You should think about this in terms of target frequencies.  What frequency 
gives the lowest SWR on your current dipole?  Where do you want your lowest 
SWR to occur in the future?  My 80 dipole is resonant around 3650, which is 
great for CW and the DX and contesting that I usually do.  But even though 
my FT950 has a limit of 3:1 on its tuner's automatic range, I can still put 
out enough of a signal to check into the Iowa SSB net on 3970, and the tuner 
doesn't complain.If you can determine these frequencies, just multiply the 
current length of each half by the inverse of the ratio of the frequencies. 
It might be 2 or 3 feet on each half of the dipole.



Lloyd Rasmussen, Kensington, MD
http://lras.home.sprynet.com
-----Original Message----- 
From: Lou Kolb
Sent: Monday, March 03, 2014 2:14 PM
To: [log in to unmask]
Subject: Re: 75 and 80 meter bands

Fred,

As I understand it, essentially, 75 meters refers to the upper half and 80
to the lower. But its the same band. Usually to figure antenna lengths you'd
need to know frequency in megahertz, not wave length in meters. So what
frequency are you planning to operate?  73, Lou  WA3MIX
Lou Kolb
Voice-over Artist:
Radio/TV Ads, Video narrations
Messages On-hold:
www.loukolb.com
----- Original Message ----- 
From: "Fred Adams" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Monday, March 03, 2014 1:37 PM
Subject: 75 and 80 meter bands


> Could someone refresh my memory as to where the 75 meter band ends and the
> 80 meter band begins.  I have an eighty meter dipole that I would like to
> shorten  for the 75 meter band and I want to know about how much I would
> have to cut off if I decide to do it.   Thanks much,