GadGetZzz

Designs of Yagi-Uda antenna capable of LVHF. HVHF,UHF, VHF and give the computations in every designs that how to construct yagi-udi antenna.
it can be also a combination of broadside array antenna and yagi uda antenna.

For that kind of bandwidth, I would recommend a Log-Periodic. Unless you wish to stack 4 Yagi-Uda antennas.

2006-12-05 22:43:09 by Jeanisen T

W3FF, Budd Drummond, shows us a prototype VHF 2 and 6 meter Yagi Antenna he has been working on. HAMCOM 2010.

I just bought a decent scanner to try to hear aviation traffic in my area. I am 11 miles from Honolulu airport and 4 miles from Kaneohe Bay MCB airfield. Using the antenna that came with, I get almost nothing from HNL (just a little airline internal traffic in the 450MHz range). There are some hills between me and HNL. The "came with" is a telescoping antenna. The system calls for 50 Ohms. I read about 1/2 wave dipole, 1/4 wave ground plane, J bars, Yagi etc. I want to pick up the best sound I can from HNL, which is directional, while still getting non-directional aircraft, though most of them will also be in a similar direction, and still keep a little broad band. In short, I want it all. What are my best choices and compromizes. I am reasonably handy and can build my own or buy, and could even put in a couple phased antennas together if that would work. Any help appreciated, or direction to the best web references. Thank you for your time

Since you seem to want the "internal" stuff in addition to the normal AM stuff down in the 125MHz region, you're talking something fairly wide band.

Those hills may hurt you at the frequencies you hope to receive. VHF tends to be a line of sight proposition.

For general coverage of VHF in an "omni" fashion, you will either need an assortment of directional and tuned antennas with a switch, or you might want to consider a "discone" style antenna. The latter doesn't have a ton of gain, but it's a reasonable compromise most of the time. Get it up just as high as local rules and neighbors will tolerate. If the coax length starts getting upwards of 50 feet, you may want to consider some better quality coax (9913 or better instead of any of the lesser RG series coax) to avoid line loss. The stuff is stiff as a board, but you'll be able to hang onto whatever signal it is you can get off your antenna.

4 miles and 11 miles aren't that tough at VHF frequencies if you've got reasonable terrain. Wish I knew just how ugly those "hills" really are.

At least you'll be assured to pick up all of the aircraft side of these comms well with a discone.

Remember -- elevate that antenna!

Coax Sources (of many possible)
http://www.hamradio.com/
http://www.radiobooks.com/products/rf910.htm
http://radioworks.com/ccoax.html

Discone Sources (of many possible)
http://www.grove-ent.com/ANT9.html
http://www.hamradio.com/
http://www.mfjenterprises.com/products.php?prodid=MFJ-1866

As for the above, I've always had very good luck with Grove and Ham Radio Outlet. Can't speak for the others.

2007-05-29 14:08:38 by Steven K