[TowerTalk] Shack wiring

[Alan Zack]

Maybe that a pk to pk reading with your shack O-Scope and do the math 
to find the RMS, Average, etc.

Pete Smith wrote:

> At 11:07 AM 1/24/2005, W8JI wrote:
> 
>> So you need two meters Pete...you need to measure the true
>> peak and you need to measure the true RMS. Capacitor input
>> supplies run off the peak, and are more sensitive to line
>> ESR at a  given power load than resistive loads like choke
>> input supplies or filaments.
> 
> 
> 
> Thanks to Tom and everyone else who wrote.  Yes, Tom's right about 110 
> vs 120 -- somewhere 50 years or so ago I formed the mental habit of 
> calling it "110." That was appropriate at the time, I think.  I'm told 
> the current ANSI spec is 120/240 +/- 5 percent.
> 
> Not having either a true RMS and true peak meter, I intend to follow the 
> advice of some others and verify that the two legs of the service are 
> within a volt or two of each other at the panel, and let the power 
> company put a recording voltmeter on the service to see if the problem 
> is there.  Frankly, I'm betting on that, because our power company is in 
> Chapter 11 and the county's population is growing fast.  I'm only a 
> couple of miles from the substation, but it's one that serves a lot of 
> the population growth.  The extreme lows I've noticed are all relatively 
> early in the morning, which suggests a peak load for heat pumps, 
> lighting, etc.
> 
> I just measured a 110 outlet close to the panel and the voltage was 
> 111.1  Upstairs, about 60 feet of wire away, with the two radios on 
> receive, I measured 110.1.  Turning off all the "radio" side (radios, 
> rotator and stack controllers, etc.) it went up to 110.8.  Just now it 
> hit 111.7 in the shack for a moment -- now 110.2.  Lots of fluctuation.  
> I don't know if these are either RMS or peak voltages (most likely some 
> fudged version, because it's not a Fluke).
> 
> Assuming the wiring is #14, my Handbook says the resistance is .252 ohms 
> per 100 feet.  Measuring at an outlet in the shack, equipment in the 
> shack is drawing through ~120 feet of that wire, right?  That doesn't 
> sound wildly off to me.
> 
> Or have I misunderstood something fundamental?  Wouldn't be the first time.
> 
> 73, Pete
> 
>   
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-- 
__________________________________________________________________________ 

Alan Zack
Amateur Radio Station K7ACZ
Las Vegas, Nevada, USA
Quality Engineer, The Boeing Company, Retired
Aviation Chief Warrant Officer, U.S. Coast Guard, Retired
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