Hi Al (GM4BAP) and the TowerTalk gang,
Thank you for saying what needed to be said... and doing it so well.
One factor also seems to be neglected.... QSB and voice peaks. It
drives me absolutely crazy trying to get any meaningful measurement
under these conditions.
The other day I was trying to compare the changing signal strength with
the changing output of my Drake L-4 in the SSB (hi pwr) mode as opposed
to the CW (lo pwr) mode... with another station (WA2MOE) who had the
same amp. The difference in input power was about 488 watts (1440w v.
952w). Frequently it was impossible to tell the difference which
position was in use. In either position the other station was always
Q5 over a distance of 2,123 miles from NJ -> AZ.
So... it begs the question.... WHAT DIFFERENCE DOES IT MAKE UNDER
ACTUAL OPERATING CONDITIONS?
If you are doing measurements on an antenna range and you need to
derive a meaningful set of measurements to explain the performance or
change in performance on an antenna under test because of an adjustment
you have made.... then calibrated field strength meters measuring
microvolts are appropriate tools. Then again, QSB is never a factor on
an antenna range. The thought of QSB on an antenna measuring range
boggles the mind!
So, what are we left with? A very unscientific toy for an S-meter.
Many of us are used to measuring voltages to three or four decimal
places and perhaps we would like some degree of precision on our
S-meters... but....why bother? If you went to the trouble of
accurately calibrating the thing on each band with a known standard
attenuator pad.... what would it mean if the same station was five or
six DB stronger or weaker from one day to the next because of changing
ionospheric conditions and in either case perfectly readable all the
while?
And how many time have you ever worked a station on a quiet band and he
had absolutely NO SIGNAL STRENGTH and was perfectly readable. Telling
him you are 5 by Zero sounds kinda stupid and you wish the damn S-meter
read something so that you could have something better to report. Why?
Of course, the answer is... it only makes a difference IN HAVING
SOMETHING TO TALK ABOUT.... not unlike the temperature or the cloud
cover or the wind speed and direction. And if you treat it as such...
fine.
I used to be an S-meter pure-ist.... but then I realized there are more
important things like moles and grubs and ground rods in bedrock and of
course....CLING-FREE!
It's only one man's humble opinion.... not meant to be taken all that
seriously. Please don't count it towards my humor quotient as I know
I've used up my share for some time to come.
73,
Roger, K2JAS
at 11:59 AM 8/11/97 +0000, you wrote:
>As Readability and Tone can only ever be an operator's subjective
>assessment, is there any point in trying to make Signal an objective
>measurement?
>
>Some people give out RS(T) reports like medals - handing out a 59+ to
>a QRP novice to make them feel good, or handing down a 338 to a
>station 100 QSOs ahead in a contest to take the wind out of their
>sails (heh heh!).
>
>Other people attach an almost religious significance to signal reports
>- hence reports like "you're 5&9+11dB off the front of my beam with
>the preamp in, 5+9 with the preamp out, 55 beaming WSW, and 5 & 6 off
>the back of the beam". Showered with these goodies, you ruin the
>moment by saying "yes, but did you get my call correct?"
>
>I often tune across a local HF net where "meaningful" RSs are handed
>out every week. Everyone is always S9, but sometimes +5dB, +22dB,
>+16dB, etc. These are groundwave QSOs, where the only meaningful
>variables are AGC/RF gain and background noise.
>
>If and when we need an accurate measurement of signal strength, we
>need something better than the vague tidings of RS(T). Perhaps a
>reading in microvolts from a separate RF meter or from a
>panadaptor/scope, could be the answer.
>
>Then we can go back to using RS(T) simply as the rubber stamp of a
>QSO.
>
>73
>Al, GM4BAP
>
>--
>FAQ on WWW: http://www.contesting.com/towertalkfaq.html
>Submissions: towertalk@contesting.com
>Administrative requests: towertalk-REQUEST@contesting.com
>Problems: owner-towertalk@contesting.com
>Search: http://www.contesting.com/km9p/search
>
--
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: owner-towertalk@contesting.com
Search: http://www.contesting.com/km9p/search
|