[Milsurplus] TCS PA cathode keying & ant matching Re: Milsurplus Digest, Vol 85, Issue 9

[Henry Mei'l's]

To minimimize/eliminate chirp, I and many others I know key the 1625 
cathodes w/the oscillator and buffer/multiplier stages running. This will 
usually result in a backwave (reduced-level key-up signal), and will not 
allow QSK unless the osc./buffer are sequence keyed some m. seconds prior to 
the keyed cathodes, via the keying relay. Grid block (sequenced) keying 
might be a better solution.

RE TCS xmtr (50 ohm & odd length end-fed), antenna matching:  I threw in the 
idea, on another reflector, of replacing the
"COND. ANT F" switch with a variable capacitor (broadcast band, 2 x 250-350 
pF) placed in parallel with the antenna output, ahead of the ant.relay --  
the vacant front-panel hole could accommodate the added capacitor and the 
original panel labeling would still be valid. The switch is a very high 
quality ceramic unit and can be used elsewhere and/or put back again if one 
wishes to restore the original circuitry. Possible future re-installation 
(restoring) should be kept in mind, with respect to retention of the 
original switch leads, when unsoldering the switch (perhaps insulating and 
fastening the leads with tape).

Henry, oz3o n2nr
>
> Today's Topics:
>
>   1. Re: R-388 (WA5CAB at cs.com)
>   2. Re: TCS-9 Output matching? (Thomas Adams)
>   3. CQ TCS ariticle year reference correction (Henry Mei'l's)
>   4. Re: TCS-9 Output matching? (Roger Basford)
>   5. TCS RX bandswitch (Ian Wilson)
>   6. 100 KC Xtal for R-388 (Rick)
>   7. Re: R-388 (Rick)
>   8. Re: R-388 (DeWitt Clay)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Fri, 6 May 2011 12:28:03 EDT
> From: WA5CAB at cs.com
> Subject: Re: [Milsurplus] R-388
> To: rickb at tx.rr.com, milsurplus at mailman.qth.net
> Message-ID: <ca549.59d8325b.3af57b93 at cs.com>
> Content-Type: text/plain; charset="US-ASCII"
>
> Rick,
>
> First, the 0A2 supplies regulated B+ to the 6BA6 HFO and Buffer, not to
> V113, the 6AQ5 audio output.  Assuming that the manual you are referring 
> to is
> TM 11-854 dated 25 April, 1952, there were four changes issued up to 25
> November 1963 (Change 3 was superceded by Change 4).  Resistor R181 was 
> changed
> at twice, first to 3100 ohms and then to 1400 ohms plus R185 of 1800 ohms.
> In the latter case, C239, 8 ufd, is added from the junction of the two
> resistors to terminal 1 of C217A,B.  R185 is installed in place of the 
> vertical
> line on the schematic from the junction of L122 and L123 to the junction 
> with
> the horizontal line above. So V113 draws its B+ through R185.
>
> There are several other changes that will or may affect your receiver.  It
> depends upon what order number your receiver was bought under, and in some
> cases what the serial number is.
>
> I sell a reprint of the TM, with changes, for $22.50 plus shipping.  Or if
> you have an original basic TM, the Changes alone are $7.50 plus postage.
>
> In a message dated 5/6/2011 9:16:16 AM Central Daylight Time,
> rickb at tx.rr.com writes:
>> This is my first venture into the circuitry of the R-388 and I have found
>> a
>> confusing circuit hopefully someone can clear up for me. In regards the
>> OA2
>> regulator (V116) the plate of the tube is connected per the  schematic to
>> R181, a 4000 ohm (probably 20 watt ) wire wound resistor. However, in
>> reality, it is connected to two 2000 ohm (or they were 2K ohm before they
>> over heated severely) in series. Of course, this is still in essence a
>> 4000
>> ohm resistor. One of these series resistors is R181 and is listed in the
>> parts section of the manual and on the schematic. The second 2000 ohm
>> series
>> resistor is labeled on the chassis as R185 and is NOT on the schematic or
>> listed in the parts section of the manual. There is a wire also not to be
>> found on the schematic soldered between the two series resistors. I do 
>> not
>> know where this wire leads yet. These are current limiting resistors and
>> the
>> output supplies the 6AQ5 (V113) audio output tube with its B+. My 
>> question
>> is, has there been an update to the schematic issued describing these
>> changes? This is not a hack someone has put in the receiver as the 
>> chassis
>> reflects the new part numbers just as it does the original part numbers
>> with
>> the exception the new numbers are a little larger type. I obviously have
>> an
>> excessive current drain in that line as one of the resistors heated to 
>> the
>> point of melting the solder on the connections. I have audio, but not
>> signal
>> whatsoever. Any help locating the addendum will be greatly appreciated.
