Date   

Re: Dirty Transmitters

Rob Sherwood
 

I think Wayne said as high as 15.5 volts, which approaches the upper end of spec. In spec is within spec, which would be 15.87 volts.  The low side spec would be below 12 volts, which would not be ideal. Rob, NC0B


On Nov 6, 2019, at 5:28 AM, Steve <99sunset@...> wrote:

I remember a comment from Elecraft saying that the K3 will transmit a cleaner signal with voltage around 13.8 to 14 volts.   I don't remember the exact comment.


Re: Dirty Transmitters

David Bunte
 

Bob -

I am not posting this to the list, as I don't think it will add anything of value... but I was surprised to see K9VUJ talk about up to 35 watts drive power to his KPA500. Your numbers are FAR more like mine. I have never bothered to adjust the digital display and the bar graph on my KPA500 as you described... so thanks for the reminder that I can do that.

I appreciate many of your posts. I do not have a technical background (my career was on the microphone side of Public Radio). After 62 years of hamming, and at age 76 I am glad I can still learn.

73 de Dave - K9FN

On Wed, Nov 6, 2019 at 8:49 AM Bob McGraw - K4TAX <rmcgraw@...> wrote:

I find that my KPA500 {s/n 3519} drives to 500 watts output on all bands with 19 to 23 watts.   I find that driving power of over 25 watts will push my KPA500 to over 500 watts.   All measurements were made with my Bird 43 into a 50.5 ohm resistive load.  {Please do not use an antenna for this measurement even if the SWR is 1:1.}  

The LED bargraph and the LCD display were correctly calibrated using the Menu / Edit and PWR ADJ feature of the KPA500.    The PWR ADJ feature DOES NOT affect the output of the amplifier.  It only affects the displayed or indicated values of both the LED display and the LCD display.  The FAULT power function is also affected by the PWR ADJ setting.

Based on earlier discussions, some amps may require more power to attain 500 watts output.

73

Bob, K4TAX


On 11/6/2019 7:09 AM, dalej via Groups.Io wrote:
Also if you have the KPA500 you only need around 30 watts to drive it and that is in the good area for IMD from 12 volt amps.  That’s were I run mine, maybe a little more 35 watts driving the KPA.  That also helps with the amp draw from a power supply.  

Dale k9vuj



On 06, Nov 2019, at 6:45, Bob McGraw - K4TAX <rmcgraw@...> wrote:

This has been stated and confirmed several times.  

A suggestion:   If you have a power supply with good regulation, no load to rated load, and you use power leads with very low resistance between the power supply and radio, you can run the power supply at 14.5 volts.  This will certainly improve the transmit IMD. 

Power leads should be of minimum length required, use #10 AWG wire, crimp on the correct terminals required for each end.   If in doubt crimp and solder terminals.  AND do connect the radio power cable direct to the power supply.  DO NOT use a DC power distribution strip.  Every connection adds resistance and results in voltage drop.  

73

Bob, K4TAX


On 11/5/2019 3:40 PM, Steve wrote:
I remember a comment from Elecraft saying that the K3 will transmit a cleaner signal with voltage around 13.8 to 14 volts.   I don't remember the exact comment.


Re: Dirty Transmitters

Bob McGraw - K4TAX
 

I find that my KPA500 {s/n 3519} drives to 500 watts output on all bands with 19 to 23 watts.   I find that driving power of over 25 watts will push my KPA500 to over 500 watts.   All measurements were made with my Bird 43 into a 50.5 ohm resistive load.  {Please do not use an antenna for this measurement even if the SWR is 1:1.}  

The LED bargraph and the LCD display were correctly calibrated using the Menu / Edit and PWR ADJ feature of the KPA500.    The PWR ADJ feature DOES NOT affect the output of the amplifier.  It only affects the displayed or indicated values of both the LED display and the LCD display.  The FAULT power function is also affected by the PWR ADJ setting.

Based on earlier discussions, some amps may require more power to attain 500 watts output.

