Spurious RF Spikes on Every Band

Randall Steffens II

Hi All, I just got my flex 6300 and I'm having strange spurious RF spikes on every band. I inserted a few pictures below.  Does this look like a power supply problem?  I'm using the MFJ 4230MVP switching power supply.  I don't have ferrites on anything yet, would that help?

I'm using a 60 foot center fed dipole fed with 450 ohm ladder line. And an old MFJ-941C manual tuner because the internal flex autotuner can't handle this antenna.  The birdies get much smaller or even disappear on most bands when I fully “detune” the antenna with the manual tuner.  But when tuned, there are tremendous spikes in every band as shown in the photos below.

One problem may be that I live in an apartment and cannot connect any RF/AC ground to the radio.  The switching power supply is grounded through the AC wall plug, but nothing else so far.

 If you'd be so kind, take a look at the screenshots below and let me know your thoughts.  Some bands it's less obvious than below, but this pattern is visible to a greater or lesser degree on every band once that band is tuned. 

Thanks! Randy Steffens

Mike

That looks like a cheap Chinese power supply. I would start unplugging things and see if it disappears

Steve WS5W

I agree with Mike, In an apartment it can be your neighbors p/s also. look for battery chargers (hand tools  and motorized scooters ...) anything with a wall wart or brick p/s. 
Steve 

Randall Steffens II

Yeah, it was cheep. But it had good reviews on Amazon and eham!  I'll see if I can turn off my breakers and isolate if anything else in my apartment could be causing this. 

WK2Y

Try running on a battery if you can.  In receive, the Flex doesn't draw much current.
That will clearly identify if the power supply is the culprit.

Steve WS5W

I had a stack of networking equipment that was puttong lot of noise on the to the a/c. This between the stackand the UPS cleaned it up.
https://www.arraysolutions.com/ac-7a?search=ac%20filter

Steve WS5W

And a SDRPlay and a laptop are great for RFI hunting,

Ken - NM9P

The MFJ PS is usually pretty clean so my bet is some other power supply. That particular pattern looks like my wife’s laptop computer power supply.

Someone from Flex, either Tim or Dudley, once told me: “ The great thing about the SDR is that you can see everything on the band. The bad thing is that you can see EVERYTHING on the band — even all the crud that you never noticed on a legacy rig. “

You will find that you now can see exactly why electronic pollution is a big issue for a lot of folks!

Dave - WB5NHL

Regarding your grounding situation, checkout this web site. Lots of good info. I have used 1/4 wave counterpoise per band very successfully. http://www.radioworks.com/nbgnd.html

It is hard to see....  what is the spacing of the pulses?

Randall Steffens II

It's approx.  every 40 kilohertz or so.

I'll check the site!  Thank you!

Randy

Randall Steffens II

Very interesting Ken.  Thanks for the feedback.  I'll see what I can unplug - then test again.
Randy

Randall Steffens II

Thanks for the recommendations Steve. Would an RTL-SDR work as well for this purpose as the SDRPlay?  It's significantly cheeper! 

Thanks!
Randy

Randall Steffens II

I'll see if I can use my car battery to test it out.  

Thanks!

Randy

Steve WS5W

If it does HF, I dont remember how low it goes.

Bob G W1GLV

My air conditioner produces those spikes when it's running. Had to install a filter to get rid of them. I live in Florida.

Rhett Aultman

My cable modem throws off birdies, so I've been looking for something like this.

Michael Coslo

If those spikes are like that on every band, do a reset of the radio and see what happens.

Andy - KU7T

My heat pump does exactly that. Make sure you turn that one off first and verify (I guess flipping breakers will force you to do that). It maybe your neighbor's too. Andy KU7T

Randall Steffens II

Yes, very useful!  Thanks!

Randall Steffens II

I'll definitely check that.  Thanks for the suggestion Bob!
Randy

Randall Steffens II

I'll check on that.  Thanks for the suggestion!
Randy

Randall Steffens II

Ok - I'll try that.  Do I reset by pressing the power button on the radio until the blinking white light appears?
Randy

David Ahrendts

Randy, I would try a few things.
1) Cannot speak to the integrity of the MFJ PS -- Powerx gets superb reviews -- but consider swapping it out with a loaner PS to see if that's your problem. Switching power supplies are often the culprit.

