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Re: [RFI] Ultrasonic Dish

To: Lee K7TJR <k7tjr@msn.com>
Subject: Re: [RFI] Ultrasonic Dish
From: Hisashi T Fujinaka <htodd@twofifty.com>
Date: Wed, 2 Jan 2013 13:41:13 -0800 (PST)
List-post: <rfi@contesting.com">mailto:rfi@contesting.com>
On Wed, 2 Jan 2013, Lee K7TJR wrote:

Obviously receiver sensitivity is another important factor. I bought
the Midnight Science RX2 and was not happy. The new RX3 is much more
sensitive. I have no idea how it compares with the expensive
commercial units. I bought all the parts to build the W1TRC
receiver, intending to compare it with my RX3 on the test range, but
simply haven't had time and energy to do it (yet). I wish I could
get my hands on a Radar Engineers 250 for side by side comparison on
the range, but that seems highly unlikely.

  I have had the chance to compare my snow sled dish versus the
ARRL dish versus the Radar Engineers dish. There is NO comparison.
I was able to get right down to the very arcing bolt with the Radar
unit and only able to hear that arcing was present with either of the
other two. This was from about 40 feet away from a bolt on the
cross arms of a pole.
  Paul and others are right, it is about dish and dish illumination
accuracy to get the best from an ultrasonic dish. As with most
receiving systems, gain is easy to get and narrow beam patterns take
accuracy.

I'm just looking to tell WHICH POLE is arcing. I can't do much about it
and the power company in my area is going to re-check my findings
anyway. I think one of the issues with people trying to find exact
parabolic reflectors vs something "good enough" is what sort of
resolution they're looking for.

Once I can determine which pole it is, can I see the arcing through
binoculars? I don't remember if anyones discussed that.

--
Hisashi T Fujinaka - htodd@twofifty.com
BSEE(6/86) + BSChem(3/95) + BAEnglish(8/95) + MSCS(8/03) + $2.50 = latte
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