[600MRG] S meters and noise...

[Edward R Cole]

Dave,

Interesting numbers.  With my 43 x 130 foot 
inverted-L and using a SDR-IQ Rx I recall my 
receiver noise floor was -132 dBm.  With antenna 
the local noise varied from -115 to -95 
dBm.  WSPR improves SNR by use of very narrow 
detection bandwidth in the Hz range (that reduces 
the amount of noise energy vs signal).  My SDR-IQ 
running Spectravue software displays in dBm so no 
s-meter.  My K3 is now upgraded to operate on 
470-KHz range so it has an s-meter (not in use on 630m as yet).

80m noise floor using an inverted-V runs S8 on 
the K3.  Hope that is not indicative of what I should expect on 630m.

That big loop probably helps SNR quite a bit.  I 
always had in mind a small rotatable Rx loop with 
preamp but haven't got around to building either.

My inverted-L is on the ground due to failure of 
one end support in November extreme wind 
storm.  I am toying with constructing a folded 
unipole vertical (Like one half of a folded 
dipole) with top wires in Tee configuration to 
replace the Inverted-L (next spring/summer).  The 
original 50-foot tower used for one end support 
will only be 30-foot when put back up so having 
to rethink the design using another tower.

73, Ed - KL7UW

At 04:29 AM 1/18/2021, Dave Riley via 600MRG wrote:
>Content-Type: multipart/alternative;
>  boundary="------------C80E0AE468D8F586ECBE56CA"
>Content-Language: en-US
>
>It has been decades of battle trying to hear 
>signals out of this local noise, mostly from 
>33KV 3/phase lines going by, especially on 630m..
>
>To establish a base line and find my starting 
>point I converted some numbers essential to this quest..
>
>dBm      uV    S meter
>
>-73Â Â Â Â Â Â Â  50Â Â Â Â Â Â Â  S9
>-79Â Â  Â Â Â Â  25Â Â  Â Â Â Â  S8 Â
>-85Â Â  Â Â Â Â  12.5 Â Â Â  S7
>-91Â Â Â  Â Â Â Â  6.3Â Â Â  Â  S6
>-97Â Â Â  Â Â Â Â  3.2Â Â Â Â Â  S5
>-103Â Â Â Â Â Â  1.6Â Â Â Â Â  S4
>-109Â Â Â Â Â Â Â Â  .8Â Â Â Â Â  S3
>-115Â Â Â  Â Â Â Â  .4Â Â Â Â Â  S2
>-121Â Â Â Â Â Â Â Â  .2Â Â Â Â Â  S1
>-127Â Â Â Â Â Â Â Â  .1Â Â Â Â Â  S0
>
>The SDRdx receiver indicates approx. -132 for a 
>noise floor and no problem as my continuous noise on 630m now is S5 +/-..
>I think that WSPR sigs are good for digging in 
>to the noise @ about 20db below noise floor.. ( maybe )
>There are plenty of other noises around the 
>house for sure but @ 630m this is no big problem..
>
>This is where I am at present as to receiving more sigs on 630..
>The receive antenna is a 400' tuned vertical 
>loop that hears everything including the S5 noise..
>To date the best noise antenna input to a home 
>brew Dallas Lankford phaser is a 300' RG6 tuned 
>loop on the ground directly beneath the vertical loop..
>
>This quest has been an exhausting effort but at 
>least I'm hearing great DX for what seems like the very first time..
>
>Conversely I test wspr on 30m which at times can 
>be -130 noise or so...  It's nice to wake up in 
>the morning and see all WAC-7 continents with good S/N..
>
>Recently I found a very quiet 630m receive 
>location but it would require a wifi hop back to 
>the house.. Next project?? Has anyone done this??
>
>Thanks for your opinions..  DaveR aa1a
>
>Â Â  Â Â Â  Â Â Â
>______________________________________________________________
>600MRG mailing list
>Home: http://mailman.qth.net/mailman/listinfo/600mrg
>Help: http://mailman.qth.net/mmfaq.htm
>Post: mailto:600MRG at mailman.qth.net
>
>This list hosted by: https://www.qsl.net
>Please help support this email list: https://www.qsl.net/donate.html

73, Ed - KL7UW
   http://www.kl7uw.com
Dubus-NA Business mail:
   dubususa at gmail.com 
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/600mrg/attachments/20210118/5e2a4c9f/attachment.html>