Re: [IRCA] AC twin lead or speaker wire for lead in.

["Craig Healy" <bubba@xxxxxxxxxxxxxxxxxxxx>]

> > "Dallas Lankford uses ordinary AC twin lead or speaker wire.  He says it
> > works better than coax.  With a balun, of course."
>
> I use a coax with a 100' run NE of the ewe balun.  Would using AC twin
> lead or speaker wire affect the directional pickup of the ewe?  Would
> noise level increase  The above method would be less expensive than
> buying coax and the connectors.  Much easier to replace when my lab
> chews on a the coax cable.

I suppose the best way to test it is to disconnect the far end.  Either
short the center to the shield, or (better) terminate it on a shielded 50
ohm dunny antenna.  In my tests, both Radio Shack RG-58 and good quality RG6
TV lead in had a significant amount of undesired signal.  For example, with
150 feet of RG-58 rolled out in my yard and terminated in a shielded dummy
load, I still could hear all of my normal locals at good level.  WSKO-790
was at S9+20 for example.  No type of grounding made the least bit of
change.  If you have significant signal, then it's worth a shot to try
replacing it with a balanced line.

Coincidentally, I just finished testing a 150' run of CAT5 ethernet cable
this afternoon.  I made a 100 ohm termination for the far end, and a 100 ohm
to 50 ohm balun.  Leakage signals dropped a significant amount.  I could
hear the strongest locals, but not much else.  A real improvement.  I took
one of my 30" copper tube loop antennas and wound a second pickup on the
toroid.  I used six turns connected to a standard RJ-45 jack.  Plugged in
the ethernet, and had nice signal levels on the radio.  Turning the loop did
show significant nulling, unlike when I tried to use it with the RG-58 coax.

It's only a short test, but results are encouraging.

Parts:

Home Depot CAT5 indoor/outdoor cable bought in a 500' carton size.  Used a
150' run with nornmal RJ-45 ethernet connectors on the ends.

Homemade balun:  BNC connector to 8 turns on a FT-87-J toroid core.  12
turns punched down to an RJ-45 ethernet jack.  I will experiment with
different turns eventually.  That ratio was just a guess pulled out of thin
air.

Antenna end is the six turns through the FT-240-75 toroid which is on the
30" copper tube loop.

I only used the blue/blue-white pair in the cable.  The other three pairs
were left unconnected.  Further tests will involve grounding one or more
pairs and seeing if grounds at either end make any reduction in the input
leakage signal.

Craig Healy
Providence, RI

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