The AM Forum

I have an RCA BTA-1MX in my future as I decided to "go for the gusto" and pass on the BC610H. It will live in the garage. I have read some postings about building a frame for the bottom using 2" x 1/4" angle iron and installing the casters on the frame. Here is a link to McMaster Carr

http://www.mcmaster.com/#standard-casters/=w6en3g

I believe the transmitter weighs in at 1100 lbs and is 7' high. My garage ceiling is at 8' 3". So, low profile is preferred for the casters. I figure each caster will need to be rated at least for 1/2 the total weight or 600 lbs.

I understand the dangers of tipping.

Any thoughts?

FEELEEP

My Gates BC-1J weighs about 935 lbs and I have a low ceiling in the basement. I put 4 steel wheels (from Northern) under it and bolted them to the bottom plate where the large transformers are mounted. The wheels are about 4 inches in diameter. This leaves the transmitter only about 1 inch taller than it was before and the wheels are recessed most of the way under the base. My base-plate is about 3/8 inches thick, if it were thinner you may have to add a thicker plate of steel under the existing one.

I used non castering wheels so I could put them on the far corners for stability and even it they weren't recessed in the base it could get tippy when the wheels caster. I can pull it away from the wall easily and if I have to turn it, it's easy to pull it sideways on the steel wheels on the concrete. I avoided rubber wheels since they wouldn't slide sideways easily and the would flat-spot when standing for months.

Since the transmitter is taller during the act of standing it up after bolting on the wheels with it laying on it's back I had to make sure to stand it up where the tall corner could rise between the floor joists.

  Appliance Rollers:

http://www.amazon.com/Shepherd-Hardware-9603-Adjustable-Appliance/dp/B000FKBSRE%3FSubscriptionId%3DAKIAILSHYYTFIVPWUY6Q%26tag%3Dduckduckgo-d-20%26linkCode%3Dxm2%26camp%3D2025%26creative%3D165953%26creativeASIN%3DB000FKBSRE

/Dan

The transmitter weighs a ton, it has a welded steel base assembly that’s easy to attach to but I would be very frightened of attaching wheels directly to the base. I would build up at least a small set of outriggers that would extend out six to eight inches in front of the transmitter and behind, or an appliance cart to distribute the load that extends beyond the base of the transmitter. Being the only things that open and close are the front and rear doors and that there is no access to the sides  I don’t think you need supports off the sides but without something extending out the front and back of the transmitter it can become unstable and be dangerous. If you have the front or back door open and its gets pulled forward and down it can fall and kill you! The T-368 when it’s on wheels has outriggers to prevent it from tipping over when you pull the drawers out and I have always been amazed by the stupid people who remove the dolly style base and attach wheels to the transmitter just so they can put it up agents the wall or keep from stubbing there toe on the outriggers, almost as stupid as removing the interlocks.
The RCA is huge and heavy, although about a third to half its mass is located in the bottom third there is still a lot of weight stacked in that above its center of gravity and its very stable on a concrete floor but you got to think about messing with wheels because once it shifts its weight beyond tipping point not a lot is going to stop it from coming down.

Can you install it with one of the sides flush against a wall; eg. RH side looking from the front? I was thinking of setting it on top of several patio blocks in a continuous pattern to get it elevated off the concrete floor about 1/2 to 1", depending on the thickness of the blocks. The patio blocks would be a continuous pattern with no gaps.

Remember, you may want to or have to get rid of the thing at some point, and there might not be anyone who wants it...
Home brew makes a lot more sense then using something that was built for low fixed frequency and continuous service (lots of weight).

1000lb xmtr isn't going to bother a concrete floor.  Probably it can handle a ton/sq ft.  My machine shop probably weights in at more than 35,000 Lbs on a garage concrete floor.  Last summer I sold five machines so the load dropped about 14,000 Lbs

You might be better to just set the xmtr directly on the floor away from the wall so you can get behind it and not put any casters on it.

Fred

I'd love to have the space to install it on the floor in one place and have access from the back without moving it. Ideally I'd like to have the transmitter faces in the shack and the backs open up into the shop space but that's not in the cards.

Wheels it is and they are very stable since mine don't castor, they're at the far corners and most of the weight is at the bottom of the transmitter. I could probably chin myself on the open back door, except that the door wouldn't take it.

The T-368 is a different animal with drawers that slide out. It needs the outriggers!

You can install it flush on both sides to walls or other transmitters.

Small diameter wheels do not roll well on rough surfaces. That leads to pushing and pulling - exactly what you do not want. Probably ok IF you set up a hitch point on the floor in front and behind to hitch a come-along to pull with, off another hitch point on the base of the BC xmitr...

...large diameter wheels do far better, and they make steel wheels with outers of poly stuff that are designed for heavy loads, but maybe not this heavy...

I use pipes for moving heavy machinery on concrete floors.

                _-_-bear

I'm always casting about for new transmitters... ;)

Good on you for going big!