2) Pay close attention to every cable in and out of your Flex, especially the cable delivering 12VDC to your Flex. If you're using black-red zip line with Anderson Power poles (which are great for certain applications), know that the zip line is very susceptible to RFI -- it's like a little antenna just scooping up RF and delivering it to the radio. Solution: use SHIELDED twisted line cable which you could still use with Anderson Power Poles if you want. The people who strung the first telephone lines learned this lesson: twisted cable pair discourages RFI. Shielding with all cables recommended.

3) You could try the MFJ AC line filter, https://www.mfjenterprises.com/Product.php?productid=MFJ-1164B -- but be aware you really need an Earth ground to make it 100% effective. I have two

4) Buy a ton of ferrite beads. Clamp-ons work well. Use them on every cable -- coax, audio, CAT6/7.

5) On CAT cable, in my system RFI hunt, I discovered one of the nosiest devices near my Flex was my D-Link switch which manages a dozen devices within 3-feet of the radio. So this  noise-maker had 15 CAT6 cables just radiating noise. I changed every CAT6 cable to CAT7 which is heavily shielded CAT6, and added some clamp on ferrite to many of the cables especially those close to the Flex. Solved that noise.

6) One of the biggest noise makers around my Flex was the LG monitor. I love LG. There's a 4K 55-incher in my living room. But, with the Flex, the LG used a wall-wart switching power supply with an unusual 24VDC output that produced very heavy RFI near the Flex, so I could not add it to my highly filtered 12VDC West Mountain Radio Rig Runner  -- http://www.westmountainradio.com/rigrunner.php  -- powered by a Powerwerx PS. So I switched to a Samsung which had a more standard 12VDC system, dumped the Samsung wall-wart, and connected TWISTED PAIR and SHIELDED cable to the RIGrunner/Powerx. Noise solved. In fact, I run two monitors with the FLEX 6500. Gaming monitors -- very fast.

7) A common RF sniffing tool is an aircraft band radio which is AM roughly 108-130 MHz. Squelch it wide open and go hunting around your apartment. I had a Yaesu HT that had aircraft band. It's a real eye opener what makes RF noise. 

8) And finally, look for obvious things like touch lamps made in China which are not Part 15 approved. Huge noise makers. Others: old plasma TVs, fluorescent lights, fish tank motors, etc. Someone once traced a ton of RF to an old coffee maker with an arcing connection to the heating element! Brought down the entire neighborhood.

Good luck. Any of these steps may help reduce that noise for you. Been there. Conquered it. 73s.

David Ahrendts, KK6DA, Los Angeles
   

Craig Williams

Nice link, thanks.

Craig Williams

I bet if you put one of these in a grounded metal box it would help. Also torroid's on all the control cables. https://enerdoor.com/products/view/fin33-single-phase-rfi-filter 

Randall Steffens II

What a useful post!  Thank you David!  I really appreciate this advice.
Randy

Dave - WB5NHL

At this rate I'd be looking for a poorly filtered switching power supply or wallwart. Good luck   let us know what you find.

Vox Deus

Yup.

Randall Steffens II

Just thought I'd update everyone on this!  The problem turned out to be that cheep MFJ power supply!  Thanks so much for your input.  I replaced it with an old Astron linear supply bought used on Ebay and things are FAR better.

But now another smaller repetitive widespread spike is evident, it's approx. every 60 kilohertz - and is especially obvious from about 14-26 megahertz.  

If I zoom in on the spike, its obvious that each spike is made up of about 5 smaller spikes close together.  See the photos below.

I switch off all the breakers in my house except the one powering the radio, and it's still there.  Also, it's not intermittent - it's there all day, and all times of the day. 

Anyone have ideas about what might be causing this?

Thanks!
Randy

Here are a couple samples of the signal I'm seeing scattered around different bands. 





Here are two, close-up zoomed views of one of those signals. 

Stan VA7NF

Welcome to the best and worst thing about the 6000 series - The panadapter.  Now you can see what is out there

Make a directional wire loop (Optional: with a ferrite rod for the low bands) and start sniffing

Randall Steffens II

Thanks for the reply! What material did you read to get details on how to build the wire loop? I see a lot on google, but if there are any particular books or websites you’d recommend on the subject, that would be great to know. Thanks again, Randy