ADT-200A Fully DSP transceiver

[juergen piezo]

Hi Dave

Minor differences of a few Db here and there does not mean much  in the real world for most operators. Considering how perfect the ADAT radio is in all aspects of its design, any criticism just seems like jealous nitt-picking.

I have been wanting to buy a K3 now  since its release, which is almost two years now. However I am unwilling to invest in a product that is essentially unfinished.

 Its been almost two years now  and the radio still has missing features and functions. While I admire those who staunchly defend Elecraft and their own love of the K3, I do want something thats 100% out of the box  with all features working. The P3 is another case in point how long will it take before its as good as say the Yaesu DMU, 2 years as well?

The ADAT appears to be a finished product,  all its core features have been delivered with excellent styling and  engineering. I dont know how so many can be so critical of this well designed radio. It has a perfect receiver, transmitter, S-meter, CW keying sidebands and  probably the worlds best IMD performance from a transmitter. It really delivers a knockout blows against the K3. These several  key feature advantages over the K3 would be attractive to more operators than few Db in receiver performance. If Ulrich Rhode N1UL owns one, it says a lot about the radios design excellence!

Anyway if I had to choose today between buying a K3 or an ADAT I would probably buy the ADAT, which I only found out about  from reading this list! I dont see how the K3 could be improved  to feature match the ADAT, it would take a new design from Elecraft.

73, John



The electrical specs of this radio may not be as "good" as the K3 or other radios for that matter but, you can't ignore the construction of this radio.

It looks like it is using mil-spec construction techniques, which isn't cheap to implement.

If the Elecraft radios had an option to purchase thicker aluminum panels, which shouldn't be a real expensive option, it would give it the feel of something that will be a $4k+ radio (with options).  Although we may not like the Asian brands, it's pretty tough to ignore what a sub $1k radio gives you in terms of mechanical construction techniques.

Dave



     
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[Brett Howard]

See and personally I'm quite loathed to the idea of owning a radio thats
"done".  I suppose my K1 is "done" and I still love that little rig but
thats a completely different style of rig and by no means my primary
radio.  But like I said, I'll be disappointed the day the K3 is
considered "done".  That being said I'm sure I'll keep it around until
its considered a boat anchor.  But everything in my shack I've either
personally built or put together from a kit.  Gives a better sense of
ownership to me.  

Thankfully amateur radio is full of choices and I welcome you to vote
with your dollars wherever you wish to.

~Brett (KC7OTG)

On Fri, 2009-08-21 at 23:28 -0700, juergen piezo wrote:

> Hi Dave
>
> Minor differences of a few Db here and there does not mean much  in the real world for most operators. Considering how perfect the ADAT radio is in all aspects of its design, any criticism just seems like jealous nitt-picking.
>
> I have been wanting to buy a K3 now  since its release, which is almost two years now. However I am unwilling to invest in a product that is essentially unfinished.
>
>  Its been almost two years now  and the radio still has missing features and functions. While I admire those who staunchly defend Elecraft and their own love of the K3, I do want something thats 100% out of the box  with all features working. The P3 is another case in point how long will it take before its as good as say the Yaesu DMU, 2 years as well?
>
> The ADAT appears to be a finished product,  all its core features have been delivered with excellent styling and  engineering. I dont know how so many can be so critical of this well designed radio. It has a perfect receiver, transmitter, S-meter, CW keying sidebands and  probably the worlds best IMD performance from a transmitter. It really delivers a knockout blows against the K3. These several  key feature advantages over the K3 would be attractive to more operators than few Db in receiver performance. If Ulrich Rhode N1UL owns one, it says a lot about the radios design excellence!
>
> Anyway if I had to choose today between buying a K3 or an ADAT I would probably buy the ADAT, which I only found out about  from reading this list! I dont see how the K3 could be improved  to feature match the ADAT, it would take a new design from Elecraft.
>
> 73, John
>
>
>
> The electrical specs of this radio may not be as "good" as the K3 or other radios for that matter but, you can't ignore the construction of this radio.
>
> It looks like it is using mil-spec construction techniques, which isn't cheap to implement.
>
> If the Elecraft radios had an option to purchase thicker aluminum panels, which shouldn't be a real expensive option, it would give it the feel of something that will be a $4k+ radio (with options).  Although we may not like the Asian brands, it's pretty tough to ignore what a sub $1k radio gives you in terms of mechanical construction techniques.
>
> Dave
>
>
>
>      
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[Bill W4ZV]

juergen piezo wrote

I have been wanting to buy a K3 now  since its release, which is almost two years now. However I am unwilling to invest in a product that is essentially unfinished.