>> Please, excuse my long winded description.
>> Rick/K5IAR
>
> Robert & Susan Downs - Houston
> wa5cab dot com (Web Store)
> MVPA 9480
>
>
> ------------------------------
>
> Message: 2
> Date: Fri, 06 May 2011 12:04:56 -0600
> From: Thomas Adams <quixote2 at ix.netcom.com>
> Subject: Re: [Milsurplus] TCS-9 Output matching?
> To: Roger at new-gate.co.uk,"WA5CAB at cs.com" <WA5CAB at cs.com>
> Cc: milsurplus at mailman.qth.net
> Message-ID: <E1QIOTy-00018H-Kk at elasmtp-curtail.atl.sa.earthlink.net>
> Content-Type: text/plain; charset="us-ascii"; format=flowed
>
> At 03:29 06-05-11, Roger Basford wrote:
>>Hi Robert and Group,
>>
>>Just to say thanks to all who came through with suggestions about the
>>TCS-9 loading.
>>
>>This morning, using my 66ft inverted "L" I tried a 2 gang 365pf variable
>>cap to ground from the antenna terminal and that brought up a good
>>output on 3575 kc, the vintage equipment CW frequency here. There was
>>no-one about so I QSYed to 5260 kc and carefully set the '9 up against
>>the frequency counter in the shack. Loaded pretty well there too. Heard
>>G4ALD calling CQ and after a quick call he gave me 579 with a  bit of
>>chirp on his homebrew 10 watt rig, path about 120 miles, so well pleased
>>with that.
>>
>>73 all,
>>
>>Roger/G3VKM - Norfolk, England.
>
> CONGRATULATIONS!!!    :o)
>
>
> Re. the chirp; that seems a perpetual problem with the TCS.
>
> With mine, everything is good on 160 and 80. I get a slight chirp on
> 40, but it's acceptable.
>
> On only one occasion have I fired it up on 30 metres. I sounded sort
> of ranchy to me (I have
> my rig set up for a sidetone), but when I heard a Cuban calling CQ a
> few KHz up from me, I
> answered him anyway.
>
> Even tho it's a case of The Pot commenting upon The Kettle's
> incipient Negritude, you REALLY
> KNOW that you have a chirp problem when a CUBAN operator complains about 
> it!
>
> BTW, I meant to mention...   I'm cheating a little bit with my TCS.
>
> The PAs are rewired so that BOTH 1625s are in use in AM mode
> (overruled the filament
> switch).
>
> Also, for a bit more power...   my homebrewed power supply provides a
> PA and modulator
> plate voltage of 550 VDC under load.
>
> Finally...  I have to keep my bug in 1st gear when it's on the TCS.
> I'd say that the keying relay
> follows pretty well to maybe 15 - 18 WPM, but it gets shaky from there.
>
>
> Mr. T.   W9LBB
>
>
>
>
>
> ------------------------------
>
> Message: 3
> Date: Fri, 6 May 2011 20:07:29 +0200
> From: "Henry Mei'l's" <meils at get2net.dk>
> Subject: [Milsurplus] CQ TCS ariticle year reference correction
> To: <milsurplus at mailman.qth.net>
> Message-ID: <36C6072C62764605903A1FD7C8D63A0A at ejerf59be5593b>
> Content-Type: text/plain; charset="Windows-1252"
>
> My TCS output mod article is in Nov., 1960, p.71 (not 1970, that was 
> another article I wrote about Danish radio pioneers).
> BTW also realized that the series connecting position of  "ANT. COND. F" 
> (50pF capacitor switch) could be retained, also
> shunting or  with other fixed or variable values if series capacitance 
> should be needed as  either for coax or end fed antennas and on particular 
> frequencies.
> Access could be via a panel hole. I try to avoid altering front panel 
> control functions and original panel
> appearance and strive to retain as preserve as much of the original design 
> and construction as possible.
