[ARC5] [Milsurplus] Opinions on ARR-7

Mon Aug 27 14:21:14 EDT 2012

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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