Fore me, any radio without true diversity is "unfinished" (and the ADAT does not yet have it).  I'll never buy another radio without true diversity.  

Definitions of "unfinished" may depend on whether the user plans to use the feature in question.  I don't SWL so features like Synchronous Detection for AM are completely unimportant to me.

73,  Bill  W4ZV

[P.B. Christensen]

> "The ADAT appears to be a finished product,  all its core features have
> been delivered with excellent styling and  engineering."

The ADT-200A's core architecture is complete, leaving room for a
considerable amount of future upgrades.  The unit includes an Ethernet port
for a web server, in addition to a USB port, and a plethora of other
connectivity.

In many respects, the ADT-200A is very much at a stage where the K3 was at
the time of its product launch.  For example, the K3 did not have true
diversity at first, and yet many folks went ahead and made the purchase
anyway (myself included), realizing that it would come -- and it did.
Neither the K3, nor the ADT-200A will ever be "complete" products.  But
that's a positive attribute since the designs can evolve as consumer demand
changes.  The same is true of the Flex series.

> "I dont know how so many can be so critical of this well designed radio."

I do not see the comments here as being negatively critical of the ADT-200A.
Without knowledge of the the tranceiver's capabilities, there's a tendency
to be skeptical.  Nothing wrong with that.

>" It has a perfect receiver, transmitter, S-meter, CW keying sidebands and
>probably the worlds best IMD performance from a transmitter. It really
>delivers a knockout blows against the K3. These several  key feature
>advantages over the K3 would be attractive to more operators than few Db in
>receiver performance. If Ulrich Rhode N1UL owns one, it says a lot about
>the radios design excellence!"

My purchase of the ADT-200A was based largely on Ulrich Rhode's comments.
The ADT-200A does not have a perfect receiver.  It's a different kind of
receiver.  As technology allows for nearly Herculean receiver performance,
it becomes more difficult to classify one type as being "better" than
another.  That largely depends on what measurement category is most useful
to the individual operator (e.g., close-in DR, phase noise, Tx IMD, etc).

> "Anyway if I had to choose today between buying a K3 or an ADAT I would
> probably buy the ADAT, which I only found out about  from reading this
> list! I dont see how the K3 could be improved  to feature match the ADAT,
> it would take a new design from Elecraft."

Careful!  The ADT-200A users a basic front panel user interface with many
menus.  I suspect that contesters may not like it without use of a software
control program.

I have no intention of selling my K3.  Both the K3 and ADT-200A are unique
for the attributes they offer.  That said, I would really like to see
Elecraft design their own rendition of a direct-RF-sampled transceiver as
just another product in their mix.  I would like to see a black box design
with a built-in web server, use of interchangeable front panels sizes for
portable and base station use, and implementation of adaptive
pre-distortion.

Paul, W9AC

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[Bill W4ZV]

P.B. Christensen wrote

The ADT-200A does not have a perfect receiver.  It's a different kind of
receiver.  As technology allows for nearly Herculean receiver performance,
it becomes more difficult to classify one type as being "better" than
another.  That largely depends on what measurement category is most useful
to the individual operator (e.g., close-in DR, phase noise, Tx IMD, etc).

Paul I did a brief scan of the manual and have a question.  The overall block diagram shows a BPF ahead of the ADC, yet I saw the following comment:

"In the digital receiver the full signal spectrum is fed directly to a high resolution A/D converter. All signal processing is made digitally, which is ideal as it relates to distortions and noise. Since algorithms are determined by software, uniform performance parameters are obtained. Another benefit of this technology is the high degree of functional flexibility. New functions can be added by simple software download."

