[Amps] wire paint Re: Amps Digest, Vol 131, Issue 64

Sat Nov 30 14:05:36 EST 2013

if I were you I would get  some motor winding paint varnish from grainger or 
your sherwin williams store its good for 2.5kv per mil of film must be baked 
on to raise the kv rating

N9IWW

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From: amps-request at contesting.com
Sent: Saturday, November 30, 2013 1:44 PM
To: amps at contesting.com
Subject: Amps Digest, Vol 131, Issue 64

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Today's Topics:

   1. Re: Chinese  FU-724F (Carl)
   2. Re: Adhesive for plate choke? (Carl)
   3. Re: Adhesive for plate choke? (peter chadwick)
   4. Re: Bleeder resistor across screen grid terminal (Bill Turner)
   5. Re: Adhesive for plate choke? (Bill Turner)
   6. Re: Adhesive for plate choke? (Mike)
   7. Re: Adhesive for plate choke? (Mike)
   8. Re: Adhesive for plate choke? (iain macdonnell - N6ML)
   9. Re: GS-35b Amplifier (jeff millar)

----------------------------------------------------------------------

Message: 1
Date: Fri, 29 Nov 2013 11:02:24 -0500
From: "Carl" <km1h at jeremy.mv.com>
To: <gdaught6 at stanford.edu>, <amps at contesting.com>
Subject: Re: [Amps] Chinese  FU-724F
Message-ID: <AE5D0FED27424C5AA6DDEB6B6CF2EC33 at computer1>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original

----- Original Message ----- 
From: <gdaught6 at stanford.edu>
To: <amps at contesting.com>
Sent: Wednesday, November 27, 2013 11:53 AM
Subject: Re: [Amps] Chinese FU-724F

> Hsu wrote...
>
>> I found a Chinese cheap triode for industry, filamnet 6V/50A;
>> Pamax=2.5kW; Grid diss=150W;Umax=6kV;
>> u=70, you know most industrial triodes are low/ meidum u tubes, but
>> this one is high u tube.
>> As it is  idustial tube , so the  price is cheap.Any suggestion?does
>> it  fit hamradio well?
>
> Look at the mu (amplification factor) for the 3-500Z, or the 8877, for
> example:  160
> and 200.  With a mu of 70, it will take considerably more drive power than
> what is
> usual for amateur service.
>
> 73,
>
> George T Daughters, K6GT
> CU in the California QSO Party (CQP)
> October 4-5, 2014

No argument there but many rigs have excess power to burn and many others
use an IPA to drive a YC-156 and other tubes with handles anyway. That is
what the ALS-600, SB-1000, AL-80 family, etc are used for.

Also several of the old glass tetrodes popularly used in GG wind up with an
effective mu not much above the FU-724F, especially when run at a voltage
well below their maximum. Think 4-1000A or a 4-400 used in a SB-220.

Carl
KM1H

------------------------------

Message: 2
Date: Fri, 29 Nov 2013 11:04:53 -0500
From: "Carl" <km1h at jeremy.mv.com>
To: "iain macdonnell - N6ML" <ar at dseven.org>, "AMPS"
<amps at contesting.com>
Subject: Re: [Amps] Adhesive for plate choke?
Message-ID: <6F385FED42784A42ADC3AC8AD87CFC2B at computer1>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original

Why? A replacement is only $20 and an improvement over early AL-1200's. It
took Ameritron 3 tries to get it right.

Carl
KM1H

----- Original Message ----- 
From: "iain macdonnell - N6ML" <ar at dseven.org>
To: "AMPS" <amps at contesting.com>
Sent: Wednesday, November 27, 2013 3:17 PM
Subject: [Amps] Adhesive for plate choke?

> I'm going to attempt to rewind a plate choke for my AL-1200, using the
> old form from the one I blew before. What is the recommend adhesive
> for this application? I've read about home-brew "Q-Dope"[1] - would
> that work? Other suggestions? I'd prefer something that's not going to
> be flammable when in use...
>
> 73,
>
>    ~iain / N6ML
>
>
> [1] http://www.cliftonlaboratories.com/coil_coating_compounds.htm
> _______________________________________________
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> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
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------------------------------

Message: 3
Date: Fri, 29 Nov 2013 17:32:53 +0100
From: peter chadwick <g8on at fsmail.net>
To: iain macdonnell - N6ML <ar at dseven.org>, AMPS <amps at contesting.com>
Subject: Re: [Amps] Adhesive for plate choke?
Message-ID: <1800184.16471385742772938.JavaMail.www at wwinf3715>
Content-Type: text/plain; charset=UTF-8

If the choke is going to get hot, I'd be wary of Q dope, as it may well 
start melting. I've had decent results with minimal loss of Q with some of 
the 5 minute epoxy cements.

