I have an unmodified late model R4C. I am looking to add the GUF-1 first IF
filter - went to the website for INRAD and noted that though they list two
first IF 8 pole filters, with shape factors of 1.7 and 1.8 respectively, the
1.7 is out of stock. How different is performance really between these two
filters?
Appreciate the help -
Hank WM1V
-----Original Message-----
From: <drakelist-requ...@zerobeat.net>
Sent 8/13/2011 12:00:01 PM
To: drakelist@zerobeat.net
Subject: Drakelist Digest, Vol 38, Issue 25
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Contents of Drakelist digest..." Today's Topics: 1. Drake 4 Series PTOs (Steve
Wedge) 2. Re: PTO capacitors..... (Steve Wedge) 3. Re: PTO capacitors.....
(Garey Barrell) 4. Re: PTO capacitors..... (john) 5. Drake front panels (Henry
Foglesong) 6. Re: Drake front panels (K9sqg) 7. Re: Drake front panels
(kc9...@aol.com)
---------------------------------------------------------------------- Message:
1 Date: Fri, 12 Aug 2011 12:40:56 -0400 (GMT-04:00) From: Steve Wedge
<w1es1...@earthlink.net> To: "drakelist@zerobeat.net" <drakelist@zerobeat.net>,
Garey Barrell <k4...@mindspring.com> Subject: [Drakelist] Drake 4 Series PTOs
Message-ID:
<17608133.1313167256432.javamail.r...@wamui-junio.atl.sa.earthlink.net>
Content-Type: text/plain; charset=UTF-8 Garey - I'll take some decent photos of
my R-4A PTO when I take it apart again next week, as well as some close-ups of
the bad kidney-bean SM cap (3000 pf). I'll email them to you once I'm done.
Right now, I still have the .003 disc ceramic in the PTO and ran it for several
hours last night and still had decent-sounding signals and no jumping. The
audio did begin to sound harsher as everything warmed up - which could be
something else (won't know until I have the twins working together again and
can switch PTO's). I also noticed that the phenolic PTO board in mine (an early
13-tuber) has several insulated jumper wires on the component side and that the
3000 pf SM was mounted through the holes but mounted on the solder side of the
board. Again, I'll get some pics together next week. I'm trying to get all this
together and working again ASAP, as I am expecting my "new" B-Line any day now.
73, Steve, W1ES/4 Date: Thu, 11 Aug 2011 16:46:51 -0400 From: Garey Barrell
<k4...@mindspring.com> To: drakelist <Drakelist@zerobeat.net> Subject:
[Drakelist] Drake 4 Series PTOs Message-ID: <4e443fbb.4060...@mindspring.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed It's now
official...... The Drake PTOs seem to be 'all over the map' as far as what you
might find inside the can. I have worked on perhaps a half-dozen in 'recent'
times, and ALL were different. Some were 'close' to the schematic for what they
were found in, but more were not. Now we know that some were replaced by Drake
over the years, and apparently they put in whatever they had on hand. I just
opened a PTO out of and marked R-4B, and in scoping out the circuit, the board
is closest to a late TR-4C PTO schematic! It has the output clipping diode, and
most values are comparable to the much later PTO, including the
semi-conductors. It covers 500 kHz, not 600 kHz. I understand it's possible
that this is a cobble job, but the linearity and tempco are good, which 'may'
be significant. I would be very interested in any photos of any PTO PC boards
that you have occasion to open, indicating what they were take out of, model
and s/n. -- 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B,
C-Line and TR-4/C Service Supplement CDs ------------------------------
Message: 2 Date: Fri, 12 Aug 2011 12:47:47 -0400 (GMT-04:00) From: Steve Wedge
<w1es1...@earthlink.net> To: "drakelist@zerobeat.net" <drakelist@zerobeat.net>
Subject: Re: [Drakelist] PTO capacitors..... Message-ID:
<6222481.1313167667712.javamail.r...@wamui-junio.atl.sa.earthlink.net>
Content-Type: text/plain; charset=UTF-8 THAT was a question I meant to ask
after looking at the cap I pulled: yes, it was marked "EM" and I was wondering
if that was a vendor or characteristic designator (like NP0, Z5U, etc). Now I
know. Thanks for the insight. I ordered some replacements from a guy on eBay
for very cheap ($1.25 each + about $3.60 shipping). Seeing as Mouser's prices
on these were north of $6 apiece, I figured a buck-and-a-quarter each was worth
the risk. 73, Steve, W1ES/4 Date: Thu, 11 Aug 2011 23:16:55 -0400 From: Garey
Barrell <k4...@mindspring.com> To: Fred or Ski <wb8...@frontier.com> Cc:
drakelist <drakelist@zerobeat.net> Subject: Re: [Drakelist] PTO capacitors.....
Message-ID: <4e449b27.6000...@mindspring.com> Content-Type: text/plain;
charset=ISO-8859-1; format=flowed Ski - Yes, those are the 'Dur-Mica' style
caps made by 'Electro-Motive', and used by Drake. That some are failing almost
50 years later isn't all that surprising. I haven't run into these failures
until just the last couple of years, so perhaps they're all ready to fail! :-)
CDE also makes them, and I think the 'Dur-Mica' tag belongs to them. But silver
migration seems to be a problem with many silver mica caps. Early 'postage
stamp' types were the worst, and it was blamed on poor sealing of the
lead/package interface. But then the epoxy dipped type developed similar
problems, just some years later. 73, Garey - K4OAH Glen Allen, VA Drake 2-B,
2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs <www.k4oah.com>
------------------------------ Message: 3 Date: Fri, 12 Aug 2011 13:24:13 -0400
From: Garey Barrell <k4...@mindspring.com> To: drakelist
<drakelist@zerobeat.net> Subject: Re: [Drakelist] PTO capacitors.....
