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.
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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>
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