But to the point, DON"T MOUNT IT WITH THE WHEELS UNDERNEATH IT! :o

Put them just outside the vertical line of the cabinet.  I spent time in a hospital due to an idiot's method as described and had a triple rack bay fall on me.  Mount them as I say and you just can't turn the thing over accidentally.

Also, make all of 'em swivel. It will be a lot easier to move around. 

I know that TX intimately, and 4" solid plastic wheels with ball bearings will do just fine.  Rubber is subject to flat-spotting after awhile.

73DG

Centerline both axes? Did you use a frame of welded channel or what??
BTW, the old radio book you sent me gets read in the throne room….a rare honor. Right next to Churchill's history of WW1 "The World Crisis".

 When I got my T-368 there were two opinions on should I use the T-368  base with the steel wheels and the out riggers. One guy who has a T-368 suggested I remove the base and put on casters under the chassis, then there was using the base which after some thought I decided to do. Main reason was the extra work but I didn't like the added foot print. and decided I could always change that later.

   Now a year and a half later I'm glad I kept the base, it doesn't take up that much more floor space and the steel wheels are easy to move on my garage concrete floor. Those steel wheels also don't get a flat spot after sitting for awhile unlike the plastic wheels I have on a table that has much less weight than the T-368.

What TOM shows is correct in terms of location.  I like mine out front, and the rear projection keeps it from banging the wall with handles, eTc.

I normally use two pieces of 3/8 A36 4" wide flat.  They would stick out about 4" either end.

Easy to drill, and stout enuf for a 2KLb TX any day of the week.  You would drill 10 holes in each, more or less.

I'd set the TX on it's side and mount them up for front-to-back mount, or on it's back for side-to side, but that is not as stable when in front of it.  Keep in mind just how much the doors weigh on it when opened...

73DG

I used these on both of my benches, and the test gear bench (http://i670.photobucket.com/albums/vv62/mikeinkcmo/testgear/Bench%20New/NuTstBnch34_zps0b47591b.jpg) is pushing a ton in weight.

http://www.northerntool.com/shop/tools/product_40248_40248 (http://www.northerntool.com/shop/tools/product_40248_40248)

Lots cheaper, and you can weld them to some angle or make a "furniture" dolly using some 2 X 6's.

   Amazing....


          We can make this more complicated than "Health Care"...

/Dan

I have a BTA-1MX restored for 160, and a BTA-1M partially restored.  I put 4 inch rubber-tired casters on each cabinet, bolted directly to the bottom plate, with clearance for the casters to swivel.  With or without the weight of the four heavy-metal transformers and inductors on the bottom deck, neither cabinet has any tendency to fall over, even with the door open.

I believe outriggers are not necessary for this transmitter, and with these casters it rolls easily over the concrete basement floor. 

Now if I could get a 160 antenna up, it would be on the air.  Spring is around the corner, so I should be able to do that soon.

front and rear projections are good safety measures. Some rigs like the BTA-250L have iron halfway up the cabinet on the vertical chassis and are shallow. There are two 2x12 planks under it, sticking out 1 FT front and rear. No casters yet.

Moving the heavy steel Bud three bay rack cabinet with the wheels underneath that injured me was "just fine" until an unnoticed power cord stopped it dead, inertia prevailed, and six Ampex 350 recorders came down on me, and getting a spindle shaft in the back was no fun.

It only takes once to completely forget all the aesthetics.. :o.

73DG

I also have a BTA-1M with 4" swivel casters bolted directly to the bottom plate. No problems at all with stability, but it has the shutter doors so there is no added weight leverage when they are opened.

I may be over cautious in my statement but I am a big believer in safety first! The transmitter is stable enough that when sitting on a concrete floor I have no problems climbing up to access the top by resting a ladder on the side. It’s a very stable design but if for some reason it were able to be shifted off its center of gravity and start to fall it’s going to be a big issue. Maybe it’s only a one in a thousand chance that if you have this on wheels and had the front or back door all the way open and for some strange reason someone decides to hang on it so it starts to fall forward or backward it may tip over, once it starts to fall that’s it and if your underneath it forget it. You’re done. Unlike working with a DX-60 broadcast transmitters present an entire group of ways to seriously damage or kill you so why take any unnecessary chances? In the years I have been working in radio I know of one engineer who electrocuted himself by defeating interlocks and attempting to adjust a tank circuit and one tower rigger that fell down a thousand foot tower by not following simple safety procedures so perhaps I may be a bit overcautious.
 Running big transmitters can be big fun, big electronics, lots of power and the like but it comes with big responsibility, you all may think I take this too seriously but that’s how I see it.

No, not at all. Caution is never a bad thing.

This hits home with me. I recently bought a HB transmitter from a SK estate. They told me that it was in the garage and that I could pull it out and look it over. Well, as soon as I tried to walk it forward, I was dancing with a 350# 6" tall transmitter. Very top and front heavy. After a little excitement everything was OK. I was thinking of some outriggers and I think I'm going with the T-368 base design.

Mike