I have been following this thread and find it very interesting, particularly
as a Mechanical Engineer I have to read it slowly but may I comment --
1, I don't know the details of Icom's protection system, but the ones I have
seen sense reflected power, well actually it will be the voltage detected at
the sensor against an assumed impedance of 50 ohms (50+j0). The actual SWR
at which the protection will come into play will be a function of feedline
impedance (which will, in practice, have a reactive element), feedline
losses, antenna impedance and efficiency. -- If it's a problem - just add a
few feet of coax!!
2, It shows an underlying belief in SWR as the be all and end all of antenna
systems.
3, Many years ago now I had the opportunity to visit the main Naval
transmitting station in the UK. Utilising frequencies from VLF to VHF their
antenna systems were out of this world. But the majority were fed with 600
ohm open line across many kilometres of open ground. I recall one of our
guys asking about SWR. The station chief just shrugged. One of the main HF
transmitters was opened for maintenance and contained a large number of
4CX250 valves connected in parallel - not the easiest valve to run.
So what should we be doing; as an instructor I see and hear a hell of a lot
of myths about SWR and do try to correct them within my own understanding of
the subject. But I do have to hand it to those who fully understand the
subject and who take the time to explain it at the level of our examination
system, which cannot be easy.
Perhaps we should send this to the mythbusters and see if thay can blow it
away!!
Anyway, I am now going to browse my RadCom back numbers for a revision
session.
73
Peter
GM8GAX
K2 #04027
P.S. My Mechanical Engineering comment was to give you Electronic and Radio
Engineers a little laugh. I can read as fast as you, any slowing down now is
due to age, eye sight etc.
_______________________________________________
Elecraft mailing list
Post to: Elecraft@mailman.qth.net
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com
