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Why is KX3 phase noise so much less than the K3 ?

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Larry Lopez

Why is KX3 phase noise so much less than the K3 ?

http://www.sherweng.com/table.html

The LO Noise (dBc/Hz):

144 KX3
138 K3
130 R390A
121 FT-1000D
117 ICOM 720A

I'm wondering why the KX3 Lo noise is so much better than the K3.
The R390A value strange since the first local oscillator is a quartz crystal.

I've owned a Icom 720A and own a FT-1000D.
Ive never owned a K3, KX3 or a R390A.

Larry

Bill-3

Re: Why is KX3 phase noise so much less than the K3 ?

Can anyone really hear the difference between any of the top rated rigs
(Sherwood list) in the real world (not in a lab)?

Bill K-Line

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Mike Harris-9

Re: Why is KX3 phase noise so much less than the K3 ?

Yes, when your neighbours FTDX5000 at 300 metres away spews noise over
three adjacent bands. Compounded by idling the FT and making up the
power with an amp which only makes the problem worse by another 15dB.
Adjacent bands are clear when a Dunestar BPF filter inserted between his
FT and amp. My K3 doesn't offer him the same problem.

Regards,

Mike VP8NO

On 02/04/2014 10:25, Bill W2BLC wrote:
> Can anyone really hear the difference between any of the top rated rigs
> (Sherwood list) in the real world (not in a lab)?
>
> Bill K-Line
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Phil Wheeler-2

Re: Why is KX3 phase noise so much less than the K3 ?

The FTdx5000 does that in RX mode? Nasty! :-)

Phil W7OX

On 4/2/14, 7:17 AM, Mike Harris wrote:

> Yes, when your neighbours FTDX5000 at 300 metres
> away spews noise over three adjacent bands.
> Compounded by idling the FT and making up the
> power with an amp which only makes the problem
> worse by another 15dB. Adjacent bands are clear
> when a Dunestar BPF filter inserted between his
> FT and amp. My K3 doesn't offer him the same
> problem.
>
> Regards,
>
> Mike VP8NO
>
> On 02/04/2014 10:25, Bill W2BLC wrote:
>> Can anyone really hear the difference between
>> any of the top rated rigs
>> (Sherwood list) in the real world (not in a lab)?
>>
>> Bill K-Line

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Matt Zilmer-3

Re: Why is KX3 phase noise so much less than the K3 ?

In reply to this post by Bill-3

It's easy to demonstrate this. My real-world setting is Field Day,
and the example is actually what my team experienced.

Take four rigs in a Field Day setting, within 100 yards of each other.
Make sure one of them is a K3, and the others are Y/K/I types.

On the same band, any of the Y/K/I rigs will create so much wideband
[phase] noise on transmit that none of the other rigs are usable on
receive. Transmit on the K3 and all the other rigs are usable on
receive (same band, mind you). No BPF required in this case.

This is very real-world. It's also the reason DXpeditioners use
Elecraft products in close proximity with no ill effects. Field Day
is just my Regular Joe example of the same thing.

Yes, there is a huge difference - not just a statistic for the charts.

73,
matt W6NIA

On Wed, 02 Apr 2014 09:25:53 -0400, you wrote:

>Can anyone really hear the difference between any of the top rated rigs
>(Sherwood list) in the real world (not in a lab)?
>
>Bill K-Line
>
>
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Matt Zilmer, W6NIA
--
"Give me six hours to chop down a tree and I will
spend the first four sharpening the axe." -A. Lincoln
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Don Wilhelm-4

Re: Why is KX3 phase noise so much less than the K3 ?

In reply to this post by Phil Wheeler-2

Not that I know of, but when it transmits, it wipes out nearby receivers.

73,
Don W3FPR

On 4/2/2014 10:55 AM, Phil Wheeler wrote:
> The FTdx5000 does that in RX mode? Nasty! :-)
>

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wayne burdick

Re: Why is KX3 phase noise so much less than the K3 ?

Administrator

In reply to this post by Larry Lopez

The K3 and KX3 both have very low phase noise. It can vary a bit from band to band and from one unit to the next. Sherwood measured one example of each, but typically both measure right around -140 dBc/Hz at 20 kHz.

When we designed the K3, we were trying to improve on the phase noise numbers usually found in transceivers with synthesized local oscillators. Typical values were -110 to -120 dBc/Hz, and this definitely impacted stations within close proximity of each other. By using a very high C/L ratio in the K3's VCO, we achieved numbers in the -140 range, and our field testers in close proximity could no longer hear each other at all.