73

Bob, K4TAX


On 11/6/2019 7:09 AM, dalej via Groups.Io wrote:
Also if you have the KPA500 you only need around 30 watts to drive it and that is in the good area for IMD from 12 volt amps.  That’s were I run mine, maybe a little more 35 watts driving the KPA.  That also helps with the amp draw from a power supply.  

Dale k9vuj



On 06, Nov 2019, at 6:45, Bob McGraw - K4TAX <rmcgraw@...> wrote:

This has been stated and confirmed several times.  

A suggestion:   If you have a power supply with good regulation, no load to rated load, and you use power leads with very low resistance between the power supply and radio, you can run the power supply at 14.5 volts.  This will certainly improve the transmit IMD. 

Power leads should be of minimum length required, use #10 AWG wire, crimp on the correct terminals required for each end.   If in doubt crimp and solder terminals.  AND do connect the radio power cable direct to the power supply.  DO NOT use a DC power distribution strip.  Every connection adds resistance and results in voltage drop.  

73

Bob, K4TAX


On 11/5/2019 3:40 PM, Steve wrote:
I remember a comment from Elecraft saying that the K3 will transmit a cleaner signal with voltage around 13.8 to 14 volts.   I don't remember the exact comment.


Re: Dirty Transmitters

Dale, K9VUJ
 

Also if you have the KPA500 you only need around 30 watts to drive it and that is in the good area for IMD from 12 volt amps.  That’s were I run mine, maybe a little more 35 watts driving the KPA.  That also helps with the amp draw from a power supply.  

Dale k9vuj



On 06, Nov 2019, at 6:45, Bob McGraw - K4TAX <rmcgraw@...> wrote:

This has been stated and confirmed several times.  

A suggestion:   If you have a power supply with good regulation, no load to rated load, and you use power leads with very low resistance between the power supply and radio, you can run the power supply at 14.5 volts.  This will certainly improve the transmit IMD. 

Power leads should be of minimum length required, use #10 AWG wire, crimp on the correct terminals required for each end.   If in doubt crimp and solder terminals.  AND do connect the radio power cable direct to the power supply.  DO NOT use a DC power distribution strip.  Every connection adds resistance and results in voltage drop.  

73

Bob, K4TAX


On 11/5/2019 3:40 PM, Steve wrote:
I remember a comment from Elecraft saying that the K3 will transmit a cleaner signal with voltage around 13.8 to 14 volts.   I don't remember the exact comment.


Re: Dirty Transmitters

Bob McGraw - K4TAX
 

This has been stated and confirmed several times.  

A suggestion:   If you have a power supply with good regulation, no load to rated load, and you use power leads with very low resistance between the power supply and radio, you can run the power supply at 14.5 volts.  This will certainly improve the transmit IMD. 

Power leads should be of minimum length required, use #10 AWG wire, crimp on the correct terminals required for each end.   If in doubt crimp and solder terminals.  AND do connect the radio power cable direct to the power supply.  DO NOT use a DC power distribution strip.  Every connection adds resistance and results in voltage drop.  

73

Bob, K4TAX


On 11/5/2019 3:40 PM, Steve wrote:
I remember a comment from Elecraft saying that the K3 will transmit a cleaner signal with voltage around 13.8 to 14 volts.   I don't remember the exact comment.


Re: Dirty Transmitters

Steve
 

I remember a comment from Elecraft saying that the K3 will transmit a cleaner signal with voltage around 13.8 to 14 volts.   I don't remember the exact comment.


Re: Join elecraft group

GRANT YOUNGMAN <ghyoungman@...>
 

On Nov 4, 2019, at 9:45 PM, Robin Kidd <w4ien@comcast.net> wrote:

What is the address of the Schulman site?

7


Re: Join elecraft group

Robin Kidd <w4ien@...>
 

What is the address of the Schulman site?

72/73,
EM73vx
Robin
G-QRP #12386
SKCC #7294
W4IEN 
w4ien@...


