[Milsurplus] [ARC5] 500 Kc XMTR

[Richard]

I think the theoretical PLC problem has mostly gone away as they have 
been changing to fiber for easier maintainability and reliability.  
Thirty years ago the LF/MF region was loaded with dead carriers, PLC 
signals.  They were considered unintentional radiators, but radiated 
very well indeed.  Now I don't hear any. When an amateur band was first 
proposed there was pandemonium and unreasoned fear among power people, 
fearing we would trip their PLC relays and pull the power grid down.  
Reality is PLC signals are measured in volts, vs microvolts for radiated 
signals.  The only place radiated signals are heard on PLC circuits is 
near megawatt navy transmitters.  We have all heard radio noise under 
power lines, well it's much worse when you couple directly to the line.  
Big power transformers have significant capacitance to ground and look 
like a bypass capacitor at radio frequencies, so they need traps at each 
end of the line, plus a high voltage capacitor to couple to the line.  
This is big stuff because the inductor must pass line current, 600 
amperes or more. (etc, etc, etc.)

WNE, licensed a year or two ago for 472 and 500 Kc as the New England 
Historical Radio Society, was grandfathered in.  This is actually Steve 
Russell, WA1HUD, in Stoneham MA.  Last year he was sending the North 
Atlantic weather forecast nightly using an emergency transmitter at 
about 40 Watts, is now working on QRO, and hoping for better results. 
(Usually gale winds, fog, 40 foot seas, ice, and I'm glad I never went 
to sea...)

Richard, AA1P


On 09/17/2017 04:19 PM, Kenneth G. Gordon wrote:
> On 17 Sep 2017 at 19:38, Hubert Miller wrote:
>
>> What was the rationale for the power limit? RFI to civilians?
>> -Hue
> No. Not at all. Several reasons, among them, possible interference to PLC.
>
> In addition, the USCG claims ownership of that spectrum. They have had plans for years to
> install high-accuracy ground-mounted GPS systems there, although they have never, ever,
> gotten funding for it, and the new eLoran will work better anyway.
>
> FYI, I have been involved in trying to "resurrect" the 600 meter band for at least the past 20
> years. I started the forum, 600MRG, for 600 Meter Research Group then, and still support it
> now.
>
> At one time, we had worked very hard to get a group license to operate in that band, 450 to
> 510 kHz, and had the license in hand after at least 2 years of work, one or two of our group
> actually got on the air, and the USCG suddenly shut the entire effort down as they had been
> "missed" in the discussions which the FCC had initiated with users of that band.
>
> BTW, there were certain FCC agents who enthusiasticlly supported our efforts and gave us
> very significant help to get our license. We were both very grateful and somewhat surprised
> at their efforts.
>
> After that, within a few years, some started to apply for, and receive, experimental licenses
> to operate on spot frequencies in the band.
>
> Then Dr. Fred Rabb (I forget his call) managed, after at least 3 years of work, to get a
> "group" experimental license to operate over a very small range of frequencies in the band.
> He had to have help from the ARRL to finally get action out of the FCC.
>
> Then things built from there.
>
> So, from my perspective, it has taken at least 20 years to get to where we are now.
>
> In addition, of course, there is the group, most of whom are hams, who put KPH back on the
> air. It turns out that many of the original coastal 600 meter stations, and even some ships,
> had valid licenses for operation in that band which had never expired, and which the FCC
> will still renew today. In fact, I know of at least one case where someone in the midwest
> applied for and received a NEW license for such a station.
>
> Ken W7EKB
>
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