[Antennas] Diminishing Returns

[Raymond LaRue]

I guess I'll have to chime in as I was the instigator of the project
KA4INM refers to.

Tony W4TAS was the builder of the HF to 440mhz linear translator.  He
did an excellent job in designing and building it.  The first stage was
a passive mixer with a good high level of injection.  

We checked it thoroughly for it's noise floor, compression limits and
linearity within the designed input operating range.  It had less than 1
db variation at all expected operating inputs/outputs.  Within the same
narrow frequency and input range, it was very accurate.  This was
considered more than sufficient, for our intended purposes.  

It allowed: unattended remote operation of the sense antenna,
translator, etc. and all interested parties to be at one test site where
a reference transmitter, etc. and the Tektronix 2710 SA were located.
The microprocessor in the 2710 did the signal calculations for us.

We spent the entire day testing a number of vertical fixed and mobile
antennas on 40 and 20 meters.  We did it mainly for the benefit of those
who participated, but did not intend to publish the results.  We who
were there did not consider it a "waste of time".  All thoroughly
enjoyed and learned from the exercise. 

I still have the original data and translator.  The translator performed
so well, I will use it again.  

Anyone can attempt the same thing with their own set of criteria and
equipments.  But please don't knock someone else's efforts to gain new
insights and understandings, into the antenna sciences.

Ray, W4BYG
A1-Op, BPL, PSA's, ARRL life, Past SCM GA.


Raymond LaRue
Vice President, Broadcast Engineering
SkyAngel US, LLC
3001 Keith Street, NW
Cleveland, TN 37312

www.skyangel.com

-----Original Message-----
From: antennas-bounces at mailman.qth.net
[mailto:antennas-bounces at mailman.qth.net] On Behalf Of Chris Boone
Sent: Thursday, June 04, 2009 12:54 PM
To: 'a'
Subject: Re: [Antennas] Diminishing Returns

-----Original Message-----

   Every mobile antenna tested (connected to the same radial system) and
the "isopole" 40 meter antenna (up 10 feet) did no better than 10 dB
below the reference antenna.

   The above antennas under test were the transmit antenna (through the
same Bird Watt meter fed from the same transmitter, steady carrier) and
the signal was received over a thousand feet away and relayed back on
the 440 band by a linear translator and measured on a spectrum analyzer.
(everything was pre-tested) 
    Ron  KA4INM - I'm proud to be Chuck's pop!
______________________________________________________________

I'd LIKE to see THAT "Linear translator"....sorry but that was a waste
of time and not very accurate in signal strength...just have a spectrum
analyzer with a live human 1000ft away taking readings. Would have been
more accurate.

BTW Cebik's page (and my own experience) confirms; 4 radials ELEVATED
will do better than anything buried...AND there is not a BIG noticeable
improvement going BEYOND 4 radials.....(at least a 1/4wave but doesn't
have to be exact...just MINIMUM 1/4wave....I used a vertical with 4 60ft
elevated radials on 80-10m 6 yrs ago...the vertical met all specs on all
bands...the 60ft radials, 1/4wl at 75mts, is what did the trick)_

Chris
WB5ITT
FCC Commercial PG-9-5322 since 1974
Frequency Coordinator, Society of Broadcast Engineers Consulting
Engineer/Owner, SE TX Telecom and Broadcasting

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