On Nov 4, 2019, at 21:43, Larry <telegrapher@q.com> wrote:


Paolo, there is a nice K3 selling on the Schulman auction site.  You just have to be the top bidder.  
Larry  W0OGH



Sent from my Verizon, Samsung Galaxy smartphone

-------- Original message --------
From: Paolo NERVI <Iu1cyf@...>
Date: 11/3/19 1:09 AM (GMT-07:00)
To: elecraft-k3@groups.io
Subject: [Elecraft-K3] Join elecraft group

Hi,
I'd like to join this group.
I own a elecraft KX3 and i love to buy a K3 or a K3S.
73 de Paolo.

IU1CYF
Eng. Paolo Nervi
Turin Italy


Re: Join elecraft group

Larry
 

Paolo, there is a nice K3 selling on the Schulman auction site.  You just have to be the top bidder.  
Larry  W0OGH



Sent from my Verizon, Samsung Galaxy smartphone

-------- Original message --------
From: Paolo NERVI <Iu1cyf@...>
Date: 11/3/19 1:09 AM (GMT-07:00)
To: elecraft-k3@groups.io
Subject: [Elecraft-K3] Join elecraft group

Hi,
I'd like to join this group.
I own a elecraft KX3 and i love to buy a K3 or a K3S.
73 de Paolo.

IU1CYF
Eng. Paolo Nervi
Turin Italy


Re: Dirty Transmitters

Rob Sherwood
 

Yes it makes a difference as to the voltage, and voltage drop in some long cables, plus the fuses and holders, can exacerbate the issue.  I set my Astrons at 14.3 volts to compensate for a typical voltage drop of 0.5 volts.  I haven’t seen a night and day difference between 13.8 at the radio and a half to a full volt higher (within the +/- 15% typical spec), but as one goes much lower than 13.8 IMD can measurably degrade.  

 

I guess the question is what is significant, and would anyone on the receive end notice?  13.8 to 14.3 volts, I doubt it.  At 12.0 volts, maybe so since the degradation might be several dB. (5 dB?) Who knows without an actual measurement on an individual rig.  Of course the IMD varies band by band, and tests in the lab are done into a resistive power attenuator, not an real antenna.

 

Rob, NC0B 

 

From: Elecraft-K3@groups.io [mailto:Elecraft-K3@groups.io] On Behalf Of Bob Novas via Groups.Io
Sent: Monday, November 04, 2019 10:54 AM
To: Elecraft-K3@groups.io
Subject: Re: [Elecraft-K3] Dirty Transmitters

 

Is there any difference between 12V and 13.8V or 14.1V, e.g., does it matter if you’re running off a run down battery?  Should you run the voltage up to the max if you’re running on AC?  Just curious if a volt or two makes a significant difference. If it does, maybe it’d be worth running as high a voltage as you can safely. Bob - W3DK

 

From: Elecraft-K3@groups.io [mailto:Elecraft-K3@groups.io] On Behalf Of Drew Vonada-Smith K3PA
Sent: Monday, November 04, 2019 12:07 PM
To: Elecraft-K3@groups.io
Subject: Re: [Elecraft-K3] Dirty Transmitters

 

The K3 has nice low phase noise, but no SS transmitter running at 12 V has great IMD.  So no, the K3 is not an especially clean TX on SSB.  By no means the worst either, of course.

73,

Drew K3PA


Re: RS-232 to USB A cable KD8DZ

Bob McGraw - K4TAX
 

I agree, the K3IOB solves many issues and makes digital operation easy to configure and use and highly reliable day in and day out.  Fewer cables, fewer connectors, fewer adjustments to get incorrect. 

73

Bob, K4TAX

On 11/4/2019 6:51 PM, Mel Marcus wrote:
Still a fairly new K3 user, but using the k3iob seems to answer a lot of the questions. It allows for usb to usb without converting to serial.  also when using digital modes, there is no need for an external sound card, such as the signal link.

I realize the K3Frugals will kill me for mentioning it.

