[OKDXA] Radios and noise

[Rick]

17 Meters................
At 20:52 and 20:53.

On 1/27/2017 3:43 PM, John Geiger wrote:
> What band was this on?
>
> On Fri, Jan 27, 2017 at 3:37 PM, Rick <K9KK at atlinkwifi.com> wrote:
>
>> Yes, Roger.  I believe you are correct on all counts.
>> I */_think I have also heard _/*the term "NOISE POWER" used in this
>> context ???
>> Hey, just had an interesting contact(s).
>> I worked New Caledonia*LONG* path and New Zealand *SHORT* path.
>> I did NOT even hear New Caledonia short path ???
>> Since they are neighbors that is very strange.
>> My guess is that the New Caledonia station was aiming long path ???
>> OR~~~~~who knows ?????
>> 73 Rick
>> K9KK
>>
>>
>> On 1/27/2017 3:16 PM, Roger Simpson wrote:
>>
>>> Gentlemen:
>>>
>>> Thanks for your replies regarding S Meter Readings on CW vs. SSB. I never
>>> thought of this before but I guess you are saying that assuming the signal
>>> level for every 10Hz slot from 7,100,000 Hz up to 7,101,000 Hz was exactly
>>> -60 Dbm then the way receivers are designed then if your total bandwidth is
>>> say 2.4Khz then you are going to hear more noise out of the speaker than
>>> you would if you have a 500Hz bandwidth -- given that the background noise
>>> on the band is the "same" in any given 10Hz slot.
>>>
>>> I guess I was a little slow to the draw but I did not realize that the S
>>> meter was reporting on the aggregate signal that is in the bandwidth -- not
>>> just the strongest signal.  I guess another way to say this is that the
>>> S-meter reading relates to how loud the noise is that is heard on the
>>> speaker -- assuming that the audio level "volume control" is not changed as
>>> you change modes / filters.
>>>
>>> I guess I've been living in a cave over here. I just did an experiment on
>>> CW where everything stays exactly the same except I switch from a 250Hz
>>> filter, to a 500Hz filter, and then a 1200Hz filter. Lo and behold the
>>> S-meter changes. So the S-meter doesn't really have a DIRECT correlation to
>>> the noise level going on in the band. So I can't just say I've got a high
>>> noise level [or a low noise level] on 40m right now because my S meter says
>>> some given reading.
>>>
>>> Implicit in this is that if W5XYZ says "the noise level on 40m CW right
>>> now is S9" and W5ABC says "over here at my QTH the noise level on 40CW is
>>> S6" it could be that they are both seeing the same thing. We don't know
>>> unless we know what the bandwidth is that they are using. Also, of course,
>>> who is to say that rig manufacturer X and rig manufacturer Y have
>>> comparable S meter readings even if the mode and bandwidth are the same.
>>> Also various stations have different antennas. An antenna with a 40meter 3
>>> element yagi at 100 feet might given a different "noise level S meter
>>> reading" than a 40m dipole at 40 feet.
>>>
>>> I guess it is the margin between the signal to noise in terms of DBs that
>>> is important -- not some particular noise level S meter reading.
>>>
>>> 73  Roger  K5RKS
>>>
>>>
>>>
>>>
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