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Hi,?
I am am since a year a radio amateur, and i am learing moren and more but also finding interference issues here and i want to find them and if possible eliminate them. For this i ordered the TinySA as tool.
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I am suffering of a disturbance signal over the 2m and 70 cm band, it seems it is extreem strong and has a lot of harmonics toe. The idea is to make analyses during lets say an hour and find out of the interference is time driven or nog, and how wide this interferance is over the bands. On my SDR i can only see a part of it.?
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Attached some of the sreenshots i made, and if someone recognise it, please tell me what it could be, it is day and night...?
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An approach, or point out documents and or youtube recordings that could help me are welcome. in the filename is de date and time, it seems the issue is every 10 minutes but i am not 100% sure, this is also something i would like to learn if i could make a recording of the spectrum and that way find the spikes in time.?
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Thanks for your suggestions?
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Eelco de PD1EG
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Hi,
If you mean the short horizontal bar, that looks like noise just increased briefly on entire band. It's difficult to say what that is.
But if you're talking about the vertical lines visible in equal spacing and one is zoomed on subsequent picture. That to me looks like an inverter or a switch mode power supply. Probably a rather small one to cover 2m (or it has wiring that happens to favour that band).
The tiny telescopic antenna should be good enough to pick that up if it comes from your house. Just walk around and try to find it. I'd set a fast scan rate and maybe max hold. Go into a room, max hold for 60s, see how bad is it. Go into the next room. And so on.
As for specific frequency you gave to experiment. Sometimes it is better to set very wide to see few MHz. Sometimes it's better to zoom in on one line.
Mind they may drift in frequency as the device heats up/cools down or the load on it changes.
73, F
On Sat, 1 Feb 2025, 07:36 eelcodegraaff via , <eelcodegraaff= [email protected]> wrote: Hi,?
I am am since a year a radio amateur, and i am learing moren and more but also finding interference issues here and i want to find them and if possible eliminate them. For this i ordered the TinySA as tool.
?
I am suffering of a disturbance signal over the 2m and 70 cm band, it seems it is extreem strong and has a lot of harmonics toe. The idea is to make analyses during lets say an hour and find out of the interference is time driven or nog, and how wide this interferance is over the bands. On my SDR i can only see a part of it.?
?
Attached some of the sreenshots i made, and if someone recognise it, please tell me what it could be, it is day and night...?
?
An approach, or point out documents and or youtube recordings that could help me are welcome. in the filename is de date and time, it seems the issue is every 10 minutes but i am not 100% sure, this is also something i would like to learn if i could make a recording of the spectrum and that way find the spikes in time.?
?
Thanks for your suggestions?
?
Eelco de PD1EG
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These are signals in the ISM band. The horizontal bar is a nearby (outdoor?) sensor. They are very wideband and pita for shure.?
These signals are very common in urban surroundings..
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On Sat, Feb 1, 2025 at 11:35 AM, pa3cqn wrote:
These are signals in the ISM band. The horizontal bar is a nearby (outdoor?) sensor. They are very wideband and pita for shure.?
These signals are very common in urban surroundings..
?
?
Thanks for your reply.
The red segment, is a quite loud signal, and from what i have seen is is spread over the 2m and 70cm band. And, we seem to see this signal not only in my house but also surrounding houses in a distance of more than 500 meters. What brings us to to a discussion i have with some other HAM'd. does someone make use of amplifiers whitout knowing what is gooing on on the bands. There are a lot of preppers and also hobbyists that like to see if they can strengten a signal without knowing the effects of it. The Red signal transmittion gives over the whole horizontal image a signal and i hink it is in fact "splatter"? over the a wide frequency area.? It is not harmonics but in this case that high energy it spreads way to far.?
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What i am searcing for is :
1) Could i use TinyGS to make messurements to see how wide signal is "splattering"?
2) Am i able to make a recording into the TinyGS for lets say 2 hours since it comes in waves but not om a standard rithm.
