On 6/29/20 10:33 AM, n0tt1@juno.com wrote:
OK, thanks Jim,
Interesting why Bendix would call this thing (in part) a
"modulator"...nothing
in there to modulate a RF signal that I know about....just a high power
50-ohm dummy load.
It's a dummy load for a modulator, so the nomenclature might have been
arranged that way, and along the line, a comma or something got dropped.
that is, it might have been "Dummy Load, Modulator"
73,
Charlie, N0TT
On Sun, 28 Jun 2020 20:04:01 -0700 jimlux <jimlux@earthlink.net> writes:
On 6/28/20 7:32 PM, n0tt1@juno.com wrote:
Thanks to Jim and Chuck!
Definately non-inductive for this application, but the power
rating
is, I don't know. I know it was used at a 5KW AM radio station
for
some testing. I should have mentioned that the glass tubes look
like common florescent tubes....white in color with no hint of
carbon,
etc. I would do some more examination but I sure don't want to
risk
breaking one of them. They are now back in their case, sealed by
a
"jillion" screws!!!
I looked at
https://theelectrostore.com/content/datasheets/kanthal_globar_resistors.p
df
Doesn't appear to be anything similar in appearance, but like Jim
said
there's
lots of area for cooling. It could be that there's something
inside the
tubes which can't been seen.
Unfortunately I threw away some electronic industrial catalogs
from the
late 1960's
era. Oh! BTW, this dummy load was made by Bendix and it's called
a
"Dummy Load Modulator". Not sure what the "modulator" reference
means.
I do have photos if anyone wants a look.
probably either an AM transmitter or radar transmitter.
The modulator in a radar transmitter is the thing that generates HV
pulses of the correct length and voltage.
The modulator in a AM transmitter is an audio amplifier that puts
out as
much audio power as used in the RF.
73,
Charlie, N0TT
On Sun, 28 Jun 2020 12:01:58 -0700 jimlux <jimlux@earthlink.net
<mailto:jimlux@earthlink.net>> writes:
> On 6/28/20 11:43 AM, n0tt1@juno.com <mailto:n0tt1@juno.com>
wrote:
> > Hello everyone,
> >
> > I recently aquired a "commercial" dummy load that I'm sure
will
> handle
> > more than 2kw.
> > There are 12, 600-Ohm resistors in parallel that measure
50-Ohms
> with a
> > Ohmmeter.
> > The resistors look like frosted glass tubes with metal end
caps.
> They
> > measure 9.5" in length
> > and 1" diameter. The number stamped on the ends is E9935R
and
> their
> > vintage is late 60's. A Google search for that exact number
> turned up
> > nothing.
> >
> > Question: Does anyone know the power rating of these
resistors
> and
> > what type of resistor are they?
>
> They might be non-inductive power resistors from Carborundum
corp
> (now
> part of Sandvik, as I recall). I've got a bunch of them,
although
> mine
> are grey or brown.
>
> They could also be a thin film resistor deposited on a ceramic
> substrate. Same idea - lots of area for cooling.
>
>
>
>
> >
> > I have photos.
> >
> > 73,
> > Charlie, N0TT
> >
> > _______________________________________________
> >
> >
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