[NCARC] 145.115 update, testing net tentatively scheduled

[Steve Henry]

Howdy folks-

Here's some additional information we've collected from individual emails
and some additional comments from our current technical committee chair,
George, AB0SF on diagnosing the problem and on our situation and plans:

Information:

1) There is a window from 3:30 pm to 9:30 pm daily where we can run tests,
and after approximately 12:30 pm on Saturday
2) A useful search strategy is to sweep thesuspect area at least once with
an omni-directional antenna, taking  notes on signal strength at various
intervals, then revisiting the strong points and making sweeps with a
directional antenna. One can usually get a concrete bearing well within a
half-hour.
3) Chris Kelly's comments were interesting and very much on the mark. Two
especially key new facts:
	- we now know that an earlier 145.115 repeater had two bandpass cavities.
	- Finding someone with immediate access to an intermod. calculator program
will be very helpful
4) More than a dozen radios in various locations, both commercial and
amateur, have heard the signals. This verifies the problem.
5) The Wacom set of cans that the club owns provides 80 dB TX to RX
isolation. An additional bandpass filter on each leg, or receive side only
will certainly help, but by itself, it will not eliminate TX intermod. It
will, however, significantly reduce the chances of outside IMD products
getting into our receiver.
6) This is evidently not a new problem.  We've had problems with
interference on other frequencies and also on the GWR frequency in years
past.

Updated plans:

- we're still determining hours we can use the 145.115 repeater, but we're
pretty sure Saturday at 1:00 pm will be ok
- we will probably convene a testing net at 1:00 pm on Saturday on the
145.115 with backup on the 447.257. N7GN will be the net control
- George, AB0SF will be a mobile sweep operator
- we would like to engage those who have volunteered who have directional
antennas to help us out who can listen in on 160.260 with directional
antennas.  Please check into the net on the 145.115.

Stay tuned for more info.

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