[1000mp] QST Product Reviews whitewash (long)

Mon, 15 Apr 2002 14:02:50 -0600

I have been reading the mail on these exchanges (as I expect many other are
doing). I have no idea whether or not any Kenwood or ICOM representatives
are 'reading the mail' on the FT1000MP reflector, but I certainly expect
that someone from Yaseu has seen the comments.

Ed, Joe, anyone --- Do you suppose that the marketing requirements for the
transceiver products that are being discussed include something that states,
"must be able to operate from 13.8 VDC" AND "must be capable of an RF output
into a 50 ohm load of at least 100 watts".  If that were the case, would
that not strongly dictate to the designers that the solid state devices used
in the transmitter section final amplifier must be designed to operate from
a 12-13.8 VDC voltage source. In turn, would that not make linear operation
at high power very challenging to achieve? For contest and DX radios do we
really care if they operate from 13.8 VDC (except using a high power
inverter). Maybe changing that requirement would make the design task easier
and hold the line on cost. The real issue probably is tied to marketing
volumes required or desired.

As I recall, my TS-950SDX had finals that operated at 48 VDC or so which
allowed them to achieve more linear output.

Most of us recognize that technical design is filled with compromises. As
several contributors have mentioned, they feel that  the weighting of
certain things may be 'incorrect' -- at least as they see it. Of course the
ultimate weighting of things is tied to 'will enough people buy it to
justify production'? In those days when I was associated which such
decisions it was always an agonizing choice between technical purity,
manufacturing cost and sufficient product features to assure market volume.

I suspect that if the designers were allowed to design radios that ONLY
operated CW or ONLY operated SSB and did not have to operated from 13.8 VDC
sources and did not have to include every band from 160 meters thru 6 meters
( or even 2 meters and 70 cm) the resulting products would (maybe) have
better performance within their slice of amateur life. The cost might be
unacceptable, however, because the production volumes for each segmented
product might be insufficient.

The above may or may not be the reason that many of the radios available to
us today cannot perform at state of the art levels. If, however, we become
more sensitive to the implications to the test results it is likely that
more buyers will tend to select products which have good test
characteristics. For that reason it seems important to clearly state things
much in the fashion that Joe (K4IK) has suggested, "We would expect to see
third order IMD results at least -36 dB and fifth order products at
least -46 dB." I think the follow on sentence might be softened to something
like the following: " ..in order to minimize the production of rf energy
which will reduce the ability of others to use close by frequencies". Others
may have a better choice for the words. The point is that we need some
institutional entity to be capable of the measurements and also capable of
helping amateurs understand the significance of the values measured. It
follows that that same institution needs to thoughtfully establish a
'targets' that represent acceptable, good and excellent design and
manufacturing performance which are accepted by amateurs and are known early
in the design cycle by manufacturers. I can see where a rating system of
acceptable, good and excellent could help manufacturers make design
decisions and also help amateurs select equipment while making their own
economic and performance trade-off decisions.

There really is only one national organization that has the resources and
the stature to do this -- ARRL. If we think this is an important thing for
the national organization to do (and that means it probably will have to NOT
DO something else), then we should be discussing these ideas with our
Division Directors. They will need to adjust the League policies to change
priorities for the ARRL Staff.

The number one priority for ARRL is to do those things which assure that
amateur radio has frequencies on which to operate. Almost every action and
program undertaken by the League is in some way in support of that priority.
None of us would have it any other way! Still, some part of the League
resource pool plausibly should be (and is) spent is support of proper
operation on our bands. An extension of that thought would be 'proper
operation using "acceptable" equipment.

Tod Olson, K�TO

-----Original Message-----
From: [email protected]
[mailto:[email protected]]On Behalf Of Joe Subich, K4IK
Sent: Monday, April 15, 2002 1:00 PM
To: [email protected]
Subject: RE: [1000mp] QST Product Reviews whitewash

Ed,

It would be refreshing to see: "the transmit IMD of this product is
simply not acceptable for a modern radio.  We would expect to see
third order IMD results at least -36 dB and fifth order products
at least -46 dB.  Any manufacturer that releases a product which
fails to achieve that standard simply does not care about the
amateur market!"

It is time to call them as they are and clearly condemn sloppy
designs.  If those who have the ability to accurately measure
performance in their reviews would do so, we might see more
attention to quality.

73,

   ... Joe, K4IK

> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]]On Behalf Of Hare,Ed, W1RFI
> Sent: Monday, April 15, 2002 1:10 PM
> To: '[email protected]'
> Subject: RE: [1000mp] QST Product Reviews whitewash
>
>
> The Review said:
>
> "Unfortunately, one number we'd like to have seen change greately
> in the IC-746PRO did not -- two-tone, third-order transmit IMD.
> This number indicates whether the unit will generate undesireable
> intermodulation products that can lead to splatter. On the worst-
> case band -- 10 meters in both cases -- third-order products were
> down by about 23 dB in the original '746 and about 25 dB in the
> 'PRO. In contrast, the IC-756PROIII's worst-case third-order
> products were down 30 dB -- not terrific, but getting there.
> The third order numbers were about the same on the worst-case
> VHF band, 2 meters.
>
>
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