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From: "Alan Melia" <alan.melia@btinternet.com>
To: <rsgb_lf_group@blacksheep.org>
References: <BLU146-W201F9B3FE3E982D483D89BCFA30@phx.gbl>
Date: Fri, 23 Jul 2010 23:14:32 +0100
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Subject: LF: Re: Noise R75 - rs232 from smpsu -
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Hi Laurence from memory ....I dont use laptops so didnt need do it.....the
easiest way of "decoupling" the serial comms loops,  is a pair of opto
couplers on the RS-232 there are app notes in the data sheets for most.
Alan G3NYK

----- Original Message ----- 
From: "Laurence KL7UK" <hellozerohellozero@hotmail.com>
To: <lowfer@mailman.qth.net>; <rsgb_lf_group@blacksheep.org>
Sent: Friday, July 23, 2010 9:47 PM
Subject: LF: Noise R75 - rs232 from smpsu -





Anyone done any common mode noise mitigation from the RS232 port of the R75
Rx> - the noise coming up from the SMPSU/processor from the old Dell puter -
cable is double screened - choking off using J (75) type has seen little
improvement - this is my last hurdle to unimpeded remote rx on 137 - any
pointers appreciated - everythings bonded and Ive tried the on/off earth
tricks at various locations -



Anyone had any success of powering a Dell D series from a non standard non
switched PSU? (the noise goes away when the DC from the Black Dell brick is
removed but it may also be partially screen/processor noise...)



with thanks



Laurence Kl7UK

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