Date   
Re: phase noise

Rob Sherwood
 

Field Day is the most likely place we run into both transmitted composite noise and serious RMDR limitations.  Multi-transmitter contesters, too, but they already know that is a big problem. 

Rob, NC0B


On Jan 12, 2019, at 6:11 PM, James C. Hall, MD via Groups.Io <heartdoc@...> wrote:

This has been a great thread and I spent a lot of today studying phase noise. It sounds like it’s really not a good idea to amplify QRP transceivers such as FT-817/818, KX1/2/3, etc.

Been looking at how this effects Field Day operations as well.

73, Jamie
WB4YDL


On Jan 12, 2019, at 5:17 PM, Rob Sherwood <rob@...> wrote:

Hi Fred,

 

You are not hurting the amp or the K3, but you are making the transmitted noise much worse.

 

Here is an example. 

 

I use an IC-7300 on 630 meters with a transverter that only requires 5 watts of drive. If I back off the Icom to 5 watts, my transmitted noise seriously degrades.  Since on 630m I need more loss on receive anyway, I put a 10-dB 75-watt Bird attenuator between the output of the 7300 and the input of the transverter.  Now I can run the 7300 at 50 watts instead of 5 watts.  This improved my transmitted noise by 9 dB.

 

On another subject in respect to the K3, if you are running the K3 at 10 watts, the PA is out of the circuit.  On SSB the odd-order transmit IMD (splatter) at 10 to 12 watts is poor compared if the K3 is run at 35 to 45 watts.  If I wanted a cleaner SSB signal from a transmit IMD standpoint, I would run the rig at around 35 watts and whatever the KPA-500 put out.  I would also have my K3 power supply set for 14. 5 volts, and have a nice short power cable from the power supply to the rig so the voltage drop in the wire was minimal.

 

Rob, NC0B

 

From: Elecraft-K3@groups.io [mailto:Elecraft-K3@groups.io] On Behalf Of Fred-K0FG
Sent: Saturday, January 12, 2019 3:23 PM
To: Elecraft-K3@groups.io
Subject: [Elecraft-K3] phase noise

 

After the discussion about phase noise I have a question.   When I want to operate at an output power of 100 watts, or a little above, I frequently turn on the KPA500 and turn the power out on the K3 down to 6-10 watts.  Was thinking I was being kind to the amp and to the K3.   Am I wrong in doing that?   Am I doing more harm than good?

Fred, K0FG

 


If this email is spam, report it to www.OnlyMyEmail.com



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Re: phase noise

James C. Hall, MD
 

This has been a great thread and I spent a lot of today studying phase noise. It sounds like it’s really not a good idea to amplify QRP transceivers such as FT-817/818, KX1/2/3, etc.

Been looking at how this effects Field Day operations as well.

73, Jamie
WB4YDL


On Jan 12, 2019, at 5:17 PM, Rob Sherwood <rob@...> wrote:

Hi Fred,

 

You are not hurting the amp or the K3, but you are making the transmitted noise much worse.

 

Here is an example. 

 

I use an IC-7300 on 630 meters with a transverter that only requires 5 watts of drive. If I back off the Icom to 5 watts, my transmitted noise seriously degrades.  Since on 630m I need more loss on receive anyway, I put a 10-dB 75-watt Bird attenuator between the output of the 7300 and the input of the transverter.  Now I can run the 7300 at 50 watts instead of 5 watts.  This improved my transmitted noise by 9 dB.

 

On another subject in respect to the K3, if you are running the K3 at 10 watts, the PA is out of the circuit.  On SSB the odd-order transmit IMD (splatter) at 10 to 12 watts is poor compared if the K3 is run at 35 to 45 watts.  If I wanted a cleaner SSB signal from a transmit IMD standpoint, I would run the rig at around 35 watts and whatever the KPA-500 put out.  I would also have my K3 power supply set for 14. 5 volts, and have a nice short power cable from the power supply to the rig so the voltage drop in the wire was minimal.

 

Rob, NC0B

 

From: Elecraft-K3@groups.io [mailto:Elecraft-K3@groups.io] On Behalf Of Fred-K0FG
Sent: Saturday, January 12, 2019 3:23 PM
To: Elecraft-K3@groups.io
Subject: [Elecraft-K3] phase noise

 

After the discussion about phase noise I have a question.   When I want to operate at an output power of 100 watts, or a little above, I frequently turn on the KPA500 and turn the power out on the K3 down to 6-10 watts.  Was thinking I was being kind to the amp and to the K3.   Am I wrong in doing that?   Am I doing more harm than good?

Fred, K0FG

 


If this email is spam, report it to www.OnlyMyEmail.com

Re: phase noise

Rob Sherwood
 

Hi Fred,

 

You are not hurting the amp or the K3, but you are making the transmitted noise much worse.

 

Here is an example. 

 

I use an IC-7300 on 630 meters with a transverter that only requires 5 watts of drive. If I back off the Icom to 5 watts, my transmitted noise seriously degrades.  Since on 630m I need more loss on receive anyway, I put a 10-dB 75-watt Bird attenuator between the output of the 7300 and the input of the transverter.  Now I can run the 7300 at 50 watts instead of 5 watts.  This improved my transmitted noise by 9 dB.

