[1000mp] System gain in the 1000MP station

[Hans Remeeus]

Hello dear friends,

There have always been many discussions about power output, dB's and signal =
strength.

In our country (The Netherlands) officially a maximum power output of 400 =
Watts is allowed. We live with 16,000,000 people in a very small country, =
so interference is a subject here.

I own the Mark V with the TL922. Really a great combination! A used TL922 =
cost about $1200 here. In Germany they are cheaper (about $1000). I have =
the TL922 with two Amperex 3-500Z(G).

I only use the linear with SSB during some nets on 80 meters and during =
pile-ups. With CW and digital modes I don't need the linear; operating =
practice is superior to some dB's more. When I use the linear I switch to =
Class A on the Mark V and a maximum input power of 50 Watts. In combination =
with a good adjustment of the linear this means a very clear signal with =
less risk of interference.

My experience with power output, dB's and signal strength:
Between 10 and 100 Watts (10 dB): big difference! Most of the time at least =
3 S-points.
Between 50 and 500 Watts (10 dB): 2-3 S-points difference.
Between 100 and 1000 Watts (10 dB): noticeable difference, but not more =
then 1 S-point.

By the way. I think that is hard to make comparisation between two contests =
in two different years. RF Propagation will be the major item when you =
compare the two logs, I suppose. Parhaps I am wrong...

Enjoy our great hobby and kind regards.

Hans, OE/PA1HR/P at the moment.


---------------------------------------
From: "Robert Shohet" <kq2m@mags.net>
Subject: Re: [1000mp] System gain in the 1000MP station
Date: 26-02-2002 18:43:42
---------------------------------------
> 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



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