On Sep 14, 2020, at 11:03 AM, [email protected] wrote:
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Today's Topics:
1. Why predistortion ? (JR)
2. Re: Why predistortion ? (Wayne Burdick)
3. Re: Why predistortion ? (E.H. Russell)
4. Re: Why predistortion ? (Randy Farmer)
5. KAT500: Fails to tune, and shows 3:1 on good antenna on 18
MHz. (Dave Cole)
6. Re: KAT500: Fails to tune, and shows 3:1 on good antenna on
18 MHz. (Dick Dievendorff)
7. Re: KAT500: Fails to tune, and shows 3:1 on good antenna on
18 MHz. (Ken Winterling)
8. Why predistortion ? (John Harper)
9. Re: Why predistortion ? (Wes)
10. Re: Why predistortion ? (W2xj)
11. Re: KAT500: Fails to tune, and shows 3:1 on good antenna on
18 MHz. (Dave Cole)
12. Re: KAT500: Fails to tune, and shows 3:1 on good antenna on
18 MHz. (Dave Cole)
13. Re: Why predistortion ? (David Gilbert)
14. Re: Why predistortion ? (Bill Frantz)
15. Re: Why predistortion ? (Wayne Burdick)
16. Re: Why predistortion ? (Jim Brown)
17. Re: Why predistortion ? (Jim Brown)
18. Re: Why predistortion ? (David Gilbert)
19. Elecraft CW Net Report (kevinr)
20. Re: KAT500: Fails to tune, and shows 3:1 on good antenna on
18 MHz. (Dave Cole)
21. Re: KAT500: Fails to tune, and shows 3:1 on good antenna on
18 MHz. (Ken Winterling)
22. 630 meter operation on the K4 (Nigel Lemaire)
23. Re: Why predistortion ? (Charlie T)
24. Re: Why predistortion ? (Charlie T)
25. Re: Why predistortion ? (Dr. William J. Schmidt)
----------------------------------------------------------------------
Message: 1
Date: Sun, 13 Sep 2020 17:32:21 -0400
From: JR <[email protected]>
To: [email protected]
Subject: [Elecraft] Why predistortion ?
Message-ID: <[email protected]>
Content-Type: text/plain; charset=utf-8; format=flowed
Why are so many ops obsessed with predistortion?
The Elecraft K-Line already produces some of the cleanest, purest
transmit signals around.?? Do we need predistortion ?? If so, why, and
how much better is it than what we already have?? Should I wait to buy a
new rig until that is available?
Thanks and Happy Trails to all.?? K8JHR
_________________________________
------------------------------
Message: 2
Date: Sun, 13 Sep 2020 15:03:00 -0700
From: Wayne Burdick <[email protected]>
To: JR <[email protected]>
Cc: [email protected]
Subject: Re: [Elecraft] Why predistortion ?
Message-ID: <[email protected]>
Content-Type: text/plain; charset=utf-8
Hi JR,
Virtually all class-AB-biased amplifier stages have worst-case 3rd-order IMD
in the range of -30 dBc (ARRL method) on some HF bands. This reflects a
limitation in the state of the art. Even with adequate feedback and bias, an
amplifier operated in the vicinity of its 1 dB compression point (where it is
most efficient) will exhibit such characteristics.
To improve on this you either need to operate class A, which is highly
inefficient, or use predistortion.
A small number of commercial transceivers are now providing predistortion, in
some cases as an optional/experimental setting (that not everyone uses, or at
least not all the time). There are constraints on predistortion power range
imposed by the headroom limit of the amplifier stage itself. Go over that point
and distortion will be worse than without predistortion.
Predistortion, correctly applied, can reduce interference between adjacent
stations on a crowded band. This is a factor at least some fraction of the time
during typical amateur radio use. Beyond that, the motivation for a ?pure?
signal exemplifies the amateur spirit of cooperation, and is an example of
keeping the hobby on the forefront of electrical design.
Wayne,
N6KR
----
elecraft.com
On Sep 13, 2020, at 2:34 PM, JR <[email protected]> wrote:
?Why are so many ops obsessed with predistortion?
The Elecraft K-Line already produces some of the cleanest, purest transmit
signals around. Do we need predistortion ? If so, why, and how much better
is it than what we already have? Should I wait to buy a new rig until that is
available?
Thanks and Happy Trails to all. K8JHR
_________________________________
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[email protected]
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Message delivered to [email protected]
------------------------------
Message: 3
Date: Sun, 13 Sep 2020 18:41:52 -0400
From: "E.H. Russell" <[email protected]>
To: "'Wayne Burdick'" <[email protected]>, "'JR'"
<[email protected]>
Cc: [email protected]
Subject: Re: [Elecraft] Why predistortion ?
Message-ID: <[email protected]>
Content-Type: text/plain; charset="utf-8"
Well put.
TKS,
73 ED W2RF
-----Original Message-----
From: [email protected] <[email protected]> On
Behalf Of Wayne Burdick
Sent: Sunday, September 13, 2020 6:03 PM
To: JR <[email protected]>
Cc: [email protected]
Subject: Re: [Elecraft] Why predistortion ?
