Richard Clark wrote:
On Thu, 16 Dec 2004 10:42:48 -0600, "Matt"
wrote:

Can I make a slot antenna out of round pipe rather then rectangular?


Hi Matt,

Round pipe is quite common.

Any URL with examples, plans, calcilations ?
Any book ?

All I find are rectangular WG slot.
Only "Alford Slot" but that isnt what we talk about.

73!

On Sat, 18 Dec 2004 09:52:07 +0100, Darko
wrote:
Any URL with examples, plans, calcilations ?
Any book ?

All I find are rectangular WG slot.
Only "Alford Slot" but that isnt what we talk about.

Hi OM,

It isn't? Why? This one is available at:
http://www.eta.chalmers.se/~pgp/alfo...lford_eng.html
and seems a perfectly useful introduction to the topic.

http://www.qsl.net/kd2bd/slot.html
discusses other factors, such as the slot length that affects the
elevation gain profile.

http://members.ij.net/packrats/Slot_...a/Slot_ant.pdf
is more the classic discussion using standard waveguide materials with
an array of slots. This in turn offers a link:
http://www.ham-radio.com/sbms/sd/slotant.htm
that leads to a BASIC program for calculating the dimensions for these
standard waveguides.

http://hjem.get2net.dk/ole_nykjaer/o...lotant_sma.jpg
contains another slot array, but this page illustrates the probe
excitation connector construction (one of those things I made a point
of, however, loop coupling is more flexible).

http://www.caron-inc.com/search/103/related.php
contains a lot of individual links that I won't go into.

there were 17,700 hits for the term "slot antenna," and these few were
on page one. I will leave it to you two correspondents to research
further and ask questions (I will anticipate the first: "Scale those
you find interesting to your own frequency").

To respond to Bart's point about modalities (the Alford Slot Antenna
would seem to be immune, whereas these traditional arrays would be
prone to his discussion): there are simple techniques to force modes
through the usages of thin sheet metal diaphragms and masks. Working
with the plumbing in these frequencies is both hands-on and conceptual
visualization friendly - sort of like Fields in a bottle.

73's
Richard Clark, KB7QHC

Richard Clark wrote:
On Sat, 18 Dec 2004 09:52:07 +0100, Darko
wrote:

Any URL with examples, plans, calcilations ?
Any book ?

All I find are rectangular WG slot.
Only "Alford Slot" but that isnt what we talk about.


Hi OM,

It isn't? Why? This one is available at:
http://www.eta.chalmers.se/~pgp/alfo...lford_eng.html
and seems a perfectly useful introduction to the topic.

Hi Richard !

Yes, this is Alford, kind of slot antenna.
But we searching for "round pipe slot WG antenna" not using usual Wave
Guides.
Just for info, not for build, rectangular, standard WG slot antenna is
much easy to make.

73 !

On Sun, 19 Dec 2004 01:03:10 +0100, Darko
wrote:
But we searching for "round pipe slot WG antenna" not using usual Wave
Guides.

Hi OM,

This is a contradiction.

The Alford type is not the usual waveguide. Round waveguides are more
frequently used for rotating connections (RADAR), and only for short
sections. The Alford type is a classic "Slot Antenna" and, in fact,
is not a waveguide at all.

I did provide square waveguide slot antennas and you did not respond
to them.

If you reject both round and square examples, then there is not much
left to talk about.

73's
Richard Clark, KB7QHC