As Ive mentioned here many times I started by removing noise sources around
the house as well as at a few cooperative neighbors. That involved Mix 33
1/2" x 7.5" rods and 43, 75 and 77 mix 2.4" toroids. Ive been doing this for
decades at 2 homes and long before most of the current crop of noise
suspects were even on the market.
That work continues and I can get up and personal with a battery radio to
each part I suppress as well as listen right at the AC panel.
The main feedline is 750' of 1/2" CATV hardline thats been in place since
late 1989 and is checked a few times a year with a 75 Ohm CATV load at the
far end. It is always dead quiet with just a single 4' ground rod driven at
an angle about 30' from the switching hub and then another about 100' the
house where it goes elevated over the lawn and down into the house using
RG-6 quad shield for the final 25' into and inside the house. The switch is
a RCS-8 with 750' of elevated unshielded control wires with a big 31 toroid
about every 100' since its in a narrow strip about 30' wide between the N/S
Beverage and the ends of elevated radials for 80 and 160. It was fine
without them on the ground but not at 6.5' tacked to trees where RF
triggered relays at times and seemed to couple noise into the Beverage. At
almost $7 a pop from Mouser it was a pricy education........but the 1000'
reel of wire was free maybe 20 years ago. Amidon prices are a rip off.
Another relay hub is fed with twin runs of elevated RG-6 quad from two more
2 wire bi directionals and about 250' and 200' of coax.
No ferrites at all on any feedline and the 73-202 transformers are using the
dual sleeves (4 per core) Ive also championed here to provide minimal
coupling C.
All Beverages have their own antenna ground rod and radials at both ends as
well as a rod before the relay boxes for the last 2 mentioned. Some
Beverages at the rear relay box start only 10-30' from it so Ive used only 2
4' rods about 8' apart at the box for all 8 feeds. All unselected feeds just
float, no resistors used but doesnt seem to hurt anything; relays likely
have enough isolation and there is no daisy chaining thru multiple relays as
did the old RCS-4
Carl
KM1H
----- Original Message -----
From: "Herb Schoenbohm" <herbs@vitelcom.net>
To: <jim@audiosystemsgroup.com>
Cc: <topband@contesting.com>
Sent: Tuesday, November 20, 2012 12:00 PM
Subject: Re: Topband: Where to ground the Beverage feedline?
Only if this before buying all those expensive 3' Type 31 Ferrite Rings I
could have saved some money. I though that having many 250-350 foot
lengths of RG-6 feedlines running all over the radial system (ROG's or
radials on the ground) as well as having nearby 80 and 40 meter verticals
that during some contests where I am operating on 160 and a guest is
operating via remote control on 80 and 40, that trapping as much RF from
the Receive Only coax shields made sense. on some Beverages I would get
a de-sense making copy of weak signals very problematic. So I installed
12 turns on a 3 inch ferrite on both sides of a common ground bus and
several ground rods outside and about 20 feet from the shack. I also have
inline a KD9SV band pass filter with the Beverage bank output and now it
is possible to co-exist with other operators on higher bands running full
power.
Maybe getting a higher quality flooded coax meant for direct burial would
have been a better way to go but this is not convenient with the low cost
of cable TV RG-6 even here. The coax shield at the feed transformer on
both the single wire and reversible Beverages is not grounded, only the
Beverage side secondary has a ground connection.
So now I am not sure if I have really been wasting time this way. f it
helps the debate I plan to take a very noisy Chinese switching supply
running from a car battery and an 800 watt inverter and lay it running on
several RG6 runs coming back to the shack at about 200 feet away while
checking the difference in noise reduction.
I thought that these toroid rings, although expensive, would buy me so
isolation from cable induce noise, whatever the source. Winding some turns
through these toroids of the AC power cable on the wife's entertainment
center as made all IX vanish in the living room. But if it was wrong to
buy all these type 31 ferrite rings, keep you eyes on e-Bay soon.
Herb, KV4FZ
On 11/20/2012 12:44 AM, Jim Brown wrote:
On 11/19/2012 12:25 PM, Tom W8JI wrote:
If the feedline is bonded to the same ground on both sides of the choke,
any choke would do no good at all. It would be shorted.
I was not suggesting the same ground electrode, rather widely spaced
electrodes.
73, Jim K9YC
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