[MRCA] MRCA Digest, Vol 119, Issue 13

Thomas Cook kc7rjt at msn.com
Tue Mar 11 22:52:16 EDT 2014


Hello Al and "Z",
I talked to another ham and he informed me mike has a J-37, not a J-38.
I am sorry I wasted anyone's time.
Dimensions Center to Center for J-37 Please?
 
Thanks for putting up with me,
 
Tom
 

 
> From: mrca-request at mailman.qth.net
> Subject: MRCA Digest, Vol 119, Issue 13
> To: mrca at mailman.qth.net
> Date: Tue, 11 Mar 2014 19:42:43 -0400
> 
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> Today's Topics:
> 
>    1. M and S report from Chickenland (B. Smith)
>    2. ARC-5/SCR-274-N IF Coil Mod -Continued (D. Platt)
>    3. J-38 mounting hole distance. (Thomas Cook)
>    4. Re: J-38 mounting hole distance. (Al Klase)
>    5. Re: J-38 mounting hole distance. (B. Smith)
> 
> 
> ----------------------------------------------------------------------
> 
> Message: 1
> Date: Tue, 11 Mar 2014 12:40:34 -0400
> From: "B. Smith" <smithab11 at comcast.net>
> To: mrca at mailman.qth.net
> Subject: [MRCA] M and S report from Chickenland
> Message-ID: <531F3C82.4020705 at comcast.net>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> 
> Whew, sigs down today     - - - .
> 
>   N3FRQ very readable bout S4. NN2K loud and clear. Switching back and 
> forth between the doublet and the 200 foot loop, the loop always wins on 
> receive. When WA3EJT(call correct?) switched his antennas sigs here came 
> up couple of S units. KK1K at the end was fairly loud.
> 
> Z
> 
> 
> ------------------------------
> 
> Message: 2
> Date: Tue, 11 Mar 2014 13:30:18 -0400
> From: "D. Platt" <jeepp at comcast.net>
> To: ARC5 at mailman.QTH.net, 	Military Radio Collectors Association
> 	<mrca at mailman.qth.net>
> Subject: [MRCA] ARC-5/SCR-274-N IF Coil Mod -Continued
> Message-ID: <531F482A.5020202 at comcast.net>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> 
> Gentlemen,
> 
> The plot thickens, as they say.  I completed a second set of coils from 
> another similar receiver.  The mechanical setup for securing the coil 
> bobbins and spacers was different on this one.  Whereas the initial set 
> of coils used a long screw up through both coils and terminated at the 
> phenolic spacer bar with a nut, this second set has a shorter screw 
> coming down through the spacer bar and threaded into the lowermost 
> ceramic spacer.  The screw coming from the bottom of the coil assy is a 
> short one and threads into the lowermost spacer.  So, the procedure on 
> this one was a bit different.
> 
> At this point, I'll assume that there are just two setups for securing 
> the coil bobbins.  Both types use the same size and spaced ceramic 
> spacers.  In this second type, it may be necessary to adjust either of 
> the two resonating caps such that the plates do not block access for the 
> loosening of the securing screw (from the top). After clearing access to 
> the screw, holding the lowermost spacer with a tiny long-nose or 
> hemostat, unscrew the securing screw from the spacer.  Then, remove the 
> screw securing the spacer from the bottom of the coil assy.
> 
> At this point, the lowermost spacer may be carefully jimmied out of the 
> coil assy.  Using a soldering iron, heat and slide the wires going to 
> the lower coil down a bit to provide some slack.  It may be necessary to 
> re-heat and re-solder these wires to ensure continuity.  After providing 
> some slack in the wires, its possible to move the lower coil downward to 
> provide the necessary increase in spacing.  In my case, I inserted a 
> nylon washer between the bottom of the coil assy and the bottom of the 
> coil bobbin and added a dollop of epoxy to secure the coil bobbin.  I 
> then added some epoxy to the top of this bobbin and to the top and 