Mel
NE9A


Re: RS-232 to USB A cable KD8DZ

Mel Marcus
 

Still a fairly new K3 user, but using the k3iob seems to answer a lot of the questions. It allows for usb to usb without converting to serial.  also when using digital modes, there is no need for an external sound card, such as the signal link.

I realize the K3Frugals will kill me for mentioning it.

Mel
NE9A

-------- Original Message --------
Subject: Re: [Elecraft-K3] RS-232 to USB A cable KD8DZ
From: "Stephen Walls" <swalls46@...>
Date: Mon, November 04, 2019 7:37 am
To: elecraft-k3@groups.io

frugal---yes

BUT----you get what you pay for


in my world,  

PROLIFIC = run the other way as fast as you can ! ! ! !

Steve K4ELI


Re: Dirty Transmitters

 

Amplifier "headroom" increases with supply voltage, so the answer to all four of your questions is Yes.

73,
Wayne
N6KR

On Nov 4, 2019, at 9:53 AM, Bob Novas via Groups.Io <bob.novas=verizon.net@groups.io> wrote:

Is there any difference between 12V and 13.8V or 14.1V, e.g., does it matter if you’re running off a run down battery? Should you run the voltage up to the max if you’re running on AC? Just curious if a volt or two makes a significant difference. If it does, maybe it’d be worth running as high a voltage as you can safely. Bob - W3DK

From: Elecraft-K3@groups.io [mailto:Elecraft-K3@groups.io] On Behalf Of Drew Vonada-Smith K3PA
Sent: Monday, November 04, 2019 12:07 PM
To: Elecraft-K3@groups.io
Subject: Re: [Elecraft-K3] Dirty Transmitters

The K3 has nice low phase noise, but no SS transmitter running at 12 V has great IMD. So no, the K3 is not an especially clean TX on SSB. By no means the worst either, of course.

73,

Drew K3PA


Re: Dirty Transmitters

Roger N1RJ <n1rj@...>
 

Why not just parallel two 50 watt modules? A common technique in
high power amplifiers.

73, Roger

On 11/4/2019 3:27 PM, Joe Subich, W4TV wrote:
On 2019-11-04 12:06 PM, Drew Vonada-Smith K3PA wrote:
The K3 has nice low phase noise, but no SS transmitter running at 12 V has great IMD.
The issue is that 12V transistors are simply not capable of providing
the "clean" voltage swings necessary to generate 100 - 120W peak power.
A typical transistor/FET has a series output impedance of around 1 - 1.5
Ohms. Thus if the peak current is ~10A per device, the transistor is
operating from cut-off to saturated - with the unavoidable distortion
(clipping/saturation) at each end of that range.
Simply put, insistence on more than about 60 W PEP from a pair of 12V
devices is *asking for IMD* and "precorrection" only masks that issue.
Equipment designers should give up on 12V devices for "base station"
radios and go to 48V devices - even at 200 W PEP output levels, They should stick to 60 W output for 12V devices. 60 W output level is more
than enough to drive an amplifier in the KPA-500 class to rated output
and close (if not sufficient) for even a KPA-1500.
Redesigned with bias levels and transformers optimized for the lower
power levels, the K3/K3S could exhibit *much* - at least 10 dB - better
IMD at 50 - 60 W PEP output (although efficiency would probably suffer
for those who just absolutely need to run the rig from a battery pack
on a picnic table).
73,
... Joe, W4TV
On 2019-11-04 12:06 PM, Drew Vonada-Smith K3PA wrote:
The K3 has nice low phase noise, but no SS transmitter running at 12 V has great IMD. So no, the K3 is not an especially clean TX on SSB. By no means the worst either, of course.

73,

Drew K3PA


Re: Dirty Transmitters

Bob Novas
 

Is there any difference between 12V and 13.8V or 14.1V, e.g., does it matter if you’re running off a run down battery?  Should you run the voltage up to the max if you’re running on AC?  Just curious if a volt or two makes a significant difference. If it does, maybe it’d be worth running as high a voltage as you can safely. Bob - W3DK

 

From: Elecraft-K3@groups.io [mailto:Elecraft-K3@groups.io] On Behalf Of Drew Vonada-Smith K3PA
Sent: Monday, November 04, 2019 12:07 PM
To: Elecraft-K3@groups.io
Subject: Re: [Elecraft-K3] Dirty Transmitters

 

The K3 has nice low phase noise, but no SS transmitter running at 12 V has great IMD.  So no, the K3 is not an especially clean TX on SSB.  By no means the worst either, of course.