Hi JR,
Virtually all class-AB-biased amplifier stages have worst-case 3rd-order IMD
in the range of -30 dBc (ARRL method) on some HF bands. This reflects a
limitation in the state of the art. Even with adequate feedback and bias, an
amplifier operated in the vicinity of its 1 dB compression point (where it is
most efficient) will exhibit such characteristics.
To improve on this you either need to operate class A, which is highly
inefficient, or use predistortion.
A small number of commercial transceivers are now providing predistortion, in
some cases as an optional/experimental setting (that not everyone uses, or at
least not all the time). There are constraints on predistortion power range
imposed by the headroom limit of the amplifier stage itself. Go over that point
and distortion will be worse than without predistortion.
Predistortion, correctly applied, can reduce interference between adjacent
stations on a crowded band. This is a factor at least some fraction of the time
during typical amateur radio use. Beyond that, the motivation for a ?pure?
signal exemplifies the amateur spirit of cooperation, and is an example of
keeping the hobby on the forefront of electrical design.
Wayne,
N6KR
----
elecraft.com
On Sep 13, 2020, at 2:34 PM, JR <[email protected]> wrote:
?Why are so many ops obsessed with predistortion?
The Elecraft K-Line already produces some of the cleanest, purest transmit
signals around. Do we need predistortion ? If so, why, and how much better
is it than what we already have? Should I wait to buy a new rig until that is
available?
Thanks and Happy Trails to all. K8JHR
_________________________________
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[email protected]
This list hosted by: http://www.qsl.net Please help support this email
list: http://www.qsl.net/donate.html Message delivered to
[email protected]
______________________________________________________________
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Help: http://mailman.qth.net/mmfaq.htm
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delivered to [email protected]
------------------------------
Message: 4
Date: Sun, 13 Sep 2020 18:48:17 -0400
From: Randy Farmer <[email protected]>
To: [email protected]
Subject: Re: [Elecraft] Why predistortion ?
Message-ID: <[email protected]>
Content-Type: text/plain; charset=utf-8; format=flowed
I can testify to the effectiveness of predistortion techniques from my 5
years or so as a CDMA Cellular Base Station engineer with Motorola. The
first generation of CDMA transmitters had a very specific "spectral
mask" that had to be certified. As I recall, the transmitter output that
met the Spectral Mask requirements of something like -60 dBc outside of
the channel bandwidth showed up with essentially vertical sides (and a
very flat top) on a spectrum analyzer. Obtaining this performance was
neither cheap nor easy, and the associated testing was pretty stringent
as well. Meeting the specs demanded very sophisticated predistortion
techniques. Be glad that conventional SSB and the fairly simple
waveforms used in amateur digital comms don't require too much dynamic
headroom. The first generation CDMA waveform had a roughly 10:1, or 20dB
peak-to-average power ratio. This meant that the transmitters we
designed to produce 20W average power were actually capable of 200W
continuous output power and still met the spectral mask IMD
requirements. Putting multiple carriers through the PA required either
higher power capability or derating the power output for each individual
carrier. I no longer work in the industry, so I don't know what the
current generation of signals requires, but with the greater bandwidths
and more complex modulation schemes used now you can bet the
requirements, and therefore the transmitter design challenge, didn't get
any easier.
73...
Randy, W8FN
On 9/13/2020 6:03 PM, Wayne Burdick wrote:
Hi JR,
Virtually all class-AB-biased amplifier stages have worst-case 3rd-order IMD
in the range of -30 dBc (ARRL method) on some HF bands. This reflects a
limitation in the state of the art. Even with adequate feedback and bias, an
amplifier operated in the vicinity of its 1 dB compression point (where it is
most efficient) will exhibit such characteristics.
To improve on this you either need to operate class A, which is highly
inefficient, or use predistortion.
A small number of commercial transceivers are now providing predistortion, in
some cases as an optional/experimental setting (that not everyone uses, or at
least not all the time). There are constraints on predistortion power range
imposed by the headroom limit of the amplifier stage itself. Go over that point
and distortion will be worse than without predistortion.
Predistortion, correctly applied, can reduce interference between adjacent
stations on a crowded band. This is a factor at least some fraction of the time
during typical amateur radio use. Beyond that, the motivation for a ?pure?
signal exemplifies the amateur spirit of cooperation, and is an example of
keeping the hobby on the forefront of electrical design.
Wayne,
N6KR
----
elecraft.com
------------------------------
Message: 5
Date: Sun, 13 Sep 2020 15:48:40 -0700
From: Dave Cole <[email protected]>
To: [email protected]
Subject: [Elecraft] KAT500: Fails to tune, and shows 3:1 on good
antenna on 18 MHz.
Message-ID: <[email protected]>
Content-Type: text/plain; charset=utf-8; format=flowed
Hello,
My KAT500 which worked yesterday, now shows a 3:1 on 18 MHz., only.
