Omni VI Option 1, 2, & 3 Upgrades - 563 / 564 Differences

From the November, 1997, ARRL Product Review

Upgrading to a Plus

Ten-Tec offers three options—ranging from $75 to $275—to upgrade your existing OMNI VI (Model 563) to include some or all of the new features of the OMNI VI Plus.

Here’s the rundown:

• Option 1: For $75, you can get a kit in the mail that will let you add DSP noise reduction, move the DSP low-pass filter to the front panel, upgrade the menu, and add the new tuning speed feature. Ten-Tec says the mods are easy to install. The procedure requires replacing two socketed ICs on the logic board and putting three new labels on the front-panel keypad. When ordering, you’ll need to give Ten-Tec the number on the IC in your rig labeled “logic.” This will assure the correct firmware. The serial number alone is not sufficient. To order, call 800-833-7373 or write Ten-Tec, 1185 Dolly Parton Pkwy, Sevierville, TN 37862-3710.
• Option 2: For $125, you can get factory installation of all the features in Option 1, plus Ten-Tec will replace all nine keypad buttons instead of applying new sticker-type legends.
• Option 3: For $275, Ten-Tec will do a “complete factory upgrade” to an OMNI VI Plus. This includes everything in Option 2 plus replacement of the two circuit boards and wiring harness changes needed to add an optional filter position in the 9-MHz IF. Ten-Tec says options 2 and 3 will only be offered for a limited time. Call 800-833-7373 if you’re interested, and you’ll be put on a waiting list. You must pay shipping to Ten-Tec, but there is no charge for return shipping for customers in the continental US.

September 11, 2002

IMO the recent questions regarding the 563 and 564 are well worth understanding and commenting on and is not just "beating a dead horse". With so many Omni VI's and VI+'s now on the used market folks want to know what's up.

I bought my Omni VI 563 in November 1996, one of the last Omni VI's that were made. I sold it this past June. Being initially disappointed in the prospects of the forthcoming Orion I bought an Icom 756 Pro II, a fantastic transceiver (but we will leave that for another time.)

In July 1997 my Omni VI was returned to TenTec for the "Option III upgrade" which gave the Omni VI the electrical performance of an Omni VI+. Since 1997 the newer Omni VI+'s underwent many minor factory changes to eliminate problems and improve performance from earlier productions runs. IMO the cumulative impact of these minor changes is significant.

Here are some of the notable things I know of in no particular order:

• The silk-screening of the 564 has the "Plus" on it (dah…)
• The 564 has a different font silk-screened on the input keys from the 563 keypad. Noticeable side by side
• The later 564's replaced the crystal oven with a 2ppm TCXO on the logic board, probably the best enhancement TT did to this radio. The crystal oven eventually "cooks out" and will not hold frequency tolerances well. Try aligning one and getting it to hold frequency. The TXCO fixes that problem.
• The later 564's use slightly different BFO crystal frequencies (9.0003 USB and 9.0033LSB/CW) from earlier units, apparently to improve the alleged CW key click problem
• The later 564's have certain changes to top and bottom foil grounding on certain boards to improve 10M birdies which are a major problem with this rig.
• The BPF filter on later 564's has a broadcast band mod to improve intermod in the presence of strong local AM BCB or SW signals. Night and Day difference on my rig.
• An aftermarket mod from INRAD is available to improve the SSB audio response involving a swap of two component values. This became a semi-approved factory mod. Stock audio is degraded by passing through the DSP chip when DSP is not engaged (N1EU note: "high pass filtered" is a more accurate description than "degraded" - see Omni6 rx audio discussion)
• Later 564's use significant amounts of SMT construction

There are others. I just have forgotten them.

If there is no difference in the 563 Upgrade III and a 564 why did TT change the model number, name and affix a special label on the back of Omni VI upgrades to distinguish them from the Omni VI+?

There are indeed differences. An early 563 and a late 564 are very different radios in many respects aside form the advertised feature differences.

IMO to advertise a 563 upgrade III as a 564 as I have seen done on the auction sights is misleading.

As for me, I still have my Omni V.9 using Carl's fabulous processor chip upgrade. Man what receive audio! It stays in this shack backing up the Pro II.

All for now.

73 de N1LQ-Dave

July 2011 (comment from N1EU)

N1LQ does a great job of tracing the 564 evolution, but I'd like to offer up some comments:

1. I've spent many hours of A/B comparisons of various vintages of Omni 6/6+ from 1992 to 2001. My conclusion is that any improvements in rx noise/birdies was subtle, if at all audible, and that the earliest units performed just about as well as the latest units.

2. The Inrad mod audio improvements are slight compared to the real problem, which is the audio dsp. This is discussed elsewhere.

3. In terms of the use of SMT in later units, the logic board, PBT board, Control board and IF/AF board all became SMT. The 9Mhz Xtal Filter board was SMT from the start of production.

4. Changes were made in components in the product detector circuit on the IF/AF board of the Omni 6+ to improve intermod distortion over the Omni 6.