http://elecraft.85.s1.nabble.com/Re-Elecraft-K3-K3S-to-be-discontinued-tp7656195p7656203.html
Thank you, Bob. Rob, clarified to me. Seems most transmitters are in the same boat using solid state transmitters/amplifiers, vs. tubes.
I suppose I am the "Bob" you refer to. The section in Rob's article on Odd-Order Intermodulation he clearly explains "worse".
Our receivers have gotten much better over the years but unfortunately our transmitters and amplifiers have gotten worse. To quantify, the ARRL published a compendium of distortion products of linear amplifiers in 1997. The third order distortion was in the 40 and 50 dB PEP range. In 2019 an ARRL review of solid state legal limit amplifiers reported the third order distortion was only down 30 dB. This is a 10 to 20 dB degradation from 1997 to 2019. I'd call this "worse".
>
> “worse” seems a bit much when looking at the actual levels. Bob, did
> you mean something else? I know this is semantics….
>
> 73,
>
> Bill
>
> K9YEQ
>
>
https://wrj-tech.com/>
> *From:*
[hidden email] <
[hidden email]> *On Behalf Of
> *Rob Sherwood
> *Sent:* Sunday, November 3, 2019 5:16 PM
> *To:*
[hidden email]
> *Subject:* Re: [Elecraft-K3] K3S to be discontinued
>
> The K3S is excellent in respect to transmit composite noise. Transmit
> IMD, on the other hand, is quite different at various power levels.
> The sweet spot is around 35 watts, but much worse at 12 watts and 100
> watts. Here is composite noise data. Hopefully the formatting will
> hold up.
>
> Rob, NC0B
>
> Transmit Composite Noise Rig Comparisons 20 meters values in dBc/Hz
>
> Rig @ 100 watts 2 kHz offset 10 kHz offset
> 20 kHz offset 100 kHz offset
>
> K3S -141 n/a -143
>
> FTdx-101D -133 -137 -138
> -141
>
> IC-7851 -129 n/a -138
>
> IC-7610 -128 -130 -142
>
> Flex 6400 -122 -127 -139
>
> IC-7300 -121 -121 -124
>
> FTdx-3000 -120 n/a -121
>
> TS-890S -116 -119
> -127 -139
>
> Rig @ 30 watts 2 kHz offset 10 kHz offset
> 20 kHz offset 100 kHz offset
>
> FTdx-101D -129 -134 -135
> -137
>
> K3S -132 n/a -140
>
> IC-7851 -123 n/a -133
>
> IC-7610 -122 -124 -127
>
> Flex 6400 -120 -125 -137
>
> FTdx-3000 -117 n/a -117
>
> TS-890S -112 -115
> -124 -135
>
> IC-7300 -110 -109 -116
>
> *From:*
[hidden email] <mailto:
[hidden email]>
> [mailto:
[hidden email]] *On Behalf Of *Wes
> *Sent:* Sunday, November 03, 2019 10:32 AM
> *To:*
[hidden email] <mailto:
[hidden email]>
> *Subject:* Re: [Elecraft-K3] K3S to be discontinued
>
> If TX IMD is the issue, K3 and K3S transmitters are a real mixed bag.
> My old K3 at 30 watts is fantastic, with IMD at all frequencies better
> than -40 dBc (ARRL method). The same radio at 10W is the worst of my
> two radios, except at 24 MHz where the K3 and K3S tie at -22 dBc.
>
> It's been hard to keep up with these measurements since the KLPA3A in
> the K3S has been replaced twice and the KPA3A is IIRC, on the fourth
> version.
>
> Wes N7WS
>
> On 11/3/2019 8:16 AM, Martin Sole wrote:
>
> I suspect the quality of the transmitter particularly with regard
> to its composite noise spectrum to be a large player. Some radios
> with high end receiver performance have rudimentary (I'm being
> kind) transmitter composite noise performance.
>
> See what NK7Z, NC0B and K9YC have written about this.
>
>
> Martin, HS0ZED
>
> On 03/11/2019 21:30, Mark Morin wrote:
>
> My experience is that the type of rig does make a difference
> for close coexistence. We’ve found on DxPeditions that an
> upgraded K3 with KPA500 and a Kenwood TS-590s also with
> KPA500, can coexist quite well with antennas about 300 ft
> apart. On most bands, we can operate SSB and CW simultaneously
> with tolerable QRM. Other times we have tried different
> high-end rigs in similar setup and found that opposite end of
> same-band operation was nearly impossible due to QRM. I
> suspect it’s mostly the receivers that makes the difference.
>
> Mark VA2MM
>
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