[R-390] R-390 Digest, Vol 262, Issue 5

G G grantstorrs at aol.com
Thu May 21 12:45:42 EDT 2026 

John, while you probably don’t remember me, I asked you about that very thing at the swap meet. I was considering buying it myself before you showed up and was able to bring back to its original home. In fact I had doubled back after picking up a RCA CR-88A and deicing I still had room in the car!  Glad you were able to recover it and that it didn’t end up with a re-seller. Especially interesting heritage. 

I have my own 390 that I thought had a significant heritage, but I think it but pales compared to yours. Mine is a a regular production with a serial number of 9. The individual components have similarly early numbers in double digits,  such as 24 on the IF module. My understanding is that during the assembly process the S/N numbers didn’t necessarily match. My 390 woks well and  I like the  LC filter much better than my two 390A’s. The tuning is smoother than any other 390 I have tried. As I recall, yours was similarly smooth. 

Congratulations on being able to recover it and to say the hell with weight restirctions!

73
Grant
KC1OMA



> On May 21, 2026, at 12:00 PM, r-390-request at mailman.qth.net wrote:
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> Today's Topics:
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>   1. I'm back AKA R-390(XC-2)/URR (John Flood)
>   2. Re: I'm back AKA R-390(XC-2)/URR (Mike Peace)
>   3. Re: I'm back AKA R-390(XC-2)/URR (John Flood)
>   4. Re: I'm back AKA R-390(XC-2)/URR (Les Locklear)
>   5. Re: I'm back AKA R-390(XC-2)/URR (John Flood)
> 
> From: John Flood <kb1fqg at yahoo.com>
> Subject: [R-390] I'm back AKA R-390(XC-2)/URR
> Date: May 20, 2026 at 4:39:29 PM EDT
> To: "r-390 at mailman.qth.net" <r-390 at mailman.qth.net>
> 
> 
> Greetings,
> After the  stroke i had 3 years ago and selling off all of my R-390,R-390A,R725,and R-392's that I had because the weight exceeded what I was allowed to carry.,. one of the radios i sold followed me home from a flea.  Forgive me if I asked this before, the brain is quite dusty, This unit has a phenolic tag from Collins R-390(XC-2)/URR Serial No. 2 Order N. W36-039-SC44552.  Does any one here know what the XC-2 mod was?  The owner had a great laff when I asked him about it...  He said you should know you sold it to me!    I do recall that now and told him I must have told you!  At least i had the stroke as an excuse!  Well needless to say with the help of my son. the beastie is now inside my shack  Now starts a mission to again figure out what's so special about this one.
> John Flood  N1JAF
>    T email list: QSL.net - Donate Site
> 
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> QSL.net - Donate Site
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> 
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> 
> From: Mike Peace <mike.peace at gmail.com>
> Subject: Re: [R-390] I'm back AKA R-390(XC-2)/URR
> Date: May 20, 2026 at 4:50:44 PM EDT
> To: John Flood <kb1fqg at yahoo.com>
> Cc: "r-390 at mailman.qth.net" <r-390 at mailman.qth.net>
> 
> 
> John,
> 
> Good to hear from you, and glad the radio made it home.
> 
> Short answer: you've got something very special. That contract number,
> W36-039-SC-44552, is the original Collins development contract for the
> R-390. Under it, Collins built only three R-390 prototypes for the Signal
> Corps at Fort Monmouth before any production radios were made:
> 
>  R-390 No. 1 — January 1951
>  R-390 No. 2 — September 1951
>  R-390 No. 3 — February 1952
> 
> The "X" in (XC-2) means experimental. Your plate says Serial No. 2, so you
> almost certainly have R-390 No. 2 — the second R-390 ever built, delivered
> to Fort Monmouth in September 1951.
> 
> That's a museum-grade radio. It pre-dates the entire production run.
> 
> Before you do anything else with it, take a lot of photos — inside,
> outside, the data plate, any paper tags, any handwriting on the chassis.
> Don't clean anything off. The little details on a prototype are part of its
> history.
> 
> The primary source on these three radios is the Collins Final Engineering
> Report (CER No. 297), here:
> 
> 
> https://www.collinsradio.org/wp-content/uploads/2012/04/R390-CER-No-297-Signal-Corp-Final-Eng-Rpt-Includes-R-389.pdf
> 
> And contract background is on r-390a.net:
> 
>  https://www.r-390a.net/faq-manuf.htm
> 
> If you post some interior photos to the list, several of us can help you
> figure out exactly what's original and what isn't.
> 
> Quite a find, John.
> 
> Glad it followed you home.
