ICE filters are used quite frequently here at K8CC while competing in DX
contests in the multi-operator, multi-transmitter class. I was an early
purchaser of these filters, and have had mixed results. After getting the
filters and noticing that the drive power to the amps was noticably
reduced, I sat down one night with my six filters and tested them with a
simple setup using a IC-765 transceiver and W4 wattmeter. I recognize that
the W4 is not a lab-grade instrument, but since I was interested in loss
(essentially a ratio) it would be sufficiently accurate within the range of
measurements I would need.
Each filter is marked that the loss < 0.25 dB. Of the six filters, only
one met that specification. The worst filter was the 7 MHz unit, 130W in =
100W out. Eventually one filter failed, but it was the 80M unit. Since
these were early ICE's, I would think these were the 100W units.
In 1996 I was out in San Francisco for the World Radiosport Team
Championship, where 54 teams were equipped with near equal stations and
competed during the 1996 IARU HF Championship, but only on 40/20/15/10
meters. Each station was provided with four ICE filters, one for each
band. The technical leader overseeing the stations was Dave Leeson, W6NL
(ex-W6QHS) who is a professor at Stanford. He personally tested each of
the filters (54 x 4 = 208 filters) provided to the competitors and all met
spec.
Just a couple more data points...
73,
Dave/K8CC
--
FAQ on WWW: http://www.contesting.com/ampfaq.html
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|