3) From there is it possible to figure out, what type of device could make a transmittion at this frequency. I think the 2 meter band, where this is signal is verry visible should be such a signal, it is not lora, not an transmitter, it could be a type of packet radio signal, but, It seems to me a digital signal.
4) it could be interesting to figure out what kind of transmittion it is, like is it a lora signal, a wspr signal, a ft8 signal or packet signal, that makes it a smaller list of candidates.?
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In my opinion, the signal strengt and the way it acts on the band is uncommon for CE signed devices. It should not be there, and it it better to find the source and solve the issue.?
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We have a large transmittion tower i the area full with G5 and other ecquipmemt and maybe there is some sort of malfunction.
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I can;t imagine this is a normal and acceptable signal, it harms the reception of NOAA, Meteor, Conversations, HAB signals and so on...
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And i want to learn if it is possible to dril down to find the sources ... and maybe it is a misson impossible but, some guidance how to start would be a first step to a possible solution.?
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As stated i am new, and learning, and want to learn, and if it is a sensor, i want to find it, and see how we can solve the issue?
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I agree with you it points in the direction of a sensor (but on a frequency that is not common used for sensors as far as i know)? ... but it is one that does not comply to the regulations as fas as i know, and it is causing issues... for me as a ham ..? :-(?
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Regards
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Eelco
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Why not use your TINYSA and a directional antenna to locate the source.? That should be the first step in alleviating RFI.? Even a 3 or 4-element Yagi on 70-cm is directional enough to find the source. ?
Dave - W?LEV
On Sat, Feb 1, 2025 at 10:31?PM eelcodegraaff via <eelcodegraaff= [email protected]> wrote: On Sat, Feb 1, 2025 at 11:35 AM, pa3cqn wrote:
These are signals in the ISM band. The horizontal bar is a nearby (outdoor?) sensor. They are very wideband and pita for shure.?
These signals are very common in urban surroundings..
?
?
Thanks for your reply.
The red segment, is a quite loud signal, and from what i have seen is is spread over the 2m and 70cm band. And, we seem to see this signal not only in my house but also surrounding houses in a distance of more than 500 meters. What brings us to to a discussion i have with some other HAM'd. does someone make use of amplifiers whitout knowing what is gooing on on the bands. There are a lot of preppers and also hobbyists that like to see if they can strengten a signal without knowing the effects of it. The Red signal transmittion gives over the whole horizontal image a signal and i hink it is in fact "splatter"? over the a wide frequency area.? It is not harmonics but in this case that high energy it spreads way to far.?
?
What i am searcing for is :
1) Could i use TinyGS to make messurements to see how wide signal is "splattering"?
2) Am i able to make a recording into the TinyGS for lets say 2 hours since it comes in waves but not om a standard rithm.
3) From there is it possible to figure out, what type of device could make a transmittion at this frequency. I think the 2 meter band, where this is signal is verry visible should be such a signal, it is not lora, not an transmitter, it could be a type of packet radio signal, but, It seems to me a digital signal.
4) it could be interesting to figure out what kind of transmittion it is, like is it a lora signal, a wspr signal, a ft8 signal or packet signal, that makes it a smaller list of candidates.?
?
In my opinion, the signal strengt and the way it acts on the band is uncommon for CE signed devices. It should not be there, and it it better to find the source and solve the issue.?
?
We have a large transmittion tower i the area full with G5 and other ecquipmemt and maybe there is some sort of malfunction.
?
I can;t imagine this is a normal and acceptable signal, it harms the reception of NOAA, Meteor, Conversations, HAB signals and so on...
?
And i want to learn if it is possible to dril down to find the sources ... and maybe it is a misson impossible but, some guidance how to start would be a first step to a possible solution.?
?
As stated i am new, and learning, and want to learn, and if it is a sensor, i want to find it, and see how we can solve the issue?
?
I agree with you it points in the direction of a sensor (but on a frequency that is not common used for sensors as far as i know)? ... but it is one that does not comply to the regulations as fas as i know, and it is causing issues... for me as a ham ..? :-(?