Antenna is a single feedline to a 6BTV, and an analyzer says all is good
at low power. At 100 watts, all seems good.
All other bands seem OK at high power.
Question: When in bypass, is the entire tuner bypassed?
Question: When turned off is the tuner bypassed? Which antenna is default?
--
73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist
ARRL Asst. Director, NW Division, Technical Resources
------------------------------
Message: 6
Date: Sun, 13 Sep 2020 15:57:03 -0700
From: Dick Dievendorff <[email protected]>
To: Dave Cole <[email protected]>
Cc: [email protected]
Subject: Re: [Elecraft] KAT500: Fails to tune, and shows 3:1 on good
antenna on 18 MHz.
Message-ID: <[email protected]>
Content-Type: text/plain; charset=utf-8
When unpowered the KAT500 is bypassed, ANT1.
When the ATU is in mode BYP, yes, it?s bypassed.
73 de Dick, K6KR
On Sep 13, 2020, at 15:52, Dave Cole <[email protected]> wrote:
?Hello,
My KAT500 which worked yesterday, now shows a 3:1 on 18 MHz., only. Antenna is
a single feedline to a 6BTV, and an analyzer says all is good at low power. At
100 watts, all seems good.
All other bands seem OK at high power.
Question: When in bypass, is the entire tuner bypassed?
Question: When turned off is the tuner bypassed? Which antenna is default?
--
73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist
ARRL Asst. Director, NW Division, Technical Resources
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[email protected]
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Message delivered to [email protected]
------------------------------
Message: 7
Date: Sun, 13 Sep 2020 19:24:24 -0400
From: Ken Winterling <[email protected]>
To: Dick Dievendorff <[email protected]>
Cc: Elecraft Reflector <[email protected]>
Subject: Re: [Elecraft] KAT500: Fails to tune, and shows 3:1 on good
antenna on 18 MHz.
Message-ID:
<calk4bwijpgsxohauhbb14vcy7aps-u7cfoixybkq_rvu1zf...@mail.gmail.com>
Content-Type: text/plain; charset="UTF-8"
When you have issues like this the best test is to use a known good dummy
load. That removes the antenna system from the equation. See what happens
on 18mHz when transmitting into the summy load.
Ken
WA2LBI
On Sun, Sep 13, 2020 at 6:58 PM Dick Dievendorff <[email protected]> wrote:
When unpowered the KAT500 is bypassed, ANT1.
When the ATU is in mode BYP, yes, it?s bypassed.
73 de Dick, K6KR
On Sep 13, 2020, at 15:52, Dave Cole <[email protected]> wrote:
?Hello,
My KAT500 which worked yesterday, now shows a 3:1 on 18 MHz., only.
Antenna is a single feedline to a 6BTV, and an analyzer says all is good at
low power. At 100 watts, all seems good.
All other bands seem OK at high power.
Question: When in bypass, is the entire tuner bypassed?
Question: When turned off is the tuner bypassed? Which antenna is
default?
--
73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist
ARRL Asst. Director, NW Division, Technical Resources
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[email protected]
This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [email protected]
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[email protected]
This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [email protected]
------------------------------
Message: 8
Date: Sun, 13 Sep 2020 18:40:01 -0500
From: John Harper <[email protected]>
To: Elecraft list <[email protected]>
Subject: [Elecraft] Why predistortion ?
Message-ID:
<CAPHmH=O3V_u977xn0c9qJ1hCEyxwfdVYMXXhL30QRg=fgmv...@mail.gmail.com>
Content-Type: text/plain; charset="UTF-8"
Here's a demonstration of predistortion in use (relevant part starts at the
10-minute point):
https://www.youtube.com/watch?v=0adHZOTqTlQ
John AE5X
https://ae5x.blogspot.com
Why are so many ops obsessed with predistortion?
------------------------------
Message: 9
Date: Sun, 13 Sep 2020 17:20:39 -0700
From: Wes <[email protected]>
To: [email protected]
Subject: Re: [Elecraft] Why predistortion ?
Message-ID: <[email protected]>
Content-Type: text/plain; charset=utf-8; format=flowed
You're kidding, right?
Wes? N7WS
On 9/13/2020 2:32 PM, JR wrote:
The Elecraft K-Line already produces some of the cleanest, purest transmit
signals around....
Thanks and Happy Trails to all.?? K8JHR
------------------------------
Message: 10
Date: Sun, 13 Sep 2020 20:24:07 -0400
From: W2xj <[email protected]>
To: Wayne Burdick <[email protected]>
Cc: [email protected], JR <[email protected]>
Subject: Re: [Elecraft] Why predistortion ?
Message-ID: <[email protected]>
Content-Type: text/plain; charset=utf-8
wayne,
After you have the K4 fully put to bed, for your next project you might want
to consider an amp that is directly driven by an I/Q stream. The amplifier
will be much more efficient (less power consumption) and you start out with
less IMD before any pre-distortion.
