I haven't been following this thread closely but I think Dave makes good
points. As to the final fold-back, if I waded through this correctly, I
understand that the OP has the built-in tuner in his KX2. That solves that issue.
BTW, SWR = 15:1 is a return loss of about 1.1 dB, not 3 dB.
Wes N7WS
On 8/7/2019 5:29 PM, Mark Goldberg wrote:
You need to take into account the radio finals. When the SWR is high, My
KX3 cuts back because it gets too much reflected power. I expect the KX3,
and in fact any other radio or amplifier is similar. 15:1 is about half the
power coming back.
Regards,
Mark
W7MLG
On Wed, Aug 7, 2019 at 5:14 PM David Gilbert <[email protected]>
wrote:
Rather little of this discussion makes sense to me.
Let's look at this realistically:
1. The antenna tuner in the KX2 is rated to be good up to 10:1 SWR.
Let's assume it's good to 15:1.
2. Let's assume you're using a decent cable for portable operation like
RG-8X.
3. Let's assume that the length of your coax when operating portable is
not much more than 30 feet long.
4. Let's assume under the current solar flux conditions you're spending
most of your time on 20m or lower in frequency.
30 feet of RG-8X has a loss of 0.4 db or less for that length at those
frequencies, and per the charts in the link below the additional loss
due to a 15:1 SWR is no more than 2 dB.
http://www.astrosurf.com/luxorion/qsl-transmission-line2.htm
Maybe it's just me, but I don't think that justifies dragging along a
remote tuner. You could recover a heck of a lot more dB by simply
bringing a somewhat larger portable antenna.
73,
Dave AB7E
______________________________________________________________
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]
