Yes, I was referring to customizing the lengths of the driver based on SWR
and using a built in fine and gross tuning routine and not on the homing
routine, which is easy to do. I don't have that handy, but you can both
change the actual lengths and you can tune live and if you mess it up, can
always reset to default lengths
In my extensive conversations with Mike Mertel, parasitic and reflector
lengths are not so critical as a result of small dielectric constant
difference and unlikely makes any significant impact on ACTUAL performance.
I would focus attention on re-adjusting the driver to SWR, which is what I
did with a quite a great deal of precision. Once readjusted, it worked like
a charm
M
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of VR2BrettGraham
Sent: Wednesday, November 29, 2006 4:31 PM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] SteppIR Wind Damage
K3MH suggested about SteppIR tubes & lengths:
>Have you tried the re-calibration routine to re-set the element lengths? I
>changed tubes and also upgraded my controller 6 months ago. I apparently
>had one of the first Steppir versions. You can alter the default tuning
>lengths of the driven and other elements.
Calibrate just runs the motor(s) long enough that the
strips can be assumed to be fully retracted & therefore
extended from a known state to a known length.
Yes, you can change the element lengths yourself, but
what length to use on a parasitic element with one
new tube & one old one?
As K8IA noted, the difference on a driver can easily be
dealt with - at least based on where the SWR meter is
along the feeder.
On a parasitic element, finding the correct length for the
particular tubes being used might not be so easy.
The failure K6DGW QSPed earlier reminded me of thinking
about this when the new tube mystery first surfaced. A total
tube replacement is a no-brainer - you end up with all tubes
of type same & firmware with dimensions for those tubes.
I hope somebody somewhere might benefit if they stumble
across this post, but unless the mixed tubes are on a driver,
I suspect most users will not notice to begin with - a 100 kc
or two shift in SWR curve can be seen from shack & is
probably being actively monitored by the user. The change
in gain or pattern if a parasitic shifts that much is a bit more
subtle & is not being watched for so closely (if at all).
73, VR2BrettGraham
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