"Dave Platt" wrote in message ...

In article ,
Irv Finkleman wrote:

For starters a HP 8924C ( service monitor with tracking generator) ,
return
loss bridge, wattmeters.

I just have not tried the rubber duck antennas to see what frequency I
think
they may be for.


If the rubber ducky is measured by itself, it may not show
resonance at the right band of frequencies, however I wonder if
it uses the handheld case as part of the system, in which case
measurements might change to the anticipated range.

Just a wild guess.

That matches my own experience and experiments. An HT rubber duck
tends to use the HT case, and (via capacitive coupling) the user's
hand and body, as the "counterpoise". If you hook it to the end of a
coax cable, or directly to a service monitor's test output, the
"counterpoise" impedance will be rather different.

Also, the HT duck is often operating in fairly close proximity to
the head, with some amount of loading from that proximity affecting
its feedpoint impedance.

I've tested out a number of "ducks" by attaching them to an MFJ 256 or
269 antenna analyzer. They tend to shift apparent SWR quite a bit
depending on whether I'm holding the analyzer or not, and (if I am)
whether it's out in free space, or held near to my head as if on an HT
in use.

My impression is that most HTs have to be designed to tolerate a
rather lousy SWR on the antenna port... because it often *is* lousy.
Having an HT which burns up its final if you hold the radio wrong
would tend to cause the warranty-repair department to start raising
hell.

================================================== ============
With my dual-band Yaesu FT-530 HT, I used a rubber duck that was NOT for
that radio. I was working through a repeater that was nearly line-of-sight.
The other end of the QSO and I could barely hear each other and my poor,
little HT got very hot very quickly. I was astonished and learned a very
important lesson.

"Sal"