29-12-2018, 07:51 AM
Bo
The Australian Licence Conditions Determination (the bible - the 'LCD') states:
"
7A Spurious emission limits for an amateur station
(1) The licensee must not operate an amateur station if the emissions of the station include spurious emissions that are not attenuated below the power of the wanted emission supplied to the antenna transmission line by:
(a) for frequencies less than 30 MHz — the lesser of:
(i) 43 + 10 log (PEP) dB; and
(ii) 50 dB; or
(b) for frequencies equal to or greater than 30 MHz — the lesser of:
(i) 43 + 10 log (P) dB; and
(ii) 70 dB.
(2) In subsection (1):
P means mean power in watts supplied to the antenna transmission line.
PEP means peak envelope power in watts supplied to the antenna transmission line.
"
At HF that basically means -50dBc and 6M as -70dBc due to the "lesser of" wording although does it really mean the reverse? It could also mean -43dBc for both as that value (per (i)) is the lesser 'numerical' value given the RF power level involved (200mW). Legalese interpretation / argument ??
Given I don't know how far the Icom transceiver's receiver is set into 'S9+60' levels (i.e. saturation), the spurious signals I nominally measured / noted could be within the required tolerances. I might have to cascade a few 20dB attenuators and try to get closer-to-definitive measurements - and hope that the receiver shielding is good enough to allow them to make sense. I will give it a try at some stage soon and report my findings.
Doug
The Australian Licence Conditions Determination (the bible - the 'LCD') states:
"
7A Spurious emission limits for an amateur station
(1) The licensee must not operate an amateur station if the emissions of the station include spurious emissions that are not attenuated below the power of the wanted emission supplied to the antenna transmission line by:
(a) for frequencies less than 30 MHz — the lesser of:
(i) 43 + 10 log (PEP) dB; and
(ii) 50 dB; or
(b) for frequencies equal to or greater than 30 MHz — the lesser of:
(i) 43 + 10 log (P) dB; and
(ii) 70 dB.
(2) In subsection (1):
P means mean power in watts supplied to the antenna transmission line.
PEP means peak envelope power in watts supplied to the antenna transmission line.
"
At HF that basically means -50dBc and 6M as -70dBc due to the "lesser of" wording although does it really mean the reverse? It could also mean -43dBc for both as that value (per (i)) is the lesser 'numerical' value given the RF power level involved (200mW). Legalese interpretation / argument ??
Given I don't know how far the Icom transceiver's receiver is set into 'S9+60' levels (i.e. saturation), the spurious signals I nominally measured / noted could be within the required tolerances. I might have to cascade a few 20dB attenuators and try to get closer-to-definitive measurements - and hope that the receiver shielding is good enough to allow them to make sense. I will give it a try at some stage soon and report my findings.
Doug
Doug VK4ADC @ QG62LG51
http://www.vk4adc.com
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If you have a comment or question, post it as it may trigger or answer the query in someone else's mind.
http://www.vk4adc.com
This Forum is only going to be as interesting as the posts it contains.
If you have a comment or question, post it as it may trigger or answer the query in someone else's mind.