> bottom of the upper coil bobbin as well as to the top of the securing 
> screw.  Before adding epoxy to this screw head, ensure that it, and the 
> phenolic spacer bar, are down just far enough to keep clear of the two 
> resonating variable capacitors.  When all's well, add a bit of epoxy to 
> secure everything.  Also, be sure and check for continuity of each of 
> the coils bfore putting everything back together.  So far, thiese mods 
> have genuinly helped with selectivity.....
> 
> As I mentioned in the first posting of this procedure, after one does 
> the first coil set, the procedure is no big deal......  One needs not to 
> be a jeweler or surgeon.
> 
> Does anyone think a submission to ER, probably with photos, might be 
> informative?
> 
> Jeep - K3HVG
> 
> 
> ------------------------------
> 
> Message: 3
> Date: Tue, 11 Mar 2014 16:29:59 -0500
> From: Thomas Cook <kc7rjt at msn.com>
> To: mrca <mrca at mailman.qth.net>
> Subject: [MRCA] J-38 mounting hole distance.
> Message-ID: <SNT150-W98E7632E3214DEDE9C95696770 at phx.gbl>
> Content-Type: text/plain; charset="iso-8859-1"
> 
> Hello all,
> I have a blind friend with a J-38 and he needs it mounted on a plate.
> I made the plate but I need the distance center to center for drilling and tapping
> the plate.
>  
> I'd ask him, but i'm trying to surprise him with it.
>  
> Can anyone provide me the dimensions?
>  
>  
> Thanks and 73 de Tom KG5AJP
>  
>  
>  		 	   		  
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> ------------------------------
> 
> Message: 4
> Date: Tue, 11 Mar 2014 19:33:07 -0400
> From: Al Klase <ark at ar88.net>
> To: mrca at mailman.qth.net
> Subject: Re: [MRCA] J-38 mounting hole distance.
> Message-ID: <531F9D33.3010207 at ar88.net>
> Content-Type: text/plain; charset="iso-8859-1"; Format="flowed"
> 
> Hi Tom,
> 
> I repeatedly measure 1.550", but I'm concerned that the "design 
> dimension" might have been 1 9/16, 1.625".  Holes are tapped 6-32.
> 
> YMMV
> 
> 73,
> Al
> 
> On 3/11/2014 5:29 PM, Thomas Cook wrote:
> > Hello all,
> > I have a blind friend with a J-38 and he needs it mounted on a plate.
> > I made the plate but I need the distance center to center for drilling 
> > and tapping
> > the plate.
> >
> > I'd ask him, but i'm trying to surprise him with it.
> >
> > Can anyone provide me the dimensions?
> >
> >
> > Thanks and 73 de Tom KG5AJP
> >
> >
> >
> >
> > ______________________________________________________________
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> 
> -- 
> Al Klase -- N3FRQ
> Jersey City, NJ
> http://www.skywaves.ar88.net/
> 
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> ------------------------------
> 
> Message: 5
> Date: Tue, 11 Mar 2014 19:42:35 -0400
> From: "B. Smith" <smithab11 at comcast.net>
> To: Thomas Cook <kc7rjt at msn.com>, mrca at mailman.qth.net
> Subject: Re: [MRCA] J-38 mounting hole distance.
> Message-ID: <531F9F6B.8060909 at comcast.net>
> Content-Type: text/plain; charset="iso-8859-1"; Format="flowed"
> 
> There were several companies that made the J-38 so different 
> measurements might exist.
>   I assume he is keeping the original Bakelite  mount?  Or is he 
> mounting just the metal key portion to a plate.  Let me know I will keep 
> the J-38 handy.
> 
> Z
> 
> On 3/11/2014 5:29 PM, Thomas Cook wrote:
> > Hello all,
> > I have a blind friend with a J-38 and he needs it mounted on a plate.
> > I made the plate but I need the distance center to center for drilling 
> > and tapping
> > the plate.
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> End of MRCA Digest, Vol 119, Issue 13
> *************************************
 		 	   		  
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