I don't have installed experimental data but choose to separate the 8
type 31 large beads on Buryflex from the boom with a strip of 5/8" thick
HDPE and all were taped to the boom with Scotch 33. 6M5 over 6M5 stack.
IIRC the choke measured around 3k ohms on the bench.
Grant KZ1W
On 7/3/2022 05:09, Jim W7RY wrote:
On 7/2/2022 10:56 PM, Grant Saviers wrote:
A minor matter, but RG142 center conductor is SCCS - silver plated
copper coated steel. That makes it very strong but fatigue prone.
Some are concerned about TFE creep from the solid conductor and
recommend stranded RG400 as a result. However, I've not had problems
in FT-240 toroid chokes wound 10 years ago with 142 made from Mil
17/60-RG142 spec cable.
Paternack specs their 142 at 2400w average power at 100MHz. It will
get hot, but the TFE handles it. Best to provide easy dissipation of
the heat as K9YC recommends.
Another possible issue is to keep ferrite toroids away from the boom
and other conductors as the coupling can cause problems.
_*How far away? *__*
*_
_*73, Jim W7RY*_
Grant KZ1W
On 7/2/2022 16:13, Jim W7RY wrote:
Agreed.
RG-400 works well to. The only difference between RG-142 and RG-400,
is that RG-400 has a stranded center conductor. RG-142 has a silver
plated solid hard drawn copper center conductor.
73, Jim W7RY
On 7/2/2022 6:09 PM, john@kk9a.com wrote:
The 50MHz power average rating for RG142 is several kilowatts, why
do you
think it is inadequate?*If it is a balun problem it is most likely
connection related.*
John KK9A
Dave Sublette k4to wrote:
My six element 6M LFA is showing a high SWR and severe loss of receive
signal. This happened this afternoon as I was working the band with
500
watts from my KPA500.
To this point, the antenna was very nicely matched with a 1:1 SWR over
almost 1 MHz of bandwidth. The antenna is home brew and I made the
matching
balun per the instructions from K9YC using two toroids with six
turns each
of high quality teflon insulated, double shielded silver braid. I
think it
was RG142 purchased new from a reputable vendor in Tennessee. It has
worked
perfectly at the 100 watt level for three or four years. I had
looked at
the specs on the coax and thought it would be good for 500 watts.
Evidently not.
73,
Dave, K4TO
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|