Re: LF: LF ferrite RX antennas

["Douglas D. Williams" <kb4oer@gmail.com>]

Wow! Nice design Stefan. Very neat construction and high Q.

I wonder.....if someone were to make a large enough ferrite core antenna (not for portable use), would it even need amplification? The cost and/or size would probably be prohibitive.

On another note, is there an archive of this reflector somewhere on the web?

-Doug

2012/1/1 Stefan Schäfer <Stefan.Schaefer@iup.uni-heidelberg.de>

Hello Doug,

LF ferrite RX antennas were built and discussed here a few months ago. They perform excellent but there is no advantage against a larger loop. For me the real only advantage is the handy dimensions so it can find its place in a backpack.
I took a few russian ferrite rods from ebay.
If you want, take a look to some photos i took during constructing my antenna:

http://dl.dropbox.com/u/19882028/LF/DSC04160.JPG
http://dl.dropbox.com/u/19882028/LF/ferrite%20antenna%20parts.JPG
http://dl.dropbox.com/u/19882028/LF/inside.JPG
http://dl.dropbox.com/u/19882028/LF/Q.jpg
http://dl.dropbox.com/u/19882028/LF/arrangement.JPG
http://dl.dropbox.com/u/19882028/LF/LF-P%20RX%20RIG.JPG
http://dl.dropbox.com/u/19882028/LF/DK7FC_LF_p_active_ferrite_antenna.JPG
http://dl.dropbox.com/u/19882028/LF/DK7FC-p%20LF%20RX.jpg
http://dl.dropbox.com/u/19882028/LF/DK7FC%20LF-p%20RX%20converter.jpg

73, Stefan/DK7FC

PS: There is a design of M0BMU as well!



Am 01.01.2012 14:03, schrieb Douglas D. Williams:

Mal,

I am currently using an active e-probe antenna that was made by Jack
Smith at Clifton Laboratories. I asked him to custom modify this one
to be more sensitive than his standard version below 10 kHz, because I
plan to use it to try to receive a TA signal on your "dreamer's band".
He was able to make it quite sensitive down to 3 kHz at the expense of
using some parts with a lower voltage rating, so I have to be careful
not to short out the coax, etc. It is located about 15 meters from my
house and the base of the antenna is a mere 3 meters above ground, and
about 10 meters from the treeline.

http://i81.photobucket.com/albums/j231/Goranothos/antenna.jpg

My receiver is an Icom R75 (with CW filters), preceded by an LF
Converter of AMRAD design with a TXCO for frequency stability,
preceded by a 500 kHz low pass filter.

I also have a Wellbrook LFL1010, which is not currently in service,
but since this season is starting off so well, I may put it back up
for comparison with the e-probe.

Over the years, I have used several different antennas for LF
reception, including tuned longwires, homebrew e-probes that I
constructed,  homebrew loops, but I must say I am very impressed with
the Clifton Labs product, as well as the LFL1010, which I used last
season. Someday I would like to construct a large ferrite core
receiving antenna.

73,
Doug KB4OER








On 1/1/12, mal hamilton<g3kevmal@talktalk.net>  wrote:
 

Doug
Nice screen shot from you. You are receiving extremely well. What sort of
antenna do you use.
You might also hear/see me on 500 Khz running 10W erp

73 es tnx
de mal/g3kev