Sent from my iPad
On Sep 13, 2020, at 6:05 PM, Wayne Burdick <[email protected]> wrote:
?Hi JR,
Virtually all class-AB-biased amplifier stages have worst-case 3rd-order IMD
in the range of -30 dBc (ARRL method) on some HF bands. This reflects a
limitation in the state of the art. Even with adequate feedback and bias, an
amplifier operated in the vicinity of its 1 dB compression point (where it is
most efficient) will exhibit such characteristics.
To improve on this you either need to operate class A, which is highly
inefficient, or use predistortion.
A small number of commercial transceivers are now providing predistortion, in
some cases as an optional/experimental setting (that not everyone uses, or at
least not all the time). There are constraints on predistortion power range
imposed by the headroom limit of the amplifier stage itself. Go over that point
and distortion will be worse than without predistortion.
Predistortion, correctly applied, can reduce interference between adjacent
stations on a crowded band. This is a factor at least some fraction of the time
during typical amateur radio use. Beyond that, the motivation for a ?pure?
signal exemplifies the amateur spirit of cooperation, and is an example of
keeping the hobby on the forefront of electrical design.
Wayne,
N6KR
----
elecraft.com
On Sep 13, 2020, at 2:34 PM, JR <[email protected]> wrote:
?Why are so many ops obsessed with predistortion?
The Elecraft K-Line already produces some of the cleanest, purest transmit
signals around. Do we need predistortion ? If so, why, and how much better
is it than what we already have? Should I wait to buy a new rig until that is
available?
Thanks and Happy Trails to all. K8JHR
_________________________________
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[email protected]
This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [email protected]
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[email protected]
This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [email protected]
------------------------------
Message: 11
Date: Sun, 13 Sep 2020 17:53:36 -0700
From: Dave Cole <[email protected]>
To: Dick Dievendorff <[email protected]>
Cc: [email protected]
Subject: Re: [Elecraft] KAT500: Fails to tune, and shows 3:1 on good
antenna on 18 MHz.
Message-ID: <[email protected]>
Content-Type: text/plain; charset=utf-8; format=flowed
That helps triage the issue... Something in my antenna must have gone
wonky... I am using a 6BTV, with the 18 Meter add on kit, so the same
feedpoint is used for all bands, and they are fine... I was worried it
was the tuner. I'll go check the antenna out tonight, and in the
morning as well... THANK YOU! Knowing the tuner is bypassed in Bypass,
helps... Next is to put a dummy load on the tuner...
73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist
ARRL Asst. Director, NW Division, Technical Resources
On 9/13/20 3:57 PM, Dick Dievendorff wrote:
When unpowered the KAT500 is bypassed, ANT1.
When the ATU is in mode BYP, yes, it?s bypassed.
73 de Dick, K6KR
On Sep 13, 2020, at 15:52, Dave Cole <[email protected]> wrote:
?Hello,
My KAT500 which worked yesterday, now shows a 3:1 on 18 MHz., only. Antenna is
a single feedline to a 6BTV, and an analyzer says all is good at low power. At
100 watts, all seems good.
All other bands seem OK at high power.
Question: When in bypass, is the entire tuner bypassed?
Question: When turned off is the tuner bypassed? Which antenna is default?
--
73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist
ARRL Asst. Director, NW Division, Technical Resources
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[email protected]
This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [email protected]
------------------------------
Message: 12
Date: Sun, 13 Sep 2020 17:54:02 -0700
From: Dave Cole <[email protected]>
To: Ken Winterling <[email protected]>, Dick Dievendorff
<[email protected]>
Cc: Elecraft Reflector <[email protected]>
Subject: Re: [Elecraft] KAT500: Fails to tune, and shows 3:1 on good
antenna on 18 MHz.
Message-ID: <[email protected]>
Content-Type: text/plain; charset=utf-8; format=flowed
Thanks Ken... That is the next step... Now I need to locate one...
73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist
ARRL Asst. Director, NW Division, Technical Resources
On 9/13/20 4:24 PM, Ken Winterling wrote:
When you have issues like this the best test is to use a known good
dummy load. That removes the antenna system from the equation. See what
happens on 18mHz when transmitting into the summy load.
Ken
WA2LBI
On Sun, Sep 13, 2020 at 6:58 PM Dick Dievendorff <[email protected]
<mailto:[email protected]>> wrote:
When unpowered the KAT500 is bypassed, ANT1.
When the ATU is in mode BYP, yes, it?s bypassed.
73 de Dick, K6KR
On Sep 13, 2020, at 15:52, Dave Cole <[email protected]
<mailto:[email protected]>> wrote:
?Hello,
My KAT500 which worked yesterday, now shows a 3:1 on 18 MHz.,
only. Antenna is a single feedline to a 6BTV, and an analyzer says
all is good at low power.? At 100 watts, all seems good.
All other bands seem OK at high power.
Question:? When in bypass, is the entire tuner bypassed?
Question:? When turned off is the tuner bypassed?? Which antenna
is default?