This result was corroborated by the Ducie Island DXpedition, the first to use K3s. They told us that they had a 30-m CW station and a 30-m RTTY station both running at the same time within 1 kHz of each other.

The KX3 uses a different type of synthesizer, but the result is the same. In this case an on-chip VCO runs at a very high frequency and is then divided down to get to the HF range.

73,
Wayne
N6KR

On Apr 2, 2014, at 5:40 AM, Larry Lopez <[hidden email]> wrote:

> http://www.sherweng.com/table.html
>
> The LO Noise (dBc/Hz):
>
> 144 KX3
> 138 K3
> 130 R390A
> 121 FT-1000D
> 117 ICOM 720A
>
>
> I'm wondering why the KX3 Lo noise is so much better than the K3.
> The R390A value strange since the first local oscillator is a quartz
> crystal.
>
> I've owned a Icom 720A and own a FT-1000D.
> Ive never owned a K3, KX3 or a R390A.
>
> Larry
>
>
>
>
> --
> View this message in context: http://elecraft.365791.n2.nabble.com/Why-is-KX3-phase-noise-so-much-less-than-the-K3-tp7586369.html
> Sent from the Elecraft mailing list archive at Nabble.com.
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Don Wilhelm-4

Re: Why is KX3 phase noise so much less than the K3 ?

In reply to this post by Matt Zilmer-3

That is why I try to encourage the local Field Day group to use only
Elecraft gear. Even though we do not typically operate more than one
transceiver on a single band, the YKI types can cause problems on other
harmonically related bands. We used to have a Yaesu FT-900 on SSB, and
it caused problems.
Typically we are class 2A with a GOTA station.

73,
Don W3FPR

On 4/2/2014 11:06 AM, Matt Zilmer wrote:

> It's easy to demonstrate this. My real-world setting is Field Day,
> and the example is actually what my team experienced.
>
> Take four rigs in a Field Day setting, within 100 yards of each other.
> Make sure one of them is a K3, and the others are Y/K/I types.
>
> On the same band, any of the Y/K/I rigs will create so much wideband
> [phase] noise on transmit that none of the other rigs are usable on
> receive. Transmit on the K3 and all the other rigs are usable on
> receive (same band, mind you). No BPF required in this case.
>
> This is very real-world. It's also the reason DXpeditioners use
> Elecraft products in close proximity with no ill effects. Field Day
> is just my Regular Joe example of the same thing.
>
> Yes, there is a huge difference - not just a statistic for the charts.
>
>

Jim Sheldon

Re: Why is KX3 phase noise so much less than the K3 ?

In reply to this post by Larry Lopez

Like Don said, "not in receive", but in transmit, driving an Alpha 9500 to the full 1500 out, a close neighbor (about 5 blocks away) was noticeable on my K3 within 5-10 KHz of his transmit frequency. That said, the FTdx5000 was MUCH cleaner than the FT-1000MP he had prior to obtaining the 5000. The phase noise & key clicks from the 1000MP were horrendous but at least his huge signal did not pump the K3's AGC unless he was within my 400Hz filter passband.

I could operate the same band and within 3 KHz or so of him after he got the 5000. He, however, had problems with my 500 watt signal overloading his front end if he tried to operate within around 10KHz of me after he got the 5000. Fortunately the entire problem was solved a few months ago when he moved to an inherited farm QTH 20 or so miles from here.

W0EB

> Not that I know of, but when it transmits, it wipes out nearby
> receivers.
>
> 73,
> Don W3FPR
>
> On 4/2/2014 10:55 AM, Phil Wheeler wrote:
>> The FTdx5000 does that in RX mode? Nasty! :-)
>>
>
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Phil Wheeler-2

Re: Why is KX3 phase noise so much less than the K3 ?

In reply to this post by Matt Zilmer-3

I agree, Matt, and every rig I use now is an
Elecraft (K3, KX3, K2, ...).

But the question the OP posed was K3 vs. KX3: "I'm
wondering why the KX3 Lo noise is so much better
than the K3"

73, Phil W7OX

On 4/2/14, 8:06 AM, Matt Zilmer wrote:

Dave-5

Re: Why is KX3 phase noise so much less than the K3 ?

In reply to this post by Jim Sheldon

There was some discussion about the effects when on receive as well, I seem
to think another manufacturer, not Electraft and not one of the 'big 3' was
shown to be quite poor with it's radiated signals even on receive. Or, did
I read the lab reports incorrectly?

