[TowerTalk] 4 square for 80

[Guy Olinger K2AV]

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 at 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 at earthlink.net
>> <mailto:jimlux at 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 at audiosystemsgroup.com <mailto:jim at 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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>>
>