With 1500W of power, if the SWR is greater than 3:1 you may be exceeding
the ratings of the feedline. For example, Belden 9914 is rated at a
maximum of 300 VRMS, which is 1800W with a 50-ohm feedline or only 600W
with a 3:1 SWR. At 30 MHz, RG-8/213 style coax is typically rated at
1500W with a 1:1 SWR.
It's true that you can do more than that with low-duty-factor modes like
CW and SSB, but if you are running much more than 3:1 SWR you may be in
danger of damaging the feedline.
Alan N1AL
On 04/21/2017 06:28 AM, Jim Miller wrote:
Wes
Can you describe your affected antennas?
73
Jim ab3cv
On Apr 21, 2017, at 8:56 AM, Wes Stewart <[email protected]>
wrote:
A couple of points.
If you believe that an SWR of >3 necessarily degrades the efficiency
of an antenna, you are simply wrong.
If the "tuner" components have to be derated to this extent then
perhaps it should be called a line flattener rather than a tuner
because a lot of guys are still going to need a tuner.
On 4/21/2017 4:34 AM, [email protected] wrote: The KPA1500 tuner range
is fine. If your antennas have >3:1 SWR you need to do some work
outside. It will help your signal much more than the amp. Even when
I operated the RTTY Roundup in January after an ice storm my
antennas were within this amplifiers SWR range.
John KK9A
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[email protected]
This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [email protected]
