ADT-200A Fully DSP transceiver

[Dave, G4AON]

There are many aspects of the ADT-200A that fall short of the K3 (only 50W, some
software upgrades
being charged for, lack of front panel controls, non standard control protocol, etc).

It's an interesting development though, see: http://www.adat.ch/index_e.html

73 Dave, G4AON
K3/100 #80



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[P.B. Christensen]

> There are many aspects of the ADT-200A that fall short of the K3 (only
> 50W, some
> software upgrades
> being charged for, lack of front panel controls, non standard control
> protocol, etc).
> It's an interesting development though, see:
> http://www.adat.ch/index_e.html

>From the ADAT website:

"In the future, ADAT will publish a document with the control codes so that
other programs may be updated to operate the ADT-200A...Software updates
with new functions will be free and can be downloaded via website. Software
options (see above) will be with costs."

I recently purchased an ADAT ADT-200A and have been using it along side the
K3 for the past three weeks.  The ADAT unit's construction quality is
superb.  Fit and finish are equal in quality to high-end test equipment from
Agilent and R&S.

Presently, features like PA adaptive pre-distortion and the external 10 MHz
time-base are active.  The CW envelope is generated by the Blackman-Harris
window function and generates even less occupied spectrum bandwidth than a
raised-cosine Gaussian function.  The rise/fall time of the envelope is
determined by the CW speed.  It's interesting to watch the ramp time change
as the WPM setting of the keyer changes.  The envelope is perfectly
symmetrical and exhibits no ALC overshoot.  QSK is not implemented at this
time but is scheduled for the next major firmware release -- as are many
other features.

Obviously, with so few controls on the front panel, the ADT-200A will not
appeal to everyone, especially contesters.  Features like "dual-watch"
already exist, but engaging the function and complex splits requires going
through 1-2 layers within the menu.  An experienced operator can manipulate
this quite quickly.  It was an impediment at first, but I can engage the
transceiver in split nearly as quickly as I can with the K3.  If a
third-party control program (e.g., HRD, N4PY  etc.) was to support the
ADT-200A in the future, there's no reason why manipulating the transceiver
cannot be just as easy as it is for any other transceiver.

I have to stand by ADAT's decision to limit output power to 50W.  Since the
majority of commercially-manufactured amateur amplifiers can be driven to
full power with 50W or less, anything more than 50W, is "dumb" power until
you get well beyond 100W (IMHO, at least the 750W level).  With internal PS
and PA, the unit is smaller in size than the K3.  No built-in ATU is offered
at this time.  Modules for 2m-70cm will be offered later.

The ADT-200A is the coolest running transceiver I've ever used.  Although it
has a tiny convection fan, the unit stays cold (not just cool) to the touch,
even after a 30-minute CW QSO.  PA and PS efficiency is excellent.

Rx audio is outstanding and it's the most "analog" sounding digital receiver
I've heard.  By that I mean AGC, electrical interference "ticks" all behave
as if its a traditional analog receiver.  The 'S' meter is precisely
calibrated in both dBm and dBuV scales.  It's interesting to watch the
digital "S" meter scale drop down to -142 dBm when the pre-amp is engaged
and the antenna is disconnected.  The rig is plenty sensitive with dynamic
range on par with other directly-sampled RF receivers like the Perseus and
QS1R.  A 14-bit ADC is used but because dynamic range is a function of
process gain (composed of sample rate and bandwidth with a 10log, rather
than a 20log constant), going from 14-bits to 16-bits does not significantly
add to dynamic range.

Like the K3, it's exciting to be a part of ADAT's long-term product
development.  Being one of the first NA ops to use the ADT-200A will likely
generate a lot of follow-up questions to this post that I'm not prepared to
answer at this time.  In the future, I plan on publishing a report when time
permits.

Paul, W9AC

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[Eric Swartz - WA6HHQ]

It looks like a nice mid-performance rx, minimalist user interface,
design. Though at 4,600 swiss francs (about $4,351 U.S. plus shipping)
it is pricey for their level of rx performance.

At 50W it will not have enough drive to drive most legacy tube based
amps to full power, especially the widely used 3-500z based legacy amps
from Heath and Ameritron.

A few comparative Rx numbers from their web page versus the K3:

                K3     ADT-200A
IMDDR3        102 dB     96 dB
Blocking DR   140 dB    112 dB   (desenses 28 dB earlier than K3 RX)
2nd Order IP  +79 dBm   +60 dBm  (IMD from out of band sigs 19 dB worse
than K3)

It is an interesting design with some unique ideas. It will be fun to
see where they take it over time.

