Pete Smith wrote:
>
>It does seem as if some low-frequency RF from the monitor is getting
>into the DXD, but it's hard to see how. The DXD's case is all steel
>and with no obvious gaps in the shielding. Aside from throwing away
>the monitor (a noisy brute in the HF bands too) or moving the DXD
>(which would disrupt a good station layout), I'm stumped.
>
Sounds like magnetic pickup. Monitors put out very strong magnetic
fields.
The audio circuit is literally a circuit - a loop, including the ground
return path, and external magnetic fields will induce currents
proportional to the enclosed area of that loop.
Also, does the DXD include 1:1 audio transformers (intended to break
possible ground loops)? If so, even a small amount of flux leakage could
couple with the strong magnetic field from the monitor.
--
73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB)
Editor, 'The VHF/UHF DX Book'
http://www.ifwtech.co.uk/g3sek
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