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-   -   Measuring RF output impedance (https://www.radiobanter.com/homebrew/22946-measuring-rf-output-impedance.html)

Jan Panteltje May 2nd 04 02:15 AM

On a sunny day (Sun, 2 May 2004 02:06:09 +0200) it happened "Frank Bemelman"
wrote in
:

"Jan Panteltje" schreef in bericht
...
On a sunny day (Sat, 1 May 2004 23:37:26 +0200) it happened "Frank

Bemelman"
wrote in
:

"Jan Panteltje" schreef in bericht
...
On a sunny day (Sat, 01 May 2004 14:19:59 +0100) it happened Paul

Burridge
wrote in
:

Hi,

I have a spare RF signal generator that has an unmarked output from a
type of socket I've never seen before. What's the simplest way of
establishing its output impedance? I've had a few ideas but no doubt
someone out there will know of something better, since I always seem
to end up making unnecessary work for myself.
Any suggestions?

Load it with 50 Ohms, and measure output voltage, remove load and

measure
again.
If it is half, it is 50, else do the math.

If it is half, you've got a funny generator.


Why that?


I expect amplitudes to double or at least rise, after
removing a load. Just nitpicking ;)

Yes - sentence construction could have been more clear,
it should have been inferred as 'If it is half *before you removed it*
now that would be wrong too, 'If it WAS half' OK.
No, actually it was correct, cause 'it' referred to the first measurement.
Did you collect many nits while picking ;-)?


John Crighton May 2nd 04 03:43 AM

On Sat, 01 May 2004 14:19:59 +0100, Paul Burridge
wrote:

Hi,

I have a spare RF signal generator that has an unmarked output from a
type of socket I've never seen before. What's the simplest way of
establishing its output impedance? I've had a few ideas but no doubt
someone out there will know of something better, since I always seem
to end up making unnecessary work for myself.
Any suggestions?

p.
--

The BBC: licenced at public expense to spread lies.


Hello Paul,
what is the brand name and model number of your RF signal generator.
Can you descibe the socket to us.
Regards,
John Crighton
Sydney



John Crighton May 2nd 04 03:43 AM

On Sat, 01 May 2004 14:19:59 +0100, Paul Burridge
wrote:

Hi,

I have a spare RF signal generator that has an unmarked output from a
type of socket I've never seen before. What's the simplest way of
establishing its output impedance? I've had a few ideas but no doubt
someone out there will know of something better, since I always seem
to end up making unnecessary work for myself.
Any suggestions?

p.
--

The BBC: licenced at public expense to spread lies.


Hello Paul,
what is the brand name and model number of your RF signal generator.
Can you descibe the socket to us.
Regards,
John Crighton
Sydney



Frank Bemelman May 2nd 04 10:45 AM

"Jan Panteltje" schreef in bericht
...
On a sunny day (Sun, 2 May 2004 02:06:09 +0200) it happened "Frank

Bemelman"
wrote in
:

"Jan Panteltje" schreef in bericht
...
On a sunny day (Sat, 1 May 2004 23:37:26 +0200) it happened "Frank

Bemelman"
wrote in
:

"Jan Panteltje" schreef in bericht
...
On a sunny day (Sat, 01 May 2004 14:19:59 +0100) it happened Paul

Burridge
wrote in
:

Hi,

I have a spare RF signal generator that has an unmarked output from

a
type of socket I've never seen before. What's the simplest way of
establishing its output impedance? I've had a few ideas but no

doubt
someone out there will know of something better, since I always

seem
to end up making unnecessary work for myself.
Any suggestions?

Load it with 50 Ohms, and measure output voltage, remove load and

measure
again.
If it is half, it is 50, else do the math.

If it is half, you've got a funny generator.


Why that?


I expect amplitudes to double or at least rise, after
removing a load. Just nitpicking ;)

Yes - sentence construction could have been more clear,
it should have been inferred as 'If it is half *before you removed it*
now that would be wrong too, 'If it WAS half' OK.
No, actually it was correct, cause 'it' referred to the first measurement.
Did you collect many nits while picking ;-)?