 

On another subject in respect to the K3, if you are running the K3 at 10 watts, the PA is out of the circuit.  On SSB the odd-order transmit IMD (splatter) at 10 to 12 watts is poor compared if the K3 is run at 35 to 45 watts.  If I wanted a cleaner SSB signal from a transmit IMD standpoint, I would run the rig at around 35 watts and whatever the KPA-500 put out.  I would also have my K3 power supply set for 14. 5 volts, and have a nice short power cable from the power supply to the rig so the voltage drop in the wire was minimal.

 

Rob, NC0B

 

From: Elecraft-K3@groups.io [mailto:Elecraft-K3@groups.io] On Behalf Of Fred-K0FG
Sent: Saturday, January 12, 2019 3:23 PM
To: Elecraft-K3@groups.io
Subject: [Elecraft-K3] phase noise

 

After the discussion about phase noise I have a question.   When I want to operate at an output power of 100 watts, or a little above, I frequently turn on the KPA500 and turn the power out on the K3 down to 6-10 watts.  Was thinking I was being kind to the amp and to the K3.   Am I wrong in doing that?   Am I doing more harm than good?

Fred, K0FG

 


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Re: phase noise

Michael Blake <k9jri@...>
 

That’s an interesting question Fred as at 10 watts the low power amp is being driven pretty hard and the 100 watt amp is bypassed.  At 12 watts drive both the low power and the 100 watt amp are loafing but I am not sure that is good or bad as far as distortion goes :)

73 - Mike - K9JRI






On Jan 12, 2019, at 5:23 PM, Fred-K0FG <kzerofg@...> wrote:

After the discussion about phase noise I have a question.   When I want to operate at an output power of 100 watts, or a little above, I frequently turn on the KPA500 and turn the power out on the K3 down to 6-10 watts.  Was thinking I was being kind to the amp and to the K3.   Am I wrong in doing that?   Am I doing more harm than good?

Fred, K0FG

phase noise

Fred-K0FG
 

After the discussion about phase noise I have a question.   When I want to operate at an output power of 100 watts, or a little above, I frequently turn on the KPA500 and turn the power out on the K3 down to 6-10 watts.  Was thinking I was being kind to the amp and to the K3.   Am I wrong in doing that?   Am I doing more harm than good?

Fred, K0FG

Re: Transmit Phase Noise

harry latterman <harrylatterman@...>
 

Thank you for posting the data.  Looks interesting and a bit surprising. However you forgot my really cool 1 yr old FTdx5000MPL... You said it was a bit better then the FTdx3000. It would be interesting to see how it stacks up.  The radio was from a trade and never used. As of December it was only 1 yr old and more radio, with more features then I could ever imagine or expect.... My 3 main radios are K3/100 with the KSYN3A added, A IC-7300 that I run mostly at 30 watts driving my KPA500 and KAT500 and the FTdx5000MPL. Seems from you list I might actually have 3 fairly decent radios. Oh I can not forget my take it everywhere jewel, the KX2.  So if you do have the 5000MPL data I would love to see it. Post here or direct email. Your choice.

73 Harry K7ZOV

On Saturday, January 12, 2019, 11:06:30 AM MST, Rob Sherwood <rob@...> wrote:


Here is some data I have at both 100 watts and 30 or 35 watts for six rigs.

Different lab, different measuring equipment, different rig samples, so don’t expect absolute correlation with ARRL data.

ARRL lab data only measures phase noise, not composite noise (phase and AM noise).

Data from Contest University presentations of mine.

Note: While the listing are sorted by column 1, the ranking varies with frequency offset.

Rob

NC0B

 

Transmit Composite Noise Rig Comparisons 20 meters

Best at maximum power output, but degrades at lower power levels

 

Rig @ 100 watts                10 kHz offset, dBc/Hz     20 kHz offset, dBc/Hz     100 kHz offset, dBc/Hz

K3S                                         -141                                       n/a                                         -143

IC-7300                                 -130                                       n/a                                         -132

IC-7851                                 -129                                       n/a                                         -138

IC-7610                                 -127                                       -129                                       n/a

TS-890S                                -120                                       -129                                       n/a

FTdx-3000                           -120                                       n/a                                         -121

 

Rig @ 30 watts                   10 kHz offset, dBc/Hz     20 kHz offset, dBc/Hz     100 kHz offset, dBc/Hz

K3S                                         -132                                       n/a                                         -140

IC-7851                                 -123                                       n/a                                         -133

IC-7610                                 -122*                                     -124*                                     n/a

FTdx-3000                           -117                                       n/a                                         -117

TS-890S                                -113*                                     -122*                                     n/a

IC-7300                                 -112                                       n/a                                         -120

 

* = Power level was 35 watts

n/a = data not available

Rev D

 

Re: Transmit Phase Noise

Everett N4CY
 

Hi Rob,

Thanks for the info...

Everett N4CY

In a message dated 1/12/2019 12:06:30 PM Central Standard Time, rob@... writes:

Here is some data I have at both 100 watts and 30 or 35 watts for six rigs.

Different lab, different measuring equipment, different rig samples, so don’t expect absolute correlation with ARRL data.

