RFI From SteppIR SDA100 Controller

[Jim Brown-10]

I've been chasing a very strong, very elusive set of drifting birdies.
They were strongest on 12M, but also were present on 15M and 10M.  
Nothing affected them until I unplugged the power supply for the SDA100,
at which time they went away, and the overall noise on the band dropped
by at least 10dB.   This crap radiates  into every antenna I've got.

I've managed to attenuate this crap by at least 20 dB using chokes on
the cable that runs to the antenna, the rotor cable, and both the 120VAC
and 33VDC cables from the power supply.

If you've got an SDA100 (that's the newer, higher voltage controller),
you might want to check this.  15dB is a LOT!  The best way to see
what's going on is with a panadapter set pretty wide so that you see
birdies drifting slowly up and down. I'm using a P3.

73, Jim K9YC
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[Joe Subich, W4TV-4]

Jim,

Are you sure it's the controller and not the power supply
("brick")?  The original controller had similar reports -
usually tracked down to the 33V ("high power") switching
supply.

I'd suggest checking with Mike or John Mertel at SteppIR
about a replacement power supply.

73,

    ... Joe, W4TV


On 3/9/2011 5:43 PM, Jim Brown wrote:

> I've been chasing a very strong, very elusive set of drifting birdies.
> They were strongest on 12M, but also were present on 15M and 10M.
> Nothing affected them until I unplugged the power supply for the SDA100,
> at which time they went away, and the overall noise on the band dropped
> by at least 10dB.   This crap radiates  into every antenna I've got.
>
> I've managed to attenuate this crap by at least 20 dB using chokes on
> the cable that runs to the antenna, the rotor cable, and both the 120VAC
> and 33VDC cables from the power supply.
>
> If you've got an SDA100 (that's the newer, higher voltage controller),
> you might want to check this.  15dB is a LOT!  The best way to see
> what's going on is with a panadapter set pretty wide so that you see
> birdies drifting slowly up and down. I'm using a P3.
>
> 73, Jim K9YC
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> [hidden email]
> http://lists.contesting.com/mailman/listinfo/towertalk
>

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