[R-390] High end antenna systems

[Cecil Acuff]

While the stepIR is a decent antenna..it's weak spot is that its element 
spacing is only optimum at one frequency in its range.  Its performance 
could be enhanced if it's element spacing were adjustable in a similar way 
as its dipole lengths.

They have a nice Vertical design.  I had high hopes for it.  Took one on a 
IOTA (islands on the air) activation and put out a bunch of ground 
radials...many in the salt water with the mounting pole for the vertical in 
salt water in the evenings during high tide.  Thing would not tune 
consistantly and then got to where it wouldn't tune at all...finally 
abandoned it.  Turned out it had some type of software issues in the control 
box.

Great design though...

Cecil
K5DL
----- Original Message ----- 
From: "Sheldon Daitch" <sdaitch at kuw.ibb.gov>
To: <lester at veenstras.com>
Cc: <r-390 at mailman.qth.net>; "'Tisha Hayes'" <tisha.hayes at gmail.com>
Sent: Thursday, August 27, 2009 1:45 AM
Subject: Re: [R-390] High end antenna systems


Lester,

An interesting thought.

I suspect it might be a combination of several points.

The 4 x 4 Thomson system has 32 dipoles, 16 on
each side and the 6 x 4 TCI has 24 dipoles, I could
guess the mechanical complexity adds to the operational
and maintenance issues with the antenna system with
little increase in antenna capabilities. I am wondering, too,
if changing the electrical lengths of the dipoles without
changing their spacing has an effect on the radiation pattern
of the antenna systems, as well.

The TCI antenna can be supplied with both vertical and
horizontal slewing, and I just don't know enough about the
antenna design parameters to consider the relationship
of dipole tuning with spacing, for the effects on the slewing
operation.

If the SteppIR design is patented, there could be an issue
with paying for a license to use that technology. It would not
be the first time where a manufacturer did not use another
technology, simply based on a financial decision.

73
sheldon

Lester Veenstra wrote:
> Now that’s a rotatable array !!
>
> But it is interesting that the commercial market  with it's arrays of
> dipoles has not picked op on the SteppIR design for variable dipole 
> lengths.
>
>
>
> Lester B Veenstra  MØYCM K1YCM
> lester at veenstras.com
> m0ycm at veenstras.com
> k1ycm at veenstras.com
>
>
> US Postal Address:
> PSC 45 Box 781
> APO AE 09468 USA
>
> UK Postal Address:
> Dawn Cottage
> Norwood, Harrogate
> HG3 1SD, UK
>
>
>
> T
>
> -----Original Message-----
> From: r-390-bounces at mailman.qth.net [mailto:r-390-bounces at mailman.qth.net]
> '
> Subject: Re: [R-390] Synthesizer Phase Noise
>
> I always thought the virtue of an RLPA is they basically worked
> equally bad on all frequencies.
>
> These don't rotate, but they will slew, if you buy the
> right options:
>
> http://www.tcibr.com/?PageID=202
>
> If you need to rotate it, try this:
>
> http://www.thomsongrassvalley.com/docs/DataSheets/tbm/radio_transmission/TRB
> -SWAnt-R1.0.pdf
>
> Sheldon
>
> Lester Veenstra wrote:
>
>> Actually, the gain of those rotating LPA's is rotten. Now a nice sterba
>> curtain or rhombic is another matter.
>>
>>
>>
>>
>
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