[Boatanchors] Looking for JVL series coils

[williamhf]

Thanks to Mike Clarson I now know that there were small 5-pin coils,
made by B&W and the series was called the* "JVL" series*
of the B&W coils. Especially noteworthy is that they had an_* 
adjustable*_ link.

Does anyone have one or more of these coils which they can sell me?

Many thanks to all.

(If you haven't seen the original post regarding these coils please see 
below.)

Bill
W4DSR

*Boat Anchors Query re Information re the Original 4-20 Tank coil Link*

5-26-2005

The Hammarlund Four-Twenty Transmitter manufactured only during 1947
and 1948 seems to be fairly scarce among Boatanchor afficionados.

I acquired one recently. (I built the xmtr from a Kit in 1948; traded
it in a year or so later.) I'm getting older now and everyone knows that 
old folk's memory banks
are kinda worn and there's a certain amount of slippage.

But here's my memory of how the Final Tank Coil was tuned to the
Antenna output terminals. My memory says that there was an ADJUSTABLE 
LINK in the middle of the Final Tank Coil.

I have what seem to me to be fairly crisp memories of removing the top
cover and adjusting the Link in, or, out to get more power to the 
Antenna output terminals.
I used a $4.95 Amphenol Folded Dipole Antenna on 10 Meters and it was 
the only Coil I owned
for the four ham bands the Four-Twenty covered.

Recently, I have "pinged" for 5-pin RF TankCoils on "Boatanchors" and
the Hammarlund Reflector and happily have acquired some B&W MEL and JEL 
5 pin coils.
Now please understand that I have not yet got the Four-Twenty 
refurbished/rehabilitated but and am working along on that project.
But all these JEL and MEL  coils have either end or center FIXED links.

Why am I writing to Boatanchors? I seek to learn if there's anyone
among the Boatanchor ranks who happens to own a Hammarlund Four-Twenty 
Transmitter in ORIGINAL condition?

And/OR-------------Is there a ham out there who may not own the
transmitter but is confident that he knows how the Antenna terminals 
were coupled to the Final Tank Coil.

Here's a direct quotation from the Hammarlund Four-Twenty Owner's
Manual: "Plug-in Coils are used in the Output Circuit of the Power

Amplifier. These plug-in coils are accessible by removing the top cover 
of the
transmitter and are equipped with an output coupling arrangement with an 
adjustable tap to permit matching
the output of the transmitter to any of the conventionally used antenna 
feeder systems."

Doesn't that Quote make one feel secure and certain that somehow when 
you reached inside the top cover
you could move something which affected the coupling of the Final 
Amplifier circuit to the Antenna Output terminals?

Two current owners of the Hammarlund Four-Twenty that I have contacted 
use FIXED LINKS in their RF output circuitry.

I am convinced that there was an _*adjustable link*_ furnished by 
Hammarlund in the ORIGINAL Four-Twenty Transmitter.

Examination of the 4-20 Schematic shows a peculiar symbol (to me) for 
the output link of the Final Tank Coil System.
 (I don't know a simple way to reproduce it here) Whereas the Final tank 
coil itself is shown connected to two
definite points, the Link connected to two definite points which are the 
Antenna Input Terminals----
 BUT, BUT--- the link has an extra partial "loop" which is shown on the 
Schematic as just free-ended,
 that is, not fixed to a connecting point. The Electronics Draftsman was 
showing a different-than-conventional Link symbol.

The Photograph at RigPix /www.rigpix.com/hammarlund/four20.htm shows an 
upper central front panel control marked
 "Amplifier Tuning" but it controls the variable capacitor shunted 
across the Final Tank Coil, not a Link coil.

Any help or clues will be greatly appreciated. Thanks, guys.

Bill
W4DSR
Florida

5-26-2005 Mike Clarson, mclarson at rcc.com replied: Mike wrote:

"Maybe this will help. I do not know much about the particular
transmitter, but I have some data on the B&W coils the unit aparently uses.
You mentioned the JEL and MEL series. There were other variations.
The "Junior" inductors for use up to 75 watts input, came in the JEL series,
with link on the end, the JCL series with link in the center, _*and the JVL
series with a variable link.*_ The "Baby" inductors (up to 25 watts input)
came as the MC series, with a center tap; the MEL series, with an end link;
and the MCL series with an end link. No "Baby" units with an adjustable
link.--Mike, WV2ZOW"