[FoxHunt] Old Homing In Article

[Mark]

Hi Charles,

I was building my own doppler head at the time and I seem to remember the
reason as being that the antennas that were not in use were to be high
impedance. They were to look like they didn't exist. A non used antenna that
was terminated in 50 ohms or shorted to ground could act like a director or
reflector and put some Amplitude modulation on to the signal which could
then be AM / PM converted in the receiver and modify the resultant
direction.

This was no different to the earlier version except that it no longer
required 1/4 wavelengths to achieve the high impedance and hence the greater
bandwidth.

Mark.
VK3MD

-----Original Message-----
From: foxhunt-bounces at mailman.qth.net
[mailto:foxhunt-bounces at mailman.qth.net] On Behalf Of Charles Suprin
Sent: Monday, March 08, 2010 8:57 PM
To: Radio Direction Finding
Subject: Re: [FoxHunt] Old Homing In Article

Bob,

On that page he cites the article as an explanation of the need for 
biasing both ends.

Charles

On 3/8/2010 3:30 PM, R. Simmons wrote:
> It appears the article is on his website :
>
> http://www.homingin.com/newdopant.html
>
> He claims 20-30% BW but really it is much greater. ( if you disregard loss
> of RF sensitivity ) The PicoDopp MiniAntenna "design" frequency is around
1
> GHz, but I have used it at 146 MHz, others have used it even lower. ( but
a
> fairly strong signal is required to compensate for small antenna size )
> That = several octaves of span.
>
> Bob S.
>
>
> -----Original Message-----
> From: foxhunt-bounces at mailman.qth.net
> [mailto:foxhunt-bounces at mailman.qth.net] On Behalf Of Charles Suprin
> Sent: Monday, March 08, 2010 11:11 AM
> To: foxhunt at mailman.qth.net
> Subject: [FoxHunt] Old Homing In Article
>
> Hello Foxes and Hunters,
>
> I am looking for a copy of the Homing In article from April 1995.  It
> contains information on design decisions for k0ov's new Roanoake
> antenna system. Joe points the user to it at
> <http://homingin.com/newdopant.html>  and Bob Simmons ( WB6EYV )
> alludes to the content at
> <http://www.silcom.com/~pelican2/PicoDopp/PICO_MORE.html>. It appears
> to deal with the need for maintaining the impedance at the antenna's
> for repeatable performance.
>
> Any insight would be appreciated.
>
> Charles
> AA1VS
> ______________________________________________________________
> FoxHunt mailing list
> Home: http://mailman.qth.net/mailman/listinfo/foxhunt
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:FoxHunt at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
> ______________________________________________________________
> FoxHunt mailing list
> Home: http://mailman.qth.net/mailman/listinfo/foxhunt
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:FoxHunt at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
>    

______________________________________________________________
FoxHunt mailing list
Home: http://mailman.qth.net/mailman/listinfo/foxhunt
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:FoxHunt at mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html