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Re[2]: LF: Re: Active antennas on 136kHz, additional wire needed?

To: [email protected]
Subject: Re[2]: LF: Re: Active antennas on 136kHz, additional wire needed?
From: Chris Wilson <[email protected]>
Date: Tue, 29 Sep 2015 14:22:22 +0100
In-reply-to: <[email protected]>
Organization: Gatesgarth Developments
References: <[email protected]>, <[email protected]> <[email protected]>
Reply-to: [email protected]
Sender: [email protected]
Hello rsgb,

Tuesday, September 29, 2015


> Hello Chris,

> The "PCB-antenna" is equivalent to a 1 feet rod and though counter 
> intuitive, adding one won't help.

> As with all active whip designs, at VLF / LF / MW and lower HF the 
> whip is NOT the antenna.

> How the pa0rdt-Mini-Whip© works, can be found here:

> http://wwwhome.cs.utwente.nl/~ptdeboer/ham/tn/tn07.html

> Though some knowledgeable people don't agree, I have put the theory
> to the test and build a battery powered mini-whip with the battery 
> included in the antenna housing. The rf was transported by a 
> optical fibre link. The antenna was mounted on a non conducting 
> fibre glass pole.

> Nothing was received at all with this set up, until I put a coax 
> cable up the mast ending 5 cm below the antenna. There was no 
> connection between this cable and the circuit board, whatsoever.
> The shield of the coax cable was connected to a ground stake at the 
> bottom of the mast and it provided the necessary ground reference 
> for the ohterwise isolated antenna.

> I hope this helps.

> 73,
> Roelof Bakker, pa0rdt

> N.B. Rather than building one for one's own use, which is no problem 
> at all, I am sorry to find that some people are making money from a 
> copywrighted design. (Readily build antennas are available from the 
> designer for those unable or unwilling to build one.)


 Thanks for the info "from the horse's mouth", and I sympathize with
 your predicament of people selling your design commercially. In this
 case I just received a gift from my pal, he has little electrical
 knowledge of radio stuff, he must have remembered me saying I would
 like to try an active antenna and looked on Ebay. It was my intention
 to make one, but he beat me to it, sorry!

 It's an intriguing thing and I look forward to trying it out.




-- 
Best regards,
 Chris                            mailto:[email protected]swilson.tv


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