ARRL lab data only measures phase noise, not composite noise (phase and AM noise).

Data from Contest University presentations of mine.

Note: While the listing are sorted by column 1, the ranking varies with frequency offset.

Rob

NC0B

 

Transmit Composite Noise Rig Comparisons 20 meters

Best at maximum power output, but degrades at lower power levels

 

Rig @ 100 watts                10 kHz offset, dBc/Hz     20 kHz offset, dBc/Hz     100 kHz offset, dBc/Hz

K3S                                         -141                                       n/a                                         -143

IC-7300                                 -130                                       n/a                                         -132

IC-7851                                 -129                                       n/a                                         -138

IC-7610                                 -127                                       -129                                       n/a

TS-890S                                -120                                       -129                                       n/a

FTdx-3000                           -120                                       n/a                                         -121

 

Rig @ 30 watts                   10 kHz offset, dBc/Hz     20 kHz offset, dBc/Hz     100 kHz offset, dBc/Hz

K3S                                         -132                                       n/a                                         -140

IC-7851                                 -123                                       n/a                                         -133

IC-7610                                 -122*                                     -124*                                     n/a

FTdx-3000                           -117                                       n/a                                         -117

TS-890S                                -113*                                     -122*                                     n/a

IC-7300                                 -112                                       n/a                                         -120

 

* = Power level was 35 watts

n/a = data not available

Rev D


Re: KX3 / KXPA100 Combination for Contest Dxpediions

Everett N4CY
 

Joe,

Thanks....

Everett N4CY

In a message dated 1/12/2019 10:32:46 AM Central Standard Time, lists@... writes:


According to the ARRL Product reviews, both the K3S (and K3 with
KSYN3A) show -140 dBc or better from 2 KHz to 1 MHz.  The IC7610
is slightly better above 20 KHz at 100 W.  There is not "30W" data
for the K3/3S for comparison at reduced power output.

Among the transceivers reviewed in the last decade or so, the IC-7851
shows the lowest phase noise .... around -143 dBc (as close as I can
read the graph) from 15 KHz to 1 MHz (-140 dBc from 2-15 KHz).

73,

    ... Joe, W4TV


On 2019-01-12 8:59 AM, Everett N4CY via Groups.Io wrote:
> So where does the K3S fall into the group with regard to phase noise?
>
> Everett N4CY
>
>> On Jan 12, 2019, at 7:47 AM, Joe Subich, W4TV <lists@...> wrote:
>>
>>
>> On 2019-01-11 11:14 PM, Rob Sherwood wrote:
>>> There may be a typo in paragraph 1, sentence 2 below.
>>
>> Correct ... K3/KX3 should have been K3/K3S <G>.
>>
>> 73,
>>
>>    ... Joe, W4TV
>>
>>
>>> On 2019-01-11 11:14 PM, Rob Sherwood wrote:
>>> There may be a typo in paragraph 1, sentence 2 below.
>>> Add other poor transmitted phase noise rigs:
>>> FTdx-3000 (Wipes out 15 meters in Boulder, CO, for example, when an FT-1000MP does NOT.)
>>> FT-891 (From Bob Allison: "On the transmit side, the transmit phase is about the highest we’ve
>>> yet seen at the Lab. For this reason alone, I would be wary of pairing this transceiver
>>> with an RF amplifier."
>>> FTdx-5000 (somewhat better than the 3000)
>>> The only rig I am aware of that actually advertises low transmitted phase noise: IC-7610
>>> Rig with the highest RMDR: TS-890S, but its transmitted phase noise is modestly worse than the 7610.
>>> Another issue to consider, as the power output is reduced to drive an amp that only requires 30 to 50 watts of drive, the transmitted noise vs. the output signal goes up.  That is why the ARRL generally measures transmitted phase noise at full output and 35 watts.
>>> Note:  Transmitted noise can be phase noise and AM (amplitude) noise.  Some test equipment only measures phase noise and not composite noise, which is both phase and amplitude noise.
>>> When I measure transmitter noise with a Perseus FFT receiver, it measures composite noise.
>>> Rob, NC0B
>>> -----Original Message-----
>>> From: Elecraft-K3@groups.io [mailto:Elecraft-K3@groups.io] On Behalf Of Joe Subich, W4TV
>>> Sent: Friday, January 11, 2019 6:00 PM
>>> To: Elecraft-K3@groups.io
>>> Subject: Re: [Elecraft-K3] KX3 / KXPA100 Combination for Contest Dxpediions
>>> The *BIG PROBLEM* with the KX3/KPA100 vs. the K3 or K3S/100
>>> is the transmit phase noise of the KX3.  The KX3 transmitted
>>> phase noise is nearly 20 dB *higher* than the K3/KX3 at 2 KHz
>>> off of the transmit "carrier" (based on ARRL product review
>>> data).
>>> Using the KX3/KXPA100, particularly when driving another amp
>>> (like KPA500, KPA1500, Expert, etc). is not very neighborly.
>>> Transmit phase noise of the KX3 is comparable to some of the
>>> worst Icom rigs (IC-706mkIIg, IC-746Pro, etc.) which can
>>> wipe out a band with phase noise if driving a high power PA.
>>> For comparison at 20 KHz: Icom IC-706mkIIG -134dB, KX3 -124dB,
>>> K3S or K3 with KSYN3A <-140dB, K2 -128dB.
>>> I would be careful in considering a KX3/KXAP100 if there was
>>> a possibility of using it in a multi-transmitter situation.
>>> In general it is not wise to use any transceiver designed
>>> primarily for QRP operation with a power amplifier due to
>>> transmitted phase noise issues.  The synthesizers in rigs
>>> designed for low power operation simply are not a clean as
>>> those designed for 100W operation and/or intended to drive
>>> a high power amplifier.
>>> 73,
>>>      ... Joe, W4TV
>>>> On 2019-01-11 7:06 PM, Alan Higbie wrote:
>>>> . . . or, even better (smaller & cheaper) consider using a K2/100.
>>>>
>>>> I've traveled for DX contests - and over the years have hauled lots of different radios, i.e. Collins S-3 Line; FT-1000MP; K2/100, x2 K3/100; K3/100; KX2.
>>>>
>>>> Size vs. weight vs. performance = K2/100.
>>>>
>>>> ~ Alan K0AV
>>>>
>>> --
>>> If this email is spam, please report it to
>>> https://support.onlymyemail.com/view/report_spam/ODExMjI6MjE0NjA5MDc4ODpyb2JAbmMwYi5jb206ZGVsaXZlcmVk
>>
>>
>>
>
>
>
>
>



