[TowerTalk] Fwd: RG-149: 50 ohm/70 ohm - does it matter?

[Hans Hammarquist]

If you have a true 50 ohm load and a 75 ohm feeder you may end up with an SWR of 1:2, which many SS amps can't handle. That's the worst condition.


I am using 75 ohms myself and rarely run into problems. (That's what the tuners are for.) An "old" tube amp with a pi-filter can tolerate an SWR of 1:2 without problems.


If you have any problems, just call in the North Seeking Plast Owl". :) I do that all the time.


Hans - N2JFS



-----Original Message-----
From: kr2q <kr2q at optimum.net>
To: towertalk <towertalk at contesting.com>
Cc: towertalk <towertalk at contesting.com>
Sent: Fri, Dec 13, 2013 7:52 am
Subject: [TowerTalk] RG-149: 50 ohm/70 ohm - does it matter?


Hi....

I work in hospital administration.  My ugrad degree is in Biology and my masters 
degree is in healthcare administration.  In other words, I'm no engineer.

However, I took a look at Mikes home page and it seems like he has a "simple" 
antenna setup (ie, no stacks = no phasing concerns).

So what's the diff if it's 50/52/70/75 ohm feedline?  The mismatch (if not 50) 
will be "nothing" and therefore the extra loss will be "nothing."  Transmission 
line is always transmission line.  As long as the line itself is not "lossy," 
does it matter?

Looking for sage advice for those with degrees or prowess in this area.

de Doug KR2Q
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