Switch Mode Power Supply RFI

Just when you thought we had enough QRM on the bands, I seem to have found a new culprit yesterday - domestic CCTV systems.

Now, before we begin, CCTV isn't rare.  It's used by a large swathe of the neighbour-harassed population, so there will be one near you.

Because of their popularity, and developing HD technology, CCTV is subject to huge competition and cost pressures.  As a result, so is the quality and design of the various components.

The facts:

I bought a 'Home Guard' CCTV system with a 1TB HDD and 2 cameras.  It cost £189 at Argos, a very popular UK retail outlet.

After a full and careful installation (well, there are only a couple of basic BNC and PSU connections, after all!), I powered up to see whether there was any RFI.

Sadly, there was.  A lot of it.

The 12m band went from a totally quiet, noiseless environment to one with a S5 hash.

Here's the evidence:

So, if you buy one of these, which are probably the same kind of unit sold under endless branded guises, then chances are it will have a cost-cutting PSU, and RFI as a result.

I'm taking mine back as not fit for purpose, and a breach of European Directive 2004/108/EC, the material part for consumers being Article 5 (hat tip to UKQRM for this):

"Equipment shall be so designed and manufactured, having regard to the state of the art, as to ensure that:

(a) the electromagnetic disturbance generated does not exceed the level above which radio and telecommunications equipment or other equipment cannot operate as intended".

Argos were exceptionally good with me - they accepted the complaint and refunded me with no quibble whatsoever.  They even called me back the same day when I told them about the wider issues with selling this product.  

But, many other shop assistants will look at you with a blank face if you present them with this complaint as a basis for returning and claiming your money back.  It's understandable, but not acceptable.  It's probably best to ask for the manager, if there is one, and explain it is a piece of equipment that is probably illegal due to its RFI-generating nature, and that the problem of power supplies like this generating RFI is very well known and the reasons for it understood (omission of isolating components.)

Tell the shop you are also the holder of an OFCOM radio licence, and that you will be reporting the product to both OFCOM and the local trading standards office.

DO NOT ACCEPT the shop telling you to contact the manufacturer, even if the manufacturer asks you in their instruction leaflet to contact them 'in the event of a problem'.  This is not an equipment  operating problem for the maker to help you with, it's a basic manufacturing flaw.   It is the SELLER'S legal obligation to deal with complaints and refund you (a replacement isn't appropriate here, because it's likely all their CCTV systems will use the same PSU - you should tell them this if they dig their heels in.)

If the shop, as often happens, really digs their heels in, you can try and ask the manager to write down their reasons for refusing to accept the return and/or refund you, and then go to ask for help from your local trading standards office at the Council.  Inevitably, these are rather stretched and much less able to help than once was the case.