On 2022-07-03 6:43 AM, Dave Sublette wrote:
> The antenna is working now. I'm suspecting the relay position on the
> remote switch. As soon as it stops raining, I will check it out.
The RCS-10 is a poor design at higher frequencies ... it has one relay
feeding two relays that feed four relays to select among eight antenna
positions. That means three relay contacts in series for any antenna.
Not only is it three times the places for trouble, it is three times
the inductance and a much longer non-50 Ohm "path".
73,
... Joe, W4TV
On 2022-07-03 6:43 AM, Dave Sublette wrote:
I just checked the coax I used. It has the stranded center conductor. I
can't find the part number on it. I would hve to find the invoice. But it
is the mil spec teflon/silver coax.
K4TO
The antenna is working now. I'm suspecting the relay position on the
remote switch. As soon as it stops raining, I will check it out. Thanks
for for all the advice.
K4TO
On Sat, Jul 2, 2022 at 11:57 PM Grant Saviers <grants2@pacbell.net> 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.
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
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