Re: Transmit Phase Noise

Rob Sherwood
 

If anyone wants a PDF of the data, please send me an email direct to rob@...

Rob

-----Original Message-----
From: Elecraft-K3@groups.io [mailto:Elecraft-K3@groups.io] On Behalf Of Lou Kolb
Sent: Saturday, January 12, 2019 12:43 PM
To: Elecraft-K3@groups.io
Subject: Re: [Elecraft-K3] Transmit Phase Noise



Thanks, Rob. Putting it into text made it accessible to those of us
using screen readers. Lou WA3MIX

On 1/12/19, Rob Sherwood <rob@...> wrote:
Here is some data I have at both 100 watts and 30 or 35 watts for six rigs.
Different lab, different measuring equipment, different rig samples, so
don't expect absolute correlation with ARRL data.
ARRL lab data only measures phase noise, not composite noise (phase and AM
noise).
Data from Contest University presentations of mine.
Note: While the listing are sorted by column 1, the ranking varies with
frequency offset.
Rob
NC0B

Transmit Composite Noise Rig Comparisons 20 meters
Best at maximum power output, but degrades at lower power levels

Rig @ 100 watts 10 kHz offset, dBc/Hz 20 kHz offset, dBc/Hz 100 kHz offset, dBc/Hz
K3S -141 n/a -143
IC-7300 -130 n/a -132
IC-7851 -129 n/a -138
IC-7610 -127 -129 n/a
TS-890S -120 -129 n/a
FTdx-3000 -120 n/a -121

Rig @ 30 watts 10 kHz offset, dBc/Hz 20 kHz offset, dBc/Hz 100 kHz offset, dBc/Hz
K3S -132 n/a -140
IC-7851 -123 n/a -133
IC-7610 -122* -124* n/a
FTdx-3000 -117 n/a -117
TS-890S -113* -122* n/a
IC-7300 -112 n/a -120

* = Power level was 35 watts
n/a = data not available
Rev D

Re: Transmit Phase Noise

Lou Kolb
 

Thanks, Rob. Putting it into text made it accessible to those of us
using screen readers. Lou WA3MIX

On 1/12/19, Rob Sherwood <rob@...> wrote:
Here is some data I have at both 100 watts and 30 or 35 watts for six rigs.
Different lab, different measuring equipment, different rig samples, so
don't expect absolute correlation with ARRL data.
ARRL lab data only measures phase noise, not composite noise (phase and AM
noise).
Data from Contest University presentations of mine.
Note: While the listing are sorted by column 1, the ranking varies with
frequency offset.
Rob
NC0B

Transmit Composite Noise Rig Comparisons 20 meters
Best at maximum power output, but degrades at lower power levels

Rig @ 100 watts 10 kHz offset, dBc/Hz 20 kHz offset,
dBc/Hz 100 kHz offset, dBc/Hz
K3S -141
n/a -143
IC-7300 -130
n/a -132
IC-7851 -129
n/a -138
IC-7610 -127
-129 n/a
TS-890S -120
-129 n/a
FTdx-3000 -120
n/a -121

Rig @ 30 watts 10 kHz offset, dBc/Hz 20 kHz offset,
dBc/Hz 100 kHz offset, dBc/Hz
K3S -132
n/a -140
IC-7851 -123
n/a -133
IC-7610 -122*
-124* n/a
FTdx-3000 -117
n/a -117
TS-890S -113*
-122* n/a
IC-7300 -112
n/a -120

* = Power level was 35 watts
n/a = data not available
Rev D




Transmit Phase Noise

Rob Sherwood
 

Here is some data I have at both 100 watts and 30 or 35 watts for six rigs.

Different lab, different measuring equipment, different rig samples, so don’t expect absolute correlation with ARRL data.

ARRL lab data only measures phase noise, not composite noise (phase and AM noise).