73,

Drew K3PA


Re: RS-232 to USB A cable KD8DZ

Ken Talbott
 

No need for apology Mike, this topic will recur as long as there is a USB interface. One point not often mentioned is the fact that Prolific withdrew the software license for its driver version 3.2 and earlier (the ones that work with the pirated chip). They promised to prosecute anyone who redistributed the old driver. Never heard of any real action.

 

It’s also interesting that the chip wasn’t pirated by reverse engineering, the actual mask was stolen! That’s what allows the current driver to recognize the bogus part and not run (Error 10, Failed to Start).

 

Details on how to use these parts (but not the driver itself) can be seen at:

http://ke4rg.blogspot.com/2015/04/prolific-2303hxaxa-this-device-cannot.html

 

Note also that some rigs with the internal USB chip and a straight through cable also suffer from this gremlin, early LD-5’s for example.

 

I use the old part with no difficulty. Not hard once you understand what’s going on.

 

73 de ken ke4rg

 

From: Elecraft-K3@groups.io <Elecraft-K3@groups.io> On Behalf Of Michael Mickelson
Sent: Monday, November 4, 2019 9:12 AM
To: Elecraft-K3@groups.io
Subject: Re: [Elecraft-K3] RS-232 to USB A cable KD8DZ

 

Thanks Alan for that information very helpful.  Sorry my post has initiated so much traffic on this.  Mike kd8dz

 

On Mon, Nov 4, 2019 at 8:47 AM Alan Baker <g4gnx@...> wrote:

Sorry, but there are a lot of partial facts here.

 

Windows Update does NOT replace one manufacturer’s driver with another manufacturer’s driver - EVER!

 

The cheap Chinese cables use a clone Prolific chip, but they’re too lazy (or ignorant) to write a driver for it, hence the price. These cables will sometimes work with an old version of Prolific driver, but Windows Update is likely to update the driver to the latest PROLIFIC version, which has been fixed by Prolific to recognise the fake chip and fails to run. It is possible to prevent Windows Update from updating individual drivers, including Prolific.

 

Buy a Prolific cable from a reputable supplier. One that comes with the very latest Prolific driver. Even if Windows does update the driver, it will recognise the chip as genuine and continue to function.

 

The FTDi cable is not necessarily superior to the Prolific, but it’s the chip to use chosen by Elecraft, so it would make sense to buy the FTDi or better still, the Elecraft one.


73,

Alan. G4GNX

 

From: Steve

Sent: Sunday, November 3, 2019 11:22 PM

Subject: Re: [Elecraft-K3] RS-232 to USB A cable KD8DZ

 

The inexpensive Chinese 6 dollar cables use the Prolific drivers which are available for download.  The better cables use FTDI.  The difficulty using the Prolific cables and drivers is that each time Microsoft updates drivers, it will replace your Prolific drivers with FTDI and your cable will fail to operate.  Save yourself the difficulty buy just using the better cable to begin with.  These are available from Elecraft or RT Systems.  



--

Michael Mickelson

J. Reid Anderson Professor of Physics and Astronomy, emeritus

Denison University

740-587-0687 H

740-644-1238 M

 


Re: RS-232 to USB A cable KD8DZ

Stephen Walls
 

frugal---yes

BUT----you get what you pay for


in my world,  

PROLIFIC = run the other way as fast as you can ! ! ! !

Steve K4ELI


Re: Dirty Transmitters

Joe Subich, W4TV
 

On 2019-11-04 12:06 PM, Drew Vonada-Smith K3PA wrote:
The K3 has nice low phase noise, but no SS transmitter running at 12 V has great IMD.
The issue is that 12V transistors are simply not capable of providing
the "clean" voltage swings necessary to generate 100 - 120W peak power.