> This has always been my attitude even before the older mil gear had become 
> collectors items.
>
>
> Henry, oz3o n2nr
>
> ------------------------------
>
> Message: 4
> Date: Fri, 06 May 2011 19:46:07 +0100
> From: Roger Basford <Roger at new-gate.co.uk>
> Subject: Re: [Milsurplus] TCS-9 Output matching?
> To: Thomas Adams <quixote2 at ix.netcom.com>
> Cc: "WA5CAB at cs.com" <WA5CAB at cs.com>, milsurplus at mailman.qth.net
> Message-ID: <4DC441EF.6050002 at new-gate.co.uk>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> Hi Thomas,
>
> Thanks for the congrats!
>
> The station I worked on 60m didn't know what rig I was running but he
> did say I had  slight chirp and was I keying the oscillator?
> Straightaway I knew this chap was an old-school ham and it turned out
> his rig was home-brew.  I also use some 1980s era ex-mil solid-state
> gear on 60m and that gets reports of slight chirp too, maybe the
> military know something we don't about readability? These days, if you
> give someone a less than T9 report they are liable to get really upset,
> I don't know why as a chirpy signal would stand out in a pile-up.  Back
> when I started in ham radio in the 60s some of the hams from Warsaw Pact
> countries put out rotten notes, but at least they built their own gear
> and often had to make do with less than optimal power supplies.
>
> I'd agree on the keying speed, I bet I could beat the relay if I tried
> but it's an incentive to keep the keying to a reasonable speed. The TCS
> here is running from a Heathkit HP-13 DC/DC converter and that's poking
> out about 390 Volts to the PA, but I am going to build a mains PSU as
> well, with volts around what you are using.
>
> 73 ES TNX
>
> Roger/G3VKM
>
>
>
> On 06/05/2011 19:04, Thomas Adams wrote:
>>
>> */CONGRATULATIONS!!!    :o)
>>
>>
>> Re. the chirp; that seems a perpetual problem with the TCS.
>>
>> With mine, everything is good on 160 and 80. I get a slight chirp on
>> 40, but it's acceptable.
>>
>> On only one occasion have I fired it up on 30 metres. I sounded sort
>> of ranchy to me (I have
>> my rig set up for a sidetone), but when I heard a Cuban calling CQ a
>> few KHz up from me, I
>> answered him anyway.
>>
>> Even tho it's a case of The Pot commenting upon The Kettle's incipient
>> Negritude, you REALLY
>> KNOW that you have a chirp problem when a CUBAN operator complains
>> about it!
>>
>> BTW, I meant to mention...   I'm cheating a little bit with my TCS.
>>
>> The PAs are rewired so that BOTH 1625s are in use in AM mode
>> (overruled the filament
>> switch).
>>
>> Also, for a bit more power...   my homebrewed power supply provides a
>> PA and modulator
>> plate voltage of 550 VDC under load.
>>
>> Finally...  I have to keep my bug in 1st gear when it's on the TCS.
>> I'd say that the keying relay
>> follows pretty well to maybe 15 - 18 WPM, but it gets shaky from there.
>>
>>
>> Mr. T.   W9LBB
>>
>>
>> /*
>
>
>
> ------------------------------
>
> Message: 5
> Date: Fri, 6 May 2011 15:56:40 -0700
> From: Ian Wilson <ianmwilson73 at gmail.com>
> Subject: [Milsurplus] TCS RX bandswitch
> To: milsurplus <milsurplus at mailman.qth.net>
> Message-ID: <BANLkTik-gXtVBQFAkvuzj8miDyiV6z=3LA at mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
>
> Since we have TCS in the front of our minds - I am in need of a bandswitch
> assembly for a TCS-12. A long shot, but perhaps someone is parting one
> out...?
>
> 73, ian K3IMW
>
>
> ------------------------------
>
> Message: 6
> Date: Sat, 7 May 2011 07:36:23 -0600
> From: "Rick" <rickb at tx.rr.com>
> Subject: [Milsurplus] 100 KC Xtal for R-388
> To: <milsurplus at mailman.qth.net>
> Message-ID: <6F.A9.16951.0CC35CD4 at cdptpa-omtalb.mail.rr.com>
> Content-Type: text/plain; charset="US-ASCII"
>
> I am in need of the 100 KC calibration crystal for my R-388/URR.  Please,
> contact me off list if you have one for sale.