Data from Contest University presentations of mine.

Note: While the listing are sorted by column 1, the ranking varies with frequency offset.

Rob

NC0B

 

Transmit Composite Noise Rig Comparisons 20 meters

Best at maximum power output, but degrades at lower power levels

 

Rig @ 100 watts                10 kHz offset, dBc/Hz     20 kHz offset, dBc/Hz     100 kHz offset, dBc/Hz

K3S                                         -141                                       n/a                                         -143

IC-7300                                 -130                                       n/a                                         -132

IC-7851                                 -129                                       n/a                                         -138

IC-7610                                 -127                                       -129                                       n/a

TS-890S                                -120                                       -129                                       n/a

FTdx-3000                           -120                                       n/a                                         -121

 

Rig @ 30 watts                   10 kHz offset, dBc/Hz     20 kHz offset, dBc/Hz     100 kHz offset, dBc/Hz

K3S                                         -132                                       n/a                                         -140

IC-7851                                 -123                                       n/a                                         -133

IC-7610                                 -122*                                     -124*                                     n/a

FTdx-3000                           -117                                       n/a                                         -117

TS-890S                                -113*                                     -122*                                     n/a

IC-7300                                 -112                                       n/a                                         -120

 

* = Power level was 35 watts

n/a = data not available

Rev D

 

Re: Transmit Phase Noise

Rob Sherwood
 

Darn, the picture was stripped out by the reflector.   I’ll work around this somehow.   Rob, NC0B

 

From: Elecraft-K3@groups.io [mailto:Elecraft-K3@groups.io] On Behalf Of Rob Sherwood
Sent: Saturday, January 12, 2019 10:03 AM
To: Elecraft-K3@groups.io
Subject: [Elecraft-K3] FW: Transmit Phase Noise

 

Here is some data I have at both 100 watts and 30 watts for four rigs.

Different lab, different measuring equipment, different rig samples, so don’t expect absolute correlation with ARRL data.

ARRL lab data only measures phase noise, not composite noise (phase and AM noise).

Data from a Contest University presentation of mine.

Rob

NC0B

 

From: Rob Sherwood
Sent: Saturday, January 12, 2019 9:54 AM
To: Rob Sherwood.
Subject: Transmit Phase Noise

 

 


If this email is spam, report it to www.OnlyMyEmail.com

FW: Transmit Phase Noise

Rob Sherwood
 

Here is some data I have at both 100 watts and 30 watts for four rigs.

Different lab, different measuring equipment, different rig samples, so don’t expect absolute correlation with ARRL data.

ARRL lab data only measures phase noise, not composite noise (phase and AM noise).

Data from a Contest University presentation of mine.

Rob

NC0B

 

From: Rob Sherwood
Sent: Saturday, January 12, 2019 9:54 AM
To: Rob Sherwood.
Subject: Transmit Phase Noise

 

Re: KX3 / KXPA100 Combination for Contest Dxpediions

Joe Subich, W4TV
 

According to the ARRL Product reviews, both the K3S (and K3 with
KSYN3A) show -140 dBc or better from 2 KHz to 1 MHz. The IC7610
is slightly better above 20 KHz at 100 W. There is not "30W" data
for the K3/3S for comparison at reduced power output.

Among the transceivers reviewed in the last decade or so, the IC-7851
shows the lowest phase noise .... around -143 dBc (as close as I can
read the graph) from 15 KHz to 1 MHz (-140 dBc from 2-15 KHz).

73,

... Joe, W4TV

On 2019-01-12 8:59 AM, Everett N4CY via Groups.Io wrote:
So where does the K3S fall into the group with regard to phase noise?
Everett N4CY

On Jan 12, 2019, at 7:47 AM, Joe Subich, W4TV <lists@...> wrote:


On 2019-01-11 11:14 PM, Rob Sherwood wrote:
There may be a typo in paragraph 1, sentence 2 below.
Correct ... K3/KX3 should have been K3/K3S <G>.

