With it's own switching...why would it have a flexible coupling rather than
a knob? Why would there be no band markings. I asked you in a seperate
email if you had a manual.. You did not offer that it would not have a
manual as it was home made. So, Are you saying that you happened to have
several just like this? I have been a ham since I was 8 years old and I am
53 now. I have never seen one like this. I am sure people have home-brewed
them over the years, and you just happened to have owned most all of them?
No markings on it anywhere. Don't you think someone would have put a band
tag on it along with a knob of any sort rather that a coupling? So to change
bands you grabbed a wobbly coulpling with no pointer, no indicator, no
lettering? .
Why did you leave home brew out of your ad? Just curious. Have you not seen
almost even piece of equipment listed either have a manufacturer or a
statement that it is home made? You had so many people who wanted it. I
will pay to send it back. Refund my paypal and sell it to someone who can
read you mind. I think you are full of it if you think this thing was not
made to fit inside an amp. How long have you been a ham anyway? Bill
If I pay to send it back you should have no issue refunding my paypal. I
covered the fees plus some anyway. Remember?
----Original Message Follows----
From: amps-request@contesting.com
Reply-To: amps@contesting.com
To: amps@contesting.com
Subject: Amps Digest, Vol 53, Issue 25
Date: Thu, 17 May 2007 12:00:23 -0400
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Today's Topics:
1. Re: An inexpensive choke for a resonant filter (Steve Thompson)
2. Ameritrons on 10 meters mod (Gerold Sklott)
3. Re: An inexpensive choke for a resonant filter (Radio WC6W)
4. Re: An inexpensive choke for a resonant filter (Angel Vilaseca)
----------------------------------------------------------------------
Message: 1
Date: Wed, 16 May 2007 17:31:40 +0100
From: Steve Thompson <g8gsq@eltac.co.uk>
Subject: Re: [Amps] An inexpensive choke for a resonant filter
To: amps@contesting.com
Message-ID: <464B31EC.9060508@eltac.co.uk>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Vic K2VCO wrote:
> Angel Vilaseca wrote:
>
>
>> I wonder if a HV transformer from a microwave oven cold be recycled
>> in a HV power supply, using its secondary winding a a choke. It's big
>> and it's free!
>
>
>
> I have one of these and it looks like one side of the secondary is
> designed to be grounded. So the insulation may be poor at this point.
> If this is the case with yours, you might think about using it in the
> negative side of the power supply.
I have three here I'm experimenting with (as HV supplies). I lifted the
grounded end of the secondary on all of them - two hipot to 8kV+, the
third arcs at 3kV but a piece of Kapton tape on the frame under where
the wire comes out of the bobbin takes it beyond 8kV too.
Steve
------------------------------
Message: 2
Date: Wed, 16 May 2007 13:00:27 -0700 (PDT)
From: Gerold Sklott <gsklott@yahoo.com>
Subject: [Amps] Ameritrons on 10 meters mod
To: amps@contesting.com
Message-ID: <654284.52700.qm@web52308.mail.re2.yahoo.com>
Content-Type: text/plain; charset=iso-8859-1
I'm getting either an AL82 or AL1500 shortly. The 10
meter was never done. Can someone e mail it to me, now
that the FCC does not require a lock out anymore. A
call to Ameritron didn't help since everyone went to
Dayton. I'd like to do the mod while I have it open to
put tubes and xmfr in.
Tks much de Gerry
K1NY
____________________________________________________________________________________Luggage?
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------------------------------
Message: 3
Date: Wed, 16 May 2007 14:12:24 -0700 (PDT)
From: Radio WC6W <wc6w_amps@yahoo.com>
Subject: Re: [Amps] An inexpensive choke for a resonant filter
To: amps@contesting.com
Message-ID: <7167.97109.qm@web63915.mail.re1.yahoo.com>
Content-Type: text/plain; charset=iso-8859-1
Here are some real numbers for simulation:
A 3KW Varian plate transformer (85 lbs)
240V Primary -- 2.2 ohms DCR, 40 mHy
inductance
3200V 1A Secondary -- 22 ohms DCR, 9H
inductance
A Westinghouse 1A, 10KV choke (50 lbs)
8H & 30 ohms DCR
Doing "research" for a plate supply using microwave
oven parts, I "recycled" a dozen microwaves, garnered
from the "curb exchange", appliance "rated" from 600
watts to 1 KW.
The transformers were all wound with #14 on the
primary and #26 on the secondary. The secondaries are
all grounded at one end, though most can be easily
lifted -- Negative lead filtering is a good option in
this instance.
