That's what so nice about an AIM. It gives you all that and more on one
screen with overlaying graphs.
Take a multiband vertical and all the bands show up, or adjust the span
to look at each band. You can check the antenna and feed line from the
shack and if properly calibrated you can see just how many feet to any
discontinuity. Problems with a connector? Again, it's right there on
the screen. IOW, Generally you can trouble shoot the whole works right
from the shack.
73
Roger (K8RI)
On 11/8/2016 Tuesday 3:31 PM, Guy Olinger wrote:
Modern toys, that's what happened.
But there are some emerging, very efficient antennas where the old methods
can't possibly tell you enough to know what to do to tune it to an
efficient spot. They have tuning problems where you need to see separate
graphs of the R and X components coming to the instrument, where just plain
SWR can (and has) take one off on a wire-pruning wild goose chase.
Kind of like your car's oxygen sensor and computer controlled fuel
injection that reduces pollution from the tailpipe and improves gas
mileage. I remember tuning dual carbs for max revs, and other stuff. Now
you plug car into a computer at the dealer via a socket under the hood and
the computer tunes it up for you.
But I guess I like driving around in our mid-sized Ford Fusion Hybrid
sedan, that gets 36 mpg with my wife's awful 2 mile round-trips to Target
on a cold engine driving patterns, and gets 40-45 mpg with steady highway
driving, once 55 with a strong tailwind.
That worst case 36 mpg is better than we got with our 1965 VW Beetle, which
barely had enough HP to get up some roads in the mountains.
I do like being able to squeeze out the last 0.3 dB of antenna efficiency
with the modern instrumentation.
When I get nostalgic, I can fire up my Johnson Ranger, Collins 75A3 and
Johnson Courier amp. I can watch the ghostly blue flickering of the 866
rectifier tubes in the Courier, and remember how dreadfully exciting it all
was as a teenager.
73, Guy K2AV
On Tue, Nov 8, 2016 at 1:16 PM, Rob Atkinson <ranchorobbo@gmail.com> wrote:
You guys sure know how to take the fun out of something. What ever
happened to the time honored method of going out to the feedpoint with
a SWR analyzer, plastic cutting board, fist full of clip leads, an
assortment of coils and air variables, and playing with the toys until
some transformation to 50 ohms is achieved?
73
Rob
K5UJ
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
--
73
Roger (K8RI)
---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|