[600MRG] EIRP

[Jim Miller]

I wonder how this will all sort out? How many hams will buy or build an RF
ammeter and go through all the calculations to stay within legal limits?

73

Jim ab3cv



On Tue, Jan 27, 2015 at 1:55 PM, Eric NO3M <no3m at no3m.net> wrote:

> An additional reference from FCC: https://apps.fcc.gov/eas/
> comments/GetPublishedDocument.html?id=204&tn=255011
>
> WRC-2012 and most countries are defining 630M power limits in terms of
> EIRP, and most likely, also the FCC when they get around to it. However,
> many experimenters in the US refer to their power in terms of ERP.
> Therefore, what is claimed as 5W ERP is 8.2W EIRP.
>
> ERP = EIRP / 1.64
> EIRP = ERP * 1.64
>
> (per definition, ideal dipole [free-space?] has 2.15 dBi gain over
> isotropic radiator, or 1.64 numerical gain).
>
> So, if you are running 5W ERP, cut it back to 3W ERP to get 5W EIRP.
>
> This all begs the question..... does anyone really know what power they're
> running other than what's coming out of the final amplifier stage?!?  I'm
> sure most of pretty darn close though.
>
> 73 Eric NO3M / WG2XJM
>
>
> On 01/27/2015 01:24 PM, Rudy Severns wrote:
>
>> Ed raised a question on my calculation of EIRP to Pr, radiated power.
>> According to Fritz's note on the standard definitions ERP is defined with
>> a
>> different reference from EIRP!  ERP is referenced to a "dipole" in free
>> space while EIRP is referenced to an "isotropic" radiator.  I find that
>> distinction bizarre but from Fritz's note that appears to be what the FCC
>> has done.  Neil's (XSV) posting last week on this subject has not only the
>> calculations but Fritz's original note.  If you think Fritz's
>> interpretation
>> is wrong now would be great time to sort it out.  A couple of weeks ago I
>> misinterpreted it, using an elaborate explanation, and bought us an extra
>> 3
>> dB.  It was very disappointing to lose that.
>>
>>
>> 73, Rudy
>>
>>
>>
>
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