> 
> 73,
> 
> Mike Peace VK6ADA
> r-390a.net Administrator
> 
> On Wed, May 20, 2026 at 3:39 PM John Flood via R-390 <r-390 at mailman.qth.net>
> wrote:
> 
>> Greetings,
>> After the  stroke i had 3 years ago and selling off all of my
>> R-390,R-390A,R725,and R-392's that I had because the weight exceeded what I
>> was allowed to carry.,. one of the radios i sold followed me home from a
>> flea.  Forgive me if I asked this before, the brain is quite dusty, This
>> unit has a phenolic tag from Collins R-390(XC-2)/URR Serial No. 2 Order N.
>> W36-039-SC44552.  Does any one here know what the XC-2 mod was?  The owner
>> had a great laff when I asked him about it...  He said you should know you
>> sold it to me!    I do recall that now and told him I must have told you!
>> At least i had the stroke as an excuse!  Well needless to say with the help
>> of my son. the beastie is now inside my shack  Now starts a mission to
>> again figure out what's so special about this one.
>> John Flood  N1JAF
>>    T email list: QSL.net - Donate Site
>> 
>> |
>> |
>> |
>> |  |  |
>> 
>> |
>> 
>> |
>> |
>> |  |
>> QSL.net - Donate Site
>> 
>> 
>> |
>> 
>> |
>> 
>> |
>> 
>> 
>> 
>> 
>> ______________________________________________________________
>> R-390 mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/r-390
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:R-390 at mailman.qth.net
>> 
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
> 
> 
> 
> 
> From: John Flood <kb1fqg at yahoo.com>
> Subject: Re: [R-390] I'm back AKA R-390(XC-2)/URR
> Date: May 20, 2026 at 8:00:49 PM EDT
> To: Mike Peace <mike.peace at gmail.com>
> Cc: "r-390 at mailman.qth.net" <r-390 at mailman.qth.net>
> 
> 
> Mike,
> Why dont i have that luck when I play the lotto?!?  The first R-725 I had was a pre-production unit as well.  There were some photos of it in the E.R. article done by George Rancourt several years ago.  No cleaning, will be done  Here is one photo of the Data Plate.  There are some numbers above that  I'll get more when I can.
> John Flood N1JAF
>    On Wednesday, May 20, 2026 at 04:51:21 PM EDT, Mike Peace <mike.peace at gmail.com> wrote:  
> 
> John,
> 
> Good to hear from you, and glad the radio made it home.
> 
> Short answer: you've got something very special. That contract number, W36-039-SC-44552, is the original Collins development contract for the R-390. Under it, Collins built only three R-390 prototypes for the Signal Corps at Fort Monmouth before any production radios were made:
> 
>   R-390 No. 1 — January 1951
>   R-390 No. 2 — September 1951
>   R-390 No. 3 — February 1952
> 
> The "X" in (XC-2) means experimental. Your plate says Serial No. 2, so you almost certainly have R-390 No. 2 — the second R-390 ever built, delivered to Fort Monmouth in September 1951.
> 
> That's a museum-grade radio. It pre-dates the entire production run.
> 
> Before you do anything else with it, take a lot of photos — inside, outside, the data plate, any paper tags, any handwriting on the chassis. Don't clean anything off. The little details on a prototype are part of its history.
> 
> The primary source on these three radios is the Collins Final Engineering Report (CER No. 297), here:
> 
>   https://www.collinsradio.org/wp-content/uploads/2012/04/R390-CER-No-297-Signal-Corp-Final-Eng-Rpt-Includes-R-389.pdf
> 
> And contract background is on r-390a.net:
> 
>   https://www.r-390a.net/faq-manuf.htm
> 
> If you post some interior photos to the list, several of us can help you figure out exactly what's original and what isn't. 
> Quite a find, John. 
> Glad it followed you home.
> 
> 73,
> 
> Mike Peace VK6ADA
> r-390a.net Administrator
> On Wed, May 20, 2026 at 3:39 PM John Flood via R-390 <r-390 at mailman.qth.net> wrote:
> 
>  Greetings,
> After the  stroke i had 3 years ago and selling off all of my R-390,R-390A,R725,and R-392's that I had because the weight exceeded what I was allowed to carry.,. one of the radios i sold followed me home from a flea.  Forgive me if I asked this before, the brain is quite dusty, This unit has a phenolic tag from Collins R-390(XC-2)/URR Serial No. 2 Order N. W36-039-SC44552.  Does any one here know what the XC-2 mod was?  The owner had a great laff when I asked him about it...  He said you should know you sold it to me!    I do recall that now and told him I must have told you!  At least i had the stroke as an excuse!  Well needless to say with the help of my son. the beastie is now inside my shack  Now starts a mission to again figure out what's so special about this one.
