I was indeed involved with technical aspects of CDROM (we never produced an
audio CD but I did read the Red Book once) and I worked on early development of
processes to manufacture 2 layer DVD’s.
I then worked on magneto optic recording media, including some that never
entered the marketplace (near field optical recording).
Gary
PS: Steve J did indeed hit a brick wall with NeXT! He did a little better upon
his return to Apple.
> On Sep 11, 2016, at 4:01 PM, rick@dj0ip.de <Rick@DJ0IP.de> wrote:
>
> Gary,
>
> In a previous email I listed the 4 OM (hams) currently discussing how to test
> SDR.
> I suggest you send your recommendation to them. I am not qualified to say.
>
> In the case of the CD and optical disks in general, I hope you were only
> involved with the development and not the marketing of the product. MORONS
> like Steve Jobs were out there telling people optical disks would spell the
> end of rotating magnetic disks. NOT. Obviously that venture of his (NEXT)
> went belly up in short order.
>
> Unfortunately the people testing radios, especially all the magazines, are
> not calling the OEMs out for excessive phase noise out of their synthesizers.
> One can only speculate that they are afraid of losing advertising $$$.
> The only exception to that was Peter Hart of RSGB who ingeniously told us
> "between the lines" that the FT-1200 and FT-3000 were noisy transmitters.
> Unfortunately most people probably failed to comprehend what he was telling
> us.
>
> C’est la vie!
>
> 73 - Rick, DJ0IP
> (Nr. Frankfurt, Germany)
>
>
>
> -----Original Message-----
> From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Gary J
> FollettDukes HiFi
> Sent: Sunday, September 11, 2016 10:49 PM
> To: Discussion of Ten-Tec Equipment
> Cc: Greg S
> Subject: Re: [TenTec] OT: IP3 and Receiver Performance
>
> Many of us have been sucked in by the “early adopter” syndrome. Just look at
> the foolish long lines at the Apple Store when a new phone comes out...
>
> I personally bought a new 2011 Nissan Leaf. After 36,000 very reliable miles
> but four winters of freezing my you-know-what off going to work in winter, I
> sold it for less than 1/6 of the purchase price…
>
> I hope to not get similarly caught in Ham radio buying errors. I’ll struggle
> through with my analog radio with IF DSP until it is proven what works and
> what does not work in direct digital SDR’s.
>
> As far as testing goes, within the context of ranking SDR radios, would it
> not be a good start to first measure what was formerly known as “sensitivity”
> above the noise floor, then apply a signal of 140 dB higher than that level
> and see what happens in the receiver? Does it clip or does it continue to
> output a desired signal that is linearly tracking the input signal? This
> could be done with both in-band and out-of-band large signals to test both
> the signal dynamic range in band and also the effectiveness of any
> band-limiting filters employed.
>
> Then one could apply a known complex waveform (“standard voice", so to speak)
> to a calibrated SSB transmitter and compare the Fourier analysis of the audio
> coming out of a given receiver against the calibrated “standard voice”
> signal. The closer the receiver output is to the known modulation waveform,
> the better the radio.
>
> This is not unlike the “disk compare” test used early on in the CDROM
> business (with which I was involved in the mid 1990’s). A simple digital
> compare of the final replicated CD against the glass master was a pretty good
> measure of the overall manufacturing process. This laid the groundwork for
> determining acceptable levels in tests known as BLER (Block Error Rate),
> Radial Noise, pit jitter and so on.
>
> Finally, one could apply something like “standard CW” to the same calibrated
> transmitter and observe the quality of the decoded CW as a measure of a
> radio’s ability to handle what amounts to a square wave (overshoot, rounding
> etc.).
>
> To complete the test, one could then compare these performance measures
> against the same measures when a condition exists in which the 140 dB above
> sensitivity threshold interfering signals are applied. The less the test
> signals change, the better the receiver.
>
> I agree that analyzing the transmitter for spectral purity is equally
> important, but this is a lot easier to do, since spectrum analyzers can
> pretty well tell the story about the transmitter. The transmitter test, for
> what is now called “synthesizer phase noise” could be performed just as it is
> now, using the transmitted signal, to determine if the designer(s) did their
> jobs well on the clock oscillator.
