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Radio Interference

A

Andrewxyz

pfm Member
I've had my Hadcock 242 in situ on the Orbe for 2 weeks now and it's a definite improvement over the Tecnoarm to my ears, though I'm still not 100% convinced it's set up right..

I am though, getting a lot of radio & electronic noise interference.

I live in a small 1 room flat, so my fridge, cooker & washing machine are scant metres from the hifi. Clicks & pops are to be expected and I can live with them. However I'm also getting a lot more radio interference than I used to. Previously it was the occasional taxi or police car breaking through, but I now appear to have a foreign radio station as a low level addition to my music. For some reason this is exclusive to the right hand channel ?

The armplate has bare metal around the mounting hole and an earthing cable connected to the turntables earth point. The Hadcocks earth cable is connected to my mains blocks earth point.

Is the Hadcock prone to this ? Is there anything I can do to eliminate the problem ?
 
Don't know about the Hadcock, but try running an additional earth cable from the turntable to your amplifier. Maybe even also from your phono pre to the main amp. Also make sure your earthing to the mains is ok. Wiggle mains plugs a bit or remove and replug a few times. In fact do so with all (phono) plugs. (right channel!)

Police and Taxi FM are all in the same radio band region. FM radio is close by. Try and make out what you hear though, UHF FM is a complete different story to AM shortwave interference.

AM will much rather come in via the speaker cables or other longer, unshielded cables, like the mains. All act as great shortwave antennas. Maybe you have different lengths of speaker cables for left and right, which would explain why one channel is affected, the other not.

Picking up FM stations is a much more local and smaller problem. And this would definitely be a coming and going phenomena if you do not live right next door to a taxi/police/fm station. Meaning shifts in daytime/nightime, and generally between days. The field strengths emitted on FM/UHF are much lower than AM.

The only chance I see of picking up FM constantly is if an unshielded tonearm cable were by chance exactly 1/4th of the relevant wavelenght (35-45cm) and your phono pre were to pick this up. Possible, but only theoretically.

EDIT: Forgot to say: Further initial advice: change speaker and mains cable lengths and see what happens.
 
Other cabling is unchanged from when I was using the Tecnoarm & caused few problems. I do live near a main police station which has a honking great radio mast outside but it's rarely been an issue. I have earth points on the phono stage & step up, but they caused hum with the Tecnoarm, I'll shift the tonearm cable to them, and the amp to see if that improves anything.
 
I solved my RFI problems in 2 ways

1) Clicks from switches:- Contact suppressors put across the offending switches (easy for lights, more difficult for appliances)

2) Radio Pickup via arm leads:- Run the arm cable 3 or 4 times through a Ferrite Ring.

All I get now is the occasional Taxi Radio when its broadcasting <5 m from the house, otherwise silence
 
Welcome to Radio Moscow
This comes up a few times a year if you do a search
James (2) suggestion fixes it Run the arm cable 3 or 4 times through a Ferrite Ring.
I use the square block with a clip things from Maplin, they do them in different sizes & are designed to clamp around a single cable.
With x2 of the 10mm cable sizes I can wrap each my arm leads x1 turn thru the ferrite.
Bye Bye Moscow
 
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