Experimenter hf net organizing

David A Aitcheson - KB3EFS kb3efs at gisco.net
Wed Aug 23 23:54:36 CDT 2006


Has any consideration been given to doing a kit for this antenna

On first glance this antenna would be the "ideal standard" for a station
that is going to be set up as a lurker.  Say a _RX only_ 10m or 20m
station that is being run my a SWL or a Technician licensed ham; or for
that matter a school that does not have a licensed ham on staff but the
teacher wants to promote ham radio.

My thinking is... a standard antenna, and a standard receiver (RX-320)
should equal a standard system that would yield repeatable and results
from any one signal source.  Thus given: station A received at 1, 2, 3,
4, etc. would only vary due to propagation differences caused by
ionospheric changes. The same should be measurable in cases of B, C, D,
etc. transmitting to 1, 2, 3, 4, etc.

If the transmitters are all of the same make/model and set to the same
power levels and feeding as nearly identical antennas as possible with
the controlling being done by (maybe networked) PIC controllers; then
true scientific studies can really begin I think.

Have I interpreted correctly your plans. Thoughts?

Dave - KB3EFS(/2) Tech. [FN24bi]
Web Master http://www.propnet.org

Frank Gentges wrote:
> Terry and all,
> Terry Fox wrote:
>> For a first step for receive-only stations, I could probably get an 
>> RX-320 or PCR-1000 receiver running with an active antenna (Frank's 
>> e-field probe) fairly quickly.  I could use that for both our work 
>> here, plus the propnet - timehare the radio via the computer.
>> Frank, maybe we should look at standardizing a receive package with an
>> RX-320, active antenna (antenna tuning driven via computer and cheap A/D
>> converter), plus some sort of cheap computer as we have been talking 
>> about.
>> Would the LF active antenna up to 10 meters?  I don't remember the specs,
>> and a lot of books, magazines, etc are still packed up somewhere 
>> (garage).
> First, the RX-320 should do well at HF without the AMRAD LF 
> modification.  Thus, use it right out of the box.
> Second, the AMRAD Active antenna can be built with the J310 JFET instead 
> of the high performance CP-666 JFET.  For most users that should do the 
> job.  You can use the PC board kit and a J310 without the complexity of 
> the heat sink.  For the HF use. a whip longer than the one meter would 
> be a real help.  We would keep the PVC pipe fittings and use 12 volts DC 
> for power.  The transformer could be the same or a substitute.  We were 
> fighting interwinding capacitance to keep power line noise coupling down 
> for LF use.  It is not so much a problem at HF and everything gets simpler.
> Once I get some time (September perhaps?) I can build up a "standard 
> package" for our HF work and write it up in the newsletter so everyone 
> can duplicate it easily.  This is not that hard or time consuming.
> Then everyone else can concentrate on the other parts of the problem and 
> propnet.
> Perhaps a SoftRock receiver variant can be worked in here someplace down 
> the line.
> For a refresher on the antenna go to the AMRAD web page on it at
> http://www.amrad.org/projects/lf/actant/index.htm
> A link to the original article is provided along with many later notes 
> on the construction.
> Frank
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