On 28 May, 10:02, "Virgil Smith" wrote:
Thanks to all who replied to my query. I now have several good leads which
I'll be following up. Cheers,
-vs-
"Richard Fry" wrote in message
...
"Virgil Smith" wrote
Does anybody have a recommendation for a good book or journal article
on very short antennas? I'm trying to design the front end for a LF/VLF
receiver and would really like to know the equivalent circuit for
antennas ( both E-probe and loop ) a tenth of a wavelength or less.
________
Lately I've been working on an Excel spreadsheet to calculate the
parameters associated with electrically short, MW/LF/VLF, v-pol
antennas -- including their inverse distance groundwave fields at 1 km and
somewhat beyond, subject to their specific groundwave propagation loss.
The equations are those found in an I.R.E. publication of the pioneer
broadcast consultant Carl E. Smith, and in REFERENCE DATA FOR RADIO
ENGINEERS, published by IT&T.
Here is a sample screen clip:
http://i62.photobucket.com/albums/h8...ennaParameters...
Please let me know if you'd like to try it out. My e-mail address and
website are shown in the upper right corner of the clip linked above.
RF- Hide quoted text -
- Show quoted text -
Virgil,
You wasn't quite clear as to what short antennas means!
For instance it could refer either to element length as well as boom
length. You will not lose much gain on elements that are shortened
such that the current curve changes to a triangle shape. With respect
to boom length
booms can be shortened quite a bit over yagis by using the
Gaussian design where the elements are placed close to planar. Normal
Gaussians of this style go upto 13 dbi for much less than a 20 foot
boom length when using just three elements tho you could go upto 6
elements on such a boom length. I think that there should be a spec
for "turning radius that would meet your quest as there is so much
confusion with respect to gain versus boomlength or number of elements
which is based solely on the yagi design to the ommission of other
designs.
Art