[Amps] Amps Digest, Vol 84, Issue 63
k3vw at aol.com
k3vw at aol.com
Sun Dec 20 05:13:23 PST 2009
To all, ref. the GS-35B's efficiency: It is a medium MU triode, not a high
MU triode that folks are trying to compare to ! Willy K3VW
In a message dated 12/19/2009 9:21:18 P.M. Eastern Standard Time,
amps-request at contesting.com writes:
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Today's Topics:
1. Re: [rfamplifiers] Question about GS-35b efficiency (kd4e)
2. Topics about Class A amplifier (Hsu)
3. Re: Alternative cooling strategies for SB-220? (Mike using AT&T)
4. Re: water cooling (Ron Youvan)
5. Re: Alternative cooling strategies for SB-220? (Dave White)
6. Dentron Needs Plate Choke (Wayne King)
7. Site translator (MIKE DURKIN)
8. Re: QSK switching time...etc. (Roy)
9. Re: Alternative cooling strategies for SB-220? (texasrf at aol.com)
----------------------------------------------------------------------
Message: 1
Date: Thu, 17 Dec 2009 23:24:01 -0500
From: kd4e <doc at kd4e.com>
Subject: Re: [Amps] [rfamplifiers] Question about GS-35b efficiency
To: rfamplifiers at yahoogroups.com
Cc: Amps reflector <amps at contesting.com>
Message-ID: <4B2B03E1.6070707 at kd4e.com>
Content-Type: text/plain; charset=windows-1252; format=flowed
When I incorrectly imagined myself capable of building an
amp like this I discovered this site:
http://gs35b.com/gs35bvs8877.html
It contains an excellent charted and textually-described
explanation of the specs and practical applications of the
two - as well as a compare and contrast of the tubes.
Although the 8877 has higher "mu" it has a lower tolerance
for error.
I seem to also recall that tuned-circuit components that
work well with an 8877 may not function as efficiently with
s GS-35b due to different inductance and capacitance factors.
Of course I am the least-informed and experienced here ...
so please consider the link without my commentary and see
what the gathered wisdom here has to offer from their
hands-on experience!
73, doc KD4E
And, in case I forget, a blessed CHRIST-mas to all!
> I have a question about the plate efficiency of a GS-35b amplifier.
>
> I have built two of them for 160-10 meters, and while they worked ok, the
> efficiency was not as good as I expected. In both cases I ran them at 3
> kVDC and
> in order to get a full 1500 watts out, had to drive them to 1000 mA plate
> current. That equates to about 50% efficiency, which seemed a bit low.
>
> In both cases, I removed the GS-35b and replaced it with an 8877. With
> no other
> changes except bias diode and heater transformer, I was able to get 1500
> watts
> out with only 830 mA plate current, an efficiency of 60%. I swapped two
> different GS-35b's with the same result. Both were brand new tubes.
> Results were
> essentially the same on all bands, with a slight drop off on 15 and 10
> meters
> with all three tubes.
>
> With all of the different tubes, I set the bias for a ZSAC of about 200
mA.
>
> I have spoken to two European hams and one US ham and they have reported
> similar
> results.I wonder if the GS-35b might achieve higher efficiency at higher
> plate
> voltages?
>
> I would appreciate hearing from anyone who has made similar measurements.
>
> 73, Bill W6WRT
>
> __._,_.___
> Reply to sender <mailto:dezrat1242 at yahoo.com?subject=Question about
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> __,_._,___
--
Thanks! & 73, doc, KD4E
FS/Swap/Wanted: http://kd4e.com/swapn.html
Free OS : http://www.PuppyLinux.com
Personal: http://kd4e.com
|_|___|_|
| | & | |
/\ {|
/ \ {|
/ \ {|
/ @ \ {|
| |~_|~~~~|
| -| | |
============\ # KD4E
Have an http://ultrafidian.com day!
------------------------------
Message: 2
Date: Sun, 20 Dec 2009 08:58:11 +0800
From: "Hsu" <hsu4qro at gmail.com>
Subject: [Amps] Topics about Class A amplifier
To: <ham_amplifiers at yahoogroups.com>
Cc: amps at contesting.com
Message-ID: <1BAAF40AA74948B38564474F47073A78 at PC200912151238>
Content-Type: text/plain; charset="iso-8859-1"
a) Anyone have experience to modify his transceiver's final to Class A
mode as FT-1000MP MK V?
I think if we haven't good enough driver, the external Power amplifier
cann't be have good 3rd IMD
performance, especially for tetrode amplifier.
b)I'm planing to build an antenna muti-coupler for my 20 receivers.(
similar ROHDE/SCHWARTZ
NV-14T(http://bama.edebris.com/manuals/rohdeschwarz/nv14t/, MF-HF range)But
R/S's design seems unmodern. I want to know anyone knows about
hybrid-model or MMIC for this application?the antenna multi-couple only have 0db
power gain
, but with very good reverse isolation and very large dynamic range/3rd
IMD performance.
