>
> Just looking at the spec's, Jack, for a single 813... in Ham
> service,
> they say you can run 2500v on the plates, at 225mA, but in the same
> chart, says the max is 450w max. Sorry... the math just
> don't add up.
I think 2000 volts is max in plate modulated service.
As long as you
John, WA5BXO
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Geoff/W5OMR
Sent: Thursday, December 07, 2006 3:41 PM
To: Discussion of AM Radio in the Amateur Service
Subject: Re: [AMRadio] Pw Supply
Jack Schmidling wrote:
> In plate modulated AM service, t
Jack, I looked up the specs on the 813 that I have here, in a pdf file..
It says:
"Because of its high power sensitivity, the 813 requires very little
driving power to give full power output. For example, in class C
telegraph services under ICAS conditions, a single 813 is capable of
giving
Jack Schmidling wrote:
In plate modulated AM service, the 813's will run nice
at 2000 volts on the plates at 400ma for 2 tubes.
Just looking at the spec's, Jack, for a single 813... in Ham service,
they say you can run 2500v on the plates, at 225mA, but in the same
chart, says the max is 45
Brett gazdzinski wrote:
Looking for a transformer since 1955, or a power supply?
Actually, my brain.
But "a pair 813's modulated by a pair of 811's" was a sort of mantra in
those days. As a teenager in high school, all I could afford was an 807
modulated by a key and an S38. Now I'm rich
John E. Coleman (ARS WA5BXO) wrote:
Good info Jim:
Certainly something I never considered.
You know, since I've been running the two power supplies in series, on
my rig, I've noticed that when PS#2 is turned on, and the tubes
re-biased for 150mA, the primary current -at least- doubles
> > Why the big hurry, wait to find a good transformer,
> > they are around.
>
> I have wanted one of these since 1955. I have waited long enough
> besides, at my age, time is at a premium.
Looking for a transformer since 1955, or a power supply?
>
> > What ratings are you looking for?
>
rom: John E. Coleman (ARS WA5BXO) <[EMAIL PROTECTED]>
To: Discussion of AM Radio in the Amateur Service
Sent: Wednesday, December 6, 2006 3:28:44 PM
Subject: RE: [AMRadio] Pw Supply
Jim: (JKO)
That is an interesting statement which I had never thought of
before. Using two XFMRs like Ja
Message
From: John E. Coleman (ARS WA5BXO) <[EMAIL PROTECTED]>
To: Discussion of AM Radio in the Amateur Service
Sent: Wednesday, December 6, 2006 3:28:44 PM
Subject: RE: [AMRadio] Pw Supply
Jim: (JKO)
That is an interesting statement which I had never thought of
before. Using two XFMRs
Jim: (JKO)
That is an interesting statement which I had never thought of
before. Using two XFMRs like Jack said, seems at first to be a good theory
but as you pointed out each transformer will be looking into a half
rectifier circuit so that the duty cycle on each core and primary would be
Jim Candela wrote:
No you cannot do this. For full wave center-tap rectification the two
windings must be on the same core.
So much for that great idea.
Thanks,
js
--
PHOTO OF THE WEEK: http://schmidling.com/pow.htm
Astronomy, Beer, Cheese, Fiber,Gems, Sausage,Silver http://schmidling.co
> MFJ has a 900v one for about $100. Is there any reason why I can not
> use two of these and tie one side of the secondaries together
> and call
> that the center tap and have an 1800v ct transformer/s?
>
Reply from Jim, JKO:
No you cannot do this. For full wave center-tap rectificatio
Brett gazdzinski wrote:
I would not buy anything from MFJ!
The transformers are Ameritron for whatever that is worth.
Why the big hurry, wait to find a good transformer,
they are around.
I have wanted one of these since 1955. I have waited long enough
besides, at my age, time is at a prem
I would not buy anything from MFJ!
Why the big hurry, wait to find a good transformer,
they are around.
What ratings are you looking for?
Is it supposed to fit on the deck over that big hole?
Fair radio used to sell a nice oil filled Collins
transformer, 2250 volt ct at 650ma, 110 or 220 primary
John Lawson wrote:
On Tue, 5 Dec 2006, Jack Schmidling wrote:
I am not having much luck finding a HV xformer for my power supply so
an idea occurred to me that I would like to pass around.
