I think you're right there Jim. I see on the schematic it is named:
"DUMMY, LOAD, MODULATOR"
Charlie, N0TT
On Mon, 29 Jun 2020 11:34:43 -0700 jimlux <jimlux@earthlink.net> writes:
> 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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> >>> > >
> >>> >
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> >>> >
> >>> >
> >>> >
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> >>> >
> >>
> >>
> >
>
>
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