What amp for DXpedition?

KA9FOX at aol.com KA9FOX at aol.com
Fri Sep 9 19:03:23 EDT 1994


My first taste of being DX will be CQWW SSB at PJ7 (using special call PJ8Z).
 Will be Multi/single with N0BSH & KI4HN at Residence La Chatelaine.  You may
have read about the place in the latest CQ Magazine, Chod Harris' article.  

Anyway, I've decided that I want to buy a used portable HF amplifier that I
can take with me on the plane to PJ7 and also to any future DX spots (might
as well go now before I get some babe telling me I can't go!)

MANY of you have done this countless times, so I am asking for your input as
to which amps would be small enough and reliable for a contesting DXpedition
and fit my pocketbook.  I could afford to spent about $400-$500 tops.  I
realize I won't be bringing an Alpha 87A!!  I guess if any of you have an amp
that would fit the bill and for sale, you could also drop me a note.

I will summarize all suggestions and post in the near future.

73 Scott KA9FOX
ka9fox at aol.com

P.S.  I turn 30 on Sept. 27th (Is that how old petrified dinosaur dung is???)
 Big party on Friday Sept 23rd if anybody is gonna be near La Crosse,
Wisconsin on that date.


>From David & Barbara Leeson <0005543629 at mcimail.com>  Fri Sep  9 21:46:00 1994
From: David & Barbara Leeson <0005543629 at mcimail.com> (David & Barbara Leeson)
Date: Fri, 9 Sep 94 15:46 EST
Subject: TVI/EMC
Message-ID: <31940909204613/0005543629NA1EM at mcimail.com>

Interesting thread including VE4GV's info re 3v/m limits.  But there are
some possibilities:

Example 1:  Acoustic noise cases I've seen include averaging over, say, a
24-hour period (I know, this seems strange, but it makes almost any short-
duration loud noise average out to zip)

Example 2:  Since you can't build at your property boundary, setback
restrictions being a universal part of building permit regulations, and
you would not expect to use an indoor unit in an outdoor environment, it
seems that the EU idea of field strength at the device rather than at your
property boundary is much more reasonable...this would take advantage of
natural structure attenuation.

Example 3:  Instead of requiring the ham to reduce power to the 3 v/m level,
an alternative would be to assist the owner to make the unit operate in
whatever rf level does exist...true, this could be expensive and time-
consuming in a multi-story apartment setting, but it would be a fair way to
allow the consumer to enjoy his device(s) while the ham enjoyed his license
privileges.

Example 4:  Because near-field signal strengths decrease as the cube of
distance, a higher antenna would result in less interference potential
(and less rf exposure, too, should evidence be found that indicates a
problem in this area)...so perhaps the existence of local regulations
prohibiting putting the antenna up high enough to reduce to 3 v/m would
void the consumer's right to insist on power reduction.

Example 5:  In measuring field strength, the FCC has a practice of moving
the antenna to find the maximum, at least for Part 15 radiated-field
measurements (the actual setup is outside in the field behind the Laurel,
MD labs)...but because a consumer device can be moved to a point of lower
field, maybe some averaging over location would be reasonable.

Example 6:  Because EMC sensitivity varies with frequency, it would seem
reasonable to be able to exceed the 3 v/m limit (or whatever) on frequencies
where the ham can demonstrate that the interference level of the consumer's
device(s) is well above the 3 v/m level.

There must be dozens more of this type of idea...I've found that regulatory
bodies are staffed by living, breathing humans who generally are very 
interested in direct feedback from the folks affected by their regulation
proposals.  If you don't find out how to write and file comments, you've
abandoned your fate to others with different interests...no guarantees, but
you generally don't get what you don't ask for.

73 de Dave, W6QHS



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