[Premium-Rx] Super ferrite rod aerials

[Ben Dover]

Howdy, Brooke.

Here it is.

http://groups.yahoo.com/group/lowfrequency/



At 09:12 AM 8/3/2005 -0700, you wrote:
>Hi Ben:
>
>Can you give me a link to the Yahoo groups LF / VLF HANGOUT web page so 
>I can join.  I tried searching Yahoo gorups but could not get any hits.
>
>73,
>
>Brooke Clarke, N6GCE
>-- 
>w/Java http://www.PRC68.com
>w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml
>http://www.precisionclock.com
>
>Ben Dover wrote:
>> Funny you should mention monster ferrite antennas.
>> 
>> After working with air core loops for a number of years, I've been working
>> with a monster ferrite design of my own here for the last six or eight
months.
>> 
>> I've been going for LF and VLF coverage, and the air core design model hits
>> a brick wall re. practical dimensions for amateur designing at about 100
KHz.
>> The additional permeability of a big ferrite core makes things a whole lot
>> easier mechanically, and makes very efficient VLF recieving antennas a
quite
>> practical proposition.
>> 
>> I won't go into a whole lot of detail here, but my designs are based on
a LOT
>> of toroid cores stacked to make a BIG ferrite rod...   say, 3 to 8 feet in
>> length and over an inch in diameter. The basic loop design uses a low
noise 
>> FET preamplifier (perhaps 25 - 30 DB of gain). A lot of it's structural
design
>> is based on PVC plumbing fittings and pipe. Except for the tedium of
winding,
>> construction from scratch is easily done with hand tools, plus the usual PC
>> board work to build the preamplifier.
>> 
>> So far, I've built two of them successfully. With a 60 - 2200 pf variable
>> cap for tuning, the first went 20 - 100 KHz, and the second (still in the 
>> late stages of construction) tunes roughly 7.5 - 24 KHz.
>> 
>> If anyone is interested in them, my Yahoo group, LF / VLF HANGOUT, has some
>> messages from me with detailed information on the antennas, as well as a
lot
>> of pictures made during construction as well as the finished product.
>> 
>> If you don't want to join Yahoo groups, E-MAIL me off the list and I'd be
>> happy
>> to send you the picture files, and answer any questions you might have.
>> 
>> 
>> 73's,
>> 
>> Tom, W9LBB
>> 
>> 
>> 
>> 
>> At 10:26 AM 8/3/2005 +1000, you wrote:
>> 
>>>I recall seeing a monster ferrite aerial in the LWCA magazine pages some
>>>years ago, made of "a lot" of smaller rods glued together. It was
rotated on
>>>a small trolley and was reported to work quite well. It was several meters
>>>long and I think about 2" in diameter. You might need to find a closeout
>>>sale to match this !!
>>>I have made several smaller composite rods and they all exceed single rod
>>>performance.
>>>Rick
>>>
>>>
>>>
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>>>
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>>>
>>>
>> 
>> 
>> 
>> 
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>> 
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>> 
>> 
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