Of course, we'll keep improving the K3 too! ;-)

73, Eric  WA6HHQ


Paul Christensen wrote:
>> There are many aspects of the ADT-200A that fall short of the K3 (only
>> 50W, some
>> software upgrades
>> being charged for, lack of front panel controls, non standard control
>> protocol, etc).
>>    
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[Bill W4ZV]

D J wrote

There are many aspects of the ADT-200A that fall short of the K3 (only 50W, some
software upgrades
being charged for, lack of front panel controls, non standard control protocol, etc).

It's an interesting development though, see: http://www.adat.ch/index_e.html

73 Dave, G4AON

Price 4600 CHF = $4350 at current exchange rates (plus shipping from Switzerland).  BDR at 2 kHz looks weak at 112 dB (a problem for Field Day, multi-transmitter operation or strong local signals on the same band).  Although 4 separate receive channels are possible, it's unclear to me whether diversity RX is possible using two different antennas (...I'm guessing not in the current implementation).  

73,  Bill

[P.B. Christensen]

Eric Swartz:

> At 50W it will not have enough drive to drive most legacy tube based
> amps to full power, especially the widely used 3-500z based legacy amps
> from Heath and Ameritron.

Very true.  But I suspect few owners of the ADT-200A would even consider
using it with such an amplifier.

What the ADT-200A does presently offer -- that nobody else does at the
moment, is utilize an advanced PA pre-distortion technique (apply opposite
non-linearity) to significantly drive down transmitted RF non-linearities
(typically -50 dBc 3rd-order).

Moreover, the transceiver, right out of the box, allows the user to sample
the output of an amplifier (I plan on using an SPE 1K-FA) and feed the RF
sample back into the transceiver's monitor point such that the
pre-distortion algorithm drives down IMD of the total transmitted output.
For amateur radio, that's an extremely novel and powerful feature derived
from Mil and commercial applications.  In effect, the ADT-200A takes a
solid-state amplifier that would otherwise offer only mediocre SSB IMD
performance and turn it into one with stellar performance -- without ever
having to take a screwdriver to the amp.

That's impressive.

Paul, W9AC
 

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[P.B. Christensen]

> Although 4 separate receive channels are possible, it's unclear to me
> whether diversity RX is possible using two different antennas (...I'm
> guessing not in the current implementation).

Bill,

Not at the moment, but it's capable of full diversity with two main antenna
ports and separate Rx ports for HF and VLF.  However, 'dual watch' with a
mix of four receivers works quite well.  Full diversity will follow in a
future firmware upgrade as was the case with the K3.

Paul, W9AC


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[Bill VanAlstyne W5WVO]

Plus, it doesn't have 6 meters! Makes it pretty useless to me. They talk about
2m and up transverters coming along in future, but nothing at all about 6m.

Bill W5WVO

Eric Swartz - WA6HHQ, Elecraft wrote:

> It looks like a nice mid-performance rx, minimalist user interface,
> design. Though at 4,600 swiss francs (about $4,351 U.S. plus shipping)
> it is pricey for their level of rx performance.
>
> At 50W it will not have enough drive to drive most legacy tube based
> amps to full power, especially the widely used 3-500z based legacy
> amps from Heath and Ameritron.
>
> A few comparative Rx numbers from their web page versus the K3:
>
>                K3     ADT-200A
> IMDDR3        102 dB     96 dB
> Blocking DR   140 dB    112 dB   (desenses 28 dB earlier than K3 RX)
> 2nd Order IP  +79 dBm   +60 dBm  (IMD from out of band sigs 19 dB
> worse than K3)
>
> It is an interesting design with some unique ideas. It will be fun to
> see where they take it over time.
>
> Of course, we'll keep improving the K3 too! ;-)
>
> 73, Eric  WA6HHQ
>
>
> Paul Christensen wrote:
>>> There are many aspects of the ADT-200A that fall short of the K3
>>> (only 50W, some
>>> software upgrades
>>> being charged for, lack of front panel controls, non standard
>>> control protocol, etc).
>>>
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> Elecraft mailing list
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[Vic K2VCO]

Bill W5WVO wrote:
> Plus, it doesn't have 6 meters! Makes it pretty useless to me.

Don't forget that it also doesn't have QSK. I had QSK in 1957...
--
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco
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