Return to KLUBNL.PL main page

rsgb_lf_group
[Top] [All Lists]
<prev [Date] next>
[Advanced]
 <prev [Thread] next>

RE: LF: Noise R75 - rs232 from smpsu -

from [Laurence KL7UK] [Permanent Link][Original]
To: <[email protected]>
Subject: RE: LF: Noise R75 - rs232 from smpsu -
From: Laurence KL7UK <[email protected]>
Date: Fri, 23 Jul 2010 21:49:39 -0800
Importance: Normal
In-reply-to: <[email protected]>
References: <[email protected]>,<[email protected]>
Reply-to: [email protected]
Sender: [email protected]
Chaps - thanks for the all the advice - more to chew on -
 
Dave common mode chokes do a bit but I need more - the S meter on the main T array sits at S3 or so mostly non man made which is the best Ive had so far s/n wise but the dang noise adds a few dB (Im being really pe-nickity) - opto, Eddy boxes and more playing is needed - seems noise from the PSU getting onto the data lines mostly common I think  - opto is my best bet.
 
Cheers for the advice again on direct and indirect emails -
 
running the main "T" (actually an offset X and Y bottom loaded 50 ft vertical on 137 khz and really pleased -
 
grabber running on http://kl1x.com/alaska.html  
 
the slightest sniff of dcf39...not bad for July...
 
Laurence
 
Date: Fri, 23 Jul 2010 22:26:06 +0000
From: [email protected]
To: [email protected]
Subject: Re: LF: Noise R75 - rs232 from smpsu -

Laurence

In my remote station I put the Dell brick in an Eddy box (die-cast box) with a proper mains filter on the input and chokes and feed-through capacitors in the DC output lead. Drilled some holes for ventilation. Quiet as a mouse.
A linear PSU should also be fine but quite large.
The RS232 is unbalanced of course, but if you run it in screened cable and use a ferrite common-mode choke dies it not help?

Dave G3YXM

From: Laurence KL7UK <[email protected]>
To: [email protected]; [email protected]
Sent: Friday, 23 July, 2010 21:47:56
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

The New Busy think 9 to 5 is a cute idea. Combine multiple calendars with Hotmail. Get busy.

Hotmail is redefining busy with tools for the New Busy. Get more from your inbox. See how. =
[More with this subject...]
<Prev in Thread] Current Thread [Next in Thread>
Previous by Date:  Re: LF: WE2XGR/2 & /3 to test new ZL1BPU/ZL2AFP MSK, F4DTL
Next by Date:  LF: XGJ 24-07.jpg, henny van elst
Previous by Thread:  Re: LF: Noise R75 - rs232 from smpsu -, Dave Pick
Next by Thread:  LF: LF T/A [137kHz] XGJ last night !, "Jean-Pierre Méré (F1AFJ)"
Indexes:  [Date] [Thread] [Top] [All Lists]