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Re: LF: 23:16 136 G6AVK de EB3FRN-1 Op32 Deep Search 725 mi -40 dB

To: rsgb_lf_grou[email protected]
Subject: Re: LF: 23:16 136 G6AVK de EB3FRN-1 Op32 Deep Search 725 mi -40 dB
From: pa3abk <[email protected]>
Date: Tue, 19 May 2015 17:50:22 +0200
In-reply-to: <[email protected]>
References: <[email protected]cal> <[email protected]>
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If his building has a "metal frame" and he is able to get a firm hardware connection to that, it is worth to try. In the maritime world, e.g. drill rigs, the antenna tuner for the heli beacon is sometimes found in top of the drill tower with a small "attic" as counter poise.
The whole drill tower becomes part of the antenna.
The improved height benefits the radiation.
BTW it's very rare that in a oil hazardous enviroment these kind of antenna's are accepted.
See attachment of antenna of a drill rig Pelican.
In this link you can see the attic on top the tower:
http://www.gustomsc.com/index.php/zoo/reference-list/doc_download/596-pelican-class-drillships

Jan/pa3abk


On 19-5-2015 14:50, DK7FC wrote:
Hi Luis,

Am 19.05.2015 12:46, schrieb VIGILANT Luis Fernández:
[...]
It is amazing to check how just a little of vertical antenna height
increase can boost the Tx signal ! :-)
...so maybe it is worth to try a 10m vertical on your high rise
building? :-)
The question is .... What should be expected from a Op2H with Dynamic
Search ??
For low distances it will work as expected, i.e. about 120/30 = 4 => 6
dB 'better' but for DX you will need a stable path! This will work on
VLF but not on LF and not at all on MF.  This is why WSPR-15 is used on
LF but not on MF.
For MF, something arround QRSS-10 is the slowest useful mode i think, at
least for DX. See
https://dl.dropboxusercontent.com/u/19882028/MF/DK7FC_QRSS-10_476_KHz_12-28-2012.jpg
to get an impression how blurry a QRSS-10 MF signal becomes in some 1000
km distance.

73, Stefan


--
pa3abk <-> dordrecht jo21it
Sent by Philips STB-75 with T100

Attachment: Beacon_Pelican.jpg
Description: JPEG image

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