[TenTec] Truth in Advertising...Icom Style

[Bill Rowlett]

No, the big three just make you write a check for a new unit.



>From: "John L Merrill" <jmerrill1 at adelphia.net>
>Reply-To: tentec at contesting.com
>To: <tentec at contesting.com>
>Subject: RE: [TenTec] Truth in Advertising...Icom Style
>Date: Wed, 26 Jan 2005 19:19:13 -0500
>
>Hopefully I don't have tp reboot the ProIII :-).
>
>John N1JM
>
>-----Original Message-----
>From: tentec-bounces at contesting.com
>[mailto:tentec-bounces at contesting.com]On Behalf Of Bill Tippett
>Sent: Wednesday, January 26, 2005 7:10 PM
>To: tentec at contesting.com; orion at contesting.com
>Subject: [TenTec] Truth in Advertising...Icom Style
>
>
>March 2005 QST Product Review:
>
>http://www.arrl.org/members-only/prodrev/pdf/pr0503.pdf
>
>******************************************
>ICOM’s advertising for the PROIII
>trumpets what it calls “+30 dBm-class
>third-order intercept point” performance
>on 20 meters. This would put it on a par
>with some of the best receivers we’ve ever
>run through the Lab. Third-order intercept
>(TOI) is a number that many like to
>use as an all-in-one performance benchmark,
>since its value derives both from
>the receiver’s sensitivity and its front-end
>selectivity (specifically, two-tone, third-
>order IMD dynamic range). The more
>positive the number, the better, and TOI
>figures can also be negative.
>
>Although the PROIII Instruction
>Manual doesn’t specify the advertised TOI
>number, an ICOM Product Guide, originally
>in Japanese, spells out the measurement
>conditions: 100 kHz spacing (wider
>than our Lab’s widest 20 kHz spacing measurement),
>preamps off and a 2.4 kHz filter
>bandwidth.
>
>Nonetheless, under the least stringent
>measurement standard the ARRL Lab
>uses, the PROII came pretty close to meeting
>the +30 dBm mark. At 20 kHz spacing,
>we calculated the TOI at +25 dBm
>on 14 MHz with both preamplifiers turned
>off. That works out to a slightly less than
>a 5 dBm improvement over the PROII, all
>other things being equal.
>
>Under the same conditions at 5 kHz
>spacing—something much more akin
>to real-world amateur conditions (and
>this time well within the passband of the
>receiver’s 15 kHz roofing filter)—we
>determined the PROIII’s TOI to be
>–17 dBm, 1.8 dB better than the –18.8 dBm
>we calculated for its predecessor."
>***********************************************
>
>Whoopee...a whole 1.8 dB improvement
>at 5 kHz for another $800?  And (er......
>ahem)...Orion's IP3 was measured by
>ARRL at 5 kHz to be +22.1 dBm, a mere
>39.1 dB better (for just $300 more) but still
>below Icom's touted spec of +30 dBm.  :-)
>
>At least ARRL is getting a little tougher
>than I've seen previously (last paragraph's
>"real-world" comment).  Some day they
>may actually have the guts to call a spade
>a spade in their reviews.  Naah...not likely
>as long as Icom keeps buying all those
>advertising pages in QST.
>
>                          73,  Bill  W4ZV
>
>P.S.  I finally broke the code...PRO stands
>for PRO-fessional B.S.
>
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