[RTTY] QRM

[Stanley Zawrotny]

The RFI forum is a good source of information on tracking down sources of QRN (not QRM) in your house. Wall warts are a common source of noise. They recommend a technique similar to the one you described.

Stan, K4SBZ

"Real radio bounces off the sky."

> On Nov 11, 2016, at 5:24 PM, William Lisk <wglisk at outlook.com> wrote:
> 
> Just some thoughts regarding QRM--maybe a walk-around with a small 
> portable radio would reveal a noisy appliance, poor utility connection 
> nearby, etc.  I have a cheap, home brew wire antenna here, and the noise 
> typically runs around S4 on 160 meters and S2, S3 or less on higher 
> frequency bands--generally the higher the band, the less it is.  We are 
> in an average residential neighborhood.
> 
> Recently, I was testing reception at home by sending audio via USB from 
> my Icom IC-7100 (with built-in sound card) to my laptop PC running 
> MMTTY.  I had around S9 across several bands that night.  It turned out 
> that  a different USB cable with a better ferrite bead/slug for RF 
> suppression drove the noise down to S4. Removing the USB cable entirely 
> took the noise down to S1 (think I was on 40 meters then).  When I 
> thought about it, it made sense, because there's a lot of digital 
> chatter on USB that could splatter into HF bands without proper 
> grounding and attenuation.
> 
> Operating at our remote cabin at the family camp in the woods, with no 
> utilities, we use 12 volt solar power with batteries for 12 VDC and an 
> inverter for 120 VAC.  HF QRM is terrible with the inverter running and 
> is much reduced when shutting it off to operate the IC-7100 on the 
> batteries.
> 
> 73,
> 
> Bill/KC2EMH
> 
> 
>> On 11/11/2016 3:06 PM, Thom wrote:
>> I cannot hear them....darn
>> 
>> I have S-5 noise though
>> 
>> 
>>> On 11/11/2016 18:06, Lee Roberts wrote:
>>> 14.08910 for veterans day special event - turns out i had to invert my
>>> FSK transmit in order for him/her to copy me though.
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>> 
> 
>