?
Regards
?
Eelco
?
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In my opinion, the signal strengt and the way it acts on the band is uncommon for CE signed devices. It should not be there, and it it better to find the source and solve the issue.?
?
?
But is the signal really there? That depends on the quality of the receiver. If it is a RTL-SDR dongle it is very likely that most of it is the result of the dongle beeing overdriven, and producing a lot of internally generated mixing frequencies. e.g. At my home I have to live with a strong repeater, P2000 (*)? and broadcast stations. Plus the occasional air-band when a Liveliner (*) passes overhead. And locally there is hdmi. All of these give me signals on my dongle that are not really there.
So question one is: what receiver is used in owrx? If it is indeed the infamous dongle you might reconsider putting much effort in finding the source. Instead build a band-filter to limit the signals coming in.
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(*) for non-dutch: P2000 is a paging system for emergency services, Lifeliners are MMT choppers.
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regards,
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Henk
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QUOTE:??
In my opinion, the signal strengt and the way it acts on the band is uncommon for CE signed devices. It should not be there, . . . . . .
If it comes from China, do NOT believe any of the regulatory markings!? China just prints labels and applies them appropriately with absolutely no attention or testing to international RFI/EMC regulatory laws.? Believe me, I was in the business of RFI/EMC until a few years ago.? I've experienced this practice for at least 2 to 3 decades.
Dave - W?LEV
In my opinion, the signal strengt and the way it acts on the band is uncommon for CE signed devices. It should not be there, and it it better to find the source and solve the issue.?
?
?
But is the signal really there? That depends on the quality of the receiver. If it is a RTL-SDR dongle it is very likely that most of it is the result of the dongle beeing overdriven, and producing a lot of internally generated mixing frequencies. e.g. At my home I have to live with a strong repeater, P2000 (*)? and broadcast stations. Plus the occasional air-band when a Liveliner (*) passes overhead. And locally there is hdmi. All of these give me signals on my dongle that are not really there.
So question one is: what receiver is used in owrx? If it is indeed the infamous dongle you might reconsider putting much effort in finding the source. Instead build a band-filter to limit the signals coming in.
?
(*) for non-dutch: P2000 is a paging system for emergency services, Lifeliners are MMT choppers.
?
regards,
?
Henk
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On Sun, Feb 2, 2025 at 10:38 AM, W0LEV wrote:
China just prints labels and applies them appropriately with absolutely no attention or testing to international RFI/EMC regulatory laws.?
Dave,
This may be a bit too general.
Much of the modern electronic equipment is manufactured in China, including from very well respected brands.
It may be better to state that very cheap stuf you can buy on Aliexpress and similar webshops may lack attention to international RFI/EMC.
But even that is not always true.
An example is the tinySA. It is cheap and available on Aliexpress and we took great care it is adhering the international RFI/EMC regulatory laws.
So, as a kind request, please do not generalize too much as it does not help uncertain buyers.
--
Designer of the tinySA
For more info go to
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Ericd, you are one of the few these days!!? THANK YOU!!!
My experience over the past decade (retired) and the last three decades (working the previous 2 to retirement, I have had many.....many instances of China just printing labels.? The last 4.5 + decades, I worked as an EMC/RFI engineer for a number of companies including HP and finally StorageTek (the last one I was actually requested to cheat - which I refused and led to firing).? Not on my watch but at HP, our scanners in Germany big-time failed due to "overlooking" and completely creaming reception of TV channels 2 through 6, including commercial FM due to radiated emissions.? Of course, that put us under the microscope and forbid HP from selling scanners in the whole EU for a year.?
Another instance:? We upgraded our test computers to test our storage libraries at StorageTek (we had a good OATS).? They came with no regulatory stickers from SuperMicro.? We contacted their West Coast storefront about the issue.? They immediately ask, "How many do you need?"? A week later we received a business envelope full of "just printed" regulatory stickers.