>
> Just suggestions, not dogma…
>
> Gary
> W0DVN
>
>
>> On Sep 11, 2016, at 1:08 PM, Jim Allen <jim.allen@longhornband.net> wrote:
>>
>> Be glad you didn't pay $1400 for an Apple IIP with 16k of memory, no
>> mass storage or printer, no software other than BASIC and Little Brick
>> Out, or monitor, back when you could buy a brand new Volvo for $4000!!!
>>
>> 73 Jim Allen W6OGC
>>
>> On Sun, Sep 11, 2016 at 10:47 AM, Greg S via TenTec
>> <tentec@contesting.com>
>> wrote:
>>
>>> ........
>>>
>>>
>>> I am finding it hard to know when/where to jump into the SDR
>>> transceiver fray..... Prices are being forced down, and technology is
>>> changing FAST on some of the open source code. I bought an SDRplay,
>>> and have had a TON of fun with it, so I am seriously considering the
>>> next level. It still hurts to think about my 40" LCD, 60Hz, 720P
>>> Samsung "dumb" TV that I paid over
>>> $1700 for in 2007, but our old TV died, and we jumped in where we
>>> thought appropriate. (It still works perfectly, but draws 3 times the
>>> energy of our 60" TV that cost 25% of that $1700!!) I wouldn't want
>>> to be in Mr. Dishop's shoes in this market, but do hope he comes up
>>> with a "winner" the first time around!!! Long Live TenTec!
>>>
>>> 73, Greg, KC8HXO
>>>
>>>
>>> SNIPPED SNIPPED SNIPPED
>>> IMO there is no longer any easy way to rank them based on one or two
>>> specifications alone.
>>>
>>> Too many factors affect SDR receiver performance.
>>>
>>>
>>>
>>> I am in favor of removing all SDR radios from the list and placing
>>> them in a separate list, but I have no idea how we should do this.
>>>
>>> My best guess would be to use NPR testing such as Adam Farson is
>>> conducting.
>>>
>>> See: http://www.ab4oj.com/test/docs/npr_test.pdf
>>>
>>>
>>>
>>> Adam has two lists, one for traditional heterodyning radios and
>>> another for SDR radios.
>>>
>>> But this is not perfect either.
>>>
>>> As you see, the 7300 tops the list and as we all know, it has
>>> overload problems due primarily to improper gain distribution
>>> throughout its front end stages. Adam, Rob, and every test review I
>>> have read point out its overload problem.
>>>
>>>
>>>
>>> Note that the two ANANs are ranked above the 6700, even though they
>>> do not have dedicated BPF's for each ham band.
>>>
>>> I'm not sure how Adam is ranking the SDR radios. It is not only NPR
>>> figures.
>>>
>>>
>>>
>>> At this point we are way outside (above) my pay grade. I have no
>>> idea other than to put these radios in the hands of contesters and
>>> let them report on their experience.
>>>
>>>
>>>
>>> In summary, we have come a long ways since first reporting on IP3 in
>>> the 1970s.
>>>
>>> We cannot compare SDR radios to heterodyning radios based on their
>>> IP3 or
>>> DR3 results.
>>>
>>> At this point in time, I am not aware of any agreed method of testing
>>> and reporting performance levels of SDR radios.
>>>
>>> There are ongoing discussions between Rob, Adam, Bob Allison (ARRL)
>>> and Ken (ex Ten-Tec president) on how to do this.
>>>
>>>
>>>
>>> ON THE BRIGHT SIDE, this new technology has brought us great
>>> improvements in performance and as we will soon see, at an affordable
>>> price.
>>>
>>> The 7300 was just the beginning.
>>>
>>>
>>>
>>> 73
>>>
>>> Rick, DJ0IP
>>>
>>>
>>>
>>>
>>>
>>>
>>> _______________________________________________
>>> TenTec mailing list
>>> TenTec@contesting.com
>>> http://lists.contesting.com/mailman/listinfo/tentec
>>>
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