[Collins] KWM-1 in U2 aircraft

Dr. Gerald N. Johnson geraldj at netins.net
Mon Feb 6 21:12:16 EST 2017 

At 29,000 feet the tubes would probably overheat, and the PA tuning 
capacitor probably arc. And any small airgaps with PA plate voltage 
applied might arc. Adding fans and good heat dissipating small tube 
shields could help the heat problems and then going to a PA tuning 
capacitor with a greater air gap should help. Plus lowering the PA plate 
voltage and expecting less power could be a solution for the high 
altitude arcing and 6146 overheating. The high altitude cabin pressure 
didn't make life great for the pilots either.

73, Jerry, K0CQ

On 2/6/2017 1:24 AM, antqradio at sbcglobal.net wrote:
> Jerry
>
> Killing a little time before bed. Looked up the U2 to see if the cabin
> is pressurized. Well, not really. At a mission altitude of 70,000 feet,
> the cabin is at the equivalent of 29,000 feet, Seems that they have been
> lately modified to bring the cabin down to the equivalent of 15,000 feet.
> See the May, 2012 article:
> http://www.airspacemag.com/military-aviation/killer-at-70000-feet-117615369/
> So what would happen to the KWM-1 when operating at 29,000 feet?
>
> Jim
>
> *From:* Dr. Gerald N. Johnson <geraldj at netins.net>
> *To:* antqradio at sbcglobal.net
> *Cc:* "collins at mailman.qth.net" <collins at mailman.qth.net>
> *Sent:* Wednesday, February 1, 2017 5:15 PM
> *Subject:* Re: KWM-1 in U2 aircraft
>
> Best I recall the KWM-1 I saw in that U2 was behind the pilot's seat
> mounted up above the seat back or on top of the dash so the pilot could
> use its controls since it had no provisions for remote control. It had
> the crystal plug in sold for novices. It had to be accessible in flight
> to change frequency and to tune. The 618T sure took more power but it
> was remote controlled and auto tuned as was the companion antenna
> coupler, a great deal easier for the pilot to use. I can see that if the
> cabin was not pressurized the KWM-1 would need considerable modification
> to keep it from arcing around the PA tubes and tuning capacitors while
> transmitting. According to the yellow 1959 Fundamentals of Single
> Sideband there were both 12 volt and 24 volt supplies that could run the
> KWM-1 and KWM-2. 516E-1 and 516E-2.
>
> Then the museum aircraft may have been modified at the museum to install
> a stock KWM-1 because some had been used and there were no radios in the
> aircraft that got to the museum. So we can't be sure about the radio.
> There weren't very many U2 as I recall so a couple KWM-1 and the 3 618T
> mentioned in those documents may have gone a long way.
>
> 73, Jerry, K0CQ, Technical Adviser to the Collins Radio Association.
>
> On 2/1/2017 11:27 AM, antqradio at sbcglobal.net
> <mailto:antqradio at sbcglobal.net> wrote:
>  > Jerry
>  >
>  > Below are some CIA documents concerning the U2-C + (KWM-1 or SSB), there
>  > are others to be found at:
>  >
>  > https://www.cia.gov/library/readingroom/
>  >
>  > I just did a quick scan of these docs but it seems that the KWM-1 was
>  > heavily modified and mounted in the U2 nose area since it was packaged
>  > to operate at 70,000 feet. Support aircraft used either the ARC-58 or
>  > ARC-65 depending on the age of the aircraft and transceiver location.
>  > These docs are redacted and terse so several have to be read to get the
>  > full picture.
>  >
>  >
> https://www.cia.gov/library/readingroom/docs/CIA-RDP67B00511R000100240023-0.pdf
>  >
> https://www.cia.gov/library/readingroom/docs/CIA-RDP89B00569R000900250183-7.pdf
>  >
> https://www.cia.gov/library/readingroom/docs/CIA-RDP81B00878R000600030100-7.pdf
