[Milsurplus] shakey tuning

Ralph Cameron ramcam at magma.ca
Tue Mar 30 15:45:15 EDT 2021


  BODY { font-family:Arial, Helvetica, sans-serif;font-size:12px; }I
had a BC348 with shaky tuning. Turned out the bevel gear coupling had
worn on one edge and I replaced the gears by getting a local machinist
to make them. The spring loading was unsatisfactory in correcting it
because of uneven wear on the teeth. At one time there was a surplus
store in Detroit sold them  but its long gone. If you have a
machinist friend, that may be your best bet. 
 73Ralph VE3BBM
 On Tue 30/03/21  1:07 PM , milsurplus-request at mailman.qth.net sent:
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 Today's Topics: 
    1. Movie (CL in NC) 
    2. Shaky Tuning (CL in NC) 
    3. Re: Shaky Tuning (David Stinson) 
    4. Re: Shaky Tuning (arc5 at ix.netcom.com [4]) 
    5. 803 Socket -- still needed (Mark K3MSB) 

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 Message: 1 
 Date: Mon, 29 Mar 2021 13:38:41 +0000 (UTC) 
 From: CL in NC  
 To: Milsurplus  
 Subject: [Milsurplus] Movie 
 Message-ID:  
 Content-Type: text/plain; charset=UTF-8 
 Well, sounds like my movie suggestion could have loads of sequels to
it, like Indiana Jones, Star Wars, or Back to the Future.  Might only
be of interest to a small market though.  We can add paint to the
list too.  I redid an Halli S41-W for a good friend when I discovered
an old picture of him when he was a teenager in the 40's.  Every
single 41-W I had ever seen was off white, egg shell color, and it
was later that I found these were actually white. 
 Charlie in NC 
 ------------------------------ 
 Message: 2 
 Date: Tue, 30 Mar 2021 02:43:44 +0000 (UTC) 
 From: CL in NC  
 To: Milsurplus  
 Subject: [Milsurplus] Shaky Tuning 
 Message-ID:  
 Content-Type: text/plain; charset=UTF-8 
 Any thoughts on the cause of shaky tuning on a BC348 where, as you
tune through a steady carrier, the beat note jumps up and down in
freq a couple hundred cycles.? More pronounced on the higher bands. 
Could it be the backlash is not set right on the gears?  
 Tune cap seems lubricated properly, no dry bearings, rotor ground
contacts also seem like they are making good contact. The receiver
was repaired by another person years ago.  I found bad bypass caps in
the oscillator module,, tuning and tracking are just about perfect. 
 Charlie, W4MEC in NC 
 ------------------------------ 
 Message: 3 
 Date: Tue, 30 Mar 2021 06:54:52 -0500 
 From: David Stinson  
 To: CL in NC , Milsurplus 
 Subject: Re: [Milsurplus] Shaky Tuning 
 Message-ID:  
 Content-Type: text/plain; charset=utf-8; format=flowed 
 Almost certainly the backlash gears, usually the 
 one on the end of the tuning cap. 
 Take a look at this video: 
 https://www.youtube.com/watch?v=kYgCUokEgDg 
  ? It's about the TCS gears, but the tips 
 apply.? People argue with 
 me about running clean backlash gears 
 without lube, but in my experience, all 
 dousing them with oil does is attract dirt 
 to eventually gunk them up again. 
 Each to his own, of course. 
 GL OM DE Dave AB5S 
 On 3/29/2021 9:43 PM, CL in NC via Milsurplus wrote: 
 > Any thoughts on the cause of shaky tuning on a BC348 where, as you
tune through a steady carrier, the beat note jumps up and down in freq
a couple hundred cycles.? More pronounced on the higher bands.  Could
it be the backlash is not set right on the gears? 
 --  
 This email has been checked for viruses by Avast antivirus software.

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 ------------------------------ 
 Message: 4 
 Date: Tue, 30 Mar 2021 07:44:58 -0500 
 From: "arc5 at ix.netcom.com [15]"  
 To: CL in NC , Milsurplus 
 Subject: Re: [Milsurplus] Shaky Tuning 
 Message-ID:  
 Content-Type: text/plain; charset="utf-8" 
 One thing I didn't think about it the time. Not enough coffee,
LOL.If somebody's worked on it before, and you have all the crud out
of the backlash gear, make sure it's tensioned to properly. You have
to mesh a backlash gear with the worm screw that turns it with the
spring in the gear under tension, usually just one tooth is all
that's necessary. If you put too much tension it will defeat the
function and wear the gear out.I'm sure there are folks here who
remember the tensioning procedure for the backlash gear in the
bc-348. Back to work for me.??73 OM. 
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 Message: 5 
 Date: Tue, 30 Mar 2021 13:06:00 -0400 
 From: Mark K3MSB  
 To: List Milsurplus , ARC5 
 ,  MMRCG , Boatanchors List 
 Subject: [Milsurplus] 803 Socket -- still needed 
 Message-ID: 
 Content-Type: text/plain; charset="utf-8" 
 Still looking for an 803 socket that will fit my TBW-5 transmitter. 
 The socket is square and has 4 mounting holes.  The mounting holes
are 1 
 7/8 inches apart (per side). 
 The 803 sockets Hue has made available will not work in a TBW. 
 73 Mark K3MSB 
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