On 14 mayo, 22:48, Richard Clark wrote:
On Sat, 14 May 2011 12:16:00 -0700 (PDT), Wimpie
wrote:
I just thought you made some error in converting your thoughts into
sentences (we are just humans), but maybe the error was in the
thoughts already.
At the risk of removing a snippet from context, and simplifying in
language and construction:
BELOW a
* * * * transition frequency
audio amps source rated at LOW Z sourcing high power into HIGH Z loads
work.
ABOVE that
* * * * transition frequency
retail Amateur transmitters source rated at LOW Z sourcing high power
into HIGH Z loads
* * * * do not work.
I wonder if that works (sic) with these statements reversed?
Bonus question:
What is the transition frequency?
Both questions can be simply answered: the first with a binary
response, the other with a numerical response (two place precision is
OK - even one place precision is sufficient).
This is the price of subject drift:
* * "AF amp specs as proof of RF amp performance."
What a work of obscurity.
You can challenge the premise, of course; but to reduce rambling
thoughts driven by subject drift, and to remain on topic:
References:
73's
Richard Clark, KB7QHC
Hello Richard,
Part from original posting (salmonella):
"Something I haven't seen is a discussion of the source impedance of
the transmitter. My curiosity was piqued today as I took some baby
steps into EZNEC. A particular antenna had such-and-such VSWR if fed
with a 50-ohm cable and a different value if fed with a 75-ohm cable."
The subject is output impedance of a PA. I made a clear statement
regarding this in my first reaction.
Part of your posting:
Though it's a red herring typical of Ham-speak, most modern retail
100W RF transmitters for amateur service have a very low output
impedance, a fraction of an ohm [ editorial: until, of course, it goes
to the Z transformer that precedes the bandpass filter].
The above text is basically on topic, but not correct, so I suggested
a correction. In my opinion, the push-pull example is OT also.
Some snippet from you posting:
You can challenge the premise, of course; but to reduce rambling
thoughts driven by subject drift, and to remain on topic:
Are you pointing to the rambling in your own mind?
Wim
PA3DJS
www.tetech.nl