EMRFD Message Archive 14729
Message Date From Subject 14729 2018-05-03 08:02:46 drmail377 Part-90 or Part-97 Spurious Compliance?
Hi, I have a question about Part-97 versus Part-90 compliance for handheld transceivers. I'm looking at an AnyTone AT-D868UV UHF/VHF DMR+FM radio for operation in the U.S. amateur bands. In reading the manual, the transmit spurious are specified as "-36dB". Alarm bells went off.
FCC Part-97 specifies maximum spurious when transmitting in the 30-225MHz range over the power range of 0.25W <= Ptx <= 25W as: -46dBc - 10*log10(P)dBc [What about above 225MHz?]
The AT-D868UV transmit power can be set in five steps from 1W minimum to 7W maximum. So the Part-97 allowed spurious limits are: -46.00dBc at 1W and -54.45dBc at 7W transmit power. So at best, the AT-D868UV published spurious specification is 10B too high for Part-97 compliance.
The AT-D868UV Distributor says the radio is "FCC Certified". But I think he means FCC Part-90 for the Private Land Mobile Radio Service. I think Part-90 limits transmit power much lower than allowed in the amateur bands, and spurious are allowed up to -20dBc. So the -36dBc specification from the AT-D898UV manual will meet Part-90 requirements, but not Part-97.
I think that as a licensed amateur, I have to operate in the amateur bands compliant with Part-97, not Part-90. Is that correct? If it is correct, then I don't think I will be able to LEGALLY operate this AT-D898UV radio in the U.S. amateur bands due to the non-compliant spurious products.
But I am seeing LOTS of these AT-D898UV radios being sold to U.S. amateur radio operators. Are all these Hams breaking the law?
Maybe I'm missing something here? Thanks for any help.
73's, David, WB4ONA
2. ARRL Handbook 2014, Pgs.27.5-27.11
3. ARRL Handbook 2014, Fig.27.2 on Pg.27.6
14730 2018-05-03 08:12:05 Dana Myers Re: Part-90 or Part-97 Spurious Compliance? 14732 2018-05-03 08:23:09 Dana Myers Re: Part-90 or Part-97 Spurious Compliance? 14736 2018-05-03 08:50:54 arfghans Re: Part-90 or Part-97 Spurious Compliance? That radio is NOT certified for use under Part 97 for use in the amateur bands and it is illegal to use it as such. Anyone marketing it for ham use is doing us all a great disservice.Gary NA6O 14737 2018-05-03 08:53:58 drmail377 Re: Part-90 or Part-97 Spurious Compliance? Thanks Dana.
So if it has -35dBc spurious it meets Part-90 limits, but even at 1W transmit power it can NOT be legally used in the U.S. amateur radio bands because the spurs exceed the -46dBc @ 1W Part-97 spurious specification. Is this correct or not? That is my primary question.
I want to buy one of these radios, they've gotten generally good reviews. But I want to know if it is legal to operate the radio in the amateur bands in the first place.
14738 2018-05-03 09:07:33 Dana Myers Re: Part-90 or Part-97 Spurious Compliance? 14740 2018-05-03 09:30:38 Dana Myers Re: Part-90 or Part-97 Spurious Compliance? 14741 2018-05-03 09:53:41 drmail377 Re: Part-90 or Part-97 Spurious Compliance? OK Dana, Thanks for looking deeper. I'll download the report.
One of the Distributors came back to me and essentially acknowledged there's a discrepancy between Part-97 & Part-90 which seems to be what the manufacturers build for. Apparently this has come up before at the ARRL. So it seems many people just ignore Part-97 spurious limits and just be happy if the radio is Part-90 certified, at least in the Part-97 specified 30-225MHz range.
FYI: This seems to be the current Part-97 stuff applicable to this topic:
FCC §97.307 Emission standards.
Excerpt: §97.307 (e) The mean power of any spurious emission from a station transmitter or external RF power amplifier transmitting on a frequency between 30-225 MHz must be at least 60 dB below the mean power of the fundamental. For a transmitter having a mean power of 25 W or less, the mean power of any spurious emission supplied to the antenna transmission line must not exceed 25 µW and must be at least 40 dB below the mean power of the fundamental emission, but need not be reduced below the power of 10 µW. A transmitter built before April 15, 1977, or first marketed before January 1, 1978, is exempt from this requirement.
Ref: ARRL Handbook 2014, Pgs.27.5-27.11
Ref: ARRL Handbook 2014, Fig.27.2, Pg.27.6
Required Attenuation of Spurious Outputs 30-225MHz:
X = Mean power of the fundamental in Watts.
A = Attenuation with respect to the fundamental in dB (dBc).
X < 0.1W: A = 50dB + 10*log10(X)dB
0.1W <= X < 0.25W: A = 40dB
0.25W <= X <= 25W: A = 46dB + 10*log10(X)dB
X > 25W: A = 60dB
Note: The above 30-225MHz spurious attenuation mask equations above include the 25uW hard-limit in Part-97 sub-part (e). The 25uW hard-limit is the specification that defines the spurious emission attenuation specification as a piece-wise linear mask as shown in the ARRL Handbook Fig.27.2 referenced above.
Example, 0.25W <= X <= 25W:
14742 2018-05-03 10:24:34 Dana Myers Re: Part-90 or Part-97 Spurious Compliance?