chas wrote:
> My Apologies to the list - when you get in a hurry or get distracted,
> it is best sometimes to just save the message and come back later. I
> had meant to change the subject line as a new topic, though related.
> again, please forgive me.
> chas, k5dam
>
>
> Roger sub1@rogerhalstead.com wrote:
>
>> If you haven't done one before, most conversions are likely to offer a
>> surprise or two and remember the Henry amps had little or not protection
>> circuitry that you find in todays amps.
>>
>> Were it me, and it's not, unless going for a major project I'd most
>> likely leave it as is which is what I did with my 2K4.
>>
>
> I was somewhat interested in the Henry model being discussed and did
> some mad-minute googling and even called Terry (KI7M) and talked with
> him for a few minutes about it. However, isfa I can see, the Henry
> 2K4 offers nothing that my modded SB-220 cannot do as well or better
> in that it also seems to be restricted to ham bands.
>
>
I only mention the 2K4 as I had one and there is little difference
between it and the earlier floor model/classic.
The Henry offers three things. Space in which to work, a lot of iron,
and a big blower for cooling. There is plenty of room in the PS section
to add a higher voltage CCS transformer and even a screen supply if
needed for something like a GU84B. The bottom consists of two 1/4"
thick, aluminum plates. The bottom most holds the transformers, chokes,
and caps. Above that is one for bleeder resistors and "other stuff".
These plates are mounted on heavy, vertical, Aluminum angle. The
blower is *large* and mounts on the bottom of the RF deck while being
physically located in the PS section. The band switch/tank coil can be
replaced with a rotary inductor ala the Henry "Ultimate" I believe it
was called. They actually had one or two machines with rotary inductors
and higher voltages. One also used the 3CX1200, one a pair of 8877's and
I don't remember all the variations and export models.
It'd be interesting to see a compilation of models Henry offered for the
Ham market as they had 6 and 2 meter KWs with one of the 6-meter amps
running the legal limit (IIRC)
The 2K4, 2K3?, and Classic can be found for on the order of $700 (give
or take a bit) WITH good tubes. So you get a lot to work with. The
power/SWR sampler is both electrically fragile and made of "Unobtanium"
using a line sampler with glass piston caps at each end along with the
diodes. The bias module can easily be replaced with standard components
and even potted to look like the original although last I heard, Henry
Radio still has some of them. The meter switch is no longer available
and it takes some tracing to figure which wires go where and do what,
but for a few dollars a replacement (IOW, one that will work) is
available from Mouser and I'd assume many other suppliers. IIRC it's a
single wafer, three section switch.
> Rather...
> What I was hoping for, was a continuously tunable 2-30mcy amp as the
> 220 is not... it being limited to whatever the slugs are tuned to.
>
It'd be a project, but most of the Henry floor consoles (they start
around 160# and get heavier) could be converted to a continuously
tunable final. The plate choke would need to be modified and the input
circuit replaced with either one that covers the spectrum in segments or
one that is continuously tunable if fed with a SS rig. Actually I like
that approach as they have a bunch of stuff tied into the band switch
with chains, levers, and links between the front panel and the front of
the RF deck.
> I would prefer to avoid Solid State as these FETs, etc are quite
> delicate it seems. A full, wideband amp running on 2 or 3 3-500Zs
> would be SWEET! <G> Obviously I do not want it for Ham but for MARS
> use instead.
>
> I know that Henry made amps for the State Dept/DOD which were
> completely tunable from about 1.8 to 30mcy+ or, even wider than that.
>
The "Ultimate" and several others were continuously tunable to 30 MHz,
but I don't remember how low they went.
> I just don't know which model(s) they were and how available they were
> when those users went to secure satellite or whatever they are now using.
>
> Does anyone know of model numbers for those Commercial (non Amateur)
> amps??? or, anyone who would know that information?
>
I think they even had one that used 3 8877's and possibly one that used
two 3CX-1200's. There must be some one on here who has a list of what
they built over the years.
I quit frequenting e-bay when they started requiring Pay Pal.
73 and good luck,
Roger (K8RI)
> thanks
> 73 de chas, k5dam
>
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