i have had the KiwiSDR2 for a couple of days.... and
Hello,
Was hoping to get some help from the community. It has been working fine for a few days running on a Magnetic Loop WV-601 + Lana HF V2 ULNA from inside my condo. Over the past day or so, it has been degrading more and more. At first i though it was some interference, but it now is present across the entire 30mhz... i have been trying to track down sources, tried a different antenna and cables and always the same. by looking at this image, can you see what a likely culprit this could be? i have the apple power source and it is the same with other good usbc ps i have tried. tried and different lna and no dice.
Comments
How are you powering the loop amplifier ?
It is difficult to tell from your screen grab, but are there any really strong signals present that could be causing ADC overload ?
If you tune to an unoccupied part of the spectrum and listen using AM, what does it sound like ?
Can you take another grab, but with the waterfall gain set to manual, -20dBm max -110dBm min and include the spectrum display too.
Regards,
Martin
Thank you Martin... i will do so this evening. i did find a wifi extender that has an ethernet port to see if i could get the Kiwi further away from my main wifi router... the results are teh same... even with an extra long ethernet cable (cable also with a nice donut ferrite). I will take another image this evening like requested. i'm leaning towards a power supply issue. does the pattern shown above indicate ANY potential issues with the Kiwi itself? Sam
Really need to hear what this sounds like. From the waterfall I'm guessing this is some sort of arcing resulting in wide-band RFI. Like from power line problems. But really need to listen to tell. Is it available from the Internet via its serial number?
yes, it does seem like arching to me.... it is a constant tick-tick.... The kiwi is not public yet.... i have borrowed a Keysight E36312A to test it tonight.
"Tick-tick" is very likely a nearby electric fence charger. Is that a possibility where you are?
It is 99% electronic waste called on internet auctions as INTELLIGENT MICROPROCESSOR CHARGER, I had the misfortune to buy it once but I returned it the next day after purchase when I saw my waterfall, while this yellow garbage was working, it looked almost identical to yours. Something similar to the one in the picture
Not around me.... i'm severely urban. but perhaps it is lower pitch.... i'll take a recording if the power supply doesn't do the trick.
Ouch, yeah.... i am using the recommended 20W Apple branded iPhone charger.... again, it was fine for about a day, and it is getting progressively worse since. so, maybe i got a defective one. the packaging sure is Apple.
Oh, missed the first question... also from an apple 20W charger (different one)... but, tried a different LNA with internal battery, as well as without an LNA. Even tried the GA800 antenna. All the same results. That's when i moved locations and tried furthest away from WIFI router, still identical. Even tried different cables.
Will get to use this beauty tonight to discard power supply issues... if this PS doesn't fix the issue, then i can safely say it's not a PS problem!
Can we hear the noise please ?
Ideally an AM recording made on a quiet bit of spectrum.
That would provide a lot of clues.
Regards,
Martin
will do... specially if the use of this lab grade power supply still gives the problem... if not, then i know it's the PS and i will get a better/linear one instead.
With no antenna connected to the Kiwi, what does the waterfall look like?
Do you hear that noise on other radios? Do you have a portable AM radio you could use to walk around with a search for sources of noise?
Great points...
Think I found your Kiwi-2 via the proxy service. But it has a user password enabled. If you want me to take a listen please email the user (not admin) password to support@kiwisdr.com. Set a temporary password if you don't want to reveal your permanent user password. It's 3pm here so I'm around for quite a while.
pw sent via dm. thx!
I have to give back the keysight tomorrow, so i hooked it back up with the apple ps.... the pattern is the same. i'm suspecting something going on with the board perhaps. again, it was picking up signal quite nicely for the first day i had it, and it has progressively gotten worse over time. nothing inside my home has changed that i can find... i disconnected a few things i found that could be culprits, and no difference. I appreciate all your help!
Oh boy, I hardly know where to begin. There are at least 3 RFI problems from switch mode power supplies (SMPS). One of which is intermittent. Then three broadband noise sources. Two of which are intermittent. And an absolutely strange problem I've never seen before.
