It's all about making contacts anyway you can and having fun doing it! Gene, N9TF
-----Original Message----- From: Elecraft [mailto:[email protected]] On Behalf Of Wayne Burdick Sent: Friday, March 25, 2016 10:00 AM To: [email protected] Cc: [email protected] Subject: Re: [Elecraft] Strong recommendation: MFJ 18xx-series single-band whips for KX3, etc. Jim, Like I implied in my posting, portable operation is often more about convenience than signal strength. Your estimate of around 7 dB sounds reasonable. That's about 1.5 S-units, to use the vernacular. When a band is open, this loss still allows a lot of contacts to be made. Example: A couple of months ago my son and I were doing a bit of hiking/bird watching at Redwood Shores. While Griffin stalked hooded mergansers with his camera, I quickly set up my KX3 at a picnic table. I attached the whip with a right-angle BNC, along with the 13' counterpoise wire. 20 meter CW was very active with EU contest stations, most of them probably running a KW ("or so"). I called several of them running 5 W, and worked most of them on one call. I may have been down 7 dB from a full-size vertical, but I got through nonetheless. And I didn't have to frighten any birds away with my usual weight-tossing wild-west antenna deployment routine. Sometimes size doesn't matter. Wayne N6KR On Mar 24, 2016, at 11:14 AM, Jim Brown <[email protected]> wrote: > On Wed,3/23/2016 7:12 PM, Wayne Burdick wrote: >> I've been using an MFJ-1820T telescoping 20-meter whip for a few months. Considering its length (48"), results have been excellent. I typically use it with the KX3 on a picnic table at 15 W (with an external battery), or hand-held at 3 to 5 W (internal battery). > > As Tom Schiller, N6BT, famously noted, EVERYTHING WORKS, sort of. He demonstrated this by working all continents loading a lightbulb that he fed with coax. Tom is the designer of the excellent Force 12 antennas. > > I just did a quick NEC model of a 4 ft vertical with loading coil and a single quarter-wave radial laying on the ground, and compared it with a quarter-wave vertical (16.7 ft) with the same single radial. The model is for poor soil, which is typical of most mountainous QTHs. The full-size quarter-wave will be 7.4 dB louder than the shortened one. That's equivalent to reducing a 15W signal to 3W. The difference is slightly greater over better than average ground. The reduced efficiency is due to the greatly reduced radiation resistance of the shortened antenna. > > Bottom line -- yes, shortened antennas work, sort of, but full-size antennas work BETTER. If you can afford the weight of a means to support the longer antenna (typically a telescoping fiberglass pole), it's well worth it! And if a shorter antenna MUST be used, LONGER antenna, LESS coil is better. > > 73, Jim K9YC > ______________________________________________________________ > 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] ______________________________________________________________ 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]
