[RFI] Fwd: Undelivered Mail Returned to Sender

[James Jordan]

True. But don’t dismiss the benefits out of hand. Variable speed pool pumps save us several hundred dollars per month at our rental property and contest station in VP5. $45 RF filters from Schaffner on each pump reduced the noise from a problem to undetectable on any amateur band. A great trade off in my opinion and I would suspect applicable to most variable speed drives. Ham radio can coexist with energy saving. 
73,
Jim K4QPL/ VP5M 

Sent from my iPhone

> On Apr 30, 2019, at 11:46 PM, Jim Brown <jim at audiosystemsgroup.com> wrote:
> 
>> On 4/30/2019 4:38 PM, Paul wrote:
>> I might call on the RFI audience to share their experience with regular electric motors versus the newer DC motors.  I am drawn to the energy efficiency of the latter but fear the control electronics may be RFI noisy as are our baneful “wall worts”.
>> 
>> So, anyone have an opinion ?
> 
> Not an opinion -- they have no place in scientific discussions. :)
> 
> It is a FACT that the the electronic controllers for most variable speed motors are quite noisy, for the same reason that the switch-mode power supplies in today's wall warts are noisy -- poor design and construction that fails to prevent radiation and conduction of RF noise. In other words, best to avoid them.
> 
> 73, Jim K9YC
> 
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