2016-02-25 1:35 GMT+02:00 Jim Brown <k9yc@audiosystemsgroup.com>:
> On Wed,2/24/2016 6:27 AM, Jukka Klemola wrote:
>
>> I am going to think a little and make a write up somewhere on the subject
>>
>
> Rather than "think," it would probably be far better if you were to STUDY
> the documentation for modern radios and the impartial testing done by ARRL
> Labs, and published on their website. I have done that quite extensively,
> and have written it up in k9yc.com/TXNoise.pdf These are FACTS that I
> have taken the time to learn, not opinions.
>
I have referred to this Jim's document in my earlier write ups for the
Finnish audience.
Jim's study on the transmitter cleanliness is groundbreaking and really the
first of it's kind.
Jim is showing the direction of development, what RF features are going to
be important in ham radio transceivers.
We all know about the receivers.
During-operation-tuning-needs
Frequency stability
Selectivity
Dynamic range.
IP3.
Close in dynamic range.
A/D resolution
the latest is overclocking the first A/D.
All that closes in asymptotically the laws of physics.
Dynamic range is nearly 110dB for signals rather close to each other.
A mosquito produces a sound pressure level of some dB.
Speaking is somewhere at 50dB range
Shouting is maybe 10dB more
Rock concert does not really exceed 100dB, even if measured just some
meters off the speakers.
Somehow, if exaggerating a little, we can hear mosquitoes in a rock concert
with the current receiver capability.
But, taking the frequency differences and filtering into consideration, we
know better.
But it does not remove the fact we see every contest.
We are listening to the mosquitoes in between the rock concerts.
Transmitter improvements are going to be the next series of topics.
In the terms above, we need to get the rock concerts to stay put in their
own frequency property.
Not spreading their goods on the neighbors' frequency property.
The CW transmitters show an output spectrum vastly inferior to the receiver
performance.
All current SSB transmitters show output products that are too much worse
than receiver capabilities.
Any objections?
Think about transmitter chain and IMD of the finals.
No oscillator purity can rescue the signal from IMD generated at amplifier
stages.
Again, you speak of firmware upgrades for the K3 "solving" a problem with
> clicks. I've been using K3s with legal limit amps since 2008. I do not
> recall ever having an issue with clicks -- if I did, K6XX, who lives five
> miles from me, would have told me! Again, you have bad information.
>
Nah .. Jim.. please read the K3 thread I posted.
Repeating here:
http://elecraft.365791.n2.nabble.com/CW-Rise-Time-td3218979.html
I understand this so there is some possibility a small K3 population is
operational and could benefit of a SW upgrade.
About any discomfort for the frequency domain neighbors, my guess is the
discomfort of unmodified FT1000, FT2000 and FT3000 plus FT5000 is much
bigger than any K3 production lot.
Beginning with the K3 and all of its accessories, firmware upgrades are
> nearly automatic. The firmware update utility (one for Windoze and one for
> Mac) queries the radio via a serial or USB port, queries the website and
> downloads the latest firmware, asks if you want to update, and if you say
> yes, it does that.
>
Huh ?
Easier than a menu setting ?
Feels like marketing men promises.
Coming from YC-Jim, I buy the idea it is possible.
If it is already implemented, Super !
I first published TXNoise about 18 months ago. It clearly showed that Yaesu
> radios were by far the dirtiest on CW, with very excessive clicks and phase
> noise. A few months later, they issued a firmware update that significantly
> improved the keying performance of the FTDX5000 and others in that family.
> Likewise, ARRL's review of the Flex 6500 and 6700 SDRs showed really awful
> CW bandwidth. A few months later, Flex issued a firmware update that
> significantly improved the keying performance.
>
First time I referred to TXNoise.pdf was not many moths after Jim had made
the paper public.
Maybe it was weeks, not months.
I like the paper with all upgrades done to it.
Another great source of information is Sherwoodengineering receiver test
data.
http://www.sherweng.com/table.html
..everybody know this one already, I hope..
In TXNoise, I noted the connection between rise/fall time and keying
> bandwidth, and stated the simple rule that if it is adjustable, slower
> produces the cleanest result.
>
I have witnessed also a station had too sharp fall time. Rise time was
perfectly in shape.
That station owner fixed the fall time. A show of really good ham spirit.
I would like to update TXNoise with results for the 6500/6700 radios after
> their firmware upgrade, but have so far been unsuccessful in having an
> owner loan his rig for measurement. N6TA loaned his FTDX5000 for before and
> after measurements, and they are on my website.
>
> http://k9yc.com/P3_Spectrum_Measurements.pdf
>
> 73, Jim K9YC
>
TXNoise.pdf evolves, like Sherwood Engineering receiver comparison website.
These are excellent sources for information.
73,
Jukka OH6LI
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