> The 2 KHz numbers in the ARRL review are ..... AWFUL.
>
> The 2 KHz BDR is 64 dB on 80 meters.
> The 2 KHz IP3 is -19 dBm. That is not PLUS 19 but MINUS 19 dBm.
> The 2 KHz IMD dynamic range is 63 dB.
>
> WOW. This is just awful. At 2 Khz, the receiver has basically just
> collapsed. With a strong station just outside of your "500 Hz" filter,
> your receiver will basically be blocked off.
>
> Two S9 signals will produce lots of spurious emissions inside your
> passband due to 3rd order products. Myriad signals adding up on 160
> should introduce lots of ghosts in your passband.
>
> If I were serious about Topband enough to buy a new rig, this one would
> definitely NOT tempt me even if it does look like an FT-1000.
>
> Bob
> N4HY
>
To be fair, almost all of the popular transceivers other than the Orion we
have been using are little if any better than the FT-2000 at 2KC spacing.
Most just didn't known generally because until recently the ARRL didn't
measure at 2 KC
spacing.
The Icom Pro 3 IP3 is -18 dBm and IMD 78 at 5 Kc spacing! The Yaesu FT1000
Mk V Field is -6 and 69 at 5 Kc, the Kenwood TS-2000 is -17 and 68 at 5 Kc,
the Icom 746 Pro -17 and 76 at 5 Kc.
The FT-2000 at 5 Kc spacing is +20 and 84 at 5Kc spacing, much better than
all the above legacy transceivers at this spacing!
Only when you get to the new mega-buck rigs does the 2Kc spec improve. The
FT-9000 Contest ($5700) is +0 and 79 at 2 KC, the Icom 7800 ($10,000) is +21
and 86. The Orion 2 (around $4000) as a comparison is +19 and 94.
Why is the Orion so good at this spacing? Because the main receiver is Ham
Band only and, as I recall, has a relatively low first IF where sharp
roofing filters are possible, down to 300 CPS. The stock 1 Kc filter keeps
that 2Kc spaced signal out of the passband. Interestingly, the second RX
(which is general coverage) specs are much more pedestrian (noise limited
IP3, 65 db IMD). Also interesting is that at 20 kc spacing the Icom 7800 and
the FT-9000 contest AND the FT-2000 are superior to the Orion!
In a conversation with someone who should know, I was told that narrow (say
less than 3 kc) filters at the high IF's that typical general coverage
transceivers employ is not feasable at this time, at least at reasonable
cost. Here's hoping that a 1 KC roofing filter becomes available for the
FT-2000 someday...
The Elecraft K3 should also be a strong performer when it becomes available.
Regards, Kevin K3OX
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