[TenTec] Orion Dynamic Ramge

Jim Reid jimr.reid@verizon.net
Sat, 28 Sep 2002 13:13:13 -1000

Aloha Ken,

One of our Hawaii hams,  John,  KH7T,  was fortunate to
be able to attend the Ten Tec doings.  Here is part of an
e-mail he has sent back to several of us out here.  He
got an Orion on order back in June, but was not sure he
would go ahead with the delivery until after he had a chance
to see the unit at the factory.  Applicable part of his note:

"I just finished the TenTec Hamvention and Swap meet.
Got my hands on an Orion.  Also Doug Smith has been on the 
air with one  for the last couple of days.

The DSP software is working great.  100 db of DSP dynamic 
range  including 18 or more effective bits of A/D plus about 
40 db of analog  AGC.  The radio sounds great.

The control software is not quite ready for prime time.  Several 
bugs are still apparent.  They do expect to finish alpha test in 
a couple of weeks.  Apparently the person doing the control 
panel software decided in August to go back to school.  
Significant set back.   I saw  enough to say that I do want the
radio when it is finished."

John is now a believer,  hi.  Wish I could afford to order one
also.  Of course,  Scott has said I may trade in my 340 and
Pegasus towards an order,  hi.  Not sure I want to give up
the 340,  however,  even with less dynamic range than the Orion

The 100 dB DR John reports above (via 18 or more effective
A/D bits) clearly exceeds the 340 DR.  Carl Moreschi,  N4PY,
reported a few months ago about his careful DR measurement
of a 340.  Theoretically,  the range of the A/D chip (Analog
Devices AD7872) in the 340 is 84 db (14 bits A/D times 6 db per 
bit).  Carl measured the 340 as having about 65 dB of close-in 
dynamic range; he wrote:

"The procedure I used was to first set the rx340 at 100 hertz filter 
in CW mode.  I then tuned in the calibrator signal.  It measured 
-20 dbm on the S meter. I then tuned 5 khz off the signal.  

The meter then read -85 dbm.  This shows a close in dynamic range 
of 65 db.  I then turned off the calibrator, and the S meter
dropped to -140 dbm."

So,  guess the A/D dynamic range within the 340 is only 11
effective bits (6x11=66 dB DR).  But,  in about 9 months of
use,  I have not found that limiting my enjoyment of the RX-340.

73,  Jim  KH7M