And another:? Requesting reports of products which failed formal testing.? Of all my requests, I received usually around 30% of those requested.? What's even more disgusting, none of the reports applied to the product I had requested.? All.....ALL.....of them were just compilations of pages from other unrelated regulatory reports with appropriate title pages.??
More yet:? I have tested, both officially and pre-compliance, many Chinese produces which miserably failed both radiated and conducted emissions per FCC and/or the EU regulations. ?
Appliances:? The ultimate responsible party is the integrator of "components" (SMPS) which sail through customs as components.? Except for the German products we have in our 10-year old kitchen,? everyone fails both conducted and radiated emissions.? I had to install an extremely robust common mode choke on our second frig/freezer, a Kitchen Aid, to reduce both radiated and conducted emissions.? They go together as once the conducted emissions are violated, the whole house wiring lights up.? No surprise.....
To make things worse, I'm an amateur radio operator and pursue radio astronomy as yet another hobby.? Get the point???!!!
In my experience over the decades, China has taught even some of the good and upstanding companies the risk of cheating isn't that great with an FCC that no longer cares about enforcement.?
Have a read of my QRZ page for a bit more.? I could fill anyone's email inbox with stories addressing China and the regulatory world.? And let's not mention S. Korea that uses the regulatory world as a trade barrier.
Dave - W?LEV? ?
On Sun, Feb 2, 2025 at 10:38 AM, W0LEV wrote:
China just prints labels and applies them appropriately with absolutely no attention or testing to international RFI/EMC regulatory laws.?
Dave,
This may be a bit too general.
Much of the modern electronic equipment is manufactured in China, including from very well respected brands.
It may be better to state that very cheap stuf you can buy on Aliexpress and similar webshops may lack attention to international RFI/EMC.
But even that is not always true.
An example is the tinySA. It is cheap and available on Aliexpress and we took great care it is adhering the international RFI/EMC regulatory laws.
So, as a kind request, please do not generalize too much as it does not help uncertain buyers.
--
Designer of the tinySA
For more info go to
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This is interesting. There has been some other conversations with similar suggestion I did read elsewhere. But I like to understand something and prevent accidental TinyAS damage. I have a directional antenna as well that I can use. What kind of attenuator is any should I use to prevent accidental TinySA damage from overpowering it specifically when you get closer to the source. I understand that there could be some signal at any given time that is not related to source you are looking for that might happen anywhere you standing. Would community here suggest something like this switchable 2W attenuator
If TinySA, attenuator and directional antenna are setup, could someone explain here in an algorithmic way how he would go safely search for the signal?
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1. Set band start and end on TinySA.
2. What attenuator setting to start with.
3. What appropriate TinySA settings should be made related to the above attenuator value used.
4. What to pay attention on TinySA and make appropriate adjutements and try again starting from point #2 above.
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If there are additional steps which should be added to the above, please add as much as you think it is relative to know.
If any of you have some good YouTube links related to this, please share
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Thank you
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Well, that got out of hand quickly.?
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Just a remark on the subject of China-bashing: the Chinese are very well capable of producing top-quality products, if you ask them to. But consumers want things cheaper, not better. China just caters for this demand. If you want crappy non-compliant stuff they'll make it for you. 'You want a 10 dollar HT? Here it is. We could make it compliant but than it would cost you 12 dollar. It's up to you.' I own a China-made children's toy HT on PMR. It is on par with and often beats top-brand HT's. Still it was only �6,5 .
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Back to the topic:
From the images it is 99% clear to me that the receiver is the RTL-SDR dongle. I too love this little RX and it sparked a lot of interest in RF with many people.
But: it isn't the best receiver ever. It has no real front-end, it is a broad-band direct conversion sampler with a single mixer directly connected to your antenna. And worse: you have to connect it to a device that is full of unknown clock sources.?Below is a picture showing a local repeater about 1 km away. Only one signal is real ...?
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What I am trying to say is that you might see a lot of strange signals on your SDR, but chasing them with the SA might be like chasing ghosts.
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Rob, W9LOT