--
73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist
ARRL Asst. Director, NW Division, Technical Resources
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[email protected]
<mailto:[email protected]>
This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [email protected] <mailto:[email protected]>
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[email protected] <mailto:[email protected]>
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Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [email protected] <mailto:[email protected]>
------------------------------
Message: 13
Date: Sun, 13 Sep 2020 18:50:41 -0700
From: David Gilbert <[email protected]>
To: [email protected]
Subject: Re: [Elecraft] Why predistortion ?
Message-ID: <[email protected]>
Content-Type: text/plain; charset=utf-8; format=flowed
I don't know where you got the idea that the K-Line produces the
cleanest signals.? As several people have pointed out, because of the 12
volt finals the transmit IMD performance of the existing K-line is
relatively poor.
Dave?? AB7E
On 9/13/2020 2:32 PM, JR wrote:
Why are so many ops obsessed with predistortion?
The Elecraft K-Line already produces some of the cleanest, purest
transmit signals around.?? Do we need predistortion ?? If so, why, and
how much better is it than what we already have?? Should I wait to buy
a new rig until that is available?
Thanks and Happy Trails to all.?? K8JHR
------------------------------
Message: 14
Date: Sun, 13 Sep 2020 21:59:13 -0400
From: Bill Frantz <[email protected]>
To: [email protected]
Subject: Re: [Elecraft] Why predistortion ?
Message-ID:
<r480Ps-10146i-14E8D36EC339467BB106B11E38A936FF@Williams-MacBook-Pro.local>
Content-Type: text/plain; charset=UTF-8; format=flowed
Wayne is right, it's the right thing to do. And we amateurs try
to produce the best signals we can. (Ignore the wide CW signals
during contests. :-) )
But the value will also show up during multi-op situations like
running 14A during field day. Field day is much more fun if
everyone gets a chance to operate.
73 Bill AE6JV
On 9/13/20 at 6:03 PM, [email protected] (Wayne Burdick) wrote:
Predistortion, correctly applied, can reduce interference
between adjacent stations on a crowded band. This is a factor
at least some fraction of the time during typical amateur radio
use. Beyond that, the motivation for a ?pure? signal
exemplifies the amateur spirit of cooperation, and is an
example of keeping the hobby on the forefront of electrical design.
-----------------------------------------------------------------------
Bill Frantz | Privacy is dead, get over | Periwinkle
(408)348-7900 | it. | 150 Rivermead
Rd #235
www.pwpconsult.com | - Scott McNealy (1999) | Peterborough,
NH 03458
------------------------------
Message: 15
Date: Sun, 13 Sep 2020 19:14:52 -0700
From: Wayne Burdick <[email protected]>
To: David Gilbert <[email protected]>
Cc: Elecraft Reflector <[email protected]>
Subject: Re: [Elecraft] Why predistortion ?
Message-ID: <[email protected]>
Content-Type: text/plain; charset=us-ascii
12 volts is a severe constraint for MOSFET PAs. But, like a lot of other
manufacturers, we accept this constraint so the equipment can be used in a wide
variety of portable/emergency power situations. As a result we have IMD numbers
in exactly the same range as other products that are subject to this constraint.
On the other hand, our transceivers are best in class in terms of transmitted
keying bandwidth. See paper by K9YC for example. Perhaps that's what JR was
thinking of.
73,
Wayne
N6KR
On Sep 13, 2020, at 6:50 PM, David Gilbert <[email protected]> wrote:
I don't know where you got the idea that the K-Line produces the cleanest
signals. As several people have pointed out, because of the 12 volt finals the
transmit IMD performance of the existing K-line is relatively poor.
Dave AB7E
On 9/13/2020 2:32 PM, JR wrote:
Why are so many ops obsessed with predistortion?
The Elecraft K-Line already produces some of the cleanest, purest transmit
signals around. Do we need predistortion ? If so, why, and how much better
is it than what we already have? Should I wait to buy a new rig until that is
available?
Thanks and Happy Trails to all. K8JHR
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Message: 16
Date: Sun, 13 Sep 2020 21:14:47 -0700
From: Jim Brown <[email protected]>
To: [email protected]
Subject: Re: [Elecraft] Why predistortion ?
Message-ID:
<[email protected]>
Content-Type: text/plain; charset=utf-8; format=flowed
On 9/13/2020 2:32 PM, JR wrote:
The Elecraft K-Line already produces some of the cleanest, purest
transmit signals around.?? Do we need predistortion ?
If you care about a clean signal, YES! If you don't mind being a bad
neighbor, no.
73, Jim K9YC
------------------------------
Message: 17
Date: Sun, 13 Sep 2020 21:25:46 -0700
From: Jim Brown <[email protected]>
To: [email protected]
Subject: Re: [Elecraft] Why predistortion ?
Message-ID:
<[email protected]>
Content-Type: text/plain; charset=utf-8; format=flowed
On 9/13/2020 3:03 PM, Wayne Burdick wrote:
Virtually all class-AB-biased amplifier stages have worst-case 3rd-order IMD
in the range of -30 dBc (ARRL method) on some HF bands. This reflects a
limitation in the state of the art.
