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Old September 6th 04, 12:20 PM
Richard Fry
 
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"Richard Clark" wrote about the specs for Harris Broadcast Txs:
As for the specification for output impedance gone missing :-)
MW-10B SPECIFICATIONS
RF OUTPUT IMPEDANCE: 50 ohms, unbalanced.
Other output impedances available on special order.
Harris Platinum Z FM transmitter
100 ohm output impedance (unbalanced)
HARRIS SW-50 A
RF Output Impedance 300 ohms balanced, 2.0 to 1 maximum VSWR
Well, instead of reciting their complete catalogue, it is easier to
simply say I could not find any product that did not specify an output
impedance, much less that others were available on special order.

_____________

I won't try to soften this: your conclusion above doesn't just _appear_ to
be wrong, it IS wrong. 100% wrong. The impedance published by Harris is the
expected load impedance, not the tx source impedance -- which is the
convention used by all OEMs of broadcast txs (at least).

How do I know? I was the author of all of the brochures and technical data
sheets for Harris' entire FM product line for the ten years before I
retired. That any published value of impedance applied to the load
impedance expected was/is universal across the product lines: AM/FM/TV.

Your post above showing 100 ohms for a Platinum Z FM tx also is wrong. It
is designed for a 50 ohm load. Here is a link to an on-line brochure for
the current 10kW model:
http://www.broadcast.harris.com/prod.../HAR173569.pdf
Observe the statement at the bottom of the right column on the last page
thereof, which I quote below for your convenience:

"All specifications referenced to any single output frequency
(87.5-108MHz),
nominal rated output power, and 50 ohm, isolated, non-reactive load."

No other RF impedance spec is given in the very detailed list of specs
contained in these brochures.

Kindly recant your accusations.

RF