[R-390] BFO Hum Vol 150, Issue 26

Tue Oct 25 06:32:34 EDT 2016

 Over the years I've had Probably in excess of 100    R390A and R390  and 
R391  and 51J4  Rxs pass through my hands as I used to buy them at the 
government surplus  auctions............ Re The hum when you turn on the BFO 
, I have come across this a few times , and its been  due to  Filament 
cathode leakage in either the BFO or VFO 6BA6 s  which are in series with 
the 3TF7 regulator tube ,[ REPLACING one of the  Tubes should Fix the 
Problem] regarding covers I have a few spare original top and bottom covers 
, and a spare IF strip, with filters  and  a quite large quantity of the 
various size collars with the bristo screws , also I have a surplus 
''Progesteron''  VFO  and a quantity of NOS dual 450v caps in the octal 
sockets , also a Spare power Transformer for a R390 NON A  receiver, Also A 
good 390A front panel ......  I probably have lots more bits too if anyone 
is interested they can contact me via  my  email address  regards  Bernie 
Nicholson ----- Original Message ----- 
From: <r-390-request at mailman.qth.net>
To: <r-390 at mailman.qth.net>
Sent: Tuesday, October 25, 2016 10:13 AM
Subject: R-390 Digest, Vol 150, Issue 26

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> Today's Topics:
>
>   1. R-390A VFO/PTO Quality (Larry H)
>   2. Receiver dust covers (Perry Sandeen)
>   3. Re: Receiver dust covers (Al Parker)
>   4. Re: bfo hum and s meter not on zero (kg2bz at comcast.net)
>   5. R-390A RF DECK COAX CABLES IMPEDANCE (Jacques Fortin)
>   6. Re: R-390A RF DECK COAX CABLES IMPEDANCE (Charles Steinmetz)
>   7. Re: latest version "Pearls" (wli)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Thu, 20 Oct 2016 03:53:45 +0000 (UTC)
> From: Larry H <dinlarh at att.net>
> To: "r-390 at mailman.qth.net" <r-390 at mailman.qth.net>
> Subject: [R-390] R-390A VFO/PTO Quality
> Message-ID: <655480848.82372.1476935625249 at mail.yahoo.com>
> Content-Type: text/plain; charset=UTF-8
>
> Stan,  Take a look at the Pearls here:
>
>
> http://www.r-390a.net/Pearls/PTO.pdf
>
> Regards, Larry
>
>
> ------------------------------
>
> Message: 2
> Date: Thu, 20 Oct 2016 05:22:07 +0000 (UTC)
> From: Perry Sandeen <sandeenpa at yahoo.com>
> To: "r-390 at mailman.qth.net" <r-390 at mailman.qth.net>
> Subject: [R-390] Receiver dust covers
> Message-ID: <1529506914.149173.1476940927332 at mail.yahoo.com>
> Content-Type: text/plain; charset=UTF-8
>
> List,
> I did notice less noise on my R388 with the top cover on.
> All the R388's I have are missing the bottom cover as well as almost all 
> I've seen on Ebay. ?
> I don't know how much difference it makes with it missing but I suspect it 
> may be substantial as the sectioned modules have many screw holes for 
> fastening one down.
> Does anybody have experience do a shield-no shield test.
> Regards,
> Perrier
>
> ------------------------------
>
> Message: 3
> Date: Thu, 20 Oct 2016 09:28:05 -0400
> From: Al Parker <anchor at ec.rr.com>
> To: Perry Sandeen <sandeenpa at yahoo.com>, "r-390 at mailman.qth.net"
> <r-390 at mailman.qth.net>
> Subject: Re: [R-390] Receiver dust covers
> Message-ID: <67c68dbd-2319-7878-be40-1876c1945e5a at ec.rr.com>
> Content-Type: text/plain; charset=utf-8; format=flowed
>
> Hi Perrier,
> I've had and/or worked on 6 or 8 R-388's, many (maybe most) did have
> the bottom cover, few had the top.  IIRC, somewhere in the manual it
> says to do the alignment with the bottom cover on.  I remember aligning
> one w/o the cover, then realized the mistake and did it right.  Didn't
> compare performance before/after, but the re-alignment did require 
> changes.
> I hope you and your wife are doing well out there on the left coast.
> 73 (to a new ham, congrats),
>
