[OKDXA] Radios and noise

[John Geiger]

Hi Kim,

I will try that, thanks for the suggestion.

73 John AF5CC

On Mon, Jan 23, 2017 at 8:12 PM, Kim Elmore <cw_de_n5op at sbcglobal.net>
wrote:

> A new radio is unlikely to effectively deal with the noise you hear. There
> could be many sources: it could be a plethora of small switch-mode power
> supplies (SMPS) in your own home. If you can manage it, kill power at your
> house at the main breaker and see if the noise decreases. If it does, you
> can then look for the various possible sources.
>
> You didn't mention the antenna you use, but I know that on 40 m, I often
> see noise levels like what you describe on my 2 el yagi up ~50 ft when the
> band is open. You'll likely see variations between day and night. Here's a
> quick way to determine if your RF environment is quiet (little man-made
> noise): record your daytime noise level on a low band (80 or 160 m), then
> do the same at night (ou don't need a resonant antenna for this check). If
> you hear more noise at night than in the day, you're in a quiet place. Why
> does this work?  Sferics from lightning will propagate at night but be
> absorbed in the daytime. If you can hear them at night based on an
> increased noise level, you're in a pretty good place.
>
> 73,
>
> Kim N5OP
>
>
> On 1/23/2017 7:07 PM, John Geiger wrote:
>
>> I know if you buy a more expensive radio, you get a receiver that
>> (usually)
>> has better dynamic range and handles QRM conditions better, generating
>> less
>> IMD products and blocking when the band gets full of signals.  Does the
>> same hold true for QRN and electrical crud?  I know that some radios have
>> more tools than others, like noise reduction, notch filters, stuff like
>> that.  Do more expensive receivers get less affected by RFI and other
>> junk,
>> and by atmospheric noise?
>>
>> Here is my situation:  I was having some bad powerline noise from a pole
>> close to my house. The noise blanker in the radio I have took out the
>> buzz,
>> but I am seeing a S6 noise level on 40m SSB and on 20m SSB sometimes.  I
>> figured some of that came from the line noise, so I didn't think about
>> doing much until the line noise was fixed first.  Well the power company
>> came and fixed it today. The buzzing is gone!  The noise level still is
>> there, though.  I am using a Yaesu FT100D which has a great noise blanker,
>> and does have AF DSP, but it is a cheap, mobile type HF/VHF/UHF radio.  On
>> 40 meter SSB I see a S5 or S6 noise level when on SSB, and that is with
>> the
>> preamp off.  On CW it is much less because I put the 500hz CW filter in
>> line.  20 meters is sometimes the same, but sometimes on SSB the noise is
>> much lower, which I think is probably from urban crud. I live in an older
>> neighborhood where the houses are maybe 8 feet apart, if that much. I am
>> sure many neighbors have switching power supplies in all sorts of
>> electronics.
>>
>> So, is this 40 meter noise level pretty typical for most people?  Would a
>> more expensive radio like a Kenwood TS590 (which is supposed to have a
>> great receiver), Yaesu FTDX1200 or Icom 7200 be less affected by these
>> types of noises?  I can't afford much more than that right now,and would
>> like something that is fairly small enough to still take mobile or
>> portable
>> from time to time.  I did try a yaesu FT891 which is a mobile sized radio
>> and it was maybe very slightly better, but not really noticable.  A Ten
>> Tec
>> Eagle would also be small enough.
>>
>> Is this one of the compromises you have to live with when you get a
>> smaller
>> radio?
>>
>> 73 John AF5CC
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> --
>
> Kim Elmore, Ph.D. (Adj. Assoc. Prof., OU School of Meteorology, CCM, PP
> SEL/MEL/Glider, N5OP, 2nd Class Radiotelegraph, GROL)
>
> /"In theory there is no difference between theory and practice. But, in
> practice, there is." //– Attributed to many people; it’s so true that it
> doesn’t matter who said it./
>
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