SteppIR Power Suplies and Noise

MIchael Ryan

I have just begun the use of two SDA-100 SteppIr control boxes with my 6700. The second I plug one of the power supplies in, there is switching power supply noise evident on the spectrum. I have tried several different 33v supplies and all have some level of noise. I chose to experiment with the one with the least evident. I clamped on several mix 31 cores on the 33v end of the power lead and also a large F240/Mix 31 core with 9 turns on the 110v end of the power lead of the supply. This made no change in the noise level. Has anyone had trouble with the actual CONTROL BOXES making noise? Any other suggestions on how to eliminate this noise from either the supply or control box?

LarryF

Hi Michael Try to put some cores on your data cables. Is there a reason you are using the 33v supply, or is that the standard now? I have the 24v Good luck and be safe Larry ke2yc

GM7VSB

Just a thought, but it's definitely the PSU making the noise and not just the noise floor coming up as you power on the SteppIR and it makes the relays?

Mack

Michael, Yes, the 33 V SteppIR bricks do generate RFI. I find them most objectionable on 160 and 80M. I have two SteppIR Yagi antennas. One uses an SDA 2000 and the other a SDA 100 controller. I found that most of the RFI was entering my radio via my 8 element active receive array antenna. Upon trouble shooting the antenna I found several of the receivers had RFI damage from nearby lightning strikes. Upon repair the SteppIR RFI as gone. So, I recommend you carefully look at your antenna for improvements you can make. I’ll bet you don’t have RFI when connected to a dummy load with a short length of high quality coax. Others who can’t or won’t improve their transmission line or antenna have used HP Printer 33V power supplies which are very RFI free. They can be found on eBay. I hope this helps some. Good luck. 73, Mack W4AX Alpha Team

MIchael Ryan

I have several of the HP power supplies here, which I sought as they are the correct voltage and almost exactly the current requirement (or at least the suggested). They are so noisy I set them aside completely and I am using something else given to me by a friend who is in the medical supply business. The HP units I could not consider at all. I have placed clamp on cores (4 in fact) on the 33v lead and as I indicated an F204 on the 110v side, No perceivable difference so I will look at other possibilities such as you have suggested. I do not have in line at the moment a recv antenna though during the low band season I employ a Pixel loop which is now stored in the garage. The noise is easiest to see with NO antennas connected. I can even see noise from the pc monitors in the shack which when turned off of course, that disappears from the spectrum. I may the F204 cores on the A/C line to the monitors and perhaps the feeds to the computer themselves. -Mike

KD0RC

If you are seeing the noise with no antenna connected, I would guess that the noise is being conducted rather than radiated. Perhaps grounding everything would help (may not be practical with a small power supply). Some .01 uf caps across supply and control lines might also reduce the noise. 73, Len, KD0RC

Alan

Michael. -  Were you able to isolate and/or fix your SteppIR power supply noise issue?

I have recently put up a BigIR vertical with the SDA-100 controller and wanted to see if I have the same problem?

Alan
WA9WUD

Steve G1XOW

Alan

Steve G1XOW

Alan,

I can't remember exactly but it looks like an unstable wavering carrier that tends to march slowly up and down the bands. I recall that 80m and 20m were the most obvious. There was also a slight raise in the noise floor but that was hardly noticeable. I now use a linear DIY PSU and ferrite with 8-10 turns on every cable into and out of the controller as close to the connectors as possible.
Hope that helps
73 de Steve G1XOW / M1C

Alan

Thanks Steve

Alan