Trough Reflector?

[balm]

ive seen a lot about a trough corner reflector adding some 4 dbi to an antenna gain, so far in past modeling for VHF or UHF, the max added gain i came up with is about 1-1.5 dbi, & higher f/b, what am i missing, or what is the critical dimension for maximum effeciency....

Even extremely arge reflectors dont yield this added gain based on some models i did in the past

[300ohm]

the max added gain i came up with is about 1-1.5 dbi,

Max added gain over no reflector at all ? Or max added gain over a flat reflector ?

[mrvanwinkles]

Balm,

I found this book in the EE Section of my University Library (Kingston).
( Not sure if you'll find it at the neighbourhood library - kind of specific )

THE ARRL ANTENNA BOOK
copyright 1991 by
The American Radio Relay League
16th Edition
First Printing
ISBN: 0-87259-206-5

I don't know if it is the most current version of the book out ... but,

Anyway, this version has a good description of the Corner Reflector and Trough Reflector antennas. Drawings, Dimensions, Graphs, Tables of values. Advice on how to build based on frequency of use, and what you wanna achieve etc.

Some of the important parameters mentioned for the Corner & Trough Reflector antennas are:

[Corner Reflector]
angle, side length, spacing of the driven element (usually a receive dipole) from the vertex, max spacing of the reflector rods or mesh (based on frequency of use) - for good results.

[Specifically for the Trough Reflector]
Practical limits on where you can replace the vertex (corner angle) with the plane section and where you can place the receive antenna (usually a dipole)
for good results.

Gains of 13 dB to 17 dB for a single antenna are mentioned in the book.

Also, that the gain of both types of antenna can be increased by stacking more than one, and connecting them in phase (but that stacking more than 3 is usually not practical). -or- by building a wider corner or trough and having multiple receive antenna (? dipole) inside.

If you get a look at this book ... good source of practical design info.

There's lots of other good antenna info in this book.
Worth buying even ... I think ... based on what I saw inside, if you wanna get into antenna building.

Hope this helps.

Hard to describe exactly what's shown in this book on the forum. Plus ... the book is copyright.

Best to have a look at the book.

[stampeder]

tballister's use of a trough reflector on an Antennas Direct DB8:

http://www.antennahacks.com/Hacks/MyDB8.htm

[300ohm]

THE ARRL ANTENNA BOOK
copyright 1991 by
The American Radio Relay League
16th Edition
First Printing
ISBN: 0-87259-206-5

Thats a pretty old edition with a going price of 49 cents.
http://www.bookholders.com/search.as...2065&type=isbn

Still worth every penny of it, but the new one is the 21st Edition.

[balm]

ok, thanks everyone, the corners (or troughs probably) are not practical at VHF, i learned they need to be at least 110" long, each half! to be effective.

http://www.qsl.net/ve3rgw/corner.html

[300ohm]

Yeah, a vhf corner reflector is going to be a big object, heh.

[300ohm]

Here are some vhf-hi antennas using a less than optimal corner reflector:

http://www.dipolnet.com/vhf_tv_anten...ent__A1116.htm

http://www.dipolnet.com/vhf_tv_anten...ent__A0710.htm

Heres an old vhf trough reflector antenna :
http://explorepahistory.com/displayimage.php?imgId=4817

Hmm, some of those trucks in the picture are newer than 1953, I believe.