[R-390] AN/URM-25J

[Roy Morgan]

At 03:00 AM 10/22/2007, Richard Spargur wrote:
>I have an AN/URM-25J on loan from a friend to use to restore a few R-390As I
>have.  I am familiar with the AN/URM-25C, D and F models...  Does anyone 
>have a manual or some documentation that shows what an AN/URM-25J is?


Richard,

It is a URM-25D, apparently.
(But, Les notes that it has more attenuation stages.)

  Does yours:
- have a label on the front panel that says URM-25J?
- have more than normal positions on the RF output attenuator?

I found some emails in my notes about this some time ago:

>To: Joe Foley <redmenaced at yahoo.com>, r-390 at mailman.qth.net
>From: Roy Morgan <roy.morgan at nist.gov>
>Subject: Re: [R-390] URM 25D Signal Generator
>In-Reply-To: <20031207182149.69229.qmail at web14002.mail.yahoo.com>
>References: <001d01c3bcec$768cab60$0100a8c0 at HOUSEPC>
>Mime-Version: 1.0
>Content-Type: text/plain; charset="us-ascii"; format=flowed
>Sender: r-390-admin at mailman.qth.net
>Errors-To: r-390-admin at mailman.qth.net
>X-BeenThere: r-390 at mailman.qth.net
>X-Mailman-Version: 2.0.8
>Precedence: list
>List-Id: Collins Radio R-390A Military HF Receiver <r-390.mailman.qth.net>
>List-Archive: <http://mailman.qth.net/pipermail/r-390/>
>Date: Mon, 08 Dec 2003 11:05:53 -0500
>X-MailScanner:
>
>At 10:21 AM 12/7/03 -0800, Joe Foley wrote:
>
>>Speaking of signal generators, how does the URM-25J
>>stack up against the others mentioned?
>
>Joe,
>
>My guess is: about the same.
>
>>Is it substantially better than the "D" model?  Just
>>what are the differences?
>
>Can't tell you, but my notes on the URM-25 include the following messages.
>
>I assume that "more attenuation stages" means an additional step in the 
>output attenuator.  I do not have pictures with enough clarity to see if 
>this is true or not.
>
>>Subject: Re: [R-390] Tags on urm-25d
>>To: r-390 at qth.net
>>From: "Roger L Ruszkowski" <rlruszkowski at west.raytheon.com>
>>Date: Wed, 7 Nov 2001 08:32:29 -0800
>>Sender: owner-r-390 at qth.net
>>
>>I just bought a urm-25 generator from fair radio (checked unit). It looks
>>complete with all the adapters manual etc. When I was looking for one they
>>disappered off the web and epay. My unit has 2 different tags on it the
>>front panel has a urm-25d (with new screws) and the case has a urm-25j (1968
>>?) Is there anyway of knowing which one I have and what version is a
>>urm-25j?
>> >
>> > Thanks
>> > Mike
>> > mikobrien at excite.com
>>
>>Mike,
>>
>>It's a D.
>>
>>The tag is attached to the front panel.
>>The front panel is attached to the guts.
>>That is what makes the model.
>>The case is just there to keep the dust out.
>>
>>Ok so some one droped a D model into a J case.
>>Ah the wonders of interchangeable parts.
>>
>>
>>The J version is the 9th or 10th version.
>>
>>Roger.
>>
>>From: Llgpt at aol.com
>>Date: Wed, 7 Nov 2001 14:49:40 EST
>>Subject: [Hammarlund] Re: [R-390] Tags on urm-25d
>>Sender: owner-hammarlund at qth.net
>>
>>
>>In a message dated 11/07/01 10:17:21 AM, pha at pdq.com writes:
>>
>><< I thought the URM-25J was a URM-25D with a different accessory or 
>>two.  At least that was what I read on one of these lists awhile back.
>>
>>Paul
>>  >>
>>
>>And, more attenuation stages in it.
>>
>>Les


Roy




- Roy Morgan, K1LKY since 1959 - Keep 'em Glowing
13033 Downey Mill Road, Lovettsville, VA 20180
Phone 540-822-5911   Cell 301-928-7794
Work: Voice: 301-975-3254,  Fax: 301-975-6097
roy.morgan at nist.gov --