Morse code interference

my Neighbour uses morse code , he’s a ham radio operator to communicate to people all over the world, never been a problem using a Naim 5si, but just bought a 172 pre-amp , connected to the internet, and a 155XS power amplifier, getting terrible interference now when nothing when using the Intergrated amp, WHY? Anyone know?

I am a licensed amateur radio operator and have a Naim hi-fi system, so I have some experience with this subject. Did anything else coincide with the change in amplifiers? Did speaker cables change or get moved?
I have experienced speaker cables acting as wire dipole antennas and listening to my own voice come out of the speakers even with the hi-fi system unplugged and the speaker cables unplugged from the amplifiers.
I’d also suggest you physically removed the hi-fi system from the internet. It’s possible your internet cable is acting as a simple wire antenna. You can ask your neighbor to transmit CW on his radio and while he is transmitting, physically detach the internet connection and see if the interference goes away.

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You’ve got quite a few entry points for RF to couple into your system. What else is connected to it ? In addition to what’s been mentioned above, you might want to disconnect the 155 and try headphones with the 172 to see if you still get problems to help narrow down the entry point.

I’d suspect speaker cables and the 155 - it would be interesting to know the speaker cable lengths and (find out from your neighbour) what frequencies he is transmitting on when you get problems.

I think @Simon-in-Suffolk should also be able to provide useful input here.

James (licence long lapsed…)

I also a hold a CEPT class radio licence. If your neighbour was causing you RFI from their operations, which is possible, then you would only notice it when they are operating and if morse (CW) then you would hear that likely as break though - and that would be the extent of the interference - ie you hear morse from your speakers.

So if you are hearing noise that is not consistent with that then it is likely nothing to do with RFI.

If it is that - keep a log of when you are getting the interference- and discuss with your neighbour who will also be likely keeping a log - and certainly will do if he knows he may be causing interference - and if the times align - then they can mitigate it appropriately.

They may also be aware of other local sources of local RFI such as agricultural electric fences, problem PLAs, problem solar panel inverters etc - but none of this will likely have much of an effect on you - but they will on their station.

What are the laws in the UK? I think that here in the States, the radio operator has some duty to mitigate the issue – but maybe only if they are operating out of regulatory guidelines (??)

there is no law to do it in the UK if the station is operating legally - but most licensed operators are keen to resolve issues they cause, as typically an issue indicates a lack of performance or correct configuration somewhere which usually results in less effective capability - and performance is key with radio hams as they are dealing with typically such small signal levels - but from the description of the OP this has almost nothing to do with the radio operator next door - so from the description that looks like a red herring…
But if the OP had morse code coming out of their speakers then i think it would be fair to assume some correlation

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My very small experience with similar issues was that an interconnect was ‘bad’ and thus picking up RFI. This happened to be a subwoofer interconnect on loan from my dealer; it was bad and picked up some Russian-language broadcast (odd!).

Disconnecting interconnects one-by-one is a good process to follow to see if its a cable/interconnect. The old ‘process of elimination’ strategy.

ahh yes - but that is nothing to do with the neighbour, but the fact poor local connectivity has turned some of your hifi cabling into reactive tuned circuits and so are acting as radio receivers.

A radio Ham operating morse causing RFI is very easy to spot - as the interference will be modulated by morse the operator is transmitting - and so you will hear or see flicker on TV in time to the morse code at the specific times the operator is working their station - pretty rare occurrence.

The other thing is that CW (Morse) operators tend to use low power as high power is not often needed

Good points Simon - it’ll be interesting to see what the OP comes back with on the type of interference they are seeing.

First step would be to find what frequency is being transmitted. I would put money on it being HF. 73es OM to the other amateurs here.

No… that really is not that relevant. The first thing to do is keep a log of when the interference occurs, and then compare with the neighbour, and compare with the times they are working their station. If they don’t align, then it is irrelevant, and the source of the interference is elsewhere… if they align exactly then the operator can investigate why. But the interference would be modulated as morse code… would be very distinctive, and there is no mention of that in the OP description,

Hi, nothing changed apart from using Nait 5si then changing to pre amp Naim 172 and 155xs power amplifier, my neighbour was using morse code tonight so I disconnect the wi fi to the pre amp but the interference did not stop, regards…MEL

And does the interference logs align exactly with your neighbour and your interference… and you hear the the interference pulsed as morse…
In which case you should speak to your neighbour and ask them to investigate. Are you physically very close to your neighbour antennas?
Are they using wire antennas ?

Hands up. I agree that the correct approach is to first compare logs for receiver and transmitter. However once this has been done, identifying if the issue is related to a particular transmission frequency, could be very relevant.
This could help in determining where the RF is getting into the system - preamp stage? Interconnects? Mains wiring? Loudspeaker cables? - Does the interference cease when speaker cables are disconnected and headphone are used for example?

A bit more information would be useful - what is the effect of the ‘interference’ like , a buzz, a hum etc. Is it intermittent or continuos. What other items do you have connected to your 172 ?

Hi, interference is the morse code clicking noise and some buzzing, connected to the 172 pre amp is 155xs power and TV sound goes through hi fi, just changed from Nait is had no problems with that set up, all cables and speakers and DAC are the same…MEL

Is it all the time or occasionally ? how is the TV sound sent through the hi-fi - via analogue or digital connection ?

TV is connected to 172pre amp using digital connection to Audio M DAC and then to 172. Just got my neighbour to use morse code and couldn’t replicate the same problem, so still a bit of a mystery, thanks for reply…Mel

Ok so it looks like the neighbour may not be the problem. How often does this happen ? You’re not leaving a mobile phone near your equipment are you ?

Out of interest why do use the MDAC - why not use the 172 for the TV via one of its digital inputs.

Hi, no neighbour is the problem, but he’s also a good mate, been using the M DAC and Naim DAC, jury is out on the best at the moment.