[Lowfer] Rulemaking Ruminations - TWO: Supporting Data Needed

[John Andrews]

Tom,

I think you are mixing some issues here. Your comments about power would 
better describe operation in the 160-190 kHz band (1750m) under Part 15. 
Operation in the 137 kHz range in the last 11-12 years in the U.S. has 
been under Part 5, in the Experimental Service. ERP's of one watt or 
greater have been very common, produced by transmitters with hundreds or 
even thousands of watts. If you file any comments with the FCC, you 
should be careful to not to mix the two "services."

John, W1TAG

On 6/11/2015 2:58 PM, Tom Clifton via Lowfer wrote:
>> Subject: Re: [Lowfer] Rulemaking Ruminations - TWO: Supporting Data    Needed>
>>
>> I found an industry publication recently that gave some numbers of value. (http://docslide.us/documents/plcc-overview.html)  It said that PLC systems had a sensitivity of -24dbm.  So if we transmit at +30dbm we need to provide for 54db of decoupling between the antenna and the receiver.
>
> The calculations should include the actual effective radiated power.  It is pretty hard to put 1W watt into the air at 135khz.  (most people doing work at 2200m run input to the finals at a couple hundred milliwatts and have extremely inefficient antennas. Secondly, power lines by their nature are horizontal and most 2200m users have vertical antennas.  That right there gives 20db loss between transmitter and receiver.
> Therefore, it is my suggestion that within specified distances from power lines should have restrictions based on microvolts/meter at that specified distances which is how the current part 15 regulations specify what is allowed.  That would make the situation no worse than it is for existing part 15 operations.  The assumption here is that if you can't operate within  part 97 you should still be able to operate within part 15.
> https://transition.fcc.gov/Bureaus/Engineering_Technology/Documents/bulletins/oet63/oet63rev.pdf
> Also note that the existing part 15 regulations for 110-160khz are 1 Watt peak outpower for cable locating equipment and "Any" 2400/f(khz) uv/m @ 300m
>
>
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