I hope that this feature will be implemented for CW as well. CW is 100%
AM of a carrier by rectangular pulses, so any distortion in the transmit
chain results in clicks. Elecraft pioneered very clean keying waveforms;
it would be unfortunate for that to be lost with IMD in the power stages.
73, Jim K9YC
------------------------------
Message: 18
Date: Sun, 13 Sep 2020 21:43:21 -0700
From: David Gilbert <[email protected]>
To: Elecraft Reflector <[email protected]>
Subject: Re: [Elecraft] Why predistortion ?
Message-ID: <[email protected]>
Content-Type: text/plain; charset=utf-8; format=flowed
Of course, but that's a conscious choice by Elecraft and it does not
result in the "cleanest, purest signals around."? I give Elecraft tons
of credit for the other measures they have take to produce good signals,
which is why I own and will keep my upgraded K3 probably forever, but
K8JHR simply was incorrect in his comment and it makes a difference when
considering the expanding focus by folks like Sherwood and others to
clean up the bands.? When it comes to IMD, Elecraft is not one of the
better players.? The fact that that's by choice doesn't change
anything.? I suspect that 95+% of K3 rigs are used in portable/emergency
situations less than 5% of the time.
73,
Dave?? AB7E
On 9/13/2020 7:14 PM, Wayne Burdick wrote:
12 volts is a severe constraint for MOSFET PAs. But, like a lot of other
manufacturers, we accept this constraint so the equipment can be used in a wide
variety of portable/emergency power situations. As a result we have IMD numbers
in exactly the same range as other products that are subject to this constraint.
On the other hand, our transceivers are best in class in terms of transmitted
keying bandwidth. See paper by K9YC for example. Perhaps that's what JR was
thinking of.
73,
Wayne
N6KR
On Sep 13, 2020, at 6:50 PM, David Gilbert <[email protected]> wrote:
I don't know where you got the idea that the K-Line produces the cleanest
signals. As several people have pointed out, because of the 12 volt finals the
transmit IMD performance of the existing K-line is relatively poor.
Dave AB7E
On 9/13/2020 2:32 PM, JR wrote:
Why are so many ops obsessed with predistortion?
The Elecraft K-Line already produces some of the cleanest, purest transmit
signals around. Do we need predistortion ? If so, why, and how much better
is it than what we already have? Should I wait to buy a new rig until that is
available?
Thanks and Happy Trails to all. K8JHR
______________________________________________________________
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Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[email protected]
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Message delivered to [email protected]
------------------------------
Message: 19
Date: Sun, 13 Sep 2020 21:51:33 -0700
From: kevinr <[email protected]>
To: Elecraft Reflector <[email protected]>
Subject: [Elecraft] Elecraft CW Net Report
Message-ID: <[email protected]>
Content-Type: text/plain; charset=utf-8; format=flowed
Good Evening,
?? Signals were stronger than last week with less noise on both bands.?
QSB was a little higher on forty meters.? Most of you reported very nice
weather.? Even out west the weather is not too bad once you allow for
all the smoke.? It certainly makes working outside difficult.? Staying
inside helps but I still have a stuffy nose and a mild headache.? My
begonias don't like the smoke either, they are rapidly losing blossoms.
?? The forty meter net improves as the days grow shorter.? I was able
to reach Texas again.? Hopefully there will be some new sunspots this
week.? That would help my reach.
? On 14050.8 kHz at 2200z:
W0CZ - Ken - ND
NO8V - John - MI
AB9V - Mike - IN
K6XK - Roy - IA
? On 7047.5 kHz at 0045z:
W0CZ - Ken - ND
K0DTJ - Brian - CA
K6PJV - Dale - CA
W8OV - Dave - TX
I plan to work inside again this week.? I need to collect wood but
exercise in these smoky conditions makes the headaches worse. A week of
rain starting tomorrow night will help.? Maybe they will slow the fires
in the Cascades and clear our skies.? 2020 has been quite a year.? I'm
waiting for January so we can start over.
?? Until next week 73,
????? Kevin.? KD5ONS
-
cutting angle = degrees(atan2(twist, PI() * caliber))
------------------------------
Message: 20
Date: Mon, 14 Sep 2020 04:52:03 -0700
From: Dave Cole <[email protected]>
To: Elecraft Reflector <[email protected]>
Subject: Re: [Elecraft] KAT500: Fails to tune, and shows 3:1 on good
antenna on 18 MHz.
Message-ID: <[email protected]>
Content-Type: text/plain; charset=utf-8; format=flowed
Hi ken,
Added the dummy, no problems, so it is the antenna... Also, given it is
a 6BTV with the 18 meter add on, and all other bands work, it is not the
feedline...
This makes it simple to fix! It is either a break with the laws of
physics as we understand them today-- or a connection has come loose.
Given there are only two connections... I suspect it will be a simple fix.
73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist
ARRL Asst. Director, NW Division, Technical Resources
On 9/13/20 4:24 PM, Ken Winterling wrote:
When you have issues like this the best test is to use a known good
dummy load. That removes the antenna system from the equation. See what
happens on 18mHz when transmitting into the summy load.
