[Anode]

Are there any 'miniature' (15-18" boom length) LPDAs that work from VHF-hi thru UHF ? like from 200Mhz to 600Mhz ? Is it possible to diy/design such an antenna ?


Here are a couple to give you an idea of what I am talking about, but they operate only UHF and above -
http://www.winradio.com/home/ax31b.htm
http://www.ramseyelectronics.com/cgi...ction&key=LPY2

 

[serndipity]



Quote:
Originally Posted by Anode /forum/post/16824160


Are there any 'miniature' (15-18" boom length) LPDAs that work from VHF-hi thru UHF ? like from 200Mhz to 600Mhz ? Is it possible to diy/design such an antenna ?

I designed and built the LPDA shown here :

http://www.livingwellonabudget.com/s...nd-save-money/


Also see:

http://www.livingwellonabudget.com/s...d-to-know-now/


It's uses a 18" boom for the UHF TV band. On a longer boom, it is entirely feasible to build a VHF/UHF version.


The above article has references to a LPDA white paper and JAVA design calculator.


Also see: www.cebik.com . Registration is free and there is w treasure chest of information on LPDA design, including a 100 - 1000 MHz design (search term: LPDA).


If your VHF reception is not too challenging; a trick that worked well to extend the UHF LPDA to VHF, was to add extensions to the rear element, such that it electrically becomes a VHF dipole. I found that even with the extensions being orthogonal (e.g. pointing toward the front), I was able to receive VHF stations that were 40+ miles distant.

 

[ctdish]



Are there any 'miniature' (15-18" boom length) LPDAs that work from VHF-hi thru UHF ? like from 200Mhz to 600Mhz ? Is it possible to diy/design such an antenna ?

QUOTE]


The design for a VHF hi log requires that the element length and spacings are inversely proportional to frequency so they it would have elements and spacing about 2.5 times larger than a UHF log.

John

 

[Phantom Gremlin]



Quote:
Originally Posted by Anode /forum/post/16824160


Are there any 'miniature' (15-18" boom length) LPDAs that work from VHF-hi thru UHF ? like from 200Mhz to 600Mhz ? Is it possible to diy/design such an antenna ?

How far away are you from the stations? I'm about 11 miles LOS (with few obstructions) and I get good VHF-hi from my Silver Sensor (which is nominally UHF only). We haven't had any rainy weather since the switch from UHF to VHI-hi. So I don't know how well the antenna will hold up under adverse conditions.