> Al, W8UT
> www.boatanchors.org
> www.hammarlund.info
>
> "There is nothing -- absolutely nothing -- half so much
> worth doing as simply messing about in boats"
> Ratty, to Mole
>
> On 10/20/2016 1:22 AM, Perry Sandeen via R-390 wrote:
>> List,
>> I did notice less noise on my R388 with the top cover on.
>> All the R388's I have are missing the bottom cover as well as almost all 
>> I've seen on Ebay.
>> I don't know how much difference it makes with it missing but I suspect 
>> it may be substantial as the sectioned modules have many screw holes for 
>> fastening one down.
>> Does anybody have experience do a shield-no shield test.
>> Regards,
>> Perrier
>> _________________________________________________
>
>
> ------------------------------
>
> Message: 4
> Date: Mon, 24 Oct 2016 03:32:15 +0000 (UTC)
> From: kg2bz at comcast.net
> To: r-390 at mailman.qth.net
> Cc: r-390 at mailman.qth.net
> Subject: Re: [R-390] bfo hum and s meter not on zero
> Message-ID:
> <1071890100.32651840.1477279935544.JavaMail.zimbra at comcast.net>
> Content-Type: text/plain; charset=utf-8
>
>
>
> folks.  I notice a sight hum on cw and ssb with the bfo on. I also noticed 
> my s meter no longer at zero but maybe around 1/3rd scale .  this occurred 
> at the same time after I left on my receiver for several weeks. since both 
> issues are in the IF deck I'm guessing it could be a cap or the 
> neutralizing bfo cap c525 adjustment?  thanks
> Jeff KG2BZ
>
>
> ------------------------------
>
> Message: 5
> Date: Mon, 24 Oct 2016 15:20:32 -0400
> From: "Jacques Fortin" <jacques.f at videotron.ca>
> To: <r-390 at mailman.qth.net>
> Subject: [R-390] R-390A RF DECK COAX CABLES IMPEDANCE
> Message-ID: <[email protected]>
> Content-Type: text/plain; charset="US-ASCII"
>
> Hi to all,
>
> Does anybody already worked out the impedance of the coaxial cables
> connecting to the RF DECK in a R-390A ?
> They look very much like 75 ohms Teflon to me... RG-179/U ?
> Just want to be sure.
>
> 73, Jacques, VE2JFE
>
>
>
> ------------------------------
>
> Message: 6
> Date: Mon, 24 Oct 2016 19:01:11 -0400
> From: Charles Steinmetz <csteinmetz at yandex.com>
> To: r-390 at mailman.qth.net
> Subject: Re: [R-390] R-390A RF DECK COAX CABLES IMPEDANCE
> Message-ID: <580E92B7.6070909 at yandex.com>
> Content-Type: text/plain; charset=utf-8; format=flowed
>
> Jacques wrote:
>
>> Does anybody already worked out the impedance of the coaxial cables
>> connecting to the RF DECK in a R-390A ?
>> They look very much like 75 ohms Teflon to me... RG-179/U ?
>
> Or 50 ohm RG-316.
>
> Why do you want to know?  All of the coax runs in the 390A are too short
> to support wave propagation modes at the frequencies they are handling,
> so they are really operating as simple unbalanced shielded cables, not
> as transmission lines.  Note that the source and load impedances of the
> connected circuits are not matched to the coax's characterstic impedance.
>
> Any cable that fits the connectors will work fine.  If you are looking
> to optimize, choose the cable with the most effective shield.
>
> Best regards,
>
> Charles
>
>
>
>
> ------------------------------
>
> Message: 7
> Date: Mon, 24 Oct 2016 23:10:11 +0000 (UTC)
> From: wli <wli98122 at yahoo.com>
> To: <r-390 at mailman.qth.net>
> Subject: Re: [R-390] latest version "Pearls"
> Message-ID: <1400510087.15983.1477350611263 at mail.yahoo.com>
> Content-Type: text/plain; charset=UTF-8
>
> The fall issue is up thanks to Al
>
> W. Li
>
>
> ------------------------------
>
> Subject: Digest Footer
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> ------------------------------
>
> End of R-390 Digest, Vol 150, Issue 26
> **************************************
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