[Boatanchors] ARC 5 stuff - LIST

[jeremy-ca]

----- Original Message ----- 
From: "J Forster" <jfor at quik.com>
To: "Jim Brannigan" <jbrannig at optonline.net>
Cc: <boatanchors at mailman.qth.net>; "Meir WF2U" <wf2u at starband.net>
Sent: Sunday, September 23, 2007 3:56 PM
Subject: Re: [Boatanchors] ARC 5 stuff - LIST


>I used to shop at a state government warehouse for a university that I 
>worked
> with. Their mission was to take donated federal surplus and pass it on to
> deserving educational (and other) programs.
>
> I saw DOZENS of virtually new, state of the art, Tektronix (475As and 
> 485As)
> scopes being loaded into pickups so the kids in a technical high school 
> could
> practice soldering !!!
>
> If you think that sort of thing is not wasted, what is??
>
> Frankly, I'm more than disgusted with hams that think they know better 
> that the
> original designers of the equipment how it should be operated, without 
> ever
> bothering to even read the damn manuals first.


When did YOU ever see a manual for most of the WW2 surplus that was 
released? The smarter hams did a reverse engineering and wrote up the 
circuits and conversion in a series of CQ Magazine articles in the late 
40's.
It was strange to see gear released to the public by the tons but the 
manuals were still classified.





Time and again I've read about
> TVI and other spurious problems in WW II gear when some jerk has the thing
> grossly mismatched and the B+ cranked up to several times the design spec.


1500V on an ARC-5 TX? I think not. That didnt even happen with the BC375 or 
ART-13 and the famous BC-610. They were great TVI and harmonic generators 
all by themselves since there was no government (FCC)regulation on military 
gear.



The
> designers in WW II were NOT fools.


Nope, they just built to a spec that was handed to them for a very 
disposable piece of equipment. The primary criteria was ruggedness under 
combat use and easy to operate by even a Marine. (I couldnt resist)
OTOH, commercial gear had to satisfy a much wider criteria of use.



(OTOH, some of the early TV designers might
> well have been.)

Mad Man Muntz and the Hallicrafters TV come to mind.

Carl
KM1H


>
> -John
>
>
>
> Jim Brannigan wrote:
>
>> No Meir, they were not wasted.
>>
>> The Surplus radios of the 40's, 50's, 60's and even into the 70's 
>> provided a
>> boon to the radio hobby and the advancement of the electronic arts.
>> This enormous supply of cheap electronics was cut up for parts, modified
>> into early SSB transmitters and performance receivers (Q-5ers),
>> used to explore the VHF and UHF bands and some used as-is.
>> This cheap and plentiful source made it possible for many to become
>> electronics hobbyists and start electronic careers.
>> More than a few electronics firms were launched using cheap surplus
>> components.
>>
>> It is nice that a few are preserved in their original state, but it would
>> have been a shame if the prevailing wisdom was to preserve all of them,
>> then the state of electronic development would have been frozen at VJ Day
>> 1945.
>>
>> Jim
>>
>> >I also did that kind of things when I was young and stupidly thought 
>> >that
>> > there is an infinite supply of surplus radios, so modifying/destroying 
>> > a
>> > few
>> > won't matter in the long run.
>> > I know better now.
>> > The ARC-5 type transmitters if properly matched to the antenna (bear in
>> > mind
>> > the output circuit is not designed for a 50 ohm coax-fed resonant 
>> > antenna,
>> > so additional, external matching is necessary, with the TVI low-pass
>> > filter.
>> > Also, keeping the voltages to what the original system is designed for 
>> > and
>> > using it at the rated power as specified, keep everything under 
>> > control,
>> > including TVI.
>> > But in those days almost everything, including commercially 
>> > manufactured
>> > ham
>> > transmitters had TVI if further precautions were not taken.
>> > The surplus transmitters' bad reputation as to harmonics, instability 
>> > and
>> > TVI spread because hams didn't use the systems as designed, at the 
>> > supply
>> > voltages and  power levels as specified, loaded them into antennas they
>> > were
>> > not designed to work into, thereby causing all the on-the-air problems.
>> > Properly used, with original voltage levels, loading and matching them
>> > properly, makes them no worse than their contemporary ham transmitters.
>> > Many of us still use WW2 surplus equipment on the ham bands, as close 
>> > as
>> > possible to the original system configuration with original power
>> > supplies,
>> > racks, cabling, etc, as the radios were designed and we have no 
>> > problems
>> > at
>> > all.
>> >
>> > 73, Meir WF2U
>> > Landrum, SC
>> >
>> >
>> >
>> > -----Original Message-----
>> > From: boatanchors-bounces at mailman.qth.net
>> > [mailto:boatanchors-bounces at mailman.qth.net] On Behalf Of Jim Brannigan
>> > Sent: Sunday, September 23, 2007 11:43 AM
>> > To: Meir WF2U; 'RAY FRIESS'; boatanchors at mailman.qth.net
>> > Subject: Re: [Boatanchors] ARC 5 stuff - LIST
>> >
>> > I had an ARC-5 on 40CW that caused more TVI key-up than key-down.......
>> > it had most of the parts from the MD-7 modulator on a separate Power
>> > supply/modulator deck.
>> >
>> > Also, I modified one to use as a VFO for a Central Electronics 20A
>> > (9Mcs.?)
>> >
>> > Jim
>> >
>>
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>
> _______________________________________________
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> ** List Administrator - Duane Fischer, W8DBF/W9WZE **
> ** For Assistance: dfischer at usol.com **
> $$ For vintage radio info, see the HCI web site $$
> http://www.w9wze.org
>
>