73,

... Joe, W4TV


On 2019-01-11 11:14 PM, Rob Sherwood wrote:
There may be a typo in paragraph 1, sentence 2 below.
Add other poor transmitted phase noise rigs:
FTdx-3000 (Wipes out 15 meters in Boulder, CO, for example, when an FT-1000MP does NOT.)
FT-891 (From Bob Allison: "On the transmit side, the transmit phase is about the highest we’ve
yet seen at the Lab. For this reason alone, I would be wary of pairing this transceiver
with an RF amplifier."
FTdx-5000 (somewhat better than the 3000)
The only rig I am aware of that actually advertises low transmitted phase noise: IC-7610
Rig with the highest RMDR: TS-890S, but its transmitted phase noise is modestly worse than the 7610.
Another issue to consider, as the power output is reduced to drive an amp that only requires 30 to 50 watts of drive, the transmitted noise vs. the output signal goes up. That is why the ARRL generally measures transmitted phase noise at full output and 35 watts.
Note: Transmitted noise can be phase noise and AM (amplitude) noise. Some test equipment only measures phase noise and not composite noise, which is both phase and amplitude noise.
When I measure transmitter noise with a Perseus FFT receiver, it measures composite noise.
Rob, NC0B
-----Original Message-----
From: Elecraft-K3@groups.io [mailto:Elecraft-K3@groups.io] On Behalf Of Joe Subich, W4TV
Sent: Friday, January 11, 2019 6:00 PM
To: Elecraft-K3@groups.io
Subject: Re: [Elecraft-K3] KX3 / KXPA100 Combination for Contest Dxpediions
The *BIG PROBLEM* with the KX3/KPA100 vs. the K3 or K3S/100
is the transmit phase noise of the KX3. The KX3 transmitted
phase noise is nearly 20 dB *higher* than the K3/KX3 at 2 KHz
off of the transmit "carrier" (based on ARRL product review
data).
Using the KX3/KXPA100, particularly when driving another amp
(like KPA500, KPA1500, Expert, etc). is not very neighborly.
Transmit phase noise of the KX3 is comparable to some of the
worst Icom rigs (IC-706mkIIg, IC-746Pro, etc.) which can
wipe out a band with phase noise if driving a high power PA.
For comparison at 20 KHz: Icom IC-706mkIIG -134dB, KX3 -124dB,
K3S or K3 with KSYN3A <-140dB, K2 -128dB.
I would be careful in considering a KX3/KXAP100 if there was
a possibility of using it in a multi-transmitter situation.
In general it is not wise to use any transceiver designed
primarily for QRP operation with a power amplifier due to
transmitted phase noise issues. The synthesizers in rigs
designed for low power operation simply are not a clean as
those designed for 100W operation and/or intended to drive
a high power amplifier.
73,
... Joe, W4TV
On 2019-01-11 7:06 PM, Alan Higbie wrote:
. . . or, even better (smaller & cheaper) consider using a K2/100.

I've traveled for DX contests - and over the years have hauled lots of different radios, i.e. Collins S-3 Line; FT-1000MP; K2/100, x2 K3/100; K3/100; KX2.

Size vs. weight vs. performance = K2/100.

~ Alan K0AV
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Disassembly of K3/0-mini

Scott Townley
 

I have a K3/0-mini that I removed the rear bail from.  Basically I unscrewed the four screws, cracked open the case just a bit, and shook all the internal hardware (nuts/washers) out, and buttoned it back up.
Now I want to put the bail back on.  I've gotten the case fully opened up (two halves), but I'm having a challenge with the PCB that's attached to the rear half.  It appears those four black "nubs" that you can see on the back are some sort of nylon standoff that's being used for stiffening the PCB.  But it's not obvious to me how to remove them or otherwise disengage them.  Of course I'd prefer to do this without destroying them and leaving four holes in the back.
Any suggestions?
TIA,
Scott NX7U

Odd K3 KIO3 behaviour (fw related?)

Scott Townley
 

S/N 8700.  I had never upgraded the FW until about 3 weeks ago (to 5.66).  Now I occassionally get the dreaded "MCU LD"; I've had to reload 3 times so far.
I mention that only in case it's related to the subject problem.  The other night I turned the radio on and audio was coming out the speaker.  This was odd because I've always used a headset plugged into the rear (KIO3) jacks (audio was coming out the 'phones as well).  I double-checked my menu setting and verified SPKR+PH=NO.  Even stranger was when I unplugged the 'phones, audio quit coming out of the speaker.  I repeated this several times with the same result...either I had two channels of audio or none.  I had the same behaviour with the front panel 'phones jack.
Power cycling the radio had no effect.
The fix was to set SPKR+PH=YES.  When I did this nothing changed (I had audio through speaker and 'phones).  But then when I set it back to NO everything was as it should be.
Hmm...
Scott NX7U

Re: KX3 / KXPA100 Combination for Contest Dxpediions

Everett N4CY
 

So where does the K3S fall into the group with regard to phase noise?

Everett N4CY

On Jan 12, 2019, at 7:47 AM, Joe Subich, W4TV <lists@...> wrote:


On 2019-01-11 11:14 PM, Rob Sherwood wrote:
There may be a typo in paragraph 1, sentence 2 below.
Correct ... K3/KX3 should have been K3/K3S <G>.

