Yeah, i didn't catch that he was going to use the internal tuner and just forgo the external one at the other end of the coax.
In that case, I agree with Dave. 73, Mark W7MLG On Wed, Aug 7, 2019 at 6:19 PM Wes <[email protected]> wrote: > 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] ______________________________________________________________ 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]