>  >
> https://www.cia.gov/library/readingroom/docs/CIA-RDP63-00313A000600070028-9.pdf
>  >
> https://www.cia.gov/library/readingroom/docs/CIA-RDP63-00313A000600070037-9.pdf
>  >
> https://www.cia.gov/library/readingroom/docs/CIA-RDP81B00961R000100010141-9.pdf
>  >
> https://www.cia.gov/library/readingroom/docs/CIA-RDP81B00961R000100140242-3.pdf
>  >
> https://www.cia.gov/library/readingroom/docs/CIA-RDP33-02415A000400310008-4.pdf
>  >
>  >
>  > Jim
>  >
>  >
>  > *From:* Dr. Gerald N. Johnson <geraldj at netins.net
> <mailto:geraldj at netins.net>>
>  > *To:* collins at mailman.qth.net <mailto:collins at mailman.qth.net>
>  > *Sent:* Tuesday, January 31, 2017 7:27 PM
>  > *Subject:* Re: [Collins] 312B-2
>  >
>  > Some KWM-1 flew in U-2 spy planes with the crystal plug in option. I
>  > remember seeing one in the cockpit I think at the SAC museum in Nebraska
>  > several years ago.
>  >
>  > I think the KWM-1 production was all before Art's decree for random
>  > serial numbers so the highest serial number found may hint at the number
>  > produced. I know for sure that the random serial numbers applied to
>  > KWM-2 and S line.
>  >
>  > 73, Jerry, K0CQ, Technical Adviser to the Collins Radio Association.
>  >
>  > On 1/31/2017 5:26 PM, CARLSMITHSON wrote:
>  > >
>  > > There is a new group on facebook dedicated to the KWM-1 and the fellow
>  > > wanted serial numbers of their rigs. I was trying to determine just
>  > how many
>  > > KWM-1s were made and I found a listing for a 312B-2 with a paint
> chip for
>  > > $1300.
>  > >
>  > > Sonny
>  > >
>  > >
>  > >
>  > >
>  > >
>  > >
>  > >
>  > >
>  > > -----Original Message-----
>  > > From: Gary H. Harmon, Jr. [mailto:gharmon at idworld.net
> <mailto:gharmon at idworld.net>
>  > <mailto:gharmon at idworld.net <mailto:gharmon at idworld.net>>]
>  > > Sent: Tuesday, January 31, 2017 6:02 PM
>  > > To: 'CARLSMITHSON'; Collins at mailman.qth.net
> <mailto:Collins at mailman.qth.net>
>  > <mailto:Collins at mailman.qth.net <mailto:Collins at mailman.qth.net>>
>  > > Subject: RE: [Collins] 312B-2
>  > >
>  > > That's good to know. I have one plus two KWM-1s plus one AC PS and an
>  > extra
>  > > AC PS cover.
>  > >
>  > > WHY? Good question.
>  > >
>  > > 73,
>  > >
>  > > Gary H. Harmon, Jr. - K5JWK - HAM Radio and ATARI Archaeologist
>  > > 6003 Archwood
>  > > San Antonio, TX 78239-1504
>  > > (210) 657-1549<home>
>  > > (210) 884-6926<cell and text>
>  > > (210) 657-1549<FAX with prior notification> gharmon at idworld.net
> <mailto:gharmon at idworld.net>
>  > <mailto:gharmon at idworld.net <mailto:gharmon at idworld.net>>
>  > >
>  > > "Retirement = Every day is a Saturday except Sunday"
>  > > http://www.grissomroadcoc.org
> <http://www.grissomroadcoc.org/><http://www.grissomroadcoc.org/>
>  > >
>  > >
>  > > -----Original Message-----
>  > > From: Collins [mailto:collins-bounces at mailman.qth.net
> <mailto:collins-bounces at mailman.qth.net>
>  > <mailto:collins-bounces at mailman.qth.net
> <mailto:collins-bounces at mailman.qth.net>>] On Behalf Of
>  > > CARLSMITHSON
>  > > Sent: Tuesday, January 31, 2017 4:58 PM
>  > > To: Collins at mailman.qth.net <mailto:Collins at mailman.qth.net>
> <mailto:Collins at mailman.qth.net <mailto:Collins at mailman.qth.net>>
>  > > Subject: [Collins] 312B-2
>  > >
>  > > I saw somewhere that the 312-B2 speaker,directional coupler, phone
>  > patch is
>  > > possibly the rarest Collins assessor. Do any of you know what numbers
>  > were
>  > > produced?
>  > >
>  > >
>  > >
>  > > Thanks,
>  > >
>  > > Sonny Smithson..NN8K
>  > >
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