[1000mp] System gain in the 1000MP station

[Guy Olinger, K2AV]

Some db perspective...

I might not beat myself to a pulp to get a 2 db improvement, but I
will go to the mats if I think I can get 6 db. And if I have an
opportunity to keep 2 db when I'm first building up, I will.

Going from 200-800= 6 db, going to 1500 almost 3 db more. Either of
those will make a difference. The difference WILL be most obvious in
noisy and weak signal conditions. You will be in conditions where your
200 is not copyable, and your 800 is OK copy (notice I didn't say
LOUD). Over the course of a contest, it will make a difference in the
pile ups.

What is really different is to go from 100 to 1500. That's nearly 12
db. A killer difference.

Then you can add another 4-6 db over a dipole for a good 3-4 element
yagi. Let's call that 16.5 db. Change out a long run of RG8 for some
big hardline, now we're 19 db.

Go long boom and stack a pair of antennas, add some height, and now
we're 23 db over a dipole and 100w and RG8. Probably the stack does
more than just give you straight gain, and maybe ups your signal 10 db
at an important low angle that's on the downward slope of either
vertical pattern. Now you're talking getting toward 30 db over the
100w/dipole/rg8, etc station. If you manage to put a pattern MAX at
that low angle the difference is more staggering.

Now you're talking about stations that work constantly into an area,
when most don't even hear who they're working.

Having said that, I have seen someone work through a pile up with 100w
and a dipole and beat one of those +30 db stations to the dx (not on
SSB, and not when the band was marginal).

Obviously grab any part of that 30 db you can and still live a
peaceful life, but never forget that the biggest db gain of all is
between the ears.

A savvy operator with 100w and a dipole will outscore a lid + 30 db
any contest.

But a savvy operator AND that 30 db will blow off your socks
consistently except when you're smart AND lucky.

73

----- Original Message -----
From: "Robert Shohet" <kq2m@mags.net>
To: <1000mp@mailman.qth.net>
Sent: Tuesday, February 26, 2002 1:43 PM
Subject: Re: [1000mp] System gain in the 1000MP station


> All the losses and effects you mention are there equally with 200 or
800
W.  Six
> dB is still 6 dB.  IMO, 6 dB will make virtually no change in
success rate
and
> is totally inconsequential compared to being at the right place at
the
right
> time in a pile up.  The only time 6 dB would be of benefit is when
your
signal
> is buried in noise at the limit of detection.  BTW, a change in
level of 1
dB is
> generally taken to be the amount just detectable by the human ear
under
perfect
> conditions.

Virtually no change in success rate?  This simply is not true.  Why
don't
you operate all 24 hours of the IARU 2002 contest and the IARU 2003
contest
with 200 w in 2002 and 800w in 2003 and then show us your logs.   I
suspect
that if you were to operate "for real" you would see a big difference
in
score and so would we.   This comparison should hold up very well
regardless
of what antennas you are currently using.

> This is only in my very limited experience as I only work CW and
then
mostly
> QRP.

Indeed, 6 db should make a LARGER and more consistent difference under
these
cndx.

BTW, if you would like to see the "real-time" difference that 6 db
makes, go
to a large station during a DX contest.  Ask them to run High Power
and then
ask them to run with 6db LESS power.  Watch the dropoff in rate!

Bob KQ2M



_______________________________________________
List Moderator: Richard Lubash N1VXW
1000mp mailing list
1000mp@mailman.qth.net
To Change Options or Unsubscribe:
http://mailman.qth.net/mailman/listinfo/1000mp