Club House > Club Talk
Glider A & B Crets.
billscottni:
we can do the BMFA equivalents Fred. Wouldn't be any harm in us doing them and ISR recording that we did in case of any insurance claims!
EI1638:
Folks,
Please forgive my ignorance, but I don't recognise this acronym "ERP", and neither does google in the context of a transmitter.
"Power output as 100 mW ERP for any radio type and the requirement to use equipment only with a “CE” approval stamp. 5.8 Ghz Video equipment is usually limited to 25 mW ERP."
I can have a guess, but its not one I've come across before.
Chris
johnfireball:
"Effective Radiated Power"
EI1638:
Thanks John. Now I know.
Effective radiated power (ERP), synonymous with equivalent radiated power, is an IEEE standardized definition of directional radio frequency (RF) power transmitted from a theoretical half-wave dipole antenna. It is differentiated from effective (or equivalent) isotropic radiated power (EIRP) mainly by use of relative antenna gain instead of absolute gain in the calculation. In the case of ERP, antenna gain is calculated as compared to the maximum directivity of a half-wave dipole antenna, whereas EIRP is calculated using antenna gain referenced to an ideal isotropic radiator, otherwise known as "absolute" gain. The term "antenna gain" is assumed to be absolute (referenced to isotropic) unless specifically stated to be relative. The gain is then multiplied by the power actually accepted by the antenna to result in the actual ERP value (or EIRP). Power losses which occur prior to the antenna, e.g., in the transmission line or from inefficiency in the generator itself are therefore not included in the calculation of ERP or EIRP.
courtesy of wikipedia...
Happy Days:
Ha. Don't you just love jargon like that!! ::)
The antennas we use in RC flight control are basically what are known as 'dipole' type antennas which offer zero gain. So to all intents and purposes the Effective Radiated Power is just the amount of output power produced by the transmitter.
ps. If you're interested ;).....There are some types of radio antenna that focus radio energy in a particular direction, like the reflector behind a torch light bulb that concentrates all the light produced by the bulb in one direction. So although the bulb may only produce (say) 1 watt of power in total, the reflector concentrates all that light forward. So the Effective Radiated Power of the torch may be (say) 5 watts,... but only in the 'forward' direction. Clear now?.............never mind :-\
Keith
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