Top Band Antennae?
 

What is the recommended practice these days for Top Band antennae for
restricted spaces?

Many years ago (50?) it was to adapt a mobile area for fised station use.

Top Band Antennae?
 

gareth wrote:
What is the recommended practice these days for Top Band antennae for
restricted spaces?

That kind of depends on what you mean by "restricted spaces", but in
general you put up the tallest radiator you can assuming the ground
in your area is at least half way decent. Unless you are in a high
wind area, it is pretty trivial to get up to around 10 to 15 meters
tall with decent aluminum and no guys.

Many years ago (50?) it was to adapt a mobile area for fised station use.

I assume you meant mobile antenna, which is very short; a radiator that
is 4 meters tall, or about the height of a single story house, will
easily outperform a mobile whip in the same place. In addition, since
a fixed antenna can be made much sturdier, you can have more top loading
than on a mobile which further improves performance.


--
Jim Pennino

Top Band Antennae?
 

"gareth" wrote in message
...
What is the recommended practice these days for Top Band antennae for
restricted spaces?

Many years ago (50?) it was to adapt a mobile area for fised station use.



Move.

If you can't move, put up the tallest vertical you can. Put a capaticive
hat on the top and coil just under that. Then put down as many radials as
you can.

Unless you provide for tuning at the anenna, the short ones will have a very
narrow bandwidth. Not much more than the frequency it is cut for.

Top Band Antennae?
 

gareth wrote:
What is the recommended practice these days for Top Band antennae for
restricted spaces?

Many years ago (50?) it was to adapt a mobile area for fised station use.


Magnetic loop antennas require very little space. If you Google VK3YE
you will find he has a design for a homebrew loop that covers 1.8 to 21
mhz. It will not be very efficient, but you can always build a loop of
greater diameter which will raise the efficiency. There are a number of
loop designs on the net. There are an increasing number of loops being
manufactured as well. Size-wise, a magloop will outperform many full
sized antennas.

de Irv VE6BP

Top Band Antennae?
 

"Irv Finkleman VE6BP" wrote in message
...
gareth wrote:
What is the recommended practice these days for Top Band antennae for
restricted spaces?

Many years ago (50?) it was to adapt a mobile area for fised station use.


Magnetic loop antennas require very little space. If you Google VK3YE you
will find he has a design for a homebrew loop that covers 1.8 to 21 mhz.
It will not be very efficient, but you can always build a loop of
greater diameter which will raise the efficiency. There are a number of
loop designs on the net. There are an increasing number of loops being
manufactured as well. Size-wise, a magloop will outperform many full
sized antennas.

Thanks, I'll pass it on to my mate who is recently licensed and is intent
on do-it-yourself including resurecting an old Codar AT5 TX.

Top Band Antennae?
 

On Friday, February 20, 2015 at 4:16:04 PM UTC-6, wrote:
gareth wrote:
What is the recommended practice these days for Top Band antennae for
restricted spaces?

That kind of depends on what you mean by "restricted spaces", but in
general you put up the tallest radiator you can assuming the ground
in your area is at least half way decent. Unless you are in a high
wind area, it is pretty trivial to get up to around 10 to 15 meters
tall with decent aluminum and no guys.

Many years ago (50?) it was to adapt a mobile area for fised station use.

I assume you meant mobile antenna, which is very short; a radiator that
is 4 meters tall, or about the height of a single story house, will
easily outperform a mobile whip in the same place. In addition, since
a fixed antenna can be made much sturdier, you can have more top loading
than on a mobile which further improves performance.


--
Jim Pennino

You can also use top guy wires as top loading, which can easily
be longer than most conventional capacity hats. As a bonus, they
keep the antenna from blowing down if the wind huffs and puffs and
tries to blow his antenna down.

Also one good thing about large top loading is the much improved
current distribution through the whip, which can let one place the
loading coil at the base, with little degradation of the current
distribution through the whip, being as you are not depending solely
on coil location to improve current distribution.
That allows one to easily get to the coil to change taps, or one can
use a large roller coil as the inductor.
As mentioned, the bandwidth will be pretty narrow, so one really
would want a way to adjust the coil, unless they don't mind being on
the same frequency all the time. I couldn't live like that, being I often
work CW around the bottom of the band, and phone usually between 1870-
1900 khz or so..

Top Band Antennae?
 

On Fri, 20 Feb 2015 21:38:30 -0000, "gareth"
wrote:

What is the recommended practice these days for Top Band antennae for
restricted spaces?

Either the tallest helical antenna possible, or the tallest vertical
with a top hat, or a conglomeration:
http://www.hamuniverse.com/k6mm160metervertical.html
Also, add some ground radials.

A problem with short 160m antennas is that the operating bandwidth is
very small. Change frequency even slightly, and you have to retune
the antenna or antenna coupler. Short antennas also exhibit low
impedances, which implies high currents, which suggests that beefy low
loss components are needed.

Many years ago (50?) it was to adapt a mobile area for fised station use.

Huh? What's a fised station?


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Top Band Antennae?
 

On 21/02/2015 04:50, Jeff Liebermann wrote:
Huh? What's a fised station?

He means fisted station.

;-)

Top Band Antennae?
 

"Jeff Liebermann" wrote in message
...
On Fri, 20 Feb 2015 21:38:30 -0000, "gareth"
wrote:

Many years ago (50?) it was to adapt a mobile area for fised station use.

Huh? What's a fised station?

typo - one key lateralised - fixed

Top Band Antennae?
 

On Sat, 21 Feb 2015 11:09:31 -0000, "gareth"
wrote:

"Jeff Liebermann" wrote in message
.. .
On Fri, 20 Feb 2015 21:38:30 -0000, "gareth"
wrote:

Many years ago (50?) it was to adapt a mobile area for fised station use.

Huh? What's a fised station?

typo - one key lateralised - fixed

Is that because everything in the station needs fixing?

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558