[RE-wrenches] Quietest off-grid inverter HAM radio

Sat Oct 3 11:01:27 EDT 2020

I would think if the devices meet the tested Class B spec then no
advantage. Engineers can design filters for the Class B requirement. The
radiated RF may be different between two identical specced inverters of
different topology. Even that can be designed in, if there is a requirement
and it is tested for. 

The basic test anyone can do is with a 10 dollar
analog AM radio tuned to a weak station. If you can't get 5 feet back from
the inverter and hear the station, then you have work to do to suppress the
radiated garbage. An XW is about 3 feet if it is installed correctly. My
truck inverter which is transformerless, will kill AM for about 50 feet.

See what Bob says, my component level engineering is from the 1980's and
dated.  

Dave Angelini Offgrid Solar
"we go where powerlines
don't"
http://members.sti.net/offgridsolar/ [1]
e-mail offgridsolar at sti.net
[2]
text 209 813 0060

On Fri, 2 Oct 2020 11:58:15 -0600, Jay  wrote:  Hi
Bob   Is there any inherent advantage or disadvantage to non transformer
inverters?    Jay 
 On Oct 2, 2020, at 11:27 AM, "bob at midnitesolar.com" 
wrote:

This is all great advice. 

Remember that long wires can radiate
RF. PV lines and the array can make a good antenna for RFI as well as the
battery lines. 

I agree with Dave that both of those inverters are more
than likely similar. I know that the XW has a good filter on the battery
line 

right where it should be, at the exit point. 

An additional ferrite
toroid core used in common-mode filter hookup (BOTH hot and cold wires run
through the center) as close to 

the unit as possible on AC and DC wires
as well as possibly, communications lines exiting the units. Battery
temperature sense also, 

possibly. 

As for resources, Palomar link that
Roy gave is a good resource. Digikey or Mouser might also be a good place
to look for both the 

parts themselves and possibly information. 

boB

K7IQ 

  On 10/2/2020 8:57 AM, Dave Angelini Offgrid Solar wrote:  

My
advice is it is more about the installation and the distance from the
inverter, and it's devices from the station location, than the make of
equipment. There are other things also that I do to fix noise and
interference. My wife is an extra class operator and several clients have
visited to get ideas. Most any noise issue can be fixed later, unless you
are too close to the source. 

That said I mainly use XW and I would assume
Radian is similar. Below is the spec that XW is test for and has been since
2005. 

" EMC directive FCC and Industry Canada Class B " Below are 2 of
the ways that the issue is defined and measured. 

So-called "RADIATED
EMISSIONS" are picked-up WITH A test-antenna and can come from all parts of
the product INCLUDING the cables it uses (power and module interconnects).
CONDUCTED EMISSIONS are measured directly as voltages or currents on the
cables used by the product.  

Dave Angelini Offgrid Solar
"we go where
powerlines don't"
http://members.sti.net/offgridsolar/ [3]
e-mail
offgridsolar at sti.net [4]
text 209 813 0060

On Fri, 2 Oct 2020 09:35:34
-0600, Mac Lewis  [5] wrote:  Hi Wrenches,   I have a HAM radio enthusiast
that needs to replace their off-grid inverter. He would like the inverter
that puts off the least interference. I don't know a whole lot about
evaluating an inverter for this, but I am reaching out for recommendations.
Needing ~8kVa at 48V.   Thanks!   
   -- 
        Mac Lewis

"Yo solo sé
que no sé nada." -Sócrates    

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