Specifically, multiple samples of ft-991 owned by different operators would "autotune" optimally poorly ( resulting in a 99:1 on a 6-10:1 feed?) against multiple samples of, iirc, 4BTV. I suspect software bugs may play a part as well. *Shrug*
I haven't operated my 991 since, instead use my kx3 as my shack radio until my k4 arrives. Returned the 4btv to the gentleman that was kind enough to loan it to me, have a 6btv(?) awaiting erection but have been getting by with a fan dipole, reducing urgency. Have no idea what the other owner I was talking to at the Yaesu booth did about his. AD6YT On Sat, Apr 11, 2020, 11:56 PM Jim Brown <j...@audiosystemsgroup.com> wrote: > On 4/11/2020 8:14 PM, Tox wrote: > > Ft-991 (pre-A samples at least) has trouble tuning some multitrap > verticals > > for all the expected bands, this may explain why > > The things we call "antenna tuners" do nothing at all to the antenna. > Rather, they are an adjustable network that we adjust so that the rig > (or power amp) supplies power to the transmission line, and so that the > output stage is "happy." In this context, "happy" means that the output > stage is operating in a "safe" region (not likely to overheat or fail), > and that it is producing minimum distortion. > > If the antenna is poorly matched to the line, there are standing waves, > increasing the loss in the line, so less of that power gets to the antenna. > > The fact that a radio doesn't work with a multi-band vertical says more > far about the multi-band vertical than it does about the radio. Perhaps > it was assembled badly, was damaged in some way, lacked radials (if a > type that needs radials), or was installed in proximity to a vertical > metallic object. Or the feedline was defective. > > On 4/11/2020 7:57 PM, Mark Goldberg wrote: > > In addition, a Yagi operated at a non resonant frequency, especially > below > > it's design frequency is likely to not act like a Yagi at all. The > pattern > > depends on the elements being close to resonance. > > Right. ALL antenna arrays (that is, those with multiple elements) only > work at their design frequency, or a narrow band around that frequency. > That's because they work on the basis of their electrical length in > degrees, and the electrical distance in degrees between the elements. So > that 10M Yagi is nothing more than a non-resonant dipole with a random > bunch of aluminum around it. > > SWR is DEFINED by the match between the antenna and the line, and that > SWR causes additional loss. This loss causes the SWR to get smaller > along the line moving in the direction of the transmitter. When an SWR > bridge in the shack reads 5:1, the SWR at the antenna could be 10:1, > depending on the loss characteristics of the line and its length)! > > So the antenna tuner does nothing to change the SWR or the antenna. > > 73, Jim K9YC > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to scott.sm...@gmail.com > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
