Tom, W8JI, put this up in an email, simply reading part 97. Note the
term "transmitter power". Power would be measured at the output of the
final amplifying stage. A transceiver and an amp would be considered a
two part transmitter.
I know that someone once posted the result of a call to an FCC field
office with this question, but I can't find it. I remember that the
answer was "at the transmitter." Tom's logic below seems conclusive
based on the literal wording in part 97.
------------------------------------------------
peter gerba wrote:
> Where is the 1500 watts we are limited to measured from ? The output of
> the Amp ?
Section 97.313b covers this. "No station may transmit with a transmitter
power exceeding 1500 watts PEP."
Transmitter power. Not common point or feedline power.
Broadcast stations are assigned an ERP power, usually limited by field
strength in a direction(s) that bothers another station(s).
That seems clear.
73 Tom
http://lists.contesting.com/pipermail/amps/1997-April/000735.html
-------------------------------------------------
73, Guy K2AV
On Sun, Sep 25, 2016 at 11:59 PM, jimlux <jimlux@earthlink.net> wrote:
> On 9/25/16 5:53 PM, Guy Olinger wrote:
>>
>> The 1.5 kW PEP is at the amplifier output.
>>
>> That has been clarified with the FCC multiple times. Tuner, feedline,
>> antenna system losses are your problem. You are diminished by those
>> losses unless you either have no losses, or run illegally.
>>
>
> Interesting, can you point to an opinion letter or enforcement action that
> says this?
>
>> The commercial measurement scheme does not apply to the amateur service
>> except for a couple bands where that particular band references
>> effective radiated power. 1.5 kW is not allowed on those amateur bands.
>>
>> 73, Guy K2AV.
>>
>> On Sun, Sep 25, 2016 at 7:07 PM, jimlux <jimlux@earthlink.net
>> <mailto:jimlux@earthlink.net>> wrote:
>>
>> On 9/25/16 12:05 PM, Guy Olinger wrote:
>>
>> On Sun, Sep 25, 2016 at 12:25 PM, Jim Brown
>> <jim@audiosystemsgroup.com <mailto:jim@audiosystemsgroup.com>>
>>
>> wrote:
>>
>> On Sun,9/25/2016 6:49 AM, Steve London wrote:
>>
>> What problem(s) are we attempting to solve with chokes on
>> the 4-square
>>
>> feedlines ?
>>
>> Noise.
>>
>>
>>
>> Noise, yes. Gotta give you that one, but the main reason for the
>> 4 square
>> was TX gain, right? You do have listening antennas for 160 and
>> 80? So we
>> have to worry about *loss*. Loss eats up gain from patterns.
>> Loss eats up
>> amplifier output. Your *system* gain past your transceiver is
>> antenna gain
>> + amplifier gain *** minus LOSSES ***.
>>
>> Diversion of power to miscellaneous conductor paths is almost
>> universally
>> lossy and never in directions and modes desired in our attempts at
>> directional arrays.
>>
>>
>> So measure your output power at the system interface to the
>> "antenna".. put 1500 watts (total) into your 4 antennas: sum the
>> powers at each element (including if you have phased them so you
>> have a negative element). That's what commercial broadcasters do,
>> isn't it?
>>
>> The regulations don't say "amplifier output", they say
>> "PEP (peak envelope power). The average power supplied to the antenna
>> transmission line by a transmitter during one RF cycle at the crest of
>> the modulation envelope taken under normal operating conditions. "
>> "(b) No station may transmit with a transmitter power exceeding 1.5
>> kW PEP. "
>>
>> If I define my "antenna transmission line" reference plane at the
>> antenna feed points, I think that works.
>>
>>
>>
>> _______________________________________________
>>
>>
>>
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>>
>
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