73,

... Joe, W4TV


On 2019-01-11 11:14 PM, Rob Sherwood wrote:
There may be a typo in paragraph 1, sentence 2 below.
Add other poor transmitted phase noise rigs:
FTdx-3000 (Wipes out 15 meters in Boulder, CO, for example, when an FT-1000MP does NOT.)
FT-891 (From Bob Allison: "On the transmit side, the transmit phase is about the highest we’ve
yet seen at the Lab. For this reason alone, I would be wary of pairing this transceiver
with an RF amplifier."
FTdx-5000 (somewhat better than the 3000)
The only rig I am aware of that actually advertises low transmitted phase noise: IC-7610
Rig with the highest RMDR: TS-890S, but its transmitted phase noise is modestly worse than the 7610.
Another issue to consider, as the power output is reduced to drive an amp that only requires 30 to 50 watts of drive, the transmitted noise vs. the output signal goes up. That is why the ARRL generally measures transmitted phase noise at full output and 35 watts.
Note: Transmitted noise can be phase noise and AM (amplitude) noise. Some test equipment only measures phase noise and not composite noise, which is both phase and amplitude noise.
When I measure transmitter noise with a Perseus FFT receiver, it measures composite noise.
Rob, NC0B
-----Original Message-----
From: Elecraft-K3@groups.io [mailto:Elecraft-K3@groups.io] On Behalf Of Joe Subich, W4TV
Sent: Friday, January 11, 2019 6:00 PM
To: Elecraft-K3@groups.io
Subject: Re: [Elecraft-K3] KX3 / KXPA100 Combination for Contest Dxpediions
The *BIG PROBLEM* with the KX3/KPA100 vs. the K3 or K3S/100
is the transmit phase noise of the KX3. The KX3 transmitted
phase noise is nearly 20 dB *higher* than the K3/KX3 at 2 KHz
off of the transmit "carrier" (based on ARRL product review
data).
Using the KX3/KXPA100, particularly when driving another amp
(like KPA500, KPA1500, Expert, etc). is not very neighborly.
Transmit phase noise of the KX3 is comparable to some of the
worst Icom rigs (IC-706mkIIg, IC-746Pro, etc.) which can
wipe out a band with phase noise if driving a high power PA.
For comparison at 20 KHz: Icom IC-706mkIIG -134dB, KX3 -124dB,
K3S or K3 with KSYN3A <-140dB, K2 -128dB.
I would be careful in considering a KX3/KXAP100 if there was
a possibility of using it in a multi-transmitter situation.
In general it is not wise to use any transceiver designed
primarily for QRP operation with a power amplifier due to
transmitted phase noise issues. The synthesizers in rigs
designed for low power operation simply are not a clean as
those designed for 100W operation and/or intended to drive
a high power amplifier.
73,
... Joe, W4TV
On 2019-01-11 7:06 PM, Alan Higbie wrote:
. . . or, even better (smaller & cheaper) consider using a K2/100.

I've traveled for DX contests - and over the years have hauled lots of different radios, i.e. Collins S-3 Line; FT-1000MP; K2/100, x2 K3/100; K3/100; KX2.

Size vs. weight vs. performance = K2/100.

~ Alan K0AV
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Re: KX3 / KXPA100 Combination for Contest Dxpediions

Joe Subich, W4TV
 

On 2019-01-11 11:14 PM, Rob Sherwood wrote:
There may be a typo in paragraph 1, sentence 2 below.
Correct ... K3/KX3 should have been K3/K3S <G>.

73,

... Joe, W4TV


On 2019-01-11 11:14 PM, Rob Sherwood wrote:
There may be a typo in paragraph 1, sentence 2 below.
Add other poor transmitted phase noise rigs:
FTdx-3000 (Wipes out 15 meters in Boulder, CO, for example, when an FT-1000MP does NOT.)
FT-891 (From Bob Allison: "On the transmit side, the transmit phase is about the highest we’ve
yet seen at the Lab. For this reason alone, I would be wary of pairing this transceiver
with an RF amplifier."
FTdx-5000 (somewhat better than the 3000)
The only rig I am aware of that actually advertises low transmitted phase noise: IC-7610
Rig with the highest RMDR: TS-890S, but its transmitted phase noise is modestly worse than the 7610.
Another issue to consider, as the power output is reduced to drive an amp that only requires 30 to 50 watts of drive, the transmitted noise vs. the output signal goes up. That is why the ARRL generally measures transmitted phase noise at full output and 35 watts.
Note: Transmitted noise can be phase noise and AM (amplitude) noise. Some test equipment only measures phase noise and not composite noise, which is both phase and amplitude noise.
When I measure transmitter noise with a Perseus FFT receiver, it measures composite noise.
Rob, NC0B
-----Original Message-----
From: Elecraft-K3@groups.io [mailto:Elecraft-K3@groups.io] On Behalf Of Joe Subich, W4TV
Sent: Friday, January 11, 2019 6:00 PM
To: Elecraft-K3@groups.io
Subject: Re: [Elecraft-K3] KX3 / KXPA100 Combination for Contest Dxpediions
The *BIG PROBLEM* with the KX3/KPA100 vs. the K3 or K3S/100
is the transmit phase noise of the KX3. The KX3 transmitted
phase noise is nearly 20 dB *higher* than the K3/KX3 at 2 KHz
off of the transmit "carrier" (based on ARRL product review
data).
Using the KX3/KXPA100, particularly when driving another amp
(like KPA500, KPA1500, Expert, etc). is not very neighborly.
Transmit phase noise of the KX3 is comparable to some of the
worst Icom rigs (IC-706mkIIg, IC-746Pro, etc.) which can
wipe out a band with phase noise if driving a high power PA.
For comparison at 20 KHz: Icom IC-706mkIIG -134dB, KX3 -124dB,
K3S or K3 with KSYN3A <-140dB, K2 -128dB.
I would be careful in considering a KX3/KXAP100 if there was
a possibility of using it in a multi-transmitter situation.
In general it is not wise to use any transceiver designed
primarily for QRP operation with a power amplifier due to
transmitted phase noise issues. The synthesizers in rigs
designed for low power operation simply are not a clean as
those designed for 100W operation and/or intended to drive
a high power amplifier.
73,
... Joe, W4TV
On 2019-01-11 7:06 PM, Alan Higbie wrote:
. . . or, even better (smaller & cheaper) consider using a K2/100.