A typical transistor/FET has a series output impedance of around 1 - 1.5
Ohms. Thus if the peak current is ~10A per device, the transistor is
operating from cut-off to saturated - with the unavoidable distortion
(clipping/saturation) at each end of that range.

Simply put, insistence on more than about 60 W PEP from a pair of 12V
devices is *asking for IMD* and "precorrection" only masks that issue.
Equipment designers should give up on 12V devices for "base station"
radios and go to 48V devices - even at 200 W PEP output levels, They should stick to 60 W output for 12V devices. 60 W output level is more
than enough to drive an amplifier in the KPA-500 class to rated output
and close (if not sufficient) for even a KPA-1500.

Redesigned with bias levels and transformers optimized for the lower
power levels, the K3/K3S could exhibit *much* - at least 10 dB - better
IMD at 50 - 60 W PEP output (although efficiency would probably suffer
for those who just absolutely need to run the rig from a battery pack
on a picnic table).

73,

... Joe, W4TV


On 2019-11-04 12:06 PM, Drew Vonada-Smith K3PA wrote:
The K3 has nice low phase noise, but no SS transmitter running at 12 V has great IMD.  So no, the K3 is not an especially clean TX on SSB.  By no means the worst either, of course.
73,
Drew K3PA


Re: K3S to be discontinued

Rob Sherwood
 

Transmitted phase noise performance and RMDR (phase noise issues on receive) are likely of equal importance.  The K3S (or upgraded K3) excel in both cases.   Rob, NC0B

 

From: Elecraft-K3@groups.io [mailto:Elecraft-K3@groups.io] On Behalf Of Mark Morin
Sent: Sunday, November 03, 2019 7:30 AM
To: Elecraft-K3@groups.io
Subject: Re: [Elecraft-K3] K3S to be discontinued

 

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


Re: RS-232 to USB A cable KD8DZ

QUENTIN COLLIER
 

Was that the school HF band Charlie?


73, Quin G3WRR

On Monday, 4 November 2019, 17:14:41 GMT, Charlie T, k3ICH <pincon@...> wrote:


I once played a frugal horn in the school band…….

C

 

 

From: Elecraft-K3@groups.io <Elecraft-K3@groups.io> On Behalf Of Mel Marcus
Sent: Monday, November 04, 2019 11:10 AM
To: Elecraft-K3@groups.io
Subject: Re: [Elecraft-K3] RS-232 to USB A cable KD8DZ

 

but are you saying they dont value their time?

 

-------- Original Message --------
Subject: Re: [Elecraft-K3] RS-232 to USB A cable KD8DZ
From: "Ken Talbott" <ktalbott@...>
Date: Mon, November 04, 2019 6:21 am
To: <Elecraft-K3@groups.io>

Hams are frugal

Ken ke4rg

 

From: Elecraft-K3@groups.io <Elecraft-K3@groups.io> On Behalf Of Mel Marcus
Sent: Sunday, November 3, 2019 10:15 PM
To: Elecraft-K3@groups.io
Subject: Re: [Elecraft-K3] RS-232 to USB A cable KD8DZ

 

I have been watching this thread concerning the usb to serial cable.  I am not sure why people just don't purchase the Elecraft one.

 

Mel

NE9A

-------- Original Message --------
Subject: Re: [Elecraft-K3] RS-232 to USB A cable KD8DZ
From: "Steve" <99sunset@...>
Date: Sun, November 03, 2019 5:22 pm
To: Elecraft-K3@groups.io

The inexpensive Chinese 6 dollar cables use the Prolific drivers which are available for download.  The better cables use FTDI.  The difficulty using the Prolific cables and drivers is that each time Microsoft updates drivers, it will replace your Prolific drivers with FTDI and your cable will fail to operate.  Save yourself the difficulty buy just using the better cable to begin with.  These are available from Elecraft or RT Systems.  

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