Thanks Ron -
The motor on the driven works fine, at least it did on the ground. One other
anomaly
is that on the ground an analyzer showed a dip at around 6.5 Mhz with the
antenna set
at 7.150 Mhz, which SteppIR said was what to expect. In the air, the analyzer
doesn't read a dip anywhere.
The beginning of the problem was that the tapes had jumped the reels and one of
the
holes in the tape had snagged on a wire joint on the balun. So I replaced the
motor,
and the jumper from the motor to the turning loop. I think it's that piece of
coax,
specifically the connector at the motor. The driven reads about 3 ohms at the
radio
end of the coax.
There are 2 bad driver chips in the controller, but the driven is OK. I have a
board
at SteppIR getting new chips.
At the rate cranes and climbers go for, minor it's not. 2 trips so far, looking
at 2
more; :-$
73, Mike
On 5/6/2011 9:13 AM, w4lde wrote:
> Mike,
>
> When I connect only the center pin of any coax fed antenna I usually get
> more noise since the cox becomes an antenna and this includes the SteppIR.
>
> Since its a new motor and balum did you do a test of the wiring
> including running the element tape out a few inches per the test
> recommendations by SteppIR and confirm the element is wired and working
> correctly?.
>
> Did this just happen (high SWR) or did it occur after the new motor and
> balum installation?. What resistive readings are you getting on the
> driven element? Can you read voltage changes on the output from the
> controller when you command the change at the controller?
>
> It's hard to give a WAG without some additional info. Hope it's a minor
> problem to fix.
>
> 73 de
> Ron W4LDE
>
>
>
>
> On 5/5/2011 6:37 PM, Mike wrote:
>> Thanks, John -
>>
>> I'm going with the coax theory for now. It's a new motor and balun, so
>> hopefully
>> that's OK.
>>
>> 73, Mike NF4L
>>
>> On 5/5/2011 5:52 PM, john@kk9a.com wrote:
>>> It sounds like your coax is not connected to the driven element. It could
>>> be a dead balan, bad connection or that the DE is fully retracted (if that's
>>> possible with a SteppIR).
>>>
>>> GL
>>> John KK9A
>>>
>>>
>>> To: towertalk reflector<towertalk@contesting.com>
>>> Subject: [TowerTalk] Interpreting symptoms
>>> From: Mike<nf4l@nf4l.com>
>>>
>>> My SteppIR is exhibiting high SWR at all frequencies. Varying the length of
>>> the
>>> driven element does not affect it.
>>>
>>> If I plug only the center conductor of the coax into the rig the noise level
>>> is
>>> much
>>> higher than when the shield makes contact. Any SWAG's as to what this means
>>> the
>>> problem likely is?
>>>
>>> 73, Mike NF4L
>>>
>>> _______________________________________________
>>>
>>>
>>>
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>>
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