B&W Jackbar information

[W5SUM]

I was given a jackbar the other day with no markings on it whatsoever.  I'm not sure but I THINK
this may be for the highpower HTVL series of coils.

Can someone who has one, give me the measurements between the jack/sockets, so I can compare to what I have here?

Thanks in advance

73's and God bless

Ronnie - W5SUM

[K3YA]

The "Kilowatt" jack bars are easy to recognize because the banana plugs are about 3X the sized of regular banana plugs.  The ceramic bar is about 9-10 inches long for coils and longer still for the female bar. I can give you more exact dimensions tonight if this isn't enough to identify what you have there.

The 80M coils are hard to find intact because the plastic parts the hold the wire in place deteriorate and fall off. 



   

[KL7OF]

This is a 40 meter EF Johnson killowatt coil....Hope this helps

[k6hsg]

I have the problem with the plastic like material coming apart.
Is there a good way to fix this?
73, John in Tucson

[KA2DZT]

I have the problem with the plastic like material coming apart.
Is there a good way to fix this?
73, John in Tucson

Not even sure that stuff was plastic as we know plastic today.  Most all those early coils have the same problem.  The plastic like material that was used falls apart.  Another problem is that it shrinks in size which I think is the main reason the stuff falls apart.

Fixing the coils has always been a problem.  You can try glue or you'll have to remake the plastic parts.  Nobody ever said that working on old boat anchor xtmrs was easy.

Maybe someone will post some better fixes.

Fred

[WA3VJB]

HDVL coils typically have a swinging link and arm assembly, so the coil stock is split in the middle for clearance and coupling.

The plastic spacing retainers failed on mine many years ago.  I took some strips of teflon stock,clamped it, and drilled holes slightly larger than the coil wire for 80 and 40 meters. I then sliced the strips down the middle, and used heat-shrink on the ends to hold the two halves in place around the coil wires.  

This provided just enough structure to maintain the spacing of the turns. 
I think I used three on each side, six strips total, positioning them for best clearance for the swinging link.

[W7TFO]

I have successfully made new plastic spacers via this method:

Take 1/4" thick clear plexiglass and saw it into a strip of the same width as the original on a bandsaw.  (3/8" plexi for larger coils)

Drill as many holes as needed thru it, spaced to the original pitch, using a bit that is slightly larger than the wire.

Cut it again on the saw, going thru all the holes you drilled to get two strips with halfround depressions now.

Place one strip on each side of the winding after using a coat of plexiglass cement on the surfaces that will line up to make holes for the windings and clamp till set up.

Looks like new and will last a loooong time.

You can also use small nylon screws/nuts spaced close enough to keep things in line rather than glue on the larger coils.

None of this is easy, but old coils are just about all there is today, so fixing them pays.

73DG

[Opcom]

Dennis takes a piece of plastic like "plexiglass" or another type that is slightly weakened by acetone and he clamps it under the coil. Some times the original 'plastic' is usable.

He melts styrofoam cups in the acetone until it is like thick syrup, and from a beaker he dribbles a bead of the goo onto the coil above the plastic strip, where it adheres and dries, bonding to the supporting strip and permanently gluing the coil aright. This is done at each place the support is necessary.

I need to do a video of this. He is very good at it. Has anyone used this method?

[K5UJ]

I've have TVL coils where the acetone or whatever it is is falling apart and I just slathered clear crystal 2 ton epoxy over them to hold the show together. 

I was thinking if the strips are all gone, you could weave 10 pound test nylon fishing line through the coil turns then use it to hold epoxy so it sets up without dripping away.  The wire, especially on 20 meter and higher band coils is pretty stiff--some kind of material to keep the turns from touching is probably only needed on 40 and down.  maybe it is different for the KW coils though.

[k4kyv]

Where did you get your Crystal Clear Two-Ton epoxy?  I have used it for years.  It is slow setting, but one of the hardest and best adhering epoxies I have ever used for anything, and is an excellent RF dielectric. Most of my KW plug-in coils are held together with it.  But recently I went to get some more, and tried three stores where I used to buy it, and not one of them had it in stock.  All they had was that 5-minute instant crap that doesn't really harden, but remains flexible like rubber, and peels off.  Not much better than the stuff from a hot glue gun. Do they still make the crystal two-ton?

I believe the original plastic on air-dielectric coils was cellulose acetate. It eventually shrinks and finally turns to powder. It loses its dielectric properties with time as well.  I have had the plastic in coils literally catch fire while I was transmitting. Sometimes it shrinks enough to distort to coil sufficiently out of shape to break the ceramic banana-plug bar.

[KL7OF]

The 40 meter johnson coil in the picture of my earlier post is new old stock that came out of a Johnson box and was packed with newspaper dated aug 13 1947...The "plastic " spacers on it look new and have no cracks....The coil has never been in a transmitter....Maybe it is the RF or perhaps heat that breaks down the "plastic"...
   I have used Hot Glue to repair coils and it works good for about 5 or 6 years...so far....I have heard that  some hot glue doesn't like RF, but I haven't encountered any....

[k4kyv]

The coils were made by B&W, Bud, National, EF Johnson and a couple others.  I have found that the plastic on the B&W coils is the worst for self destructing, but the majority of the coils I encounter are made by them.

[K5UJ]

Yep, mine are all B&W coils.  Don, I got that epoxy because a year or two ago you recommended it    I don't remember exactly where I purchased it--I think it was Ace Hardware.  I bought it in those larger plastic squeeze bottles, not the small tubes, so I have not had to look for it since.   I think each bottle holds around 4 or 5 oz.

[W9BHI]

Don,
I just looked on line and saw it for sale at Walmart.
I noticed there were different numbers of crystal clear two ton epoxy's while looking on line.
S31, S33 and S35.
I guess some are 30 minute, 5 minute and waterproof.
Amazon sells it also.
I hope this is useful info.

Don W9BHI

[W8ACR]

The plastic strips on B&W plug in coils are almost always distorted, warped, shrunken, crumbling, or otherwise faulty. This goes for all sizes of coils - M,J,B,T, and HD. Occasionally, you come across one that was apparently stored for 50 years in a hermetically sealed, airtight, climate controlled environment and is usable.

OTOH, Johnson and BUD coils are usually in excellent condition. Obviously, their product engineers paid attention in organic chemistry class, and used plastics that have withstood the rigors of use and time.

I usually repair old B&W coils by slopping the remnants of the plastic strips with epoxy.

Ron

[KE6DF]

It seems like every question has been answered except the original one asked.

So I'll take a shot at it.

I have a jack bar for the HDV series which is the largest and highest power -- the female part the coils plug into.

It has four jacks in it, plus a center hole for attaching the link (which I don't have).

The overall length is about 10 5/8 "

The plug holes are about 1 7/8" apart.

The mounting holes are about 9 5/8 " apart.

I also have a couple of ginormous butterfly capacitors that the jack bar mounts on -- with 1/2 " spaced plates so it's made for high voltage and power.

Dave

[KM1H]

Ive heated coils and pushed flat and narrow plastic strips into the wires. Do one cool it down, do another, etc.

Used scrap from the local glass shop that does door and window work.

Carl