Surge suppressors for balanced feeders (summary)

[n0dh at comtch.iea.com]

Pete Soper <psoper at encore.com> WROTE:

>Knife switches are "out there", somewhere :-)

The "Wireman" has them listed in his catalog, dont know what they
look like though.

DAVE
N0DH/7

DIT DIT


>From claver at noao.edu (Chuck Claver)  Tue Feb  6 19:26:32 1996
From: claver at noao.edu (Chuck Claver) (Chuck Claver)
Date: Tue, 6 Feb 96 12:26:32 MST
Subject: Tower Height versus Angle...
Message-ID: <9602061926.AA01830 at taco.tuc.noao.edu>

Steve, K7LXX, wrote:

> Also, my recommendation is to put the 40M antenna at the bottom of the stack;
> an additional 10 feet up the mast is only 7% of a wavelength - not enough to
> make any significant angle improvements.
           ^^^^^^^^^^^ ^^^^^ ^^^^^^^^^^^^

True, if you are talking only about the take-off angle of the main forward lobe.
Not true, if you consider the rest of the antenna pattern, primarily
the high angle part of the pattern.  For example: a 3 element 40 meter yagi
at a height of 1/2 wavelength over perfect ground has a perfect null (>40dB)
at an angle of 90 degrees from horizontal.  This changes significantly with
small changes in antenna height (see table below).

height                approx. strength of pattern
in wavelengths        relative to main lobe
                      at an angle of 90 degrees
---------------       -------------------------
    0.600                       -15dB with secondary lobe @80deg -12dB
    0.575                       -18dB with secondary lobe @80deg -15dB
    0.550                       -20dB with secondary lobe @80deg -18dB
    0.525                       -25dB with secondary lobe @85deg -25dB
    0.500                      >-40dB 
    0.475                       -25dB
    0.450                       -20dB
    0.425                       -15dB
    0.400                       -12dB

In this exercise the take-off angle of the main lobe changes from roughly 20
degrees at a height of 0.6 wavelengths to 35 degrees at 0.4 wavelengths.

This, in turn, would change how well you reject QRM from nearby stations - 20dB
change in high angle rejection for a 10% change in height from 0.5 wavelengths
(about 70 feet) is worth thinking about.  However, this only one part of a
complex equation one needs to ballance when deciding what is best for your QTH.

For what it's worth...

Cheers - Chuck Claver
         de NJ6D

>From Eric Rosenberg <ericr at access.digex.net>  Tue Feb  6 19:26:34 1996
From: Eric Rosenberg <ericr at access.digex.net> (Eric Rosenberg)
Date: Tue, 6 Feb 1996 14:26:34 -0500 (EST)
Subject: Switching Power Supply?
Message-ID: <Pine.SUN.3.91.960206141342.29836B-100000 at access2.digex.net>


Rob --

Re: your follow-up on switching power supplies. 

Funny that Kenwood has licensed the Tektris power supply.  Last summer,
when I called EAM about their unit (actually made by Haro, a German
company), I was told that it was no longer available as Kenwood bought it
and would be selling it as a companion to the TS-50/60.  When I spoke with
him a couple of months ago, Loren Pleet, Kenwood National Sales Manager
(and former President of Orion Systems) told me that the unit would be
available in late 1995/early 1996. They even had a part number for it
(although I don't remember at the moment what it is). 
 
The question is what other switching supplies are available.  

Vectronics made a 30 amp unit, but it was large, and I do not believe it is
in production at the present time. 

Mascot Electronics (in Norway) makes a very nice unit, but it is very 
expensive, and Emtron (in Australia) makes a 20A unit.

Does anyone else have any ideas or suggestions?  I wholeheartedly agree 
with Rob that the marketplace cries out for a good switching supply!

Eric
--
Eric Rosenberg 			WD3Q, EI4VPS, YJ0AER, J20BY, etc.
Washington, DC 	
ericr at access.digex.net		wd3q at amsat.org

>From David L. Thompson" <thompson at mindspring.com  Tue Feb  6 19:58:49 1996
From: David L. Thompson" <thompson at mindspring.com (David L. Thompson)
Date: Tue, 06 Feb 1996 14:58:49 -0500
Subject: CC&R's , a growing danger to contesting
Message-ID: <199602061951.OAA24648 at borg.mindspring.com>

Sorry for this bandwidth, but CC&R's are growing and we are in danger.  All
new subdivisions in Seattle and Metro Atlanta have them and now in my area
homeowners are banding into umbrella groups call "Civic" associations that
add CC&R's to older, existing subdivisions!
I hope someone can help Tom as he moves to Seattle!    

73, Dave K4JRB
--------------------------------------------------------------------de:
rec.radio.amateur.antenna

My wife and I were up in Seattle this past week on a house hunting trip. 
We looked mainly on the east side, from Issaquah to Redmond.  There were a
lot of very nice homes.  All of the new developments have CC&R's against
antennas of any kind.  We looked everywhere, both old and new.  The best
CC&R's we could find allowed antennas up to 20' above the ridge line of
the roof, but no separate towers.

I was surprised to not see any ham radio antennas the two days we drove
around (and I looked hard).  I saw very very few TV antennas on houses,
for that matter.

Are there hams in Seattle? :-)  If so, what are you doing about antennas?

Thanks,
Tom AA6BR
-- 
Tom Taylor AA6BR
tom_taylor at taligent.com