I assume the BPF shown is simply one LPF anti-aliasing filter for rejecting signals >30 MHz.  Since the ADT was designed in Europe where 40m BCI is (still) a significant issue, how can the 112 dB BDR cope with the dynamic range of nearby broadcast stations?  Is that BPF actually a set of band limited filters?

73,  Bill

[Bill W4ZV]

Bill W4ZV wrote

Is that BPF actually a set of band limited filters?

I think I found the answer in the FAQ:

"With 4 Rx and 4 Tx VFO's, can I set each one to a different band and work cross band?"

"Yes, the VFO's can all be set to the same or to different bands, independant from its Rx-frequencies. The user must keep in mind, that each selection of a band will also switch in the appropriate halfband filter in the preselector."

Still it seems like a 40m preselector would not be sharp enough to prevent BDR issues with BC stations.

73,  Bill

[P.B. Christensen]

> I assume the BPF shown is simply one LPF anti-aliasing filter for
> rejecting
> signals >30 MHz.  Since the ADT was designed in Europe where 40m BCI is
> (still) a significant issue, how can the 112 dB BDR cope with the dynamic
> range of nearby broadcast stations?  Is that BPF actually a set of band
> limited filters?

Hi Bill,

Yes, the ADT-200A uses a total of nine automatically-switched half-octave
filters in the preselector.  The specified 112 BDR figure is quoted for 2.4
kHz BW.  As I recall, that number approaches 120 dB for typical CW BW.

I'll send you a PowerPoint presentation by private E-mail that address this
point on page 27.  It was prepared by HB9CBU and translated by Adam Farson,
VA7OJ.  The same presentation looks at diversity reception as an "add on"
under development.  The four "receivers" presently come directly off one ADC
(Lyle, there's your answer!).  So, the diversity add-on requires a companion
ADC board for true diversity (akin to the K3's need for the 2nd Rx module).

Also, regarding adaptive predistortion, one may think ADAT is achieving
spectacular Tx IMD numbers by under-utilizing a PA of higher power
capability (e.g., taking a 100W PA and simply running it at half-level).
However, the same PowerPoint presentation (page 21) shows the effect of Tx
IMD with and without AP engaged.  Without AP, 3rd-order IMD is typical of
+13VDC PA transceivers at roughly -33dBc.  With AP engaged, 3rd-order IMD is
driven down to -65 dBc at 14 MHz.  In this instance, the algorithm alone
reduced IMD by a whopping 30 dB.  Also unique to the ADT-200A is a built-in
2-tone IMD generator for testing purposes.

I also failed to mention in past posts that the ADT-200A uses solid-state
T/R switching like the K3 and an optically-isolated, solid-state MOSFET for
amp switching.  The ADT unit produces no mechanical noise when transmitting
with or without an amp.

Paul, W9AC


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[Bill W4ZV]

P.B. Christensen wrote

I'll send you a PowerPoint presentation by private E-mail that address this
point on page 27.  It was prepared by HB9CBU and translated by Adam Farson,
VA7OJ.  

For anyone else interested, the .ppt presentation is downloadable here:

http://www.adat.ch/pub/Vortrag_Hamfest_22-09-07.pdf

73,  Bill

[P.B. Christensen]

> For anyone else interested, the .ppt presentation is downloadable here:

Bill

I think that's the German language version.  I'll upload the English
version.from Adam Farson and post a link.

Paul, W9AC

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[P.B. Christensen]

And here's the English version...

http://216.229.20.37/images/ADAT%20Presentation_Hamfest_22-09-07.pdf

Paul, W9AC

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[KK7P]

> ...Also unique to the ADT-200A is a built-in
> 2-tone IMD generator for testing purposes.

K3 has this

CONFIG:2 TONE ON|OFF

:-)

73,

Lyle KK7P

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[Eric Swartz - WA6HHQ]

Lots of good info on this new design.

Let's rest this thread for now, as its rapidly reaching the max posting
threshold for a single topic :-)

Now, back to our regularly scheduled mayhem..

73, Eric  WA6HHQ
Elecraft List Moderator



_..._

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