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PA3GMP > TECH 10.01.05 15:42l 41 Lines 2026 Bytes #999 (0) @ WW
BID : 1515_PA3GMP
Read: GUEST
Subj: Re: Lightning protection
Path: DB0FHN<DB0RGB<OK0PPL<DB0RES<DK0WUE<7M3TJZ<PY1AYH<IZ0AWG<IW0GPS<IK0USA<
I0XNH<IK0MIL<UA6ADV<ZS6FB<ZS0DLD<ZS6RO<ZS0MEE
Sent: 050110/1131Z @:ZS0MEE.SRJ.GAU.ZAF.AF #:6837 [Meredale] $:1515_PA3GMP
From: PA3GMP@ZS0MEE.SRJ.GAU.ZAF.AF
To : TECH@WW
PA3GMP/TPK 1.83d Msg N§:1515 Date:08-03-2005 Time:13:25 SAST (-2 for UTC)
ZR6JDE wrote:
>I have now looked at a commercial installation of especially Television
>and FM Radio transmitters, You hardly ever hear or see any of these
>suffer "hits" or "strikes" from lightning. I was wondering why?
>Is it the perception that these guys have "unlimited" funds? Maybe?
Not unlimited, but larger than mine. I imagine that if you spend millions
and millions on a 50kW or 100kW broadcast station, the extra money spent on
adequate lightning protection is only a fraction of the total amount.
>They employ the basic priciple of a low loss (less than 10 ohm) path to
>earth from the top of the tower to dissapate any Potencial Difference
>quickly and effectively to a carpet of copper burried on the rocky hill.
>There are also no antennas right at the to of the tower. All installations
>start at least 2 m below the top of the tower on different levels.
All of that will help a lot, I'll grant you that. But another factor is the
fact that the finals of a 100kW broadcast transmitter are a bit more robust
than the transistor finals of my Yaesu ham rig. Having lightning strike two
meters from my antenna will do a lot more damage to my radio than to that
broadcast transmitter.
>My problem however still remain to protect the AC and Telcom paths to my
>equipment. My experience with rather "cheap" telephone surge protectors
>are that they are effective proportional to the price yu are prepared to
>pay.
Exactly. And even the expensive stuff is generally still consumer grade.
The highveld region of South Africa is well known as one of the
>lightning capitals of the world - I have had numerous times had to call
>telkom to com and fix the telephone line after a "strike" while the
>equipment in my qth were sucessfully protected by these units that
>dissipate the current to the mains earth.
So exactly what are you using in the shack?
73 Frank ZS/PA3GMP
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