[arrl-odv:35362] Fwd: Icom "Dynamic Predistortion" Changes to IC-7610
Some positive news. (See below.) I’d like to think this is a result of ARRL’s CSI efforts! It does show that manufacturers are taking the effort seriously though, and that ARRL can make an impact in the technical space as a benefit for members. Lots of bad clicks and chirpy signals in the CW test last weekend, including one from EU that sounded like an old spark set! Hope everybody had a great Thanksgiving. 73; Mike W7VO Sent from my iPhone, utilizing a very tiny keyboard fed from very fat fingers Begin forwarded message:
From: Mike Ritz <w7vo@comcast.net> Date: November 27, 2023 at 8:40:31 AM PST To: Alan Rovner <k7ar@comcast.net> Subject: Re: Icom "Dynamic Predistortion" Changes to IC-7610
Thanks, Al! Another ham sent me a note on this also. Icom is one of the JA manufacturers involved with the CSI. Ray Novak, N9JA is a committee member.
I don’t know if this was a direct result of CSI, but I’d like to think so! This is exactly what we were hoping would happen.
73; Mike W7VO
Sent from my iPhone, utilizing a very tiny keyboard fed from very fat fingers
On Nov 27, 2023, at 8:14 AM, Alan Rovner <k7ar@comcast.net> wrote:
Hi Mike I thought you might be interested this news as part of your Clean Signal Initiative. Icom has released new firmware for the IC-7610 that implements something called dynamic predistortion. As far as I can tell it generates a cleaner SSB signal when enabled. I'll include a photo below. While this is a good thing, it looks like it only works with their upcoming PW2 amplifier. There is ongoing discussion about whether non-Icom amps will be supported.
Also this only applies to normal SSB voice signals. CW, RTTY, FT8 or other audio tone modes have no need for this feature. In order to use