Tag Archives: rfi

Treadmill desk (part 6, hopefully the final summary)

I think I’ve got the treadmill desk sorted out finally (see all posts in this series).

Here are the parts you will need for a cheap treadmill desk:

  • Treadmill (duh!). They all say you should buy an expensive treadmill, and they are right. The one I got was very cheap new, and has lots of problems, like … It forgets how far you’ve gone after 5 minutes (so if you go to grab a cup of tea, then it resets itself). It has massive RF interference problems (now solved — see below). And it picks up mobile phone signals and emits a loud disturbing noise.
    How to get an expensive treadmill at a reasonable price? I suggest ebay. Now is about the time when those unwanted Christmas presents should start coming online …
  • RF filter. There’s only one I would recommend, which is the Tacima Mains Conditioner and Radio Frequency Interference Filter. Note that a standard “surge-protected socket” is not the same and won’t filter RFI. This looks like one of those bollox “audio buff” annealed cables that are aligned to the earth’s magnetic field and cost thousands of pounds. It’s not — this one really works, and it’s a reasonable price. Make sure you plug only the treadmill into this otherwise the leads going to other equipment will also act as antennae for the unwanted RF radiation.
  • Desk (aka “a piece of wood”). I taped a piece of wood to the arms of the treadmill with gaffer tape, and then I piled some boxes up to lift the laptop up to a comfortable height: a lo-tech, no cost solution which has proven sturdy and effective. Even food and drinks haven’t been a problem.
  • Padded trainers. Thick padded trainers have really made the difference for me. I happened to have some old trainers, but you don’t need to spend much money on this.
  • Anti-static wrist strap. Yes, with some combinations of clothes, trainers and humidity, you will start generating static. This can damage computer equipment easily, not forgetting that it bloody hurts! A cheap anti-static wrist strap cures the problem.

I’ve only been doing this for two weeks, but I feel noticeably better already. The other good thing is it doesn’t feel like exercise. I’ve done about 4 hours today, and most of the time I forgot I was on a treadmill.


Some mainstream press articles about treadmill desks: 1, 2, 3, 4, 5.


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Treadmill desk (part 4)

I’ve learned a lot about RFI this past couple of days … The treadmill radiates RFI through the power cable, back into the power socket, and from there through the entire house’s ring main. Ring mains, a UK peculiarity invented after the war to save copper, are particularly susceptible to this.

You can easily hear the interference using an analogue radio and placing the radio around the house with the treadmill on and off. This page (currently not available) has some nice graphs from a radio frequency analyzer.

The solution was to purchase a power strip with a big choke and plug the treadmill (and nothing else) into it:

Source: Amazon.co.uk

Although the lead from the treadmill to the power strip (and the treadmill triac itself) can still be heard on the radio emitting a lot of noise, it’s much better than having the entire ring main act as a huge antenna, and most importantly it no longer interrupts my ADSL line. Success!


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Treadmill desk (part 3)

Here’s a fun thing (not). I noticed today that the DSL connection was pretty rough, constantly reconnecting. It turns out after a lot of: run downstairs, check wires, DSL is OK, run back upstairs, still OK, start the treadmill and work, hmm it’s disconnected again, that this cheap treadmill is a big source of RFI that interferes with DSL.

Apparently this is a known problem: 1, 2, 3, 4.

(By the way, anyone considering getting the Roger Black GM-41001 Silver Medal Treadmill … DON’T! It may be very cheap, but it really is a piece of crap).

Why didn’t I get interference yesterday? Good question, but the router has been moved slightly, and perhaps the wire doesn’t pick it up so much.

Sadly, wrapping tinfoil around the phone line and earthing it did not work.

I ordered one of these mains conditioners with a big choke for £25 (about 10% of the cost of the treadmill). We shall see tomorrow if this works …


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