I've traveled for DX contests - and over the years have hauled lots of different radios, i.e. Collins S-3 Line; FT-1000MP; K2/100, x2 K3/100; K3/100; KX2.

Size vs. weight vs. performance = K2/100.

~ Alan K0AV
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Re: KX3 / KXPA100 Combination for Contest Dxpediions

Rob Sherwood
 

There may be a typo in paragraph 1, sentence 2 below.

Add other poor transmitted phase noise rigs:
FTdx-3000 (Wipes out 15 meters in Boulder, CO, for example, when an FT-1000MP does NOT.)

FT-891 (From Bob Allison: "On the transmit side, the transmit phase is about the highest we’ve
yet seen at the Lab. For this reason alone, I would be wary of pairing this transceiver
with an RF amplifier."

FTdx-5000 (somewhat better than the 3000)

The only rig I am aware of that actually advertises low transmitted phase noise: IC-7610
Rig with the highest RMDR: TS-890S, but its transmitted phase noise is modestly worse than the 7610.

Another issue to consider, as the power output is reduced to drive an amp that only requires 30 to 50 watts of drive, the transmitted noise vs. the output signal goes up. That is why the ARRL generally measures transmitted phase noise at full output and 35 watts.

Note: Transmitted noise can be phase noise and AM (amplitude) noise. Some test equipment only measures phase noise and not composite noise, which is both phase and amplitude noise.

When I measure transmitter noise with a Perseus FFT receiver, it measures composite noise.

Rob, NC0B

-----Original Message-----
From: Elecraft-K3@groups.io [mailto:Elecraft-K3@groups.io] On Behalf Of Joe Subich, W4TV
Sent: Friday, January 11, 2019 6:00 PM
To: Elecraft-K3@groups.io
Subject: Re: [Elecraft-K3] KX3 / KXPA100 Combination for Contest Dxpediions




The *BIG PROBLEM* with the KX3/KPA100 vs. the K3 or K3S/100
is the transmit phase noise of the KX3. The KX3 transmitted
phase noise is nearly 20 dB *higher* than the K3/KX3 at 2 KHz
off of the transmit "carrier" (based on ARRL product review
data).

Using the KX3/KXPA100, particularly when driving another amp
(like KPA500, KPA1500, Expert, etc). is not very neighborly.
Transmit phase noise of the KX3 is comparable to some of the
worst Icom rigs (IC-706mkIIg, IC-746Pro, etc.) which can
wipe out a band with phase noise if driving a high power PA.

For comparison at 20 KHz: Icom IC-706mkIIG -134dB, KX3 -124dB,
K3S or K3 with KSYN3A <-140dB, K2 -128dB.

I would be careful in considering a KX3/KXAP100 if there was
a possibility of using it in a multi-transmitter situation.

In general it is not wise to use any transceiver designed
primarily for QRP operation with a power amplifier due to
transmitted phase noise issues. The synthesizers in rigs
designed for low power operation simply are not a clean as
those designed for 100W operation and/or intended to drive
a high power amplifier.

73,

... Joe, W4TV


On 2019-01-11 7:06 PM, Alan Higbie wrote:
. . . or, even better (smaller & cheaper) consider using a K2/100.

I've traveled for DX contests - and over the years have hauled lots of different radios, i.e. Collins S-3 Line; FT-1000MP; K2/100, x2 K3/100; K3/100; KX2.

Size vs. weight vs. performance = K2/100.

~ Alan K0AV





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Re: KX3 / KXPA100 Combination for Contest Dxpediions

Joe Subich, W4TV
 

The *BIG PROBLEM* with the KX3/KPA100 vs. the K3 or K3S/100
is the transmit phase noise of the KX3. The KX3 transmitted
phase noise is nearly 20 dB *higher* than the K3/KX3 at 2 KHz
off of the transmit "carrier" (based on ARRL product review
data).

Using the KX3/KXPA100, particularly when driving another amp
(like KPA500, KPA1500, Expert, etc). is not very neighborly.
Transmit phase noise of the KX3 is comparable to some of the
worst Icom rigs (IC-706mkIIg, IC-746Pro, etc.) which can
wipe out a band with phase noise if driving a high power PA.

For comparison at 20 KHz: Icom IC-706mkIIG -134dB, KX3 -124dB,
K3S or K3 with KSYN3A <-140dB, K2 -128dB.

I would be careful in considering a KX3/KXAP100 if there was
a possibility of using it in a multi-transmitter situation.

In general it is not wise to use any transceiver designed
primarily for QRP operation with a power amplifier due to
transmitted phase noise issues. The synthesizers in rigs
designed for low power operation simply are not a clean as
those designed for 100W operation and/or intended to drive
a high power amplifier.

73,

... Joe, W4TV

On 2019-01-11 7:06 PM, Alan Higbie wrote:
. . . or, even better (smaller & cheaper) consider using a K2/100.
I've traveled for DX contests - and over the years have hauled lots of different radios, i.e. Collins S-3 Line; FT-1000MP; K2/100, x2 K3/100; K3/100; KX2.
Size vs. weight vs. performance = K2/100.
~ Alan K0AV