I find out some models, for example MHW591/592, but these model's gain are
too more(more than 35db). Any guys knows more information about the
appropriate Hybrid model/MMIC?
Thanks in advance!
73!Hsu
------------------------------
Message: 3
Date: Thu, 17 Dec 2009 15:48:47 -0600
From: "Mike using AT&T" <k9mk at flash.net>
Subject: Re: [Amps] Alternative cooling strategies for SB-220?
To: "'Carl'" <km1h at jeremy.mv.com>, "'Hardy Landskov'" <n7rt at cox.net>,
"'Colin Lamb'" <k7fm at teleport.com>, "'Roger'" <sub1 at rogerhalstead.com>
Cc: amps at contesting.com
Message-ID: <007e01ca7f62$b73d4950$25b7dbf0$@net>
Content-Type: text/plain; charset="us-ascii"
The 70V uses a 3CV1500A7.
Instant on and water cooled, it does not get better than this...
Mike
K9MK
-----Original Message-----
From: amps-bounces at contesting.com [mailto:amps-bounces at contesting.com] On
Behalf Of Carl
Sent: Thursday, December 17, 2009 2:29 PM
To: Hardy Landskov; Colin Lamb; Roger
Cc: amps at contesting.com
Subject: Re: [Amps] Alternative cooling strategies for SB-220?
That was the 1971 70V which used a modified 3CX1000A7. It was somewhat
troublesome and they soon added the 70A to the mix which used the regular
air cooled tube. A short time later the first of the 77 models came along.
Carl
KM1H
----- Original Message -----
From: "Hardy Landskov" <n7rt at cox.net>
To: "Colin Lamb" <k7fm at teleport.com>; "Roger" <sub1 at rogerhalstead.com>;
"Carl" <km1h at jeremy.mv.com>
Cc: <amps at contesting.com>
Sent: Thursday, December 17, 2009 2:57 PM
Subject: Re: [Amps] Alternative cooling strategies for SB-220?
> There was an article in QST many years ago called "The Stanley Steamer"
> which described water cooled tubes. I believe ETO built an amp based on
a
> water cooled tube that Eimac made that had 1500 watts plate dissipation.
> The principle being it takes 539 calories of heat to convert 1 gram of
> water at 100 deg C to vapor if I remember my thermodynamics correctly.
> 73 Hardy N7RT
>
> ----- Original Message -----
> From: "Colin Lamb" <k7fm at teleport.com>
> To: "Roger" <sub1 at rogerhalstead.com>; "Carl" <km1h at jeremy.mv.com>
> Cc: <amps at contesting.com>
> Sent: Thursday, December 17, 2009 11:58 AM
> Subject: Re: [Amps] Alternative cooling strategies for SB-220?
>
>
>> Water Cooling:
>>
>> Jo Jennings, W6EI, installed a converted water cooled 4CX250 in the
base
>> of his mobile whip. He converted. I think Eimac subsequently built
some
>> water cooled version based upon the results. There was a writeup in CQ
>> or QST in the fifties.
>>
>> 73, Colin K7FM
>> _______________________________________________
>> Amps mailing list
>> Amps at contesting.com
>> http://lists.contesting.com/mailman/listinfo/amps
>
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------------------------------
Message: 4
Date: Sat, 19 Dec 2009 13:20:10 +0000
From: Ron Youvan <ka4inm at tampabay.rr.com>
Subject: Re: [Amps] water cooling
To: amps <amps at contesting.com>
Message-ID: <4B2CD30A.1010109 at tampabay.rr.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> MSDC Klystrons ran around ten feet @ 32KV applied.
If they use Teflon tubing a foot might be sufficient. Different brands
are cooled differently so
it may depend on the arrangement.
--
Ron KA4INM - Of what you see in books, believe 75%. Of newspapers,
believe 50%.
And of TV news, believe 25% --
make that 5% if the anchorman wears a blazer.
------------------------------
Message: 5
Date: Thu, 17 Dec 2009 20:26:57 +0000
From: Dave White <mausoptik at btinternet.com>
Subject: Re: [Amps] Alternative cooling strategies for SB-220?
To: Hardy Landskov <n7rt at cox.net>, Colin Lamb <k7fm at teleport.com>,
Roger <sub1 at rogerhalstead.com>, Carl <km1h at jeremy.mv.com>
Cc: amps at contesting.com
Message-ID: <20091217202705.A4EC01B607D5 at dayton.contesting.com>
Content-Type: text/plain; charset="iso-8859-1"
If my memory serves me correctly the Stanley Steamer was actually a vapour
phase tube (a 3CV*** or 4CV*** as opposed to a 3CW*** etc) in a boiler
rather than a water cooled tube.
