[RTTY] QRM

[William Lisk]

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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