[Amps] [Magic Band EME] Henry 3000D Six meter conversion

Lance Collister w7gj at q.com
Mon Dec 20 08:27:50 PST 2010


Hello Steve,

Glad to see you are moving forward on your conversion project ;-)  I don't know 
how many such RF decks have found their way into the hands of deserving 6m 
operators, but I suspect there are still many of these things sitting around in 
barns and garages around the world.

Like you, I put off the conversion of mine for a number of years.  In my case, I 
obsessed about mating it with a power supply and didn't get around to putting it 
on the air until I was able to find a power supply.  However, when I actually got 
around to starting in on the RF deck, I was amazed at how fast and easy it was!  I 
mention this because I am afraid you might be overcomplicating the process.  There 
is NO machining necessary, and it is easily done using a screwdriver, a hand 
drill, and a saw.  All the unusual parts are readily available from the local 
hardware store and it is quite straightforward to assemble them to create a very 
stout 6m amp that will easily handle the high duty cycle required by JT65A mode. 
HDPE cutting boards provide a source of material for the ends of the adjustable 
coil, which are mounted to the bottom of the chassis by pieces of angle aluminum 
screwed to the bottoms.  The adjustable shaft is simply a threaded brass rod and 
the guide for the tuning slug is simply some brass hobby tubing put over some 
brass threaded rod or solid brass rod (found in the same bin as the brass hobby 
tubing).  If anybody lives further out in the boonies than I do (which is 
doubtful), such parts are easily obtained on-line here:

http://www.smallparts.com/

It also helps tremendously to have an MFJ Antenna Analyzer.  You also may find it 
necessary to purchase a few 857 style doorknob capacitors to use as blocking 
capacitors and to create the total capacitance required for loading.  Other than 
that, the most difficult thing for me to come up with was the right angle drive to 
match up at the correct height as the existing tuning dial.   I found a pair of 
surplus right angle drives and was able to couple them together to create a 
mechanical arrangement that could drive the tuning slug at the right height and 
still couple with the standard tuning dial on the front panel.  Of course, there 
are many ways you can do this, and one of the nice things about building your own 
is that you can mount the coil and the slug at whatever height is convenient for 
you, to match whatever right angle drive you come up with ;-)  You might even want 
to try a flexible shaft and avoid the entire right angle drive problem entirely!

Anyway, the bottom line is that if you basically duplicate the photos shown on the 
web page, you can easily fabricate the parts with hand tools, and will end up with 
something that tunes easily and is quite broad band.  Given the variability in the 
way the original Henry amps were constructed, I fail to see where there would be 
any advantage in anybody trying to fabricate parts that would hope to fit all 
situations anyway.

GL and VY 73, Lance


On 12/20/2010 3:52 PM, K1SG at aol.com wrote:
> A number of folks on this reflector are in progress of converting the Henry
> 2000D/3000D commercial amplifiers to 6 meters. There is a wonderful show and tell
> on this subject on W7GJ's website
> http://www.bigskyspaces.com/w7gj/6mHenry3CX3000A7.htm and I suspect many have
> already started the project. I've been making slow progress on mine, but expect to
> get it finished in the fullness of time.
> My current hang up has been with obtaining and machining the parts needed for the
> output tuning coil, particularly the slug tuning arrangement.
> I've found a friend willing to do the hard parts (the machining itself) for me.
> Would there be enough interest to do a group buy on the copper, brass and PVC
> pieces for this? It makes sense to do more than one if we're going to do it at all.
> If you have a 3000D sitting on your bench waiting for conversion to 6 meters,
> wondering about the construction of the tunable output coil, and would be
> interested in sourcing the machined parts for it, please contact me off-list.
> Thanks very much (and a tip of the hat to Lance!)
> 73,
> Steve
> Steve Gilbert
> K1SG
> K1SG at AOL.com <mailto:K1SG at AOL.com>


-- 
Lance Collister, W7GJ (ex: WA3GPL, WA1JXN, WA1JXN/C6A, ZF2OC/ZF8, E51SIX, 3D2LR)
P.O. Box 73
Frenchtown, MT  59834  USA
QTH: DN27UB
TEL: (406) 626-5728   URL: http://www.bigskyspaces.com/w7gj
LIVE MESSENGER CHAT: w7gj at hotmail.com  SKYPE: lancew7gj
2m DXCC #11, 6m DXCC #815

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