Message-ID: <4e4561bd.5080...@mindspring.com> Content-Type: text/plain;
charset=ISO-8859-1; format=flowed Ski - A little research shows that the
'Electro-Motive' (EM) corp was acquired by Cornell Dubilier (CDE) in 1978. It's
possible that CDE modified the manufacturing process, but I doubt it. I've used
these caps both professionally and amateur, and never found them to be
particularly failure prone. I was using them in the 60's for 400 MHz solid
state amplifiers built on stripline. We used an epoxy solvent to dissolve the
brown case, resulting in a capacitor consisting of a stack of silvered mica
pieces with a copper 'wrap' around the ends, that could be soldered directly to
striplines, an early form of surface mount! Obviously the idea was zero lead
inductance, and several manufacturers later offered 'special' caps that looked
just like ours for stripline use...... Actually, until a year or two ago, the
first time I saw a PTO failure caused by one, I hadn't seen any more than
random, very occasional defective Dur-Micas. I've found only a couple over the
last 50 years in any application aside from the PTO. The silver migration
problem is exacerbated by high voltages, and they are mostly used in resonant
circuits where they see MUCH lower voltages, so that may be part of the answer.
Still, the one in Steve's PTO is at least 40 years old, so that's not likely to
be a 'manufacturing defect'! :-) 73, Garey - K4OAH Glen Allen, VA Drake 2-B,
2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs <www.k4oah.com>
Fred or Ski wrote: > After working in communications for the State Police here
in Michigan for 37 years, most of our equipment was from Motorola, and we have
had several problems with silver mica capacitors made by a company that marked
there components with 'EM'. If you find a circuit that is in suspect of causing
a problem, and there is silver mica caps with 'EM' installed, replace them.
Many of our Motorola Micor radios had freq shifting and intermittant drive
which caused erratic power output. These 'EM' caps apparently had a
contamination when they were made and some didn't go bad for several years. I
would certainly check for these parts in the PTO's that are operating
intermittantly. I hope this helps... > > Good luck and 73, > > Ski-WB8YXI >
------------------------------ Message: 4 Date: Fri, 12 Aug 2011 20:19:54 -0400
From: john <joh...@nc.rr.com> To: k4...@mindspring.com,Fred or Ski
<wb8...@frontier.com> Cc: drakelist <drakelist@zerobeat.net> Subject: Re:
[Drakelist] PTO capacitors..... Message-ID:
<6.2.1.2.2.20110812201925.037bb...@pop-server.nc.rr.com> Content-Type:
text/plain; charset="us-ascii"; format=flowed At 11:16 PM 8/11/2011, Garey
Barrell wrote: >Ski - > >Yes, those are the 'Dur-Mica' style caps made by
'Electro-Motive', and >used by Drake. That some are failing almost 50 years
later Darn caps, can't even get 50 years out of 'em these days! :-) John K5MO
------------------------------ Message: 5 Date: Sat, 13 Aug 2011 05:19:56 -0000
From: "Henry Foglesong" <hwfogles...@gmail.com> To: <drakelist@zerobeat.net>
Subject: [Drakelist] Drake front panels Message-ID:
<17E77F522F7C43ECBBAD5D1CD460D24D@hamshack> Content-Type: text/plain;
charset="iso-8859-1" Has anyone had experience with replacement panels from
KF8MW, and if so, would you comment on their quality, please? --------------
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------------------------------ Message: 6 Date: Sat, 13 Aug 2011 09:17:39
-0400 (EDT) From: K9sqg <k9...@aol.com> To: hwfogles...@gmail.com,
drakelist@zerobeat.net Subject: Re: [Drakelist] Drake front panels Message-ID:
<8ce27d282c2234e-20e8-56...@webmail-d169.sysops.aol.com> Content-Type:
text/plain; charset="us-ascii" My experiences have been 100% positive. Tony is
a nice guy that does great work. 73, Evan, K9SQG -----Original Message-----
From: Henry Foglesong <hwfogles...@gmail.com> To: drakelist
<drakelist@zerobeat.net> Sent: Fri, Aug 12, 2011 9:21 pm Subject: [Drakelist]
Drake front panels Has anyone had experience with replacement panels from
KF8MW, and if so, would you comment on their quality, please?
_______________________________________________ Drakelist mailing list
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------------------------------ Message: 7 Date: Sat, 13 Aug 2011 10:55:24
-0400 (EDT) From: kc9...@aol.com To: k9...@aol.com, hwfogles...@gmail.com,
drakelist@zerobeat.net Subject: Re: [Drakelist] Drake front panels Message-ID:
<8ce27e02a5da18f-3e0-34...@webmail-d097.sysops.aol.com> Content-Type:
text/plain; charset="utf-8"; format=flowed Does he still offer them? I thought
he stopped making them? 73, Lee -----Original Message----- From: K9sqg
<k9...@aol.com> To: hwfoglesong <hwfogles...@gmail.com>; drakelist
<drakelist@zerobeat.net> Sent: Sat, Aug 13, 2011 9:19 am Subject: Re:
[Drakelist] Drake front panels My experiences have been 100% positive. ?Tony is
a nice guy that does great work. 73, Evan, K9SQG -----Original Message-----
From: Henry Foglesong <hwfogles...@gmail.com> To: drakelist
<drakelist@zerobeat.net> Sent: Fri, Aug 12, 2011 9:21 pm Subject: [Drakelist]
Drake front panels Has anyone had experience with replacement panels from
KF8MW, and if so, would you comment on their quality, please??
_______________________________________________ Drakelist mailing list
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