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Re: [TenTec] list opinion(s) on Omni VII and/versus Orion

To: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Subject: Re: [TenTec] list opinion(s) on Omni VII and/versus Orion
From: Mark <pa5mw@home.nl>
Reply-to: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Mon, 10 Dec 2018 11:26:31 +0100
List-post: <mailto:tentec@contesting.com>
The Orion (565) was never ever tested with the optional INRAD 600Hz filter (designed by W4ZV) . This 4-pole crystal is the perfect roofing filter with minimal Group Delay.  6 or 8-pole filtering, used by the competition, can be good for dynamic range specs, but a bad choice on 160m trying to dig out that weak signal in the mud. Together with the, at the time, exceptional close-by low phase noise its receiver still is top-notch.


The 2nd receiver is not contest-grade in specs but that is a challenge for the real operator using correct ATT +RF-Gain to maximise the use of its dynamic range. I have never found the theoretical limitation a problem. Not at our contest station PI4TUE, nor at home. For purists, there is the optional INRAD 45Mhz 4Khz roofing filter. that will bring another xx dB's dynamic range.

For those lucky ones there is the TenTec optional RX366 2nd receiver, which should have even better specs than the ORION's main RX. It is phase locked (can be adjusted on the fly) to the main receiver, making it on par with todays competition.


The internal sweep panaoramic screenfunction is total useless.
Today's IC7851/TS890/IC7610 are the best, but still cannot show weak signals. Any separate SDR, connected or master-slaved(via microham keyer II) is a much better solution for the serious contester/DX'er.

Last but certainly not least, making a QSO is about correctlydecoding the message from the other station.
Rob Sherwood mentions this audio reproduction quality.
This is a much underrated topic at reviewing receivers; can you hear the weak signal?
it is not only about basic distortion at the IF &AF stages.

Filtering in digital domain (like all do today) is hyped for "Brickwall filter response for better selectivity".
People are misguided by these rectangular shaped filtercurves.
In fact, these curves create massiveGroup delay distortion.
That is why <200 Hz filterwidth most top-notch transceivers sound hollow.
You cannot read a weak signal anymore.


During my own listening tests I compared typical Icom vs Elecraft vs the ORION RX performance and found an 8dB difference between worse(Icom) and the best (K2) See my measurement results at: http://pa5mw.blogspot.com/2009/12/upgrade-current-vhf-station-iv-mds.html

I found that the more round shaped digital filter curves (analog shape) performed much better than the sharp edged Icom/K3. At the TT ORION one can scout the band at BW=100Hz and not noting it is set such small. The reproduced audio is totally free from ringing. It is even better than the ORION II which according my measurements, seems slightly different tuned; 150Hz BW is the mininmal BW to use effectively at weak signal reading on Topband.

For the Icoms there is a powerfull solution; switch to 600Hz and use both IF-shifts to dial total BW back to 50 or 100Hz. This makes all the difference on especially 50MHz waek signal performance for IC756-range/7400/7600
See also Adam Farson's ICOM pages.

I have not tested any rigs after 2009, but measured the TS590 IF shape after I noticed it performs very good. Its filter curve shape(rounded edges) show a well found optimum in terms of selectivity vs audio reproduction quality.

I am sure the latest generation perform much better at all manufucturers.

Cannot understand why Elecraft did not act here; I have had numerous A/B comparisons where the ORION, K2 and even a Drake R-4C can reproduce clear audio when the K3 showed ringing zilt.
Same result can be heard at: https://www.youtube.com/watch?v=FIWSMHkSAXg

Anyone can do this weak signal comparison at home using an old analog receiver.


YMMMV

73
Mark PA5MM


On 05/12/2018 17:47, Byron Cordes via TenTec wrote:
Nothing wrong with the stock second rx for general rx in the Orion but do you really want one 
in your contest quality Ham Radio ? I think Henry was trying to say you can’t cover 
all the frequency with one radio and not to expect a lack of performance somewhere. For the 
time it was made it was first rate and now it’s a fine radio compared to any.
Byron AC9PA


Sent from my iPad

On Dec 5, 2018, at 1:25 AM, Rick@dj0ip.de wrote:

Almost all of Rob Sherwood's test reviews are posted on my web site, here:
http://www.dj0ip.de/sherwood-forest/sherwood-xcvr-tests/

I have the OM7 and O2, but I don't have a test of the O1.

73,
Rick, DJ0IP
(Nr. Frankfurt, Germany)
May the Sunspots be with us!

-----Original Message-----
From: TenTec <tentec-bounces@contesting.com> On Behalf Of Rodney
Sent: 05 December 2018 04:55
To: w2iy@verizon.net; Discussion of Ten-Tec Equipment
<tentec@contesting.com>
Subject: Re: [TenTec] list opinion(s) on Omni VII and/versus Orion

I have had both check Sherwood testing, Orion test is better has 2 reciever

-----Original Message----.-
From: Michael Tortorella
Sent: Tuesday, December 04, 2018 10:34 PM
To: 'Discussion of Ten-Tec Equipment'
Subject: [TenTec] list opinion(s) on Omni VII and/versus Orion

Folks, may we have a brief discussion of the relative merits of the Omni VII
and the Orion?  Am thinking of one or the other and would like some input.

Thanks and 73, Mike W2IY

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