Original article from: Wayne Sarosi 
 Reposted by Rob Dennis,Moderator HAM_TECH,for use of the FIDO HAM_TECH echo.
  THIS POST/SERIES NOT TO BE USED IN ANY CDROM COMPILATIONS FOR COMMERCIAL
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SUBJECT:  Log Periodic Dipole Array - Part Three
 Since the first couple of postings about this antenna,I have watched the SWR
readings and made notes of some of the propagation features of the antenna.
 The antenna's orginal design came from an older ARRL Antenna book and the
ARRL Handbook (87).
 Evidently the design has been around since dirt was invented.
 To date,the SWR has had minor changes,some for the better and some worse.
 There are no SWR readings above 1.8:1 and that is one feature that has not
changed. Most of the other changes,in SWR,have had little or no impact on the
operation. These changes may be the result of temperature changes as we have
had readings in the forties here on occation.
Front to Back notes:
 The LPDA does not have the FB ratio that a good yagi does towards the bottom
of its range,but at high end,the LPDA runs rings around the yagi.
Reception:
 I've run yagis here for years and I can honestly say that the LPDA 'hears'
better due to the capture area of the antenna.
Transmission:
 With the low SWR across the HF Band,the LPDA works well with or without a
tuner. Since I operate MARS Phone Patching for the USAF,I have had numerous
oportunities to query operators in South America and the US.
 All report that the signal is as good as the three element monoband yagi I
used before. These operations take place above the 20m band but below the 17m
band.
 When operations take place on bands above 20m,the LPDA shows improvement in
gain.
Weathering:
 The LPDA has been subjected to wind gusts of 50 mph plus with no ill 
ffects.
 The LPDA is however a great haven for the many birds we have here in 
lorida.
 I believe they have a Bar & Grill up there.
 At one time,there were no less than 63 birds on the antenna.
 After a quick carrier,there were zero. Lucky for them,they do not roost up
there at night. My phone patching output is the legal limit.
 Overall,the LPDA is the antenna for me. The design was the hardest and even
that can be done with a handheld calcuator and the text in the handbook.
 Previous postings provide the reader with all the precut values needed for
operation from 13.5 to 29.5. The 22-ft boom is about the same size as a 20m
monobander.
 If you can put up a 20m monoband yagi,then you can put up a LPDA.
 No traps,coils,or power limitation except the balun.
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- WS
--- GoldED 2.42.G1219
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