73

Peter G3RZP

========================================
Message Received: Nov 29 2013, 03:39 PM
From: "iain macdonnell - N6ML" <ar at dseven.org>
To: "AMPS" <amps at contesting.com>
Cc:
Subject: [Amps] Adhesive for plate choke?

I'm going to attempt to rewind a plate choke for my AL-1200, using the
old form from the one I blew before. What is the recommend adhesive
for this application? I've read about home-brew "Q-Dope"[1] - would
that work? Other suggestions? I'd prefer something that's not going to
be flammable when in use...

73,

     ~iain / N6ML

[1] http://www.cliftonlaboratories.com/coil_coating_compounds.htm
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Message: 4
Date: Fri, 29 Nov 2013 14:49:57 -0800
From: Bill Turner <dezrat1242 at yahoo.com>
To: Amps <amps at contesting.com>
Subject: Re: [Amps] Bleeder resistor across screen grid terminal
Message-ID: <l76i9917rp7grb6jftp1pceki0uniqut4d at 4ax.com>
Content-Type: text/plain; charset=us-ascii

ORIGINAL MESSAGE:          (may be snipped)

On Thu, 28 Nov 2013 18:08:19 -0700, K5PRO wrote:

>My point being, a stiff shunt R across screen grid is a good idea, not
>only from the standpoint of keeping the screen always terminated during
>switching, but also for circuit stability. I have done it both with and
>without the R, but these days I prefer having the shunt R there, and
>burn up some screen power from the supply.

REPLY:

It should be noted that the shunt R is only needed if you have a series type
screen regulator, which is probably the most common type. If you have a
shunt type screen regulator, the R is not needed PROVIDED the shunt
regulator draws enough idle current to supply all the secondary emission
current the screen will ever draw.

73, Bill W6WRT

------------------------------

Message: 5
Date: Fri, 29 Nov 2013 14:53:09 -0800
From: Bill Turner <dezrat1242 at yahoo.com>
To: Amps <amps at contesting.com>
Subject: Re: [Amps] Adhesive for plate choke?
Message-ID: <ph6i99trisbejcge2l6ue8bopdkspit599 at 4ax.com>
Content-Type: text/plain; charset=us-ascii

ORIGINAL MESSAGE:          (may be snipped)

On Wed, 27 Nov 2013 12:17:01 -0800, you wrote:

>
>I'm going to attempt to rewind a plate choke for my AL-1200, using the
>old form from the one I blew before. What is the recommend adhesive
>for this application? I've read about home-brew "Q-Dope"[1] - would
>that work? Other suggestions? I'd prefer something that's not going to
>be flammable when in use...
>
>73,
>
>    ~iain / N6ML

REPLY:

Whatever you do be sure to test it for resonances very carefully. Not only
will the Q-dope affect resonance, so will the exact wire you use. Different
wires have different thickness and types of enamel and therefore different
inter-winding capacitance.

Personally, I'd just buy a replacement from Ameritron and be done with it.

73, Bill W6WRT

------------------------------

Message: 6
Date: Fri, 29 Nov 2013 16:09:54 -0800
From: "Mike" <noddy1211 at comcast.net>
To: "'iain macdonnell - N6ML'" <ar at dseven.org>, "'AMPS'"
<amps at contesting.com>
Subject: Re: [Amps] Adhesive for plate choke?
Message-ID: <007e01ceed60$7fc45660$7f4d0320$@net>
Content-Type: text/plain; charset="us-ascii"

Iain,

You can purchase that Choke from RF Parts for about 20 bucks, I was going to
re-wind the one that blew in my old Clipperton Amp, it was more cost
effective to spend the 20 bucks.  The RF-Parts choke is the same as the one
Ameritron uses.

Mike/K6BR

-----Original Message-----
From: Amps [mailto:amps-bounces at contesting.com] On Behalf Of iain macdonnell
- N6ML
Sent: Wednesday, November 27, 2013 12:17 PM
To: AMPS
Subject: [Amps] Adhesive for plate choke?

I'm going to attempt to rewind a plate choke for my AL-1200, using the old
form from the one I blew before. What is the recommend adhesive for this
application? I've read about home-brew "Q-Dope"[1] - would that work? Other
suggestions? I'd prefer something that's not going to be flammable when in
use...

