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Old March 8th 06, 12:37 AM posted to rec.radio.amateur.antenna
Big Endian
 
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Default Q. about height of the ends of a doublet


My center of a 3.8 Mhz doublet is at about 35 feet and am going to drop
the ends from 30 feet to about 10 to 15 feet. Just wondering if it will
make all that much difference if any?
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Old March 8th 06, 12:46 AM posted to rec.radio.amateur.antenna
Amos Keag
 
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Default Q. about height of the ends of a doublet

NOPE!

At those heights it will be an excellent antenna for close-in work.
Close in means ~100 miles daytime and up to ~600 miles nights and evenings.

Big Endian wrote:


My center of a 3.8 Mhz doublet is at about 35 feet and am going to drop
the ends from 30 feet to about 10 to 15 feet. Just wondering if it will
make all that much difference if any?


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Old March 8th 06, 12:57 AM posted to rec.radio.amateur.antenna
 
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Default Q. about height of the ends of a doublet

It will slightly decrease the performance. I'd keep the ends
as high as possible if you want the max performance.
MK

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Old March 8th 06, 01:31 PM posted to rec.radio.amateur.antenna
Amos Keag
 
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Default Q. about height of the ends of a doublet

Where I live what I do on my property is my business as long as I comply
with the local zoning requirements.

My neighbors don't get a vote on how I install and operate my station.
The town assessor will NOT grant an abatement because my neighbors live
next to a ham station [property value argument].

I run 1 KW when required. My phones are 100% clean. My TV's are 100%
clean. My computer is 100% clean. My computer sound system is 100%
clean. My stereo system is 100% clean.

Don't be concerned about next door. Just make sure your station and
house electronics are clean.

DD, W1MCE

Big Endian wrote:

SNIPPED


I'd like to but I'm a little concerned about next door, if you know what
I mean. The poles are on the lot line and in the front yard, but in the
summer they are pretty well shielded by trees, in winter they stand out
their naked in the wind.




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Old March 8th 06, 08:55 PM posted to rec.radio.amateur.antenna
Dave Oldridge
 
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Default Q. about height of the ends of a doublet

Big Endian wrote in
:


My center of a 3.8 Mhz doublet is at about 35 feet and am going to
drop the ends from 30 feet to about 10 to 15 feet. Just wondering if
it will make all that much difference if any?


There will be a marked improvement in the low angle performance in the
direction off the ends of the antenna (the flattop is very poor at this).
This will come at the expense of a sight loss (about .8db) off the
pattern's top (where you can most afford it). You will also experience a
slight deterioration in the SWR (based on 50 ohm coax) from about 1.34 to
2.05, easily managed by any tuner, including those built into many radios.
You will also find that you need to shorten the antenna very slightly to
maintain the same resonant frequency.

This won't make it into a superior DX antenna but it may allow you to hear
things you missed before. Basically, Bob Heinlein was right. There ain't
any such thing as a free lunch.

--
Dave Oldridge+
ICQ 1800667
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Old March 8th 06, 10:46 PM posted to rec.radio.amateur.antenna
Tom Ring
 
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Default Q. about height of the ends of a doublet

Dave Oldridge wrote:

This won't make it into a superior DX antenna but it may allow you to hear
things you missed before. Basically, Bob Heinlein was right. There ain't
any such thing as a free lunch.


TANJ!

Tom
K0TAR
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