[R-390] Best approach for SSB mod on R-390A

[Les Locklear]

Yes, you can use DSB on the RX-350. Some users on eHam and the RX-350 Yahoo group gave it low marks, then changed their tune after figuring out the not so good filter implementation. in AM modes, the displayed filter values were doubled, which widened the passband and made the sync detector lose lock. An example, instead of say a 5.4 khz filter (which is actually 10.8) one can use say the 2.7 khz filter (actually 5.4 khz) and use the am upper or am lower sync detector, dial in about + or - 1350 hz (that is how the PBT is displayed) and the sync detector is wonderful. If a station is totally in the clear, use DSB and the 8.0 khz (actually 16.0 khz) for really sparkling audio.

As with any receiver, there will be those who like it and those who don't. I guess that's probably the reason for owning more than one. Although these days, my collection is the thinnest in recent memory.

I'm retired and with the sunspot cycle, I haven't listened much of late. The weather is supposed to be in the low 20's tonight, maybe I'll fire up the SP-600 and HQ-180A to keep the shack a bit warmer.


Les Locklear
Hammarlund HQ-180A
Hammarlund SP-600 Re-Engineered by John R. Leary
JRC NRD-545
Ten Tec RX-350

"As you wander through this world you see lots of funny men.
Some will rob you with a six-gun, some with a fountain pen."

--Pretty Boy Floyd





  ----- Original Message ----- 
  From: 2002tii 
  To: r-390 at mailman.qth.net 
  Sent: Sunday, January 03, 2010 9:36 PM
  Subject: Re: [R-390] Best approach for SSB mod on R-390A


  Cecil wrote:

  >I think Ten-Tec uses a DSP implementation in the RX-340 and 350.
  >Les can report on both as he has owned each and still has one.

  I have an RX340, and the synchronous detector is -- IMO -- all but 
  useless.  The WJ-8711 implementation is a tiny bit better, but also 
  -- IMO -- useless.

  I have heard from other sources what Les reported -- that SAM in the 
  RX350 is better than the 340 -- but have not had the chance to play 
  with one.  (I see that not everyone thinks the 350 SAM is great -- 
  some of the eHam.net reviewers give it low marks, for example.)

  With the 340, besides losing lock all the time, accompanied by 
  distracting clicks, a number of the other features don't work with 
  SAM on -- no notch filter or PBT, and the BW choices are limited 
  to >= 4000 Hz.  So, even if it held lock properly, it would still be 
  pretty useless because the very signals where you really need SAM are 
  the most likely to require the other tools, too.  I assume the DSP 
  just lacks the horsepower to run all the routines simultaneously, but 
  I don't know for sure.

  The blurb at the Ten-Tec website indicates that the RX350 lets you 
  use PBT, notch filter, and narrow BWs, and allows you to select 
  sidebands, with SAM on.  I don't know if you can also use SAM to hear 
  both sidebands (DSB), as you can on the 340 and R8B.  (This feature 
  can be useful to reduce atmospheric noise if neither sideband has 
  interference.)

  Best regards,

  Don




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