I have a great idea don't use the proper cable at all just use the cheapest
piece of junk and try to justify it. The fact of the matter 1.5 does
matter.For example Icom radios fold back when seeing a swr of 1.5 to one.
CHEAP is not a reason to use something yes it will work so what. Is it the
proper cable to use no. Rg6 gives you a starting loss at 1.5. Rg 59 will
work to on 75 meters it will even handle some power would I use it No.
Good luck using the wrong cable. We don't have pi networks any more.
Solid state devices want to see the proper load. They arn't rated 50-75
ohms. Yes it will work so will a coat hanger with a tuner as antenna.
----- Original Message -----
From: "Don Wilhelm" <[EMAIL PROTECTED]>
To: "Samuel Strongin" <[EMAIL PROTECTED]>
Cc: "DOUGLAS ZWIEBEL" <[EMAIL PROTECTED]>; <[email protected]>
Sent: Tuesday, November 13, 2007 9:10 AM
Subject: Re: [Elecraft] OT: pwr rating of RG6, etc
You use it because of 2 characteristics. 1) It has lower loss than an
equal physical size 50 ohm cable - and that is true even considering the
added loss due to mismatch. 2) It is conviently available and
inexpensive.
Considering the added loss due to a 1.5 SWR, look at the charts. If the
matched line loss is 2 dB, the loss when the SWR is 1.5 is only 2.1 dB.
Even if the matched line loss is 10 dB, having an SWR of 1.5 adds only 0.2
dB to the total loss. A 1.5 SWR is insignificant when considering line
loss, especially at HF.
The facts do not support the popular view that an SWR any higher than 1.0
is a bad thing. In most cases, a transmission line SWR of 2.0 or below
will work fine.
Now, there is another part to consider - the feedpoint impedance at the
output of a transceiver may have to be transformed to something closer to
50 ohms for proper, full power operation of the PA - but that is the job
of a tuner, it has nothing to do with feedline loss beyond the tuner.
Unfortunately, these two parameters get mixed together and the result is
'numerical soup'.
73,
Don W3FPR
Samuel Strongin wrote:
RG6 is 75 ohm cable. Why would you buy a great radio and worry about
performance,then go use the wrong cable. You start out at a 1.5:1 swr.
Idon't get it.
kf4yox
_______________________________________________
Elecraft mailing list
Post to: [email protected]
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
