[aprssig] Fossil-fuel-free-Fieldday Fun

Stephen black KB1CHU at AOL.COM
Thu Jun 11 10:16:55 CDT 2015


Just because you can doesn't mean you should. I might do this as an 
experiment but never involving others. The education level of different 
hams in understanding electricity is evident at every club meeting and 
field day I have been to. There are "extra"class licensees who passed a 
written test but are clueless about practical circuits as there are 
"technician"class ops who could write a book on it. I have a friend who 
holds a master electricians license and called me to install an outlet 
for him. He is a awesome test taker but a screwdriver in his hand is a 
dangerous weapon. I am not bemoaning the training levels but as a safety 
issue I find myself strongly against this idea. Steve KB1CHU


On 6/11/2015 10:12 AM, Robert Bruninga via aprssig wrote:
>
> Eventually we should get to a fossil-fuel-free fieldday.  It is easy 
> to avoid that stink-pot-foul smelling-polluting-noisey generator by 
> just running some small conductor wire to every car parked at 
> Fieldday.  Parallel them all and without drawing more than 100W from 
> each car, you can provide over a kW throughout fieldday just from 
> batteries.
>
> Just plug in 100W cigarette lighter inverters into each car, add two 
> caps and two diodes to double the 60 Hz 120v up to 330 VDC and 
> distribute that to all the operating positions.  Then just plug in 
> standard SWITCHING power supplies wherever needed to the 330VDC and 
> get all the 12v AMPS you need at each site.
>
> By upconverting to 330 VDC there are several advantages:
>
> 1)Distribution wire size is only 1% of what it would need to be at 12v 
> and only 10% of what it would be at 120v
>
> 2)You can deliver over 1 kW via simple #18 zip cord over hundreds of 
> feet and still only draw 3 amps, well below the rating of the wire.
>
> 3)You can parallel as many cars as you like at 330 VDC for distributed 
> energy
>
> 4)10 solar panels in series can provide 330 VDC at 7 amps (over 2 kW)
>
> 5)Or you can put microinverters ($125) on each solar panel to 
> gernerate the 120vac (into 330VDC) for distributed power
>
> The disadvantage is re-educating ham operators about high voltage DC 
> safety.
>
> After field day and crises at work, I hope to come up with a general 
> idea and concept, and connectors, and safety features to make this a 
> come-as-you-are way to make emergency field power not just for fielday 
> but for everyday as-needed use.
>
> Remember, every HYBRID comes to Field Day with a few kWh of energy 
> already at high voltage, and every electric car comes with 10 to 20 
> kWh of energy.  But the easiest place to tap in, is still, the 
> cigarette lighter at 12v and then  upconvert to 330 VDC for 
> distribution and then down convert back to 12v for universal usage at 
> the station…
>
> I have done that over 3000’ using nothing but one #24 wire and 
> Ground.  See http://aprs.org/aprs-swer.html
>
> But for Fieldday distances, better to avoid the ground loop and simply 
> run two-conductor zip cord or other convenient wire.
>
> If you don’t understand HV DC, then ignore this and stay away.  
> Remember even 8 year old cub scouts when I was a kid built HV Tube 
> radios as a standard requirement with open wiring on mom’s spare 
> breadboard… and none died…
>
> Bob, Wb4APR
>
>
>
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