Date: Mon, 26 Jul 2010 11:07:38 -0700
From: "Jim Brown" <jim@audiosystemsgroup.com>
Subject: Re: [TowerTalk] Gas Tube protection for remote antenna
switches;
On Mon, 26 Jul 2010 05:46:46 -0700, Jim Thomson wrote:
>## putting a shorted pl-259 in pos #1 just used up pos #1.
>Why not use a torroid.. like 45 uh... using 10-12 ga magnet wire. Then,
>the center conductor is always at DC grnd. [ on the cable heading towards
>the station.. ie: input side]
Repeat after me -- LIGHTNING IS NOT A DC EVENT, IT IS AN RF EVENT. Write it
100 times on the blackboard! :) That choke only discharges DC.
73, Jim K9YC
## Point well taken.... and I thought the same thing... abt 2 x hrs after I
made that comment.
## The problem with the ameritron RCS-10 box is.... all the un-used ports are
floating.. and not grnded
[like the as remote box's]. With the rcs-10 box.... with the power shut off
to the controller, the default is
port #1. Their book sez if you stuff a grnded pl-259 in there... then ur
coax center conductor is bonded to
tower [ via the remote box casing]
## ok... this brings up another point. What about your super high Z choke
baluns, when used on a yagi ?
They will also look like a high Z.. and probably 45-90 uh. Have you ever
measured the uh on them...say
from braid of input to the choke.. to the braid on the output side ?? What
kind of readings do you get ??
say with a run of the mill simple LCR meter. Or is the resistive component so
high, that there is little uh.
## what happens when lightning hits the DE of the yagi..or will it opt to hit
the boom /other ele's instead ??
## On the INPUT to my remote switch box on the mast, abt 3' above the top of
the tower, is where I have the
type-31 choke balun. This is to just supplement the existing bead baluns
at each yagi's DE. The idea here was,
if RF spillover gets past the existing type 43 bead baluns.... it won't get
past the type-31 balun on the input to the
remote switch box. The type-31 balun of course, is being used on all
bands..since it's on the input to the remote switch
box.
## speaking of lightning arrestor's.... mine was slated to go at the base of
the new crank up tower.. and tied in to the
3 x cadwelded 8' rods, buss system, etc. Should it be at the top of the
tower instead.... or should we be using a lightning
arrestor at both the top and bottom of the tower ?? If I install a 2nd
lightning arrestor at top of tower.... which side of the
type -31 balun should it be on ?? As is... the braids of all coax's are
bonded to top of tower [via remote switch box]
Braid of single coax is also grnded at base of tower
Tnx.... Jim VE7RF
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|