Dave (G0DJA)

----- Original Message -----
Sent: Wednesday, April 02, 2014 3:38 PM
Subject: Re: [Elecraft] Why is KX3 phase noise so much less than the K3 ?

> Like Don said, "not in receive", but in transmit, driving an Alpha 9500 to
> the full 1500 out, a close neighbor (about 5 blocks away) was noticeable
> on my K3 within 5-10 KHz of his transmit frequency. That said, the
> FTdx5000 was MUCH cleaner than the FT-1000MP he had prior to obtaining the
> 5000. The phase noise & key clicks from the 1000MP were horrendous but at
> least his huge signal did not pump the K3's AGC unless he was within my
> 400Hz filter passband.

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wayne burdick

Re: Why is KX3 phase noise so much less than the K3 ?

Administrator

You may be thinking of "reciprocal mixing," a measure of receiver performance that is impacted by synthesizer phase noise, spurs, etc.

Wayne
N6KR

On Apr 2, 2014, at 8:48 AM, "Dave" <[hidden email]> wrote:

> There was some discussion about the effects when on receive as well, I seem to think another manufacturer, not Electraft and not one of the 'big 3' was shown to be quite poor with it's radiated signals even on receive. Or, did I read the lab reports incorrectly?
>
> Dave (G0DJA)
>
> ----- Original Message ----- Sent: Wednesday, April 02, 2014 3:38 PM
> Subject: Re: [Elecraft] Why is KX3 phase noise so much less than the K3 ?
>
>
>> Like Don said, "not in receive", but in transmit, driving an Alpha 9500 to the full 1500 out, a close neighbor (about 5 blocks away) was noticeable on my K3 within 5-10 KHz of his transmit frequency. That said, the FTdx5000 was MUCH cleaner than the FT-1000MP he had prior to obtaining the 5000. The phase noise & key clicks from the 1000MP were horrendous but at least his huge signal did not pump the K3's AGC unless he was within my 400Hz filter passband.
>
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Barry K3NDM

Re: Why is KX3 phase noise so much less than the K3 ?

In reply to this post by Dave-5

Phase noise is very important on receive. If your L.O. has a high phase
noise content, the phase noise will mix with signals away from the L.O.
and bring those signals into your filter bandwidth as noise. This is
called reciprocal mixing and is essentially as described below. If you
want a radio that yields higher signal to noise ratios, everything being
equal, lower the phase noise.

73,
Barry
K3NDM

On 4/2/2014 11:48 AM, Dave wrote:

> There was some discussion about the effects when on receive as well, I
> seem to think another manufacturer, not Electraft and not one of the
> 'big 3' was shown to be quite poor with it's radiated signals even on
> receive. Or, did I read the lab reports incorrectly?
>
> Dave (G0DJA)
>
> ----- Original Message ----- Sent: Wednesday, April 02, 2014 3:38 PM
> Subject: Re: [Elecraft] Why is KX3 phase noise so much less than the K3 ?
>
>
>> Like Don said, "not in receive", but in transmit, driving an Alpha
>> 9500 to the full 1500 out, a close neighbor (about 5 blocks away) was
>> noticeable on my K3 within 5-10 KHz of his transmit frequency. That
>> said, the FTdx5000 was MUCH cleaner than the FT-1000MP he had prior
>> to obtaining the 5000. The phase noise & key clicks from the 1000MP
>> were horrendous but at least his huge signal did not pump the K3's
>> AGC unless he was within my 400Hz filter passband.
>
> ______________________________________________________________
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k6dgw

Re: Why is KX3 phase noise so much less than the K3 ?

In reply to this post by Matt Zilmer-3

I think Bill's question spoke to phase-noise on receive, not transmit.
I'm fairly certain all of us are aware of the transmit problem from some
transceivers.

To Bill's question, I'd say "No," I cannot hear the difference when the
measured noise is in the -135to -140 range, other noise sources totally
mask it for me.

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2014 Cal QSO Party 4-5 Oct 2014
- www.cqp.org

On 4/2/2014 8:06 AM, Matt Zilmer wrote:

> On the same band, any of the Y/K/I rigs will create so much wideband
> [phase] noise on transmit that none of the other rigs are usable on
> receive. Transmit on the K3 and all the other rigs are usable on
> receive (same band, mind you). No BPF required in this case.

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David Gilbert

Re: Why is KX3 phase noise so much less than the K3 ?

