[ARC5] [Milsurplus] Opinions on ARR-7

Mon Aug 27 15:00:51 EDT 2012

In general, AC gear will always run on a higher frequency line, but not on
a lower frequency line. If the frequency is below design, the power
transformers saturate and often burn out.

-John

===================

> A lot of 400 cycle powered gear was used aboard USN ships during WW2.  The
> museum battleship USS North Carolina in Wilmington, NC is equipped with
> many airborne type ECM transmitters, and they all run from a special high
> frequency AC line.  They were designed to operate from 115v 400 cycle
> power.  They would run okay on 800 cycle power, as many USN aircraft used
> that high frequency source which came from an engine-driven AC generator.
> Unfortunately I don't know how exactly this power is provided aboard ship,
> but I suspect it's through rotary converters which are powered from either
> 110v AC or (more likely) 440 v AC, 60 cycles.
>
> Yes, I have actually had my own eyes on these transmitters, in place
> aboard the ship; and yes, they are straight out-of-the-box airborne types.
>
> I have also seen a shipboard version of the GP-7 transmitter aboard the
> USS NC.  Aside from the nomenclature tag, it is exactly like the 800 (yes,
> EIGHT hundred) cycle powered GP-series carried in a/c such as the SBD and
> TBD.
>
> This transmitter was indeed used aboard the vessel, back in the day.
>
> As for the SPA-1 pulse analyzer, it was also called the APA-6.  Both
> versions had power supplies which would operate on 60-2400 cycle AC power.
>  That's right.  I have the manual right here.
>
> However, the SPA-1/APA-6 is an exception to the rule.  I am quite positive
> that the GP transmitter used 800 cycle power, and that these ECM units
> used 400 (but would run on higher frequency AC).
>
> 73
>
> Mike
> W4DSE
>
>
> --- On Mon, 8/27/12, J. Forster <jfor at quikus.com> wrote:
>
>> From: J. Forster <jfor at quikus.com>
>> Subject: Re: [ARC5] [Milsurplus]  Opinions on ARR-7
>> To: "Mike Hanz" <aaf-radio-1 at aafradio.org>
>> Cc: "ARC5 at mailman.QTH.net" <arc5 at mailman.qth.net>,
>> "Vintage-Military-RADAR at yahoogroups.com"
>> <vintage-military-radar at yahoogroups.com>, "Milsurplus at mailman.QTH.net"
>> <milsurplus at mailman.qth.net>
>> Date: Monday, August 27, 2012, 1:48 PM
>> > Like the others, I couldn't find
>> a notation for a PP-33 in any of my
>> > directories, nor ever saw one, John.
>>
>> I wa given the number in an email. My bad for not checking
>> the info before
>> using it. It really seemed logical.
>>
>> > Doesn't mean it doesn't exist - it
>> > would have been useful for a shipboard application in a
>> small ship like
>> > a submarine, I suppose.
>>
>> Exactly. I first saw the setup w/ the SPA-1 in the LIONFISH,
>> but didn't
>> search out how it was powered.
>>
>> > I'm using a PP-32/AR with my AN/ARR-7, but it
>> > does require a 400Hz supply, and I have been thinking
>> about a small
>> > series B+ regulator for the cable between the two boxes
>> because it
>> > retained the 270-280vdc B+ that the original SX-28 used
>> for most of that
>> > set.  It just makes everything run hot inside to
>> no real advantage since
>> > you don't need any audio power to speak of.  I've
>> tried running it at
>> > the 166v that the RAX used with a similar receiver
>> design and it does
>> > make things run quite a bit cooler without any apparent
>> performance
>> > compromise.
>>
>> A power supply would be easier to build with today's parts.
>> However, I'm
>> not sure I want to go there.
>>
>> > Frankly, I prefer the ARR-7 to the BC-348, partially
>> because of the
>> > flexibility of the IF selectivity settings. 
>> Having said that, it
>> > doesn't have the nice feel of an SX-28A in tuning
>> around the bands,
>> > though it does have about the same electrical
>> performance (duh).  Back
>> > when I researched it years ago, it appeared that the
>> ARR-7 was designed
>> > in 1942, most of the work being to repackage the SX-28
>> and remove the
>> > heavy parts not needed for a surveillance set, but
>> there were a few
>> > small RF and IF circuit changes that eventually found
>> their way into the
>> > slightly later SX-28A.  The motor drive mechanism
>> for it and the
>> > AN/ARR-5 (repackaged S-27/S-36 VHF set) was reportedly
>> quite fragile and
>> > had a rather short lifetime, so I don't use the ones in
>> mine except for
>> > an occasional demonstration of how they work, even
>> though I've relubed
>> > them with synthetic grease to reduce friction.  I
>> did make one small
>> > modification to it - jumpered plate and grid of the
>> anti-radiation
>> > isolation stage with a small mica capacitor soldered to
>> a couple of tube
>> > pins inserted into the tube socket. The original design
>> simply added a
>> > bunch of noise to the receiver without any useful
>> purpose.  I made the
>> > same change to the ARR-5 input stage.  Pairing
>> with an AN/APA-10
>> > panadapter and an APA-6 or -11 pulse analyzer is an
>> interesting thing to
>> > do if you have the space and power.  I normally
>> use it with an
>> > interphone amplifier to get the power for a speaker -
>> the LS-184/AIC-10
>> > - but any outboard amp can of course be used.
>>
>> Yes, that was essentially my intent.
>>
>> Best,
>>
>> -John
>>
>> ==================
>> >
>> > 73,
>> > Mike  KC4TOS
>> >
>> > On 8/26/2012 10:42 PM, J. Forster wrote:
>> >> >From N7JR:
>> >>
>> >> Power Supply, PP-32/AR
>> >> JAN Type: PP-32/AR
>> >> Nomenclature: Power Supply
>> >> Reference: AN 08-30ARR7-2
>> >> Weight: 25
>> >> Part of: ARR-7
>> >> Description: The PP-32 provides all the power
>> necessary to power three
>> >> receivers, R-45, in radio receiving set ARR-7.
>> >> Source: AN 08-30ARR7-2
>> >> Created: Wed Jul 12 19:24:04 2000
>> >> Last Modified: Wed Jul 12 19:24:04 2000
>> >>
>> >> -John
>> >> ===============
>> >
>> >
>>
>>
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