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General Category => General Radio Discussion => Topic started by: Antennae on November 09, 2013, 2238 UTC

Title: What does Sx mean in terms of signal strength?
Post by: Antennae on November 09, 2013, 2238 UTC
Hi, I'm new in these parts.  And I'm enjoying capturing pirate stations.  I would like to give the standardized reception report but I'm not sure what it is.  I see everybody giving "S" and a number in regards to signal strength.  What is it?
Title: Re: What does Sx mean in terms of signal strength?
Post by: jFarley on November 09, 2013, 2311 UTC
Here's a link to a wiki article on the subject.  It's not too technical, nor is it dumbed down.  This should give a good idea about what people are talking about.

http://en.wikipedia.org/wiki/S_meter
Title: Re: What does Sx mean in terms of signal strength?
Post by: skeezix on November 09, 2013, 2315 UTC
In addition to the s-meter, I like giving a SINPO rating. That's more subjective, but there's no standard calibration for s-meters. Ideally, a field strength meter would be best, however, they're expensive and frankly, not worth the cost for most people.

http://www.hfunderground.com/wiki/SINPO (http://www.hfunderground.com/wiki/SINPO)

Title: Re: What does Sx mean in terms of signal strength?
Post by: Antennae on November 10, 2013, 0002 UTC
Eureka.  My Radio Shack DX 398 (same as Sangean ATS 909) has a "1-10" signal strength meter. It threw me off because I've also heard references to dB and my meter doesn't have that.  However, the wikipedia site cleared that all up. 

My scientific side likes the SINPO rating.

 My meter reminds me of the movie Spinal Tap when the guy is pointing out that his amplifier is better because it goes up to 11 instead of 10 like the other amps. 

https://www.youtube.com/watch?v=4xgx4k83zzc

Title: Re: What does Sx mean in terms of signal strength?
Post by: Zoidberg on November 10, 2013, 0023 UTC
Hams' S-meters all start at 40 over 9.  Anything less is considered trolling.  Never mind that noise is 20 over 9.

Semi-seriously, S-meters are usually bias confirmation posing as science.  Even with identically calibrated receivers, different locations and antennas may result in an S7 signal that reads better than an S9+20 signal.  

SINPO is based on perceptions and usually close enough for useful feedback.  The only problem with the SINPO system for those of us in noisy urban and suburban areas is figuring out whether the fog of manmade noise emitted by our electronic toys is I=interference or N=noise.  For example, if we log "I" as high, when we're referring to local RFI/EMI, an op might mistakenly assume someone was deliberately QRMing his broadcast.  If we log RFI/EMI as "N", some folks who are accustomed to low-RFI/EMI rural settings may assume we're referring to QRN - atmosopheric noise.  

So I usually mention RFI/EMI separately from my SINPO reports.  Since I'm in a typical suburban area, mostly using an indoor antenna, RFI/EMI is usually a factor.  It can range from an S1 fog of white noise that isn't too bad at all, to S9 snap-crackle-pop that obliterates all but the strongest local MW powerhouses.  I've noticed that as more of my neighbors have switched from plasma to LED TVs, the fog of white noise is pretty tolerable now compared with five years ago.  I don't often need to tote a portable outdoors to get away from manmade noise.
Title: Re: What does Sx mean in terms of signal strength?
Post by: Antennae on November 10, 2013, 0117 UTC
Good point. I didn't think about that.  Luckily, I'm in a area with low man made noise.  One time I took my portable to the LA area. My hotel about 1/4 mile from the beach.  Reception with my whip antenna was picking of a lot of extra noise so I figured it was from the city. SW wasn't fun.  I remember finding some interesting MW stations. 

I can't wait for my next electricity outage. I plan to check my radio during it to get a baseline of what it sounds like with nothin. 
Title: Re: What does Sx mean in terms of signal strength?
Post by: skeezix on November 10, 2013, 0214 UTC
Quote
I can't wait for my next electricity outage

I tried my own here by shutting off the main breaker to the house. That wasn't enough. Still had noise.

When we lost power to the block, that was enough and was dead silent for RFI/EMI.