> John Flood  N1JAF
>     T email list: QSL.net - Donate Site
> 
> | 
> | 
> | 
> |  |  |
> 
>  |
> 
>  |
> | 
> |  | 
> QSL.net - Donate Site
> 
> 
>  |
> 
>  |
> 
>  |
> 
> 
> 
> 
> ______________________________________________________________
> R-390 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/r-390
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:R-390 at mailman.qth.net
> 
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> 
> 
> 
> 
> From: "Les Locklear" <leslocklear at outlook.com>
> Subject: Re: [R-390] I'm back AKA R-390(XC-2)/URR
> Date: May 20, 2026 at 8:21:32 PM EDT
> To: "John Flood" <kb1fqg at yahoo.com>, r-390 at mailman.qth.net
> 
> 
> Experimental, you must have been dealing with George Rancourt.
> Welcome back!
> Les
> 
> ----- Original Message -----
> From: John Flood via R-390 <r-390 at mailman.qth.net>
> Reply-To: John Flood <kb1fqg at yahoo.com>
> To: <r-390 at mailman.qth.net>
> Sent: 5/20/2026 3:39:29 PM
> Subject: [R-390] I'm back AKA R-390(XC-2)/URR
> ________________________________________________________________________________
> 
>> Greetings,
>> After the  stroke i had 3 years ago and selling off all of my R-390,R-
>> 390A,R725,and R-
>> 392's that I had because the weight exceeded what I was allowed to carry.,. one of the radios i sold followed me home from a flea.  Forgive me if I asked this before, the brain is quite dusty, This unit has a phenolic tag from Collins R-390(XC-2)/URR Serial No. 2 Order N. W36-039-SC44552.  Does any one here know what the XC-2 mod was?  The owner had a great laff when I asked him about it...  He said you should know you sold it to me!    I do recall that now and told him I must have told you!  At least i had the stroke as an excuse!  Well needless to say with the help of my son. the beastie is now inside my shack  Now starts a mission to again figure out what's so special about this one.
>> John Flood  N1JAF
>>    T email list: QSL.net - Donate Site
>> | | | |  |  |
>> |
>> |
>> | |  | QSL.net - Donate Site
>> |
>> |
>> |
>>  ______________________________________________________________
>> R-390 mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/r-390
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:R-390 at mailman.qth.net
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
> 
> 
> 
> 
> From: John Flood <kb1fqg at yahoo.com>
> Subject: Re: [R-390] I'm back AKA R-390(XC-2)/URR
> Date: May 20, 2026 at 9:50:15 PM EDT
> To: "r-390 at mailman.qth.net" <r-390 at mailman.qth.net>, Les Locklear <leslocklear at outlook.com>
> 
> 
> Hi Les,
> No the radio did not come from George  The first time I had it, I got it at a SK estate sale in MA.
> John Flood N1JAF
>    On Wednesday, May 20, 2026 at 08:21:37 PM EDT, Les Locklear <leslocklear at outlook.com> wrote:  
> 
> Experimental, you must have been dealing with George Rancourt.
> 
> Welcome back!
> 
> Les
> 
> ----- Original Message -----
> From: John Flood via R-390 <r-390 at mailman.qth.net>
> Reply-To: John Flood <kb1fqg at yahoo.com>
> To: <r-390 at mailman.qth.net>
> Sent: 5/20/2026 3:39:29 PM
> Subject: [R-390] I'm back AKA R-390(XC-2)/URR
> ________________________________________________________________________________
> 
>>   Greetings,
>> After the  stroke i had 3 years ago and selling off all of my R-390,R-
>> 390A,R725,and R-
>> 392's that I had because the weight exceeded what I was allowed to carry.,. one of the radios i sold followed me home from a flea.  Forgive me if I asked this before, the brain is quite dusty, This unit has a phenolic tag from Collins R-390(XC-2)/URR Serial No. 2 Order N. W36-039-SC44552.  Does any one here know what the XC-2 mod was?  The owner had a great laff when I asked him about it...  He said you should know you sold it to me!    I do recall that now and told him I must have told you!  At least i had the stroke as an excuse!  Well needless to say with the help of my son. the beastie is now inside my shack  Now starts a mission to again figure out what's 
>> so special about this one.
>> John Flood  N1JAF
>>     T email list: QSL.net - Donate Site
>> 
>> | 
>> | 
>> | 
>> |  |  |
>> 
>>   |
>> 
>>   |
>> | 
>> |  | 
>> QSL.net - Donate Site
>> 
>> 
>>   |
>> 
>>   |
>> 
>>   |
>> 
>> 
>> 
>>   
>> ______________________________________________________________
>> R-390 mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/r-390
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:R-390 at mailman.qth.net
>> 
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
> 
> 
> 
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