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+--- Thread: Solar Inverter Interference (/thread-655.html)
Solar Inverter Interference - VK4CV - 03-10-2018
Just joined this site a couple of days ago so this is my first post here.
A few years back I first noticed quite strong garbage around S7 to S8 all over the HF spectrum and it even extended up to 50MHz where I could detect
a few weak birdies there as well. So, using my five element beam for six metres, I determined that it appeared to peak to the north west of my house.
A very important point I observed was that as soon as the sun set the garbage would all disappear, and it would also drop to a very low level (around S1)
when a very dark cloud blocked out the sun during the day. So, I reckoned that this problem had to be caused by some device that was solar powered.
A dirty high powered solar inverter in a house close to me would be a very likely suspect.
I tried walking around the neighbourhood with a portable broadcast receiver (all I had) to see if I could locate the source. I couldn’t find any definite
source, so I thought it might be best to approach the ACMA and see if they could figure out where it was coming from. My first response went like this:
“Thank you for your email relating to interference to your amateur equipment. We are unable to resource an investigation into this matter at this time. HF Amateur
Radio systems in suburban areas are more susceptible to interference due to the size of antennas and extra sensitive equipment and can be difficult to resolve.”
That response looked like I was not going to get any help from them so I then wrote to the minister for communications via my local member Peter Dutton.
This time I got something back that was a little more encouraging:
"Mr Cooper was advised that in the first instance he should attempt to locate the interference and then try and resolve the matter cooperatively with his neighbours."
So I drafted up a polite explanation letter about the problem and dropped copies in several letter boxes around the area where I believed the problem
was originating from asking to do a test. I got no co-operation from any of them even after visiting most of them in person a few weeks later! Then
it was time to get onto the ACMA again. This time I finally managed to get an officer from the Brisbane office to come out and look into the problem.
That was in early August 18, and so far no culprit has been located. One neighbour did get around to doing a test with me but his inverter was cleared.
The others are still refusing to do a test! I’m sure the ACMA can force co-operation if they want to.
Has anyone had any experience with this type of problem and can offer any advise on how to track down a dirty inverter. Perhaps someone who has
had plenty of experience in doing “Fox Hunts” might be good at tracking down this culprit. If it’s not a dirty solar inverter, what else could it be? Sorry
about the long post, but as you can see, my interference problem has become difficult to resolve mainly because of lack of co-operation all round!
Nev VK4CV
RE: Solar Inverter Interference - VK3QI - 03-10-2018
Nev,
Don't discount an air conditioning unit or some sort of pump/solenoid device associated with a solar hot water system.
They are just as likely to be a source of interference across the HF spectrum.
Also, if you can, try and see if you can hear the noise on 144 or 432 MHz as well. If you can, then your chances of locating the source would be greater.
Good luck
Peter VK3QI
RE: Solar Inverter Interference - VK3RX - 03-10-2018
Quote:The others are still refusing to do a test! I’m sure the ACMA can force co-operation if they want to.
I'm not sure the ACMA would want to.
Perhaps in that situation when someone refuses a test, you could say something like:
"Well, if your inverter is causing the problem it may be faulty and so a potential fire hazard, so it's in your interest for us to test it - I can do it now for you and only take a couple of minutes ...."
If the lady of the house overheard the fire hazard bit, she'd be spooked
RE: Solar Inverter Interference - VK2WP - 04-10-2018
This sad tale is a result of the market being flooded by cheap imports with no regard to RFI specifications. The authorities could not care less about amateur radio in this day and age.
Am lucky where I am the nearby solar powered houses do not appear to be a problem and the local noise levels are mosty bearable.
Good luck with your quest to have the inteference resolved.
RE: Solar Inverter Interference - VK4CV - 04-10-2018
Thanks Peter, Damiem and 2WP for your replies. That's an interesting point you have raised Peter about the air conditioning unit or some sort of pump/
solenoid device being the culprit. You might like to elaborate on how they could generate radio interference because I know very little about solar heaters
except that they produce hot water from the sun. Could a solenoid/pump somehow generate radio interference? A pump could I suppose if it had worn
or dirty brushes in the electric motor part of it.
Yes Damiem, I was also wondering if the ACMA would go as far as getting a court order to force these neighbours to do a test. The way things are going
it might very well come to that!
Thanks for your comments 2WP about the cheap solar inverter imports. In my top post, I mentioned that one neighbour did get around to doing a test
with me on his inverter and it was cleared. Well apparently that neighbour has a cheap Chinese inverter that has not been approved by the Australian
government. The ACMA officer that came out has found that it has no compliance sticker on the back and he wants the entire inverter replaced! As you
can imagine, that neighbour is now quite angry and blaming me for having his inverter condemned. I heard that back from a another neighbour who is
quite friendly with him. By the way, that neighbour who lives directly at the back of me claims to be having all manner of interference problems from TVI
to computer interference, mobile phone drop outs and his car burglar alarm going off every now and then! No it's not my amateur station. I've been
totally inactive since about 2005 mainly because of the very low solar activity.
RE: Solar Inverter Interference - VK3AV - 04-10-2018
I have solar boosted electric hot water at my location. There is a controller unit that monitors - the hot water service tank water temp and the water temp in the roof mounted panel and activates a small pump to circulate the water from the roof to the tank and back when and as needed.
So during winter here (its cold) the circulation pump would seldom cut in as the water temp on the roof may only a few degrees C so low to circulate. On sunny days the roof temp can be 60+ degrees so the circulation pump cuts in. All of this is programmable.
So, that means that both the controller and the pump might be noise sources. I cant say that I have noticed it, but I have not looked for it either.
I do have multiple neighbours with solar systems (I need to do that too as my bills are huge) and there are also some electric fence units in operation in this area. Of note that during power outages for line work or due to unplanned outages caused by tree damage to lines (both happen a lot here with a hundred+ houses off line), with the HF radio on a battery my noise levels are S1 or less and at other times S5+ dependant upon the band +/- electric fence pulses.
Regards
Bernard
RE: Solar Inverter Interference - VK4CV - 05-10-2018
Thanks for the info on your solar boosted electric hot water at your location Bernard. Most of what you described about the system was new to me.
This interference here has a strange sort of buzzing sound about it. The buzz frequency would probably be about 100Hz. For this reason I doubt if
it could be caused by a faulty electric motor driving a pump, however, I wouldn't rule it out either.
You must be out in the country area to have electric fences around you. They of course can definitely cause interference and usually have a
distinctive sound about them with a sharp pulse every few seconds but I gather they are not bothering you too much.
RE: Solar Inverter Interference - VK3AV - 05-10-2018
Nev,
I had not struck this type of HWS until I moved here. The pump is small and inline with the copper pipe. Mine was replaced a while back as it developed an intermittent short that tripped the RCD and blacked out part of the house including my office/shack area until I finally worked out what was causing the problem.
I am about 35klm as the crow flies from Melbourne CBD and at 500+m elevation.
Agreed on the electric fence. Sadly, I don't have a few acres to play with or there would be another mast or two, but the block behind me is some 20 acres with the National Park on the other side of them. I have an electric fence energiser myself but it had zero impact on the Wombat that has taken to digging holes under my, and neighbours, fences during its nightly rambles. Some of the holes are around 500mm deep as as soon as I fill them in it either digs it out again or moves to another spot and digs yet another hole. Wombat - the bulldozer of the bush!
On the positive side, Icom HF radio can satisfactorily blank out the pulses from the fence etc.
Regards
Bernard