In reply to this post by Phil Wheeler-2

That's a silly comment. Last time I checked, people nearby a trashy
transmitter have to listen as well. They didn't create no smoking rules
in public places to protect smokers from their own smoke.

Dave AB7E

On 4/2/2014 7:55 AM, Phil Wheeler wrote:
> The FTdx5000 does that in RX mode? Nasty! :-)
>
> Phil W7OX

>
> On 4/2/14, 7:17 AM, Mike Harris wrote:
>> Yes, when your neighbours FTDX5000 at 300 metres away spews noise
>> over three adjacent bands. Compounded by idling the FT and making up
>> the power with an amp which only makes the problem worse by another
>> 15dB. Adjacent bands are clear when a Dunestar BPF filter inserted
>> between his FT and amp. My K3 doesn't offer him the same problem.
>>
>> Regards,
>>
>> Mike VP8NO
>>
>> On 02/04/2014 10:25, Bill W2BLC wrote:
>>> Can anyone really hear the difference between any of the top rated rigs
>>> (Sherwood list) in the real world (not in a lab)?
>>>
>>> Bill K-Line
>
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Chip Stratton

Re: Why is KX3 phase noise so much less than the K3 ?

In reply to this post by k6dgw

The KX3 isn't perfect. During SOTA activations, Gary W5ODS and I each use a
KX3, with the roofing filter option. He with an end-fed wire, and me
usually with an AlexLoop. I can often hear his code (a pink noise sound)
even when he is in a band higher in frequency, as well as when I am in a
higher band and he the lower. Sometimes turning on RX SHIFT 8kHz knocks it
out, sometimes it doesn't. Turning on the attenuator or lowering RF gain
doesn't seem to knock it out either.

Is that phase noise or another phenom?

Don't get me wrong, I do love the KX3.

Chip
AE5KA
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Charlie T, K3ICH

Re: Why is KX3 phase noise so much less than the K3 ?

In reply to this post by Mike Harris-9

Better hope there's no Flex's transmitting too close to your location
either.

Chas

>, Bill W2BLC wrote:
>> Can anyone really hear the difference between any of the top rated rigs
>> (Sherwood list) in the real world (not in a lab)?
>>
>> Bill K-Line
>
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Dave-7

Re: Why is KX3 phase noise so much less than the K3 ?

In reply to this post by Larry Lopez

Why does the ARRL lab test show the KX3 TX phase noise as about -124
dBc/Hz (Fig 5 of their report) and Sherwood show this as -144 dBc/Hz,
both at 10 kHz spacing? That is a huge difference.

The ARRL report shows that the KX3 never goes below about -135 dBc/Hz,
even 1 MHz away.

Is there an update to the ARRL lab test? Did the ARRL miss this one?

FWIW, ARRL shows the K3 at about -142 and the FTdx5000 at -135, at 10
kHz spacing.

73 de dave
ab9ca/4

On 4/2/14 7:40 AM, Larry Lopez wrote:

Bill-3

Re: Why is KX3 phase noise so much less than the K3 ?

In reply to this post by k6dgw

Thank you Fred K6DGW - you are correct - I was referring to phase noise
on RX.

So far as noise from XMIT on other rigs, I have no experience. I live in
a rural area and have an extremely low ambient noise level. A noisy RX
exposes itself immediately.

As I recall, the quietest rig I ever had back in the day was a TenTec
Corsair II. However, that was over twenty five years ago and it was analog.

Of my recent type equipment, the K3 is the quietest - most likely as
quiet as the Corsair was. Just understand, my viewpoint is from the
armchair copy side. I do not DX or contest. The K-Line is probably
overkill for what I use it for, however, it sure is awfully good at the
job (just know your rig and make the appropriate menu adjustments).

My original comment/query merely was aimed at the difference in real
world use and inside a copper lined lab.

Bill K-Line

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george fritkin

Re: Why is KX3 phase noise so much less than the K3 ?

In reply to this post by Charlie T, K3ICH

No! And I have them all. My TenTec Eagle hears as good as my FT5K and our beloved K3 and KX3

George, W6GF
On Wednesday, April 2, 2014 10:02 AM, "Charlie T, K3ICH" <[hidden email]> wrote:

Better hope there's no Flex's transmitting too close to your location
either.

Chas

>, Bill W2BLC wrote:
>> Can anyone really hear the difference between any of the top rated rigs
>> (Sherwood list) in the real world (not in a lab)?
>>
>> Bill K-Line
>
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