On 7/18/2012 5:45 PM, Ian White GM3SEK wrote:
> Jim Lux wrote:
Thanks all for the input and to Ian for the "white paper" on comparisons
of the different units.
I ended up ordering the AIM 4170 and am going through the software and
operating directions getting ready for its arrival, probably Tuesday.
I'm thinking seriously of the AA230 Pro as well as I/We do a lot of work
out at the antennas and up on the tower.
A while back some one asked me why I considered the MFJ unit as
inadequate. I apologize for not answering sooner, but I'll start by
saying my reasons may not be the same as others. First it eats
batteries like crazy. The shape and size is inconvenient for me to
carry up towers while the AA230 is much more like the commercial units.
Also the MFJ does not show the sign of the reactance.
I do find the MFJ very handy to setting up the antenna tuner. I have an
Alpha Delta 3 way coax switch Left is the analyzer to the tuner. It's
very handy for looking at the absolute value of X and adjusting for
minimum X and SWR. Knowing the sign would speed things a bit. The center
position is ground and the right position connects the rig to the tuner.
So when changing bands I can crank in the roller inductor, adjust the
tune and load, switch to the rig and I'm in business.
One of the things I really like about both the AIM470C and the AA230
Pro is they can be set to scan a range of frequencies. This is
extremely handy on multi band antennas. Some times (Like my AV640) I
have multiple resonant points for a band. (I didn't when it was working
correctly) Both will show me a graph of the swr and the frequencies of
the resonant points, IF I set the scan wide enough to include all the
points for a particular band. To top it off I can get a picture of the
entire antenna "system" using the TDR function.
One really neat function is setting up the AIM 4170 with the "air
feature" and using a lap top out at the antenna. IOW I can make changes
at the antenna and see what happens to the whole system.
On the multi band vertical I can set it up to look at the SWR on all
bands at the same time.
Another thing is saving traces (or scans) and comparing how nearby
nearby antennas affect the system.
This is just a sample of what I can do with the antenna systems. The
AIM 4170 will also work with components AND it gives me the sign and
amplitude of reactance, not just the absolute value.
At present I see a fair learning curve because the 4170 is capable of
far more than I am.
I do think that the combination of the AIM 4170C and the AA230 Pro would
give a set of instruments our club could use to help out solving those
*difficult* antenna system problems as well as possibly building
components.
Unfortunately it's supposed to get *HOT* again starting tomorrow with
Sunday near 100. So it's going to be antenna work early in the mornings
and I'm not a morning person, or in the evening when I have to fight
mosquitoes, black flies, and deer ticks (meaning long sleeve shirts)
At any rate maybe I'll know how to use the basic functions by the time
it gets here.
Next comes a spectrum analyzer but I'll wait on that until I get this
stuff working.
73
Roger (K8RI)
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