Answer one of my emails, if you're getting them
If you're *not* getting them, well, hey: ju
On Tue, 5 Dec 2006, Jack Schmidling wrote:
I am not having much luck finding a HV xformer for my power supply so an idea
occurred to me that I would like to pass around.
Answer one of my emails, if you're getting them
If you're *not* getting them, well, hey: just use the Fahwce
Brett gazdzinski wrote:
All the homebrew power supply decks have voltage and current meters,
then all the modulators and RF decks also have current meters.
If you run both rf and modulator off one power supply, you
get an indication on the power supply of the total current.
Now that I am used t
e
> Subject: Re: [AMRadio] PW Supply
>
> Brett gazdzinski wrote:
>
> > Its also poor practice to put the current meter on another deck,
> > what happens when you want to use the power supply on something
> > else?
>
> Yes indeed! How convenient to tune the RF deck w
December 03, 2006 6:46 PM
> To: Discussion of AM Radio in the Amateur Service
> Subject: Re: [AMRadio] PW Supply
>
> Brett gazdzinski wrote:
>
> > I would never use something that looked so nasty and poorly made
>
> Actually, it is very will made, laid out and laced li
Brett gazdzinski wrote:
Its also poor practice to put the current meter on another deck,
what happens when you want to use the power supply on something
else?
Yes indeed! How convenient to tune the RF deck while watching the plate
current meter about 3 feet below it.
The idea of putting a
Brett gazdzinski wrote:
I would never use something that looked so nasty and poorly made
Actually, it is very will made, laid out and laced like mil spec. I
haven't a clue what you are talking about.
like to use parts that look like they match
Just what is it that does not match? You
Maybe its to prevent some surge when the supply
is powered on. If so, it's a dumb way to do it.
The negative is through the rack (chassis ground) I would guess.
I always run a negative directly, and don't rely on
the rack, I think it would be poor practice to rely on the mounting
of the front pane
...
Brett
N2DTS
> -Original Message-
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] On Behalf Of Jack Schmidling
> Sent: Saturday, December 02, 2006 11:34 PM
> To: Discussion of AM Radio in the Amateur Service
> Subject: Re: [AMRadio] PW Supply
>
> Brett gazd
On 12/2/06, Jack Schmidling <[EMAIL PROTECTED]> wrote:
I don't see what effect it would have as a short protection.
Henry Amps did it for years on their amps. I know, I have one. Pull
too much current and that resistor will go instead of maybe the plate
xfmr.
John Coleman ARS WA5BXO wrote:
It may be the only path to ground for the power supply and measuring the
voltage across it may be the way to measure current from the power supply.
A 10 ohm resistor with 1 volt measure across it represents 100ma current.
This is common practice for the way I measu
Brett gazdzinski wrote:
The power supply looks really nasty, it does not look
like there are many good parts on it...
Hopefully, looks are deceiving. I have checked every part in it with
ohmeter, sig gen and scope and can find no faulty parts. That's not the
same as applying voltage to it
impressed with the graphs.
John, WA5BXO
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Brett gazdzinski
Sent: Saturday, December 02, 2006 8:24 PM
To: 'Discussion of AM Radio in the Amateur Service'
Subject: RE: [AMRadio] PW Supply
I usual
Coleman ARS WA5BXO
> Sent: Saturday, December 02, 2006 8:41 PM
> To: 'Discussion of AM Radio in the Amateur Service'
> Cc: [EMAIL PROTECTED]
> Subject: RE: [AMRadio] PW Supply
>
> It may be the only path to ground for the power supply and
> measuring the
> voltage
TECTED]
> [mailto:[EMAIL PROTECTED] On Behalf Of John
> Coleman ARS WA5BXO
> Sent: Saturday, December 02, 2006 8:41 PM
> To: 'Discussion of AM Radio in the Amateur Service'
> Cc: [EMAIL PROTECTED]
> Subject: RE: [AMRadio] PW Supply
>
> It may be the only path to ground f
It may be the only path to ground for the power supply and measuring the
voltage across it may be the way to measure current from the power supply.
A 10 ohm resistor with 1 volt measure across it represents 100ma current.
This is common practice for the way I measure power supply current.
BTW I f
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