This will go nicely with my K3
http://www.youtube.com/watch?v=9tIZUhu21sQ 73 Jim SM2EKM ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
On 10/17/2010 1:40 AM, Jan Erik Holm wrote:
> This will go nicely with my K3 > http://www.youtube.com/watch?v=9tIZUhu21sQ This has been debunked by antenna design experts (one of whom is a staff member of my company) as "voodoo electronics" because of the extreme losses in the conductivity of seawater versus that of the metals usually used in antennas. Better try next time.... -- 73 de K2ASP - Phil Kane Elecraft K2/100 s/n 5402 ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
On 10/17/2010 1:40 AM, Jan Erik Holm wrote:
> This will go nicely with my K3 > http://www.youtube.com/watch?v=9tIZUhu21sQ Seawater has electrical conductivity of seven *orders* of magnitude lower than copper! As a quick and dirty check, I created a simple 10m ground plane antenna in NEC-4. Four counterpoises and a vertical radiating element that is bottom fed, all of equal lengths, with the counterpoises and the feedpoint 1m above seawater (natch!) ground. All elements 0.5" in diameter. With perfectly conducting elements, the feedpoint impedance is just about 35 ohms, with a gain of 4.7 dBi. When I changed the conductivity of the vertical element to 5 mhos/ meter, while keeping the counterpoises as perfectly conducting, the computed gain dropped to -8.2 dBi and the feedpoint impedance is capacitive at 320 -i*250 ohms. I.e., something like 13 dB loss compared to using copper elements. BTW, I could not achieve resonance by extending the length of the radiating element -- I guess you will need a KAT500 in addition to that KPA500 which you use to make up for the missing 13 dB. This could make a good water heater. All that power has to go *somewhere* :-). 73 Chen, W7AY ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
CONTENTS DELETED
The author has deleted this message.
|
In reply to this post by Kok Chen
There's another warning sign in the text accompanying the video. My
pseudoscience alarm went off when I read the following: "SPAWAR Systems Center Pacific has developed a technology that uses the magnetic induction properties of sodium chloride (salt) in sea water to create UHF/VHF/HF antenna." This is meaningless jargon...magnetic properties of salt or salt water have nothing to do with it. The aforementioned alarm is always triggered by "magnetic" being used in conjunction with "antenna." 73 and thanks for listening, Carl WS7L K3 #486 > -----Original Message----- > > > This will go nicely with my K3 > > http://www.youtube.com/watch?v=9tIZUhu21sQ > > Seawater has electrical conductivity of seven *orders* of > magnitude lower than copper! > ... > ... > This could make a good water heater. All that power has to go > *somewhere* :-). ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
In reply to this post by Kok Chen
Actually, a pretty casual Google search will turn up homebrew designs using a can of high-concentration salt water as an inexpensive (though not very stable) dummy load. And that's pretty much what the salt water "antenna" would be. 73, Dave AB7E On 10/17/2010 11:30 AM, Kok Chen wrote: > On 10/17/2010 1:40 AM, Jan Erik Holm wrote: > >> This will go nicely with my K3 >> http://www.youtube.com/watch?v=9tIZUhu21sQ > Seawater has electrical conductivity of seven *orders* of magnitude > lower than copper! > > As a quick and dirty check, I created a simple 10m ground plane > antenna in NEC-4. Four counterpoises and a vertical radiating element > that is bottom fed, all of equal lengths, with the counterpoises and > the feedpoint 1m above seawater (natch!) ground. All elements 0.5" in > diameter. > > With perfectly conducting elements, the feedpoint impedance is just > about 35 ohms, with a gain of 4.7 dBi. > > When I changed the conductivity of the vertical element to 5 mhos/ > meter, while keeping the counterpoises as perfectly conducting, the > computed gain dropped to -8.2 dBi and the feedpoint impedance is > capacitive at 320 -i*250 ohms. > > I.e., something like 13 dB loss compared to using copper elements. > > BTW, I could not achieve resonance by extending the length of the > radiating element -- I guess you will need a KAT500 in addition to > that KPA500 which you use to make up for the missing 13 dB. > > This could make a good water heater. All that power has to go > *somewhere* :-). > > 73 > Chen, W7AY > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
Free forum by Nabble | Edit this page |