Eimac published this as an amateur service newsletter or similar. I do
have a copy somewhere if you'd like me to copy it. Actually I have all the
Eimac bulletins and keep meaning to scan them when I get some of that rare
resource called 'time'
Cheers
Dave G0OIL
-----Original Message-----
From: "Hardy Landskov" <n7rt at cox.net>
To: "Colin Lamb" <k7fm at teleport.com>; "Roger" <sub1 at rogerhalstead.com>;
"Carl" <km1h at jeremy.mv.com>
Cc: amps at contesting.com
Sent: 17/12/2009 19:57
Subject: Re: [Amps] Alternative cooling strategies for SB-220?
There was an article in QST many years ago called "The Stanley Steamer"
which described water cooled tubes. I believe ETO built an amp based on a
water cooled tube that Eimac made that had 1500 watts plate dissipation.
The
principle being it takes 539 calories of heat to convert 1 gram of water
at
100 deg C to vapor if I remember my thermodynamics correctly.
73 Hardy N7RT
----- Original Message -----
From: "Colin Lamb" <k7fm at teleport.com>
To: "Roger" <sub1 at rogerhalstead.com>; "Carl" <km1h at jeremy.mv.com>
Cc: <amps at contesting.com>
Sent: Thursday, December 17, 2009 11:58 AM
Subject: Re: [Amps] Alternative cooling strategies for SB-220?
[truncated by sender]
------------------------------
Message: 6
Date: Fri, 18 Dec 2009 05:15:07 -0500
From: "Wayne King" <n2wk at rochester.rr.com>
Subject: [Amps] Dentron Needs Plate Choke
To: <amps at contesting.com>
Message-ID: <001FDAF99B904691A1FDCA1EFDEFBDED at WAYNEKING>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
I need to replace the plate choke in my DTR-2000L. It's arching and
causing
an intermittent buzz on the air. Anyone have some old spare parts (plate
choke) from these amps or the MLA series laying around? If not what would
be
a suitable replacement and from who?
73, and Season's Greeting,
Wayne N2WK
------------------------------
Message: 7
Date: Sat, 19 Dec 2009 07:57:23 -0800
From: MIKE DURKIN <patriot121 at msn.com>
Subject: [Amps] Site translator
To: amps fourm <amps at contesting.com>
Message-ID: <COL110-W154DBF396C04C031C84D2492840 at phx.gbl>
Content-Type: text/plain; charset="iso-8859-1"
Any one know of a web page translator that translates the WHOLE page?? I
tried Googles trnslator and it only trnslated the first 20 lines or so... of
this page
http://www.cqham.ru/HiFi_Contester_EX8A.htm or an english version ....
Mike
KC7NOA
_________________________________________________________________
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------------------------------
Message: 8
Date: Sat, 19 Dec 2009 10:07:24 -0600
From: "Roy" <royanjoy at ncn.net>
Subject: Re: [Amps] QSK switching time...etc.
To: <amps at contesting.com>
Message-ID: <E5844B57ED6F4FFF835C686EBC4E018A at RoyPC>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
About,
"...When back biased a diode exhibits a varactor effect: it acts as a
capacitance, whose magnitude is inversely proportional with the applied
voltage. Even a few Pico farads in series with the receive path can have a
disastrous effect on the receiver. Sooo the receive path has to be back
biased by high voltage too!
This characteristic is exhibited even by the very highest quality PIN
diodes, like those manufactured by Chelton especially for the purpose. I
know: I used them when I was working, designing multikilowatt amplifiers
for
the army. (etc.)"
True only if you are using separates. With a transceiver, the rig is in
transmit mode during key downs. Receiver is disconnected then from the
PINs.
73, Roy K6XK
------------------------------
Message: 9
Date: Thu, 17 Dec 2009 16:26:53 EST
From: texasrf at aol.com
Subject: Re: [Amps] Alternative cooling strategies for SB-220?
To: mausoptik at btinternet.com, k7fm at teleport.com,
sub1 at rogerhalstead.com, km1h at jeremy.mv.com
Cc: amps at contesting.com
Message-ID: <1925.66e48d64.385bfc1d at aol.com>
Content-Type: text/plain; charset="US-ASCII"
You can narrow it down to only 10 issues by referring to the yearly index
in the December issues in those days.
73,
Gerald K5GW
In a message dated 12/17/2009 2:17:39 P.M. Central Standard Time,
mausoptik at btinternet.com writes:
Colin, can you narrow it down a bit beyond 'the fifties'? I have most
QSTs
from that era but if you or anyone can narrow it below 120 issues.....
Cheers
Dave
-----Original Message-----
From: "Colin Lamb" <k7fm at teleport.com>
To: "Roger" <sub1 at rogerhalstead.com>; "Carl" <km1h at jeremy.mv.com>
Cc: amps at contesting.com
Sent: 17/12/2009 18:58
Subject: Re: [Amps] Alternative cooling strategies for SB-220?
Water Cooling:
Jo Jennings, W6EI, installed a converted water cooled 4CX250 in the base
of his mobile whip. He converted. I think Eimac subsequently built some
water cooled version based upon the results. There was a writeup in CQ
or
QST in the fifties.
73, Colin K7FM
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