>
> Thanks.. Rick/K5IAR
>
>
>
> ------------------------------
>
> Message: 7
> Date: Sat, 7 May 2011 07:59:00 -0600
> From: "Rick" <rickb at tx.rr.com>
> Subject: Re: [Milsurplus] R-388
> To: <milsurplus at mailman.qth.net>
> Message-ID: <25.0E.09483.D0245CD4 at cdptpa-omtalb.mail.rr.com>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Thanks Robert for the information. I found the change noted on the 
> schematic
> pasted to the inside of the top cover for R181 later on. When I get back 
> in
> the shack later today I'll see if I have the TM you referred to and 
> contact
> you as to whether I want the changes only or the entire manual. I replaced
> the two resistors, R181 and R185. This corrected the problem and the
> receiver works beautifully.
>
> Thanks again for your help...
> Rick/K5IAR
>
> ________________________________________
> From: WA5CAB at cs.com [mailto:WA5CAB at cs.com]
> Sent: Friday, May 06, 2011 10:28 AM
> To: rickb at tx.rr.com; milsurplus at mailman.qth.net
> Subject: Re: [Milsurplus] R-388
>
> Rick,
>
> First, the 0A2 supplies regulated B+ to the 6BA6 HFO and Buffer, not to
> V113, the 6AQ5 audio output.? Assuming that the manual you are referring 
> to
> is TM 11-854 dated 25 April, 1952, there were four changes issued up to 25
> November 1963 (Change 3 was superceded by Change 4).? Resistor R181 was
> changed at twice, first to 3100 ohms and then to 1400 ohms plus R185 of 
> 1800
> ohms.? In the latter case, C239, 8 ufd, is added from the junction of the
> two resistors to terminal 1 of C217A,B.? R185 is installed in place of the
> vertical line on the schematic from the junction of L122 and L123 to the
> junction with the horizontal line above. So V113 draws its B+ through 
> R185.
>
> There are several other changes that will or may affect your receiver.? It
> depends upon what order number your receiver was bought under, and in some
> cases what the serial number is.
>
> I sell a reprint of the TM, with changes, for $22.50 plus shipping.? Or if
> you have an original basic TM, the Changes alone are $7.50 plus postage.
>
> In a message dated 5/6/2011 9:16:16 AM Central Daylight Time,
> rickb at tx.rr.com writes:
>
> This is my first venture into the circuitry of the R-388 and I have found 
> a
> confusing circuit hopefully someone can clear up for me. In regards the 
> OA2
> regulator (V116) the plate of the tube is connected per the? schematic to
> R181, a 4000 ohm (probably 20 watt ) wire wound resistor. However, in
> reality, it is connected to two 2000 ohm (or they were 2K ohm before they
> over heated severely) in series. Of course, this is still in essence a 
> 4000
> ohm resistor. One of these series resistors is R181 and is listed in the
> parts section of the manual and on the schematic. The second 2000 ohm 
> series
> resistor is labeled on the chassis as R185 and is NOT on the schematic or
> listed in the parts section of the manual. There is a wire also not to be
> found on the schematic soldered between the two series resistors. I do not
> know where this wire leads yet. These are current limiting resistors and 
> the
> output supplies the 6AQ5 (V113) audio output tube with its B+. My question
> is, has there been an update to the schematic issued describing these
> changes? This is not a hack someone has put in the receiver as the chassis
> reflects the new part numbers just as it does the original part numbers 
> with
> the exception the new numbers are a little larger type. I obviously have 
> an
> excessive current drain in that line as one of the resistors heated to the
> point of melting the solder on the connections. I have audio, but not 
> signal
> whatsoever. Any help locating the addendum will be greatly appreciated.
> Please, excuse my long winded description.
> Rick/K5IAR
>
>
> Robert & Susan Downs - Houston
> wa5cab dot com (Web Store)
> MVPA 9480
> ________________________________________
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 10.0.1325 / Virus Database: 1500/3619 - Release Date: 05/06/11
>
>
>
> ------------------------------
>
> Message: 8
> Date: Sat, 7 May 2011 08:47:41 -0700 (PDT)
> From: DeWitt Clay <n4qnx at yahoo.com>
> Subject: Re: [Milsurplus] R-388
> To: Rick <rickb at tx.rr.com>
> Cc: milsurplus <milsurplus at mailman.qth.net>
> Message-ID: <766225.43524.qm at web84202.mail.re3.yahoo.com>
> Content-Type: text/plain; charset=iso-8859-1
>
> Hi Rick,
> Suggest checkout the cause of the?resisters overheating. If a filter cap 
> was
> added to the junction of the two resisters or if there is a filter cap (to
> ground) at the?output resister side, check?the cap(s) ?for high leakage or 
> the
> new resisters won't last long before they overheat and go bad.