Ken
WA2LBI
On Sun, Sep 13, 2020 at 6:58 PM Dick Dievendorff <[email protected]
<mailto:[email protected]>> wrote:
When unpowered the KAT500 is bypassed, ANT1.
When the ATU is in mode BYP, yes, it?s bypassed.
73 de Dick, K6KR
On Sep 13, 2020, at 15:52, Dave Cole <[email protected]
<mailto:[email protected]>> wrote:
?Hello,
My KAT500 which worked yesterday, now shows a 3:1 on 18 MHz.,
only. Antenna is a single feedline to a 6BTV, and an analyzer says
all is good at low power.? At 100 watts, all seems good.
All other bands seem OK at high power.
Question:? When in bypass, is the entire tuner bypassed?
Question:? When turned off is the tuner bypassed?? Which antenna
is default?
--
73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist
ARRL Asst. Director, NW Division, Technical Resources
______________________________________________________________
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<mailto:[email protected]>
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------------------------------
Message: 21
Date: Mon, 14 Sep 2020 07:54:32 -0400
From: Ken Winterling <[email protected]>
To: Dave Cole <[email protected]>
Cc: Elecraft Reflector <[email protected]>
Subject: Re: [Elecraft] KAT500: Fails to tune, and shows 3:1 on good
antenna on 18 MHz.
Message-ID:
<calk4bwj_yephov1l5o3tgz3q4dwc_b4zt99mrd22g3-rk88...@mail.gmail.com>
Content-Type: text/plain; charset="UTF-8"
GL!
Ken
WA2LBI
On Mon, Sep 14, 2020 at 7:53 AM Dave Cole <[email protected]> wrote:
Hi ken,
Added the dummy, no problems, so it is the antenna... Also, given it is
a 6BTV with the 18 meter add on, and all other bands work, it is not the
feedline...
This makes it simple to fix! It is either a break with the laws of
physics as we understand them today-- or a connection has come loose.
Given there are only two connections... I suspect it will be a simple fix.
73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist
ARRL Asst. Director, NW Division, Technical Resources
On 9/13/20 4:24 PM, Ken Winterling wrote:
When you have issues like this the best test is to use a known good
dummy load. That removes the antenna system from the equation. See what
happens on 18mHz when transmitting into the summy load.
Ken
WA2LBI
On Sun, Sep 13, 2020 at 6:58 PM Dick Dievendorff <[email protected]
<mailto:[email protected]>> wrote:
When unpowered the KAT500 is bypassed, ANT1.
When the ATU is in mode BYP, yes, it?s bypassed.
73 de Dick, K6KR
On Sep 13, 2020, at 15:52, Dave Cole <[email protected]
<mailto:[email protected]>> wrote:
?Hello,
My KAT500 which worked yesterday, now shows a 3:1 on 18 MHz.,
only. Antenna is a single feedline to a 6BTV, and an analyzer says
all is good at low power. At 100 watts, all seems good.
All other bands seem OK at high power.
Question: When in bypass, is the entire tuner bypassed?
Question: When turned off is the tuner bypassed? Which antenna
is default?
--
73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist
ARRL Asst. Director, NW Division, Technical Resources
______________________________________________________________
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<mailto:[email protected]>
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http://www.qsl.net/donate.html
Message delivered to [email protected] <mailto:[email protected]>
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[email protected]>
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Message delivered to [email protected]
------------------------------
Message: 22
Date: Mon, 14 Sep 2020 08:10:55 -0700
From: Nigel Lemaire <[email protected]>
To: [email protected]
Subject: [Elecraft] 630 meter operation on the K4
Message-ID: <[email protected]>
Content-Type: text/plain; charset=utf-8; format=flowed
Wondering what capabilities the K4 will have on this (these) bands...
73
Nigel
Wa6MSE
------------------------------
Message: 23
Date: Sun, 13 Sep 2020 22:42:02 -0400
From: "Charlie T" <[email protected]>
To: <[email protected]>
Subject: Re: [Elecraft] Why predistortion ?
Message-ID: <[email protected]>
Content-Type: text/plain; charset="UTF-8"
According to Rob Sherwood, the Collins 32S-3 produces the cleanest SSB signal
on the air of any commercial amateur radio transmitters.
73, Charlie k3ICH
-----Original Message-----
From: [email protected] <[email protected]> On
Behalf Of David Gilbert
Sent: Sunday, September 13, 2020 9:51 PM
To: [email protected]
Subject: Re: [Elecraft] Why predistortion ?
I don't know where you got the idea that the K-Line produces the cleanest
signals. As several people have pointed out, because of the 12 volt finals the
transmit IMD performance of the existing K-line is relatively poor.
Dave AB7E
On 9/13/2020 2:32 PM, JR wrote:
Why are so many ops obsessed with predistortion?
