[Milsurplus] Dittmore-Friemuth

Mon Jun 25 13:40:17 EDT 2018

Duh!!!!  Where did I get Bruce from?My apologies Mike!Jim

      From: Jim Whartenby <antqradio at sbcglobal.net>
 To: "Milsurplus at mailman.qth.net >> Milsurplus" <Milsurplus at mailman.qth.net> 
 Sent: Monday, June 25, 2018 12:37 PM
 Subject: Re: [Milsurplus] Dittmore-Friemuth

BruceI think you are on to something.  I'm beginning to believe that the Dittmore-Freimuth R-390A receivers were used as prove-of-concept models to show that the Dittmore-Freimuth manufactured mechanical filters were up to the task of being a second source for Collins.  These receivers were built under a 1968 contract which seems to be quite late in the game.  It is reported that all of these D-F receivers have EAC modules with just D-F filters and a D-F nomenclature tag.  The D-F tags made it easy to identify which receivers had the new filters.
I also have seen (and repaired) a URC-32 (KWT-6 Type 8) Stabilized Master Oscillator so D-F more then once second sourced Collins.
The number of Dittmore-Freimuth R-390As is reported to be 215 but I think that this number represents the highest serial number found.  Don't think anyone still around knows for sure just how many were actually built under that contract.
I have also found ceramic filters installed in R-1051 receivers which looked to have been original to the receiver IF filter module.Regards,Jim

      From: Bruce Gentry <ka2ivy at verizon.net>
 To: "Milsurplus at mailman.qth.net >> Milsurplus" <Milsurplus at mailman.qth.net> 
 Sent: Monday, June 25, 2018 11:12 AM
 Subject: Re: [Milsurplus] Dittmore-Friemuth

 How long did the DOD follow the "no one exclusive supplier" policy?ï¿½ï¿½ The name I rememberï¿½ from those times is Lavoie Labs. They made clones of Tektronix scopes and Hewlett Packard signal generators, and maybe more.ï¿½ The clones seemed to work as well as the originals, but I don't know how interchangable parts were from clone to original. 
  ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ Bruce Gentry, KA2IVY

 On 6/25/18 11:39 AM, Michael Bittner wrote:

FWIW, I have an R-390 style mechanical filter marked DF-455-2CB, made by Dittmore-Freimuth, Mikwaukee.ï¿½ Mike W6MAB ï¿½ ï¿½ 
 ----- Original Message -----  From: Jim Whartenby  To: Milsurplus at mailman.qth.net  Sent: Sunday, June 24, 2018 14:07 Subject: [Milsurplus] Dittmore-Friemuth 
   Does anyone have any information on the Dittmore-Friemuth Corporation of Milwaukee, Wisconsin? ï¿½There is a few lines on the radiomuseum site and there is also a Federal Court ruling from the 1960s but I found nothing more useful using Mr. Google. ï¿½ 
  I know that they made modules for the URC-32 and they added some practical modifications to the SMO RF tuner. ï¿½Perhaps they also supplied modules for other military radio equipment, including the manufacture of mechanical filters and telegraph keys, but I can find nothing more about them. ï¿½ 
  I assume that they were acquired by a larger firm? ï¿½Any thoughts?
  Jim  

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