Re: [Elecraft_K3] Re: Re： New Kenwood TS0-590

[Joe Subich, W4TV-4]

 > Argument was that when the sunspot cycle peaks and especially with
 > beam antennas that rigs with down conversion will suffer from image
 > and IF rejection perhaps overload on 6-17m and that's why Kenwood
 > chose that approach.

More likely because:
   1) the Kenwood DDS could not be made clean above 33 MHz or it might
      have been limited to 35 MHz (21.5 + 11.375 = 32.875 MHz).
   2) Kenwood did not want to spend the money to design and build
      and align 10 (11 if you count 60 Meters) high performance filters
      necessary to cover each amateur band plus eight more high
      performance filters (ca. 4 MHz each) necessary to cover the
      spaces between bands.
   3) Kenwood did not want to accept a "hole" in coverage around the
      11.374 MHz first IF.

By the way, the TS-590 is limited to two high performance roofing
filters (2.7 KHz and 500 Hz).  No option for additional filtering
at other bandwidths ... they make up some BS about an advanced,
"level-optimized AGC even for signals that slip between the Roofing
Filter and the final IF passband" (brochure, page 3).

73,

    ... Joe, W4TV


On 10/18/2010 9:38 PM, Mike Rodgers wrote:
> Unusual conversion scheme..... An argument was put forth on the 590
> group that I don't know if it hasmerit. What do you guys think????
>
> Argument was that when the sunspot cycle peaks and especially with
beam antennas that rigs with down conversion will suffer from image and
> IF rejection perhaps overload on 6-17m and that's why Kenwood chose
that approach.
>
> If that were the case and signals that strong, looks like you could
attenuate or rf gain. As far as the k3 is concerned, I've read it has
extremely sharp bandpass filters for each band and I suppose that would
help. And it has extremely good numbers on 14 MHz and 70db rejection on
50 Mhz and I assume it would be better on

> 28Mhz than 50Mhz would it not?
>
> Does this idea have any merit? I'm hoping to get my k3 by year end.
> Happy QSO'ing.       Mike R
>
> On Oct 18, 2010, at 8:16 PM, "Rob Sherwood"<[hidden email]>  wrote:
>
> I am supposed to see a friend's TS-590 sometime after CQ WW SSB, along with an FT-5000.  The Kenwood will require more lab time than normal due to its architecture.  I don't understand the reason for the unusual conversion scheme.   73, Rob Sherwood, NC0B
>
>>>> "Joe Subich, W4TV"<[hidden email]>  10/18/2010 7:10 PM>>>
>
> Looks like I missed a few other "tricks" (not treats) in the TS-590.
>
> I refer the reader to Kenwood's own brochure for the TS-590 at:
> <http://www.kenwoodusa.com/UserFiles/File/UnitedStates/Communications/AMA/Brochures/TS-590.pdf>
> and their ad on the rear cover of QST for
> November 2010.
>
> The brochure and the manual are at odds about "down-conversion"
> on 60 meters. The manual (Specifications, pg 82) says the 5 MHz
> band uses down-conversion, the brochure (pg 3) omits 60 Meters
> in the list of bands that use down-conversion. Both sources and
> the ad are clear that down-conversion is not used when the receive
> bandwidth is more than 2.7 KHz (can you say ESSB), in AM or FM.
> Instead the rig switches to the "conventional" up-convert to VHF
> system.
>
> The brochure also makes another strange claim ... the TS-590 uses
> a "bare" DDS to drive the down-conversion mixer (pg 3) and claims
> that architecture is "cleaner" with less reciprocal mixing than a
> conventional PLL/VCO synthesizer. The brochure shows a picture
> of an Analog Devices AD9951 DDS ... I haven't checked recently but
> last I heard the Analog Devices and similar DDS products had some
> serious close-in spurs which resulted in poor wideband SFDR and
> *MORE* reciprocal mixing than a well designed PLL/VCO synthesizer,
> not less.
>
> Taken with the lack of a sub-receiver, no input for a separate
> receive antenna, no wideband IF for a panadapter, a 12V power
> amplifier, etc. the TS-590 is looking more and more like a warmed
> over TS-2000 with a "gimmicky" (partial) amateur bands only front
> end and not the serious, higher performance transceiver it was made
> out to be.
>
> When the serious testing begins, I hope independent engineers like
> Rob Sherwood, Peter Hart and the ARRL Labs will compare performance
> on 20 vs. 17 meters and check other issues like reciprocal mixing
> and IMDDR3 for *both* "front ends."
>
> 73,
>
> ... Joe, W4TV
>
>> On Mon, Oct 18, 2010 at 10:52 AM, Joe Subich, W4TV<[hidden email]>  wrote:
>>>
>>>> Believe me or not. The designer of TS590 also a K3 owner.
>>>
>>> He sure made some very questionable choices if he had a K3 to
>>> copy from!
>>>
>>> The TS-590 only uses the down conversion/roofing filter system
>>> on the 160, 80, 60, 40, 20 and 15 meter amateur bands! Outside
>>> those bands and above 21 MHz it is a conventional up conversion
>>> design. Why he chose to do what amounts to a complete second
>>> receiver from the antenna to the 24 KHz DSP last IF/demodulator
>>> is complete mystery. For essentially the same parts cost he
>>> could have included a second, lower performance receiver like
>>> the FT-5000.
>>>
>>> 73,
>>>
>>> ... Joe, W4TV
>>>
>>>
>>> On 10/18/2010 10:11 AM, Johnny Siu wrote:
>>>> Believe me or not. The designer of TS590 also a K3 owner. I met him in Aug
>>>> 2010 in Tokyo.
>>>>
>>>> cheers,
>>>>
>>>> Johnny VR2XMC
>>>>
>>>>
>>>>
>>>>
>>>> ________________________________
>>>> 寄件人﹕ "[hidden email]"<[hidden email]>
>>>> 收件人﹕ [hidden email]
>>>> 傳送日期﹕ 2010/10/18 (一) 10:05:40 PM
>>>> 主題： [Elecraft] New Kenwood TS0-590
>>>>
>>>> I finally got a chance to see the new Kenwood rig at HRO in Portland
>>>> last Saturday. Didn't get to play with it for very long as there were
>>>> too many others who wanted to play with it too. Anyway, it seems like a
>>>> nice radio--sounded good--looks good--but still missing lots of things
>>>> we get with a K3. It does seem like an obvious attempt to compete
>>>> somewhat with the K3, but it's NOT a true contender for a lot of
>>>> reasons.
>>>>
>>>> The ergonomics were fairly good, and unlike Yaesu, for example, they
>>>> don't bury everything deep in a menu system. But you still have to push
>>>> buttons a few extra times. For example, setting power level and keyer
>>>> speed takes a couple of extra pushes of buttons vs. the K3. Like I said
>>>> above, I didn't really get to play with it very long, but I'm certain
>>>> you would be giving up a lot if you opted for this vs. a K3.
>>>>
>>>> The folks at Pacificon probably got a better chance to look at the new
>>>> Kenwood. At least it shows that Kenwood is still in the amateur radio
>>>> business, which I think is a good thing.
>>>>
>>>> Dave W7AQK
>>>>
>
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