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Dressler ara30

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mike lee

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Jul 4, 2009, 12:58:38 PM7/4/09
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Hi all I use an Dressler ARA 30 active antenna, how ever the PSU that I
used to power it 12V has gone belly up and in doing so it has melted a
resistor inside the little box that comes with the antenna.
Inside the box are 2 caps and 1 resistor, I can not get any colour code
from it due to the damage so I cant simply replace it.

Does any one know what this resistor could be please?

TIA,

Mike.

RFI-EMI-GUY

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Jul 5, 2009, 4:56:45 PM7/5/09
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Could very well be an RF choke that happens to look like a resistor. Are
you sure the preamp itself is not fried?

--
Joe Leikhim K4SAT
"The RFI-EMI-GUY"�

"Use only Genuine Interocitor Parts" Tom Servo ;-P

Dale Parfitt

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Jul 5, 2009, 8:41:24 PM7/5/09
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"RFI-EMI-GUY" <Rhyo...@NETTALLY.COM> wrote in message
news:4a511350$0$11818$9a6e...@unlimited.newshosting.com...
I agree with Joe- the preamp may have gone west. Some power inserters do use
a series resistor- but more often a choke. The only reason for it to burn up
would be excessive current draw by the preamp- or a kinked and shorted
feedline.
Put a VOM across the preamp input and see what the input resistance looks
like. Tantalums on the input often short when exposed a surge.

Dale W4OP
Dale W4OP


RFI-EMI-GUY

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Jul 5, 2009, 9:24:57 PM7/5/09
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The only case I could see where it might be a resistor is if a MMIC like
a MAR-6 is the amplifier device. In that case calculating the resistor
would be easy per the device spec sheet. It doesn't look like Dressler
has published a schematic, so some reverse engineering might be in order.

--
Joe Leikhim K4SAT
"The RFI-EMI-GUY"�

"Use only Genuine Interocitor Parts" Tom Servo ;-P

Dale Parfitt

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Jul 6, 2009, 2:10:08 AM7/6/09
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>> I agree with Joe- the preamp may have gone west. Some power inserters
do use
>> a series resistor- but more often a choke. The only reason for it to burn
>> up would be excessive current draw by the preamp- or a kinked and shorted
>> feedline.
>> Put a VOM across the preamp input and see what the input resistance looks
>> like. Tantalums on the input often short when exposed a surge.
>>
>> Dale W4OP
>> Dale W4OP
> The only case I could see where it might be a resistor is if a MMIC like a
> MAR-6 is the amplifier device. In that case calculating the resistor would
> be easy per the device spec sheet. It doesn't look like Dressler has
> published a schematic, so some reverse engineering might be in order.
>
> --
> Joe Leikhim K4SAT
> "The RFI-EMI-GUY"�
>
The resistive voltage divider/ isolator was fairly common in some of the LF
power inserters- Burhans et al:
http://members.shaw.ca/ve7sl/burhans.html

Dale W4OP


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