[TowerTalk] RFI From SteppIR SDA100 Controller and PSU

[Jim Brown]

Note this from Ron.  What this means is that you cannot use a DB-series 
SteppIR as an RX antenna for this test, because killing power to the 
controller essentially disconnects the SteppIR from the feedline.  So 
you must listen for noise with some OTHER antenna when you're making 
this test with a DB-series SteppIR.

A portable radio that can listen to the HF bands makes an excellent 
probe for RF noise. I use a Kenwood TH-F6A and a Tecsun PL-380 for this 
purpose. Fire up the stuff, move the radio around wiring connected to 
the suspect equipment. When you hear noise, suspect that equipment.  
Noise is radiated by wires carrying that RF noise current, and received 
by our antennas.

73, Jim K9YC


-------- Original Message --------
Subject: 	RE: [NCCC] RFI From SDA 100 Controller and PSU
Date: 	Mon, 25 Nov 2013 15:32:39 -0800
From: 	Ron Castro <ronc at sonic.net>
Reply-To: 	<ronc at sonic.net>
Organization: 	Results Radio, LLC
To: 	<k9yc at arrl.net>, <SteppIR at yahoogroups.com>



Jim:

I would add that if you are using any of the SteppIR DB series antennas,
cutting the power will cause the relays in the coax switch to disconnect the
main coax from all of the elements.  Also, the relays in all of the possible
driven elements will 'normal' to passive, shorting the center insulators.
That makes testing for RFI from the controller almost impossible, although
if you can isolate the conductor that activates the appropriate relays (I
think both the switch and passive/active relays in each element use the same
control wire) and apply voltage to it from a linear supply, you can test it
that way.

        Ron Castro
            N6IE
     www.N6IE.com

Member:
                       ARRL
      Redwood Empire DX Assn.
  Northern California Contest Club
Northern California DX Foundation

-----Original Message-----
From: NCCC [mailto:nccc-bounces at contesting.com] On Behalf Of Jim Brown
Sent: November 25, 2013 3:04 PM
To: SteppIR at yahoogroups.com
Subject: [NCCC] RFI From SDA 100 Controller and PSU

Two more of my local friends (W6GJB and W6OAT) have narrowed down severe RF
noise to their SDA100 controller. The PSU, a VERY noisy switching PSU, is
the major offender, but the controller itself also puts out some noise.

If you are experiencing RF noise, turn off your SDA100, unplug the PSU from
the AC line, and listen carefully on all bands. You'll need to tune the
SteppIR to each band, one at a time, before powering down the controller.
If you SteppIR is a beam and far from the shack, point it directly to the
shack before doing your tests.

SteppIR send me a relatively quieter replacement for my 33V supply, but I
still heard it on antennas that are close to my shack (especially on 160M),
so I've gone back to a vintage home brew linear regulated power supply that
I bought from the estate of a neighbor ham.  That PSU, of course, is dead
quiet, but I still hear noise on 160M on the vertical that's right outside
the shack. Hence, when I'm on 160M, I have to kill power to the SDA100.

73, Jim K9YC