Topband: Using shielded CAT5 data cable as feedline for active antenna; benefits of multi-turn K9AY loop/SAL/etc?

PA3CSG pa3csg at
Sat Jan 2 11:52:52 EST 2016


I tried to measure this UTP cable as a receive line. For the results see:

The plan is only slowly moving forward:

To use one twisted pair as a receive line
One pair as the supply voltage
One pair to communicate via a RS485 protocol to control a several RX 
antennas / K9AY and to control the gain of the preamp as well.
One pair left.

Since the discussion is going this way, how about the above idea?

I have not tried it but would be interested in your comments.

Regards & HNY!

Geert PA3CSG

Op 02-01-16 om 16:45 schreef Pete Smith N4ZR:
> I was recently reading a web page by LZ1AQ 
> <>.  It is full of fascinating data and 
> design equations for the use of small magnetic loop antennas.  There 
> were two points, in particular, that caught my layman's attention:
> 1.  He recommends using shielded CAT5 data cable with RJ-45 connectors 
> as feedline.  The obvious advantage is having three pairs left over 
> for voltage supply and control.  See 
> <> for more information.
> 2.  He cites experimental data showing that coplanar crossed loops and 
> multi-turn quad loops both offer very significant improvement in the 
> recovered signalcompared with a single loop.  See 
> <> 
> to check whether I got this right. Anyway, it occurred to me to ask if 
> anyone has ever tried multiturn K9AY, SAL or flag/pennant receiving 
> antennas, and did you see something similar?
> Any other critiques of his design would be appreciated.  The price is 
> certainly right, and the construction looks good. A couple of 1-meter 
> coplanar loops wouldn't be at all hard to construct.

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