> 73, DeWitt
>
>
>
> ----- Original Message ----
> From: Rick <rickb at tx.rr.com>
> To: milsurplus at mailman.qth.net
> Sent: Sat, May 7, 2011 9:59:00 AM
> Subject: Re: [Milsurplus] R-388
>
> Thanks Robert for the information. I found the change noted on the 
> schematic
> pasted to the inside of the top cover for R181 later on. When I get back 
> in
> the shack later today I'll see if I have the TM you referred to and 
> contact
> you as to whether I want the changes only or the entire manual. I replaced
> the two resistors, R181 and R185. This corrected the problem and the
> receiver works beautifully.
>
> Thanks again for your help...
> Rick/K5IAR
>
> ________________________________________
> From: WA5CAB at cs.com [mailto:WA5CAB at cs.com]
> Sent: Friday, May 06, 2011 10:28 AM
> To: rickb at tx.rr.com; milsurplus at mailman.qth.net
> Subject: Re: [Milsurplus] R-388
>
> Rick,
>
> First, the 0A2 supplies regulated B+ to the 6BA6 HFO and Buffer, not to
> V113, the 6AQ5 audio output.? Assuming that the manual you are referring 
> to
> is TM 11-854 dated 25 April, 1952, there were four changes issued up to 25
> November 1963 (Change 3 was superceded by Change 4).? Resistor R181 was
> changed at twice, first to 3100 ohms and then to 1400 ohms plus R185 of 
> 1800
> ohms.? In the latter case, C239, 8 ufd, is added from the junction of the
> two resistors to terminal 1 of C217A,B.? R185 is installed in place of the
> vertical line on the schematic from the junction of L122 and L123 to the
> junction with the horizontal line above. So V113 draws its B+ through 
> R185.
>
> There are several other changes that will or may affect your receiver.? It
> depends upon what order number your receiver was bought under, and in some
> cases what the serial number is.
>
> I sell a reprint of the TM, with changes, for $22.50 plus shipping.? Or if
> you have an original basic TM, the Changes alone are $7.50 plus postage.
>
> In a message dated 5/6/2011 9:16:16 AM Central Daylight Time,
> rickb at tx.rr.com writes:
>
> This is my first venture into the circuitry of the R-388 and I have found 
> a
> confusing circuit hopefully someone can clear up for me. In regards the 
> OA2
> regulator (V116) the plate of the tube is connected per the? schematic to
> R181, a 4000 ohm (probably 20 watt ) wire wound resistor. However, in
> reality, it is connected to two 2000 ohm (or they were 2K ohm before they
> over heated severely) in series. Of course, this is still in essence a 
> 4000
> ohm resistor. One of these series resistors is R181 and is listed in the
> parts section of the manual and on the schematic. The second 2000 ohm 
> series
> resistor is labeled on the chassis as R185 and is NOT on the schematic or
> listed in the parts section of the manual. There is a wire also not to be
> found on the schematic soldered between the two series resistors. I do not
> know where this wire leads yet. These are current limiting resistors and 
> the
> output supplies the 6AQ5 (V113) audio output tube with its B+. My question
> is, has there been an update to the schematic issued describing these
> changes? This is not a hack someone has put in the receiver as the chassis
> reflects the new part numbers just as it does the original part numbers 
> with
> the exception the new numbers are a little larger type. I obviously have 
> an
> excessive current drain in that line as one of the resistors heated to the
> point of melting the solder on the connections. I have audio, but not 
> signal
> whatsoever. Any help locating the addendum will be greatly appreciated.
> Please, excuse my long winded description.
> Rick/K5IAR
>
>
> Robert & Susan Downs - Houston
> wa5cab dot com (Web Store)
> MVPA 9480
> ________________________________________
>>>
> End of Milsurplus Digest, Vol 85, Issue 9
> *****************************************