Re: [Elecraft] Elecraft AX-1 Whip Antenna
> On Sep 22, 2022, at 9:47 AM, Jim Clymer wrote: > > > > On Thu, Sep 22, 2022, 11:28 AM Wayne Burdick wrote: > Yes indeed. > > This is why you need an ATU when using such antennas. The ATU can correct for > terrain, counterpoise length and deployment, body capacitance, conductors > associated with other connected devices, etc. > > Wayne > > So that would lead me to believe that matching requirements for bicycle > mobile with a trailing counterpoise would be a moving target. I haven't tried that myself but yeah, probably. However, radios like the KX2 and KX3 are tolerant of dynamic SWR variations. For example if you hit the ATU button at some point and the SWR goes to 1:1, then walk (or bike) over varied terrain that causes the SWR To vary from 1:1 to 2:1, the radio won't complain. Only if the SWR gets really high will power rollback occur. Without the ATU, and using an electrically short/narrowband antenna, you might see SWR vary from 1:1 to 10:1. Wayne N6KR __ 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
[Elecraft] K4 Youtube Videos
Hi Guys, I am not seeing very much in the way of Youtube videos for K4 in comparison to TS890, IC7610, Ftdx101. With more K4's being delivered lately maybe someone will do some everyday SSB/Cw demo videos? ;-) de Wb8yqj Don Carlsbad, Ca. USA __ 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
Re: [Elecraft] Elecraft AX-1 Whip Antenna
On Thu, Sep 22, 2022, 11:28 AM Wayne Burdick wrote: > Yes indeed. > > This is why you need an ATU when using such antennas. The ATU can correct > for terrain, counterpoise length and deployment, body capacitance, > conductors associated with other connected devices, etc. > > Wayne > So that would lead me to believe that matching requirements for bicycle > mobile with a trailing counterpoise would be a moving target. Jim - WS6X > __ 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
Re: [Elecraft] Elecraft AX-1 Whip Antenna
Yes indeed. This is why you need an ATU when using such antennas. The ATU can correct for terrain, counterpoise length and deployment, body capacitance, conductors associated with other connected devices, etc. Wayne > On Sep 21, 2022, at 11:52 PM, Dave (NK7Z) wrote: > > Then I believe the case, and everything connected to the case ground, will > become part of the antenna system. > > 73, > Dave, > https://www.nk7z.net > On 9/21/22 23:08, Wayne Burdick wrote: >>> So yes, it CAN be a fact that the coax feedline to the AX1 could be doing >>> more of the radiating than the whip, depending on length. :) >>> >>> 73, Jim K9YC >> The primary use-case for the AX1 is directly attached the radio -- coax >> length zero. >> Wayne >> N6KR >> __ >> 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 d...@nk7z.net > > __ > 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 n...@elecraft.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
Re: [Elecraft] Elecraft AX-1 Whip Antenna
On 9/21/2022 11:52 PM, Dave (NK7Z) wrote: Then I believe the case, and everything connected to the case ground, will become part of the antenna system. Yep. The counterpoise for VHF/UHF talkies is the operator's body, capacity coupled to the case. It's also possible to improve TX slightly (a dB or two) by adding a quarter-wave wire under the screw-on mount for the antenna. That's equivalent to Wayne suggests by trailing a wire. 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 arch...@mail-archive.com
Re: [Elecraft] Elecraft AX-1 Whip Antenna
Then I believe the case, and everything connected to the case ground, will become part of the antenna system. 73, Dave, https://www.nk7z.net On 9/21/22 23:08, Wayne Burdick wrote: So yes, it CAN be a fact that the coax feedline to the AX1 could be doing more of the radiating than the whip, depending on length. :) 73, Jim K9YC The primary use-case for the AX1 is directly attached the radio -- coax length zero. Wayne N6KR __ 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 d...@nk7z.net __ 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
Re: [Elecraft] Elecraft AX-1 Whip Antenna
> So yes, it CAN be a fact that the coax feedline to the AX1 could be doing > more of the radiating than the whip, depending on length. :) > > 73, Jim K9YC The primary use-case for the AX1 is directly attached the radio -- coax length zero. Wayne N6KR __ 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
Re: [Elecraft] Elecraft AX-1 Whip Antenna
On 9/21/2022 7:29 PM, David Gilbert wrote: It is my opinion, however, that most of the radiating on an AX1 (or any other short loaded whip) is being done by the counterpoise wire and/or the shield of the coax. The coil and whip are matching aids. In FACT, not opinion, if you model ANY end-fed antenna, including those matching elements, feedline and whatever it is connected to as part of the model as wires, then set the modeling software to display the currents on the wires, you will find that all of those wires are carrying RF current that varies along the antenna with the open far end near zero, with peaks and nulls corresponding to wavelength. Antennas work by RF current producing an EM field, and it is the parts of the antenna carrying the greatest current that does the most radiating. If we're in the shack, all of the wiring that connects to the shield of the coax, including house wiring, bonding connections, etc., carries that current, if we haven't provided an intentional counterpoise, like a radial system. The earth is a big resistor, and makes a lousy return for antenna current -- it's like adding a resistor in series with the antenna. So if we're in the field and want the antenna to work well, we throw a length on the ground to act as a counterpoise, or use a long piece of coax to be the counterpoise. An every better trick is to elevate the counterpoise by throwing it over some brush or even into a tree, which reduces ground losses. Wayne's suggestion for pedestrian or bicycle mobile is to trail that counterpoise. Another point. NEC does not correctly model current distribution in an antenna around and inductor, and inductors don't radiate -- they're only matching elements, but the do change current distribution. There was excellent work in QEX 8-10 years ago showing that the base of an antenna that resonates to a quarter-wave was the worst place to put a loading coil, because that's where current is the greatest, and it's radiating capability is wasted. It was a two-part piece, the first part a thorough description of the measurement system (which included field strength), the second part field strength measurements for a half dozen conditions of where the loading was placed. This principle is why smart builders of verticals for 160 and 80M use top loading in the form of horizontal wire(s) at the top to form a Tee or inverted-L, with the horizontal wire at the top adding capacitance. So yes, it CAN be a fact that the coax feedline to the AX1 could be doing more of the radiating than the whip, depending on length. :) 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 arch...@mail-archive.com
