Latest Revelations About Audio Problems in the Orion II
There have been several posts to the Ten Tec board on contesting.com (TenTec@contesting.com) and the Orion group at Yahoogroups regarding distorted audio on certain Orion II’s. My first impression was that the problem was related to RFI, power supply problems, overdrive on the mic input or some other operator error, but after hearing two of the effected units on the air during the week of March 20, 2006, I was convinced that the problem was real and caused by a defect in those particular units. Only a few seem to be effected, since, by and large, the Orion II’s have excellent audio, especially when fed with a good quality microphone, alone or in combination with pre-processing equipment, such as the W2IHY boxes. My uneducated guess is that the problem will be found in the DAC/ADC chips on the logic board. I heard that one unit with the problem that was sent back to Ten Tec was still there after a month as of this writing (3/24/06).
Mp3 examples of Orions with and without the audio problem can be heard at http://www.k6kdk.net. The .mp3 shown as N9AU is an O2 that has the problem. There are clips with my O2 and other original Orions with the 1.372 and 1.373.b2 firmware.
It should also be mentioned that there is a growing consensus among the Orion 1 owners that the v. 1.37x firmware had better transmit audio than the v. 2.0xx or any of the Orion II’s. The sound has been described as being more ‘robust’ and having more bass. My frequency response testing shows that the Orion II (which never had a version 1 firmware set) does not meet the published specifications in the lower frequencies. I have never tested an original Orion with either v. 1.xxx or v. 2.xxx firmware, but it would be very interesting to see if these observations can be borne out by testing.
Notes About the NR Function
This has been another hotly debated toping on the TT lists! How does it work, how should it work, is the new better than the old. Having never heard the old, I can’t comment, however many of the O1 owners on the list have switched back from the 2.05x firmware to 1.37x only because of the NR, which they claim is significantly better in the old version.
Measuring and comparing different noise reduction schemes is virtually impossible, due to the complex nature of human auditory system. Objective testing can tell us certain things, but it is a subjective evaluation that determines whether a signal that could not be copied before NR can afterward. The complexity of evaluation is compounded by the fact that every receiving condition is different, with different types and amounts of noise and interference as well as uniquely different types signals you are trying to copy. Therefore, we can’t just ‘stick a meter on it’ like we can in most other measurements.
In my limited experience in using NR in the TS-870 and the IC706MIIG, I can honestly say that I have never been able to copy a signal with NR that I couldn’t copy with out it. That’s not to say that DSP NR can’t give some improvement on an already-readable signal, but in my experience, it’s not much.
Maybe our expectations of the capabilities of DSP are too high as a result of what we see in the media. On TV, a CSI detective can say the magic words “enhance that!” and a blurry security camera photo can suddenly reveal a perfect license number on a car parked six blocks away! A scratchy cell-phone call recorded on a cheap answering machine can be ‘processed’ to identify the exact brand of whisky the bartender was pouring when the ‘perp’ made the damning call from a noisy tavern. Of course, the cops just happen to have that special “whisky pouring sound identifier” software that beeps and bleeps and shows pictures of every known whisky bottle on Earth on a 50” Plasma HDTV screen until the right one pops up, accompanied by big colorful flashing letters saying “Match Found!!!” Only on TV!
The Orion II’s NR scheme has helped make some marginal CW easier to copy for me by using what sounds like a downward-expansion process that acts a bit like a squelch between the dits and dahs. The RF Gain has to be to set just right and constantly adjusted. And that‘s about at good as it gets with today’s technology and the limited amount of processing capability available. It doesn’t do much for SSB.
NASA can pull excellent photographs from micro-powered transmitters in deep space, but remember that the signals are put through intensive processing by high-power computers that crunch the data for fairly long periods of time to get what we see. I’ll be happy if I can get R-3 CW signal up to R-3.5 to work a new country!
As I mentioned before, many of the O1 owners prefer the v. 1 NR to the v. 2 NR, and my question for Ten Tec is: can the new scheme and the old scheme both be in the firmware and menu selectable? The Kenwood TS-870 had such a system with one process called Line Enhance and another called SPAC. As it turned out, neither one worked very well, but it was a nice touch to allow the user a choice, even if they were both lousy ones!