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Old February 3rd 07, 06:08 PM posted to rec.radio.amateur.antenna
Richard Clark Richard Clark is offline
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First recorded activity by RadioBanter: Jul 2006
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Default Advice for 75m Mobile Field Strength measurements

On 3 Feb 2007 05:24:08 -0800, "k1drw" wrote:

- Would the MFJ-802 be an adequate measuring device for our use ? Any
caveats ?


Hi Dennis,

Only that its purchase may be to lend the appearance of credibility
beyond the instrument's capacity to deliver it. This instrument, as
it should be, is dirt-simple to construct; and for your purposes
should have a digital readout. You can achieve the same thing by
using a DVM connected to the meter's terminals, but by that time you
could as easily build a detector box with DVM pin jacks and an antenna
connector.

- What test FIELD environment should we try to arrange (e.g. large
empty parking lot, or a rural open field) ?


As others point out, consistency in testing is paramount. All those
tested will suffer/benefit equally under same conditions.

- When testing each vehicle, what space should separate it from other
vehicles waiting to be tested ?


Where do you want to aim the signal? Think about it, you have an
array of antennas, one driven and the rest parasitic and parked
nearby. Does this remind you of something? Does spacing and
proximity count? Same admonition applies if you have the test group
near your detector antenna.

Think in terms of wavelength. Stay out of near fields.

- Should the vehicle sit stationery, or be moving in a circle ?


As long as you are as far away so as to not perceive the shift in
signal strength on the basis of path length variation. Is a 30 foot
turning radius tested 300 feet away going to matter? Terrain may have
some bearing here.

A dry run is encouraged.

73's
Richard Clark, KB7QHC