The secondary inductances measured between 9 & 22 H
with the shunts in place. The secondary resistances
measured between 70 & 110 ohms. They weigh from 8 to
10 lbs each.
The capacitors run between .72uF and 1uF with the
median around .9 uF.
Perhaps, two or three "matched" microwave
transformer secondaries connected in parallel with 3
or 4 of their caps connected in series, then across
the transformers would be a good substitute for a real
8Hy 1A choke.
And a couple more data points for the resonant
choke filtering thread:
The Collins 30S-1 used 8H & .15 uF in the plate
supply and 3.5H and .5 uF in the screen supply.
I once used the 8H Westinghouse part noted above
& .2uF@5KV in a resonant configuration in my 4CX1000A
power supply. See:
http://wc6w.50webs.com/wc6wamps/index.html?fr131.html
73 & Good afternoon,
Marv WC6W
http://wc6w.50webs.com/
*
____________________________________________________________________________________Sick
sense of humor? Visit Yahoo! TV's
Comedy with an Edge to see what's on, when.
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------------------------------
Message: 4
Date: Thu, 17 May 2007 10:13:43 +0200
From: Angel Vilaseca <AVILASECA@BLUEWIN.CH>
Subject: Re: [Amps] An inexpensive choke for a resonant filter
To: Radio WC6W <wc6w_amps@yahoo.com>
Cc: amps@contesting.com
Message-ID: <464C0EB7.5090102@BLUEWIN.CH>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Marv,
Thank you for this very useful information.
Maybe the primary of a microwave oven could be wired in series with the
secondary (forward or backwards, depending on the inductance you want)
and be used to "fine tune" the total inductance by adding or removing
some turns.
Has any other group member experimented with microwave oven transformers
used as chokes?
Also, I wonder how much protection against overcurrent at resonance can
be expected from the magnetic shunts of the microwave oven transformers?
Can it be said that the magnetic shunts would lower the Q of the
resonant filter?
And that they would do so without dissipating any heat?
Lowering the Q of the resonant choke would be a good thing in terms of
safety. On the other hand, this would probably reduce 120 Hz ripple
attenuation.
Any ideas?
Vy 73 de Angel HB9SLV
Radio WC6W a ?crit :
> Here are some real numbers for simulation:
>
> A 3KW Varian plate transformer (85 lbs)
> 240V Primary -- 2.2 ohms DCR, 40 mHy
>inductance
> 3200V 1A Secondary -- 22 ohms DCR, 9H
>inductance
>
> A Westinghouse 1A, 10KV choke (50 lbs)
> 8H & 30 ohms DCR
>
> Doing "research" for a plate supply using microwave
>oven parts, I "recycled" a dozen microwaves, garnered
>from the "curb exchange", appliance "rated" from 600
>watts to 1 KW.
>
> The transformers were all wound with #14 on the
>primary and #26 on the secondary. The secondaries are
>all grounded at one end, though most can be easily
>lifted -- Negative lead filtering is a good option in
>this instance.
>
> The secondary inductances measured between 9 & 22 H
>with the shunts in place. The secondary resistances
>measured between 70 & 110 ohms. They weigh from 8 to
>10 lbs each.
>
> The capacitors run between .72uF and 1uF with the
>median around .9 uF.
>
> Perhaps, two or three "matched" microwave
>transformer secondaries connected in parallel with 3
>or 4 of their caps connected in series, then across
>the transformers would be a good substitute for a real
>8Hy 1A choke.
>
> And a couple more data points for the resonant
>choke filtering thread:
>
> The Collins 30S-1 used 8H & .15 uF in the plate
>supply and 3.5H and .5 uF in the screen supply.
>
> I once used the 8H Westinghouse part noted above
>& .2uF@5KV in a resonant configuration in my 4CX1000A
>power supply. See:
>http://wc6w.50webs.com/wc6wamps/index.html?fr131.html
>
>73 & Good afternoon,
> Marv WC6W
>
>http://wc6w.50webs.com/
>
>
>
>
>
>
>
>*
>
>
>
>____________________________________________________________________________________Sick
>
sense of humor? Visit Yahoo! TV's
>Comedy with an Edge to see what's on, when.
>http://tv.yahoo.com/collections/222
>_______________________________________________
>Amps mailing list
>Amps@contesting.com
>http://lists.contesting.com/mailman/listinfo/amps
>
>
>
------------------------------
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