The Elecraft K-Line already produces some of the cleanest, purest
transmit signals around. Do we need predistortion ? If so, why, and
how much better is it than what we already have? Should I wait to buy
a new rig until that is available?
Thanks and Happy Trails to all. K8JHR
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[email protected]
This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html Message
delivered to [email protected]
------------------------------
Message: 24
Date: Mon, 14 Sep 2020 07:29:48 -0400
From: "Charlie T" <[email protected]>
To: <[email protected]>
Subject: Re: [Elecraft] Why predistortion ?
Message-ID: <[email protected]>
Content-Type: text/plain; charset="UTF-8"
Maybe I'm missing something here, but it would seem to me that if an FET
linear amplifier running from 50 V or higher is considerably cleaner than one
running from 12 V, that, for a high end rig, a simple step-up switching supply
could solve the problem. But, that obviously adds to the cost so it IS
somewhat of a conundrum.
However, implementing the pre-distortion function IS probably a better
long-term solution.
73, Charlie k3ICH
-----Original Message-----
From: [email protected] <[email protected]> On
Behalf Of David Gilbert
Sent: Monday, September 14, 2020 12:43 AM
To: Elecraft Reflector <[email protected]>
Subject: Re: [Elecraft] Why predistortion ?
Of course, but that's a conscious choice by Elecraft and it does not result in the
"cleanest, purest signals around." I give Elecraft tons of credit for the
other measures they have take to produce good signals, which is why I own and will keep
my upgraded K3 probably forever, but K8JHR simply was incorrect in his comment and it
makes a difference when considering the expanding focus by folks like Sherwood and others
to clean up the bands. When it comes to IMD, Elecraft is not one of the better players.
The fact that that's by choice doesn't change anything. I suspect that 95+% of K3 rigs
are used in portable/emergency situations less than 5% of the time.
73,
Dave AB7E
On 9/13/2020 7:14 PM, Wayne Burdick wrote:
12 volts is a severe constraint for MOSFET PAs. But, like a lot of other
manufacturers, we accept this constraint so the equipment can be used in a wide
variety of portable/emergency power situations. As a result we have IMD numbers
in exactly the same range as other products that are subject to this constraint.
On the other hand, our transceivers are best in class in terms of transmitted
keying bandwidth. See paper by K9YC for example. Perhaps that's what JR was
thinking of.
73,
Wayne
N6KR
On Sep 13, 2020, at 6:50 PM, David Gilbert <[email protected]> wrote:
I don't know where you got the idea that the K-Line produces the cleanest
signals. As several people have pointed out, because of the 12 volt finals the
transmit IMD performance of the existing K-line is relatively poor.
Dave AB7E
On 9/13/2020 2:32 PM, JR wrote:
Why are so many ops obsessed with predistortion?
The Elecraft K-Line already produces some of the cleanest, purest transmit
signals around. Do we need predistortion ? If so, why, and how much better
is it than what we already have? Should I wait to buy a new rig until that is
available?
Thanks and Happy Trails to all. K8JHR
______________________________________________________________
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Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[email protected]
This list hosted by: http://www.qsl.net Please help support this
email list: http://www.qsl.net/donate.html Message delivered to
[email protected]
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delivered to [email protected]
------------------------------
Message: 25
Date: Mon, 14 Sep 2020 11:00:25 -0500
From: "Dr. William J. Schmidt" <[email protected]>
To: "'Elecraft List'" <[email protected]>
Subject: Re: [Elecraft] Why predistortion ?
Message-ID: <[email protected]>
Content-Type: text/plain; charset="iso-8859-1"
6AU6 - 6CL6 - 6146A trio is a very and associated circuitry produces some of
the lowest distortion products when run at the right conditions (voltages,
etc). Note at 75 watts the 6146 is in its sweet spot.
Dr. William J. Schmidt - K9HZ
email:? [email protected]
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Charlie T
Sent: Sunday, September 13, 2020 9:42 PM
To: [email protected]
Subject: Re: [Elecraft] Why predistortion ?
According to Rob Sherwood, the Collins 32S-3 produces the cleanest SSB
signal on the air of any commercial amateur radio transmitters.
73, Charlie k3ICH
-----Original Message-----
From: [email protected] <[email protected]> On
Behalf Of David Gilbert
Sent: Sunday, September 13, 2020 9:51 PM
To: [email protected]
Subject: Re: [Elecraft] Why predistortion ?
I don't know where you got the idea that the K-Line produces the cleanest
signals. As several people have pointed out, because of the 12 volt finals
the transmit IMD performance of the existing K-line is relatively poor.
Dave AB7E
On 9/13/2020 2:32 PM, JR wrote:
Why are so many ops obsessed with predistortion?
The Elecraft K-Line already produces some of the cleanest, purest
transmit signals around. Do we need predistortion ? If so, why, and
how much better is it than what we already have? Should I wait to buy
a new rig until that is available?
Thanks and Happy Trails to all. K8JHR
______________________________________________________________
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Help: http://mailman.qth.net/mmfaq.htm
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End of Elecraft Digest, Vol 197, Issue 18
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