[hpsdr] Star-10 Transceiver article in QEX

[Giancarlo Moda]

Hi Bob,

thank you very much for sharing your comments wit all
of us (me plus the other members...hi).
I have not seen QEX article and I d not know if I will
ever see it (unless I get a copy)so I cannot comments.
I had a few mails/newsgroup (I forgot which one)
exchanges with Dentrea. I did not know about him
before this time, sorry ... I have no Dentron and
about DDS I read a few articles from Ulrich -
N1UL/DJ2LR, Colin - G3SBI .. and got some samples from
AD ... I also visited his web page.

I am a normal ham ... I had no doubt his STAR-10 is a
very professional design but ... how many ham can
reproduce it? How was he able to make measurements?
and others ???
...but I had the impression he is out of time or he
does not see further than his garden ...

It was strange for me to discover he does not know
anything about the G3SBI's H-Mode Mixer ... as Colin
is the person that remved the mixer from the critical
stages in a receiver ... OK if he does not know about
me ... but also h does not know about the high
performance projects like the CDG2000 and Peter,
G3XJP, STAR - Software Transmitter And Receiver ...
and Software Defined Radio, vulgaris SDR...

It is strange ... from what I have been reading in his
web page he seems to be a very intelligent and clever
engineer ... it is pity one may be seen completely
negative because he got "stuck" in the time... I hope
it does not happen to me ....

73

Gian
I7SWX



Message: 3
Date: Sun, 11 Nov 2007 19:44:26 -0500
From: Robert McGwier <rwmcgwier at gmail.com>
Subject: [hpsdr] Star-10 Transceiver article in QEX
To: qex at arrl.org
Cc: softrock40 at yahoogroups.com, uwsdr at yahoogroups.com,
Flex Radio
	<flexradio at flex-radio.biz>,	gnuradio mailing list
	<discuss-gnuradio at gnu.org>,	High Performance Software
Defined Radio
	Discussion List <hpsdr at hpsdr.org>
Message-ID: <4737A1EA.9090403 at gmail.com>
Content-Type: text/plain; charset=windows-1252;
format=flowed

Dear QEX Editor:

Cornell Drentea, designer of Dentron amplifiers, and
one of the many
 who 
claim to have invented DDS referenced PLL's (he has as
good a case as 
any) has shown a beautiful example of serious
professional engineering 
in his Star-10 article and he is to be congratulated
on a brilliant 
design and beautiful craftsmanship in building it.  It
is a very clever
 
and beautifully done traditional design.

This notwithstanding, I have to say that I am
particularly disappointed
 
that the editors of QEX allowed the tone of the
article to go
 unchecked. 
I have comments on the "commentary" and the
pseudoscience in the
 article.

As the ARRL Software Defined Working Group Chairman, 
I found much of 
his commentary both insulting and just plain wrong
both personally and 
in my position as a member of this working group.  Let
me go through my
 
objections in detail. Drentea refers to several
projects as "so called 
software defined radio" projects.  The so called
software defined radio
 
projects to which he refers are now in use in the
Department of
 Defense, 
  Department of Justice, Department of Transportation,
 and many radio 
astronomy sites and many laboratories in many
countries.  Virginia
 Tech, 
the premiere university in the United States for
Mobile and Wireless 
communications engineering education has one of the
strongest, if not 
the strongest, software defined radio program in the
country and it is 
but one.  This and many other universities use
GnuRadio, DttSP, and
 more 
which are the objects of Drentea's scorn.  The
SOFTWARE defines them as
 
software defined radios and they meet every definition
of a software 
defined radio in the recent FCC rules on SDR and
cognitive radio in 
their application to the SDR-1000, Flex 5000,
Softrock, Universal 
Software Radio Peripheral, HPSDR, uwSDR, and more.

In a clear reference to Flex Radio's SDR-1000,  Flex
5000A, Softrock, 
Norcal 2030 and other radios based upon the Quadrature
Sampling
 Detector 
or Tayloe detector (balanced or unbalanced), Drentea
denies that the 
measurements made by the ARRL labs in the review of
the SDR-1000 and
 the 
reviews made of the Flex 5000A by Rob Sherwood
(published recently in 
Passport to HF and soon on his web site) constitute
credible
 authorities 
on the characterization of radios.  Having never seen
any of Drentea's 
measurements of his own radio, I cannot attest to the
credibility of
 his 
measurements but I do have a comment.  As a person who
works 
professionally to do software radio for the U.S.
government, I do not 
know of a lab that can measure 150 dB of IMD dynamic
range.  The 
required purity of the oscillators alone involved in
both the Star-10 
and the test equipment is beyond imagining.  The
PRODUCT of their
 noises 
must be so low as to require something like
temperatures that are 
physically impossible to get and have the oscillators
continue to 
function!  The editorial board of QEX should not allow
such ridiculous 
claims to go into print.

Finally, let me state as emphatically as possible. 
Neither the QSD or 
the Tayloe mixers are direct conversion receivers of
the type Drentea 
refers to in his article.  He simply does not
understand what they are.
 
  Having analyzed the QSD in the SDR-1000 with the
mathematics of 
Laplace Transforms to find both its transitory and
steady state 
response, I can assure you, he simply does not know
what he is talking 
about and has made a fool of himself.

To say that I am disappointed is to really understate
the situation. I 
am livid beyond almost all repair.

Bob
N4HY

-- 
AMSAT Director and VP Engineering. Member: ARRL,
AMSAT-DL,
TAPR, Packrats, NJQRP, QRP ARCI, QCWA, FRC. ARRL SDR
WG Chair
?An optimist may see a light where there is none, but
why
must the pessimist always run to blow it out??
Descartes





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