Topband: Short Receive Antennas

[Jon Zaimes AA1K]

Hi Jerry,

I have two of them. Don't use them very often but they do work. I've even had limited success with nulling my own TX signal to allow hearing signals on the band at the same time as transmitting.

73/Jon AA1K

At 08:41 PM 12/13/04, you wrote:
>Talking about "noise cancelling", what about the MFJ-1025 which claims to provide a "60 db null to wipe out noise and QRM" using a separate external receive antenna (maybe a beverage or a small loop??). It even has an "RF sense T/R switch" that "automatically bypasses the receiver when transmitting".
>Has anyone tried one of these things? Does it work at all?
>
>73, Jerry K3BZ
>
>----- Original Message ----- From: "Donald Chester" <k4kyv at hotmail.com>
>To: <Topband at contesting.com>
>Sent: Sunday, December 12, 2004 2:49 PM
>Subject: Re: Topband: Short Receive Antennas
>
>
>>
>>>You might want to look at an article in QST by K6STI, who
>>>experimented/made a "noise-cancelling" antenna. It was
>>>a wire antenna, 25 or more feet on a side, with open wire feed
>>>lines from two opposing corners that went to a center pole and
>>>box with a matching xfmr, etc.  One of the feed lines was twisted 180 deg
>>>to cancel local noise signals.  QST article was Sep 1995, page 33.
>>>and pages following....might be worth a look.
>>I built one of those a few years ago, and still have it.  While it occasionally provides better reception than my other antennas, most of the time its performance is disappointing.  I pretty much consider mine wasted effort.
>>
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