Topband: Crazy RX antenna Question

[Bill Wichers]

Two things to keep in mind here:

1 - The shield of the CATV drop should be grounded at the entrance to
every subscriber along the route as per electrical code.
2 - The shield of the hardline on the poles is bonded to the strand
(steel support wire) at each tap and possibly everywhere if it's the
bare-aluminum-jacketed kind of hardline. The strand is supposed to be
bonded to ground at *every pole*. 

I think with all those grounds at all kinds of randomly spaced locations
you won't get very good antenna performance from the shield, if it
receives anything at all. 

I've never really seen a voltage between the shield of a drop and
ground, but you might get a DC ground-loop current. You should, at
minimum, capacitively couple to the shield if you want to try using it
as a receive antenna. I think the performance will be very poor though
if anything at all.

You might have better luck seeing if your incoming phone line has any
unused pairs available. Depending on how your drop is run, those might
work better -- just make sure there is no voltage on them first.
Remember also that the "big" phone cables on the poles are normally
shielded, so you're still probably going to get pretty poor performance.
You'd also be running a receive antenna right inside a cable with all
kinds of weird DSL frequencies so you'd probably get a lot of nasty
noise.

  -Bill KB8WYP



> I typically use a 1/4 WL inverted L on TB, with 23 or so radials that
are
> NOT in a 360 deg ring around the feed.. they go from about 340-65deg (
> even
> spaced ) and NO more than 60' long.
> Obviously reception is not great, but when sigs are REALLY super good
fore
> most.. I hear DX...barely.
> 
> I live in a big city and all their CATV feed is above ground..behind
my
> home running the length of my block ( well over 1000' ) and at about a
> height of 13' is the CATV feed, here goes the crazy question...
> Has any one ever tried to use the SHIELD of their CATV house drop..
for a
> VERY long RX antenna?
> 
> I do realize other ppl are 'wired in' and that there are CATV amps all
> along that line..as well as consumer products, TV's ect ect  again
more
> curious than anything.
> 
> On my TS940S I have a RX only port that I could try this on, but dont
want
> to just do it w/o asking the 'been there done that' crowd.
> 
> Also.. I do not subscribe to Cable TV or Internet or VOIP Service
FWIW.
> 
> Yes I really realize this is a very outlandish question.. but Im very
> curious, and I dont want to just 'try it' and then damage something.
If
> there is no voltage measurable on the Shield .. would it still
possibly
> damage the rig if I gave it a try?
> 
> Almost embarrassed to sign this email,
> 
> DE
> 
> -Steve Raas N2JDQ
> _______________________________________________
> UR RST IS ... ... ..9 QSB QSB - hw? BK