other 1KW tube RCA predecessors. You probably know the 1S has an Italian connection, making it all the more exotic. It was the last of RCA's tube kilowatt line.

As station engineering stood there "helping," he put the 4-400s on top of a filing cabinet. Sure enough, one of them rolled off and hit the concrete floor. Sickening sound.  So we had a set of three, probably high mileage anyway, but still.

Pulled the thing out of there and into the back of a liftgate truck, then unloaded it by myself. Dumped the iron and the rack on the back doorstep of Frank, KB3AHE who lived just a few miles away from the station.

Rang the bell and ran.

Actually, his wife Carol was there and gracious enough to accept the unexpected delivery.  A totally different reception than some earlier transmitter rescue, under cover of darkness, in the rain, pushing bits of an RA1000 toward a certain someone's side door basement.

We got caught on that one.

[KL7OF]

The RCA I have was given to me by an independent engineer in Butte Montana...Kf7eh and me went to Butte in the middle of winter in my flatbed truck......We came home with a parts rig Gates 500 ...The RCA BTA1S and a bunch of b-cast parts from said engineer's storage....The transmitters were stacked inside a long wheelbase Dodge 1 ton van parked in the street in front of this guys house...all the iron was still in the transmitters and the tx's were on their sides in the van...It was a cold winter day about 10 deg F and there was about 3 inches of ice  on the street..The three of us were able to slide the transmitters out of the van and stand them up on the icy street..I backed the flatbed up close to a transmitter and we tipped it toward the bed and then slid it on... It was a grunt, but the icy flatbed helped....Did that twice and threw some straps and a tarp over the load and headed for home.  I didn't have any hydraulic equipment (excavator) in those days so we unloaded the RCA at KF7EH's QTH  by hand and sliding
off the flatbed on some homemade rollers and plywood..All the iron was still in there..Same thing with the Gates 500...I parted out the 500 as the top end was gone and Kf7eh got the RCA going  and then we hauled it over to my place where it has undergone some more mods...It has been in operation here for 8 or so years...My gates BC1G was hauled here by the engineer that removed it from a station...He hauled it with everything in it , including the tubes..Lying down on a boat trailer...It fired right up on the original frequency and everything worked.....So much for removing the iron from a b-cast tx......That's my story(s) and I'm sticking to it...

[John K5PRO]

Fun story. No one is arguing that BC tx cannot be relocated with iron in place. When I designed broadcast transmitters for a living at BE in Quincy, we always shipped vertical on a pallet. The mechanical engineers never designed for horizontal movement. Transformers were bolted to a thicker base plate than a standard rack had, sometimes gussets and steel reinforcement pads were welded on the underneath side. The weakness is the bolts, however. If 5/16 or 3/8 inch bolts are stainless steel, there is hope. Its when you hit bumps with your trailer that doesn't have good suspension, that things can break loose and pulverize components. Since we hams don't have $20K invested in the rig, we can live with the disasters if they occur.

I recently found a 3 kW RF plasma products amplifier in a junk yard here, and paid $75 for it, mainly for the nice parts including 5CX1500. I got lazy and laid it on it's back, front side up, on my trailer. When I got home, 20 miles later, the front panels for the power supply unit and the RF deck were bent inwards where the weight was hanging on the rack ears. That was a mistake.