73,

    ~iain / N6ML

[1] http://www.cliftonlaboratories.com/coil_coating_compounds.htm
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Message: 7
Date: Fri, 29 Nov 2013 16:15:40 -0800
From: "Mike" <noddy1211 at comcast.net>
To: "'iain macdonnell - N6ML'" <ar at dseven.org>, "'AMPS'"
<amps at contesting.com>
Subject: Re: [Amps] Adhesive for plate choke?
Message-ID: <008201ceed61$4d8ed520$e8ac7f60$@net>
Content-Type: text/plain; charset="us-ascii"

http://www.rfparts.com/catalogsearch/result/?q=ameritron+plate+choke

forgot the link.

Mike/K6BR

-----Original Message-----
From: Amps [mailto:amps-bounces at contesting.com] On Behalf Of iain macdonnell
- N6ML
Sent: Wednesday, November 27, 2013 12:17 PM
To: AMPS
Subject: [Amps] Adhesive for plate choke?

I'm going to attempt to rewind a plate choke for my AL-1200, using the old
form from the one I blew before. What is the recommend adhesive for this
application? I've read about home-brew "Q-Dope"[1] - would that work? Other
suggestions? I'd prefer something that's not going to be flammable when in
use...

73,

    ~iain / N6ML

[1] http://www.cliftonlaboratories.com/coil_coating_compounds.htm
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Message: 8
Date: Fri, 29 Nov 2013 19:26:39 -0800
From: iain macdonnell - N6ML <ar at dseven.org>
To: Mike <noddy1211 at comcast.net>
Cc: AMPS <amps at contesting.com>
Subject: Re: [Amps] Adhesive for plate choke?
Message-ID:
<CACDL7B0pzi4B4wWq-YiPOQAz_8p3cYRS51C1GVA02=SAFu+6hA at mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1

Yes, I know I can buy a replacement. I already did. The original in my
AL-1200 was the single-section type, and I blew it on 17m. I want to
use the form from that original to wind a clone of the newer
three-section design. I'm sure it doesn't make economical sense, if I
put some value on my time, but maybe I'll learn something in the
process. Actually, I already did - research led me to W8JI's web page
that describes how the sectioning shifts the series resonances away
from the WARC bands...

73,

    ~iain / N6ML

On Fri, Nov 29, 2013 at 4:15 PM, Mike <noddy1211 at comcast.net> wrote:
> http://www.rfparts.com/catalogsearch/result/?q=ameritron+plate+choke
>
> forgot the link.
>
> Mike/K6BR
>
> -----Original Message-----
> From: Amps [mailto:amps-bounces at contesting.com] On Behalf Of iain 
> macdonnell
> - N6ML
> Sent: Wednesday, November 27, 2013 12:17 PM
> To: AMPS
> Subject: [Amps] Adhesive for plate choke?
>
> I'm going to attempt to rewind a plate choke for my AL-1200, using the old
> form from the one I blew before. What is the recommend adhesive for this
> application? I've read about home-brew "Q-Dope"[1] - would that work? 
> Other
> suggestions? I'd prefer something that's not going to be flammable when in
> use...
>
> 73,
>
>     ~iain / N6ML
>
>
> [1] http://www.cliftonlaboratories.com/coil_coating_compounds.htm
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
>
> ---
> This email is free from viruses and malware because avast! Antivirus 
> protection is active.
> http://www.avast.com
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------------------------------

Message: 9
Date: Sat, 30 Nov 2013 10:15:17 -0500
From: jeff millar <wa1hco at wa1hco.net>
To: amps at contesting.com
Subject: Re: [Amps] GS-35b Amplifier
Message-ID: <529A0105.8010202 at wa1hco.net>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

Hi Nuno...

See Below

On 11/29/2013 05:08 AM, Nuno Lopes wrote:
> Hi all,
>
> This will be my first big project like this, I'm in the beginning of start
> my first project with an amplifier, and have some questions.
>
> I'll start from the Anode tank first then working around that, I'm 
> thinking
> to make an tank like this one (
> http://home.earthlink.net/~wd7s/images/photo2a.jpg ) with the
> dimensions 7.874" Wide by 11.81" Deep, the tube will be 1.97" from each
> side and back of the tank, will there be any problem with that?
The output network has currents that flow in three loops,
    1) Plate,  Tune cap, Grid
    2) Tune Cap, Coil, Load Cap
    3) Load Cap, Output Coax

The ground return path for each of these loops is critical to performance

The design you have shown in the wd7s site has a grid return current path 
with
several aluminum chassis joints.  Front panel, to bottom chassis, to grid 
box.

The best design for return current flow puts the tube grid, tune cap, load 
cap,
and output connector
  on the same sheet of aluminum and build from there.

The wd7s design works if each aluminum joint is made to carry high RF 
current with
minimum voltage drop.

jeff, wa1hco

------------------------------

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End of Amps Digest, Vol 131, Issue 64
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