Well, I also wondered what it means to Paul, once he has
figured out that output impedance. Will it change his life
dramatically... ;)

--
Thanks, Frank.
(remove 'x' and 'invalid' when replying by email)







Frank Bemelman May 2nd 04 10:45 AM

"Jan Panteltje" schreef in bericht
...
On a sunny day (Sun, 2 May 2004 02:06:09 +0200) it happened "Frank

Bemelman"
wrote in
:

"Jan Panteltje" schreef in bericht
...
On a sunny day (Sat, 1 May 2004 23:37:26 +0200) it happened "Frank

Bemelman"
wrote in
:

"Jan Panteltje" schreef in bericht
...
On a sunny day (Sat, 01 May 2004 14:19:59 +0100) it happened Paul

Burridge
wrote in
:

Hi,

I have a spare RF signal generator that has an unmarked output from

a
type of socket I've never seen before. What's the simplest way of
establishing its output impedance? I've had a few ideas but no

doubt
someone out there will know of something better, since I always

seem
to end up making unnecessary work for myself.
Any suggestions?

Load it with 50 Ohms, and measure output voltage, remove load and

measure
again.
If it is half, it is 50, else do the math.

If it is half, you've got a funny generator.


Why that?


I expect amplitudes to double or at least rise, after
removing a load. Just nitpicking ;)

Yes - sentence construction could have been more clear,
it should have been inferred as 'If it is half *before you removed it*
now that would be wrong too, 'If it WAS half' OK.
No, actually it was correct, cause 'it' referred to the first measurement.
Did you collect many nits while picking ;-)?


Well, I also wondered what it means to Paul, once he has
figured out that output impedance. Will it change his life
dramatically... ;)

--
Thanks, Frank.
(remove 'x' and 'invalid' when replying by email)







Fred Bartoli May 2nd 04 11:02 AM


"Frank Bemelman" a écrit dans le message
news: ...

Well, I also wondered what it means to Paul, once he has
figured out that output impedance. Will it change his life
dramatically... ;)


Sure. He now have a nice opportunity to ask the same question once more ;-)

Thanks,
Fred.


BTW, got some news of our goldmine order ?
Not that I'm longing to have it, but they do seem to be waaaay slooooow....




Fred Bartoli May 2nd 04 11:02 AM


"Frank Bemelman" a écrit dans le message
news: ...

Well, I also wondered what it means to Paul, once he has
figured out that output impedance. Will it change his life
dramatically... ;)


Sure. He now have a nice opportunity to ask the same question once more ;-)

Thanks,
Fred.


BTW, got some news of our goldmine order ?
Not that I'm longing to have it, but they do seem to be waaaay slooooow....




Frank Bemelman May 2nd 04 11:54 AM

"Fred Bartoli"
r_AndThisToo schreef in
bericht ...

"Frank Bemelman" a écrit dans le message
news: ...

Well, I also wondered what it means to Paul, once he has
figured out that output impedance. Will it change his life
dramatically... ;)


Sure. He now have a nice opportunity to ask the same question once more

;-)

Thanks,
Fred.


BTW, got some news of our goldmine order ?
Not that I'm longing to have it, but they do seem to be waaaay

slooooow....

The last news was it got shipped on 21 april. I expect it 'real soon now'.

--
Thanks, Frank.
(remove 'x' and 'invalid' when replying by email)



Frank Bemelman May 2nd 04 11:54 AM

"Fred Bartoli"
r_AndThisToo schreef in
bericht ...

"Frank Bemelman" a écrit dans le message
news: ...

Well, I also wondered what it means to Paul, once he has
figured out that output impedance. Will it change his life
dramatically... ;)


Sure. He now have a nice opportunity to ask the same question once more

;-)

Thanks,
Fred.


BTW, got some news of our goldmine order ?
Not that I'm longing to have it, but they do seem to be waaaay

slooooow....

The last news was it got shipped on 21 april. I expect it 'real soon now'.

--
Thanks, Frank.
(remove 'x' and 'invalid' when replying by email)



Paul Burridge May 2nd 04 02:08 PM

On Sun, 02 May 2004 02:43:18 GMT, (John Crighton)
wrote:


Hello Paul,
what is the brand name and model number of your RF signal generator.
Can you descibe the socket to us.


Thanks John (and others).

The model number ain't gonna mean a lot to anyone as this is a very
old piece of kit (1950s) that I keep mainly out of a sense of
reverence for the past. :-) It's an old ex-RAF AVO. I have posted a
picture of the socket to a.b.s.e under this same thread title...
BTW, there's a 5p coin shown for scale, but since that won't mean much
to anyone outside Britain, the outer of the socket is approx. 1" in
diameter (which won't mean much to anyone in europe but it serves them
right for adopting the metric system.:-))

--

The BBC: licenced at public expense to spread lies.


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