They make the overall wide-band waterfall look bad. But the Kiwi is not completely unusable. For example it was 9pm local time when I listened and 40m FT8 was working okay. The noise floor was an S5. Not great, but probably okay considering the loop and noise sources.
The SMPSs are at 24, 97 and 150 kHz. 97 is very strong and responsible for narrow harmonics all through lower HF. 24 kHz is wide and the harmonics widen as the frequency increases. So it becomes a general raising of the noise floor at HF. 150 kHz is also wide, but seems to switch on and off. It's not clear if harmonics from here are causing trouble.
Broadband noise: There is an intermittent broadband noise that sounds like a loose connection to me. It goes all the way to 30 MHz. So it's not frequency selective like a lightning pulse. There is this general S5 noise pedestal between 21 and 27 MHz. But between 25 and 27 MHz it's much worse with a "buzzing" sound in AMW mode.
Then, strangest of all, is a signal every 1 MHz, exactly on each MHz, from 3 MHz upward. So it wipes out WWV on 5, 10, 15 MHz etc. I have no idea what this is. Never heard anything like it before.
So in your location you're probably never going to have great reception. Unless you can track down each of these noise sources to something locally you can eliminate.
Oh dear, that doesn't sound good.
However, from experience. Most noise tends to be conducted, and if it's really strong, it's more than likely to be from something in your own home, or something very close to it.
If you can run the KiWi, or another receiver, from a battery supply, and turn off your entire mains supply at the big switch. It will give you a good indication, to know if it is something under your control.
See if you can build a simple passive Direction Finding loop to use with your KiWi. If the noise is really strong, a 1m length of wire, bent into a circle will probably be enough for you to be able to locate the strongest noise sources.
It's usually easier to null out the noise source, so you are looking through the loop at the source when the signal is minimised. Moving around and taking cross bearings will help to narrow it down.
Items like house wiring and plumbing can re-radiate noise from different sources, so don't be misled by this.
Good hunting,
Martin
Thank you both for your input. One last thing i'm doing this evening to compare is i'm buiding a Pi5 to run OpenWebRX+ with an RSPDX-R2 from the same location, power supply, amp and antenna. I have been running a Spy+ as well from a similar location. Although my signal from the black-hole i live in is not great, i was getting much better signal quality. I even got a fairly clean Fax transmission from Pt Reyes the first day i had the Kiwi. Sure, something could have been turned on that's causing the bulk of the issue, but this implies several sources causing issues now. Again, it was pretty good the first day i had it and it has been getting progressively worse.
if i get similar results, i'll try to hunt-down the culprits.
Most likely you will, so good hunting.
Oh and folks will soon be turning on their cheap Chinese made Christmas lights and decorations, so expect things to get worse for a month or so, until they get packed away again ready for next year.
Regards,
Martin
Question... how far away from my KIWISDR and/or Antenna should i generally be concerned with RFI/EMI emitters? i don't expect to be completely anechoic, but i would like to greatly reduce... i have an ethernet isolator, linear power supply, and way better antenna cabling on the way. So, i would like to concentrate on sleuthing within X feet from the KIWI/Antenna. where X is?
Thank you!
It's not that easy, as it depends on the source, and whatever it is connected to.
Especially as John has already indicated that there is likely to be more than one source.
That's why I suggest switching off your power at the main board, you will then be able to see what is under your control, and what is external.
Bringing the power back up, breaker by breaker, should allow you to better narrow down the location of a noise source.
Concentrate on one specific signal at a time, some of them will appear on many other frequencies.
Get rid of the worst offender first, and then gradually work on the others.
Be as methodical as possible.
Regards,
Martin
You mentioned you live in a condo? I assume that might be like a modern apartment building (just nicer!)? with other apartments around you?
Are you able to take the antenna outside to a balcony and slowly rotate the antenna to see if the interference / noise reduces?
While the noise you are hearing may not be related, being pragmatic (as Martin has suggested) is the way to go. Things like cheap power supplies, wifi extenders :-) routers and switches.
Keen to know how you get on. :-)