[TowerTalk] Hygain LP-1010

[Paul Christensen]

>"Maybe it’s a myth but I've always understood LP's to be equally poor everywhere. Not great FB - nor gain.:

A myth equal to that of all vertical antennas being poor radiators in all directions.  Of course, verticals are often poor radiators when the other half of the antenna is missing or there are appreciable ground losses from poor or missing radial systems.

My experience with LPDAs has shown very good F/B of at least 20 dB on all bands from a Tennadyne T14-HD.  The #1 caveat with the LPDA is that the gain-to-boom length ratio is poor.  While the T14 has a 42 ft. boom, 4Nec2 shows that 90% of radiated power comes from 2, and sometimes 3 active elements from the string of 14.  Some literature I've read indicates that all elements are active from a traditional LPDA.  Well, they are - but the majority of elements are not very active at all.  This is seen during NEC modeling.  In effect, the LPDA's performance is roughly equal to a 2-3 element full size Yagi on a short boom.  

BTW, the Tennadyne web site shows 8.5 dBd of free-space gain for the T14-HD.  Not even close.  It's actually about 5.5 dBd.  Using W8IO's LPDA modeling software, I calculate a boom length of over 200 ft. with normal sigma and tau values to get that kind of gain.  Why?  A 200+ ft. boom means that the active elements are now spread out over perhaps 30 ft.  The only viable way to construct such an antenna is with wire elements strung between two large supports with no ability to change directions.  

Probably a better solution is the newer optimized LPDAs since in the amateur service we don’t need continuous, end-to-end coverage from our antennas.  Despite the limitations of the T14-HD, there were some practical reasons why we chose it over other types but that can be discussed in another thread.

Paul, W9AC




 


Original Message-----
From: Richard Thorne
Sent: Tuesday, June 13, 2017 2:12 PM
To: Towertalk
Subject: [TowerTalk] Hygain LP-1010

Anyone have any experience with a Hy-Gain LP-1010 ( 10M through 30M
coverage)  Looking for mechanical and performance info.

Rich - N5ZC

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