Hi Pete,
The suggestion...
> >> the impedance method described in the RF-1 manual. Put a temporary
> >> short on the far end, and adjust the frequency of the RF-1 until
> >> you see minimum Z.
You ask:
> Actually, wouldn't it be better to leave the far end open, so that you
only
> get Z minima at 1/2 wave intervals?
Definitely not.
If the far end is open, the measured Z becomes maximum at multiples of 1/2
wl (not minimum).
Maximum Z measurements are more subject to instrument errors than minimum Z
measurements.
I'd get the cable close at 7 MHz or lower, and "fine trim" the cable at the
low end of 28 MHz. That way small errors in length would show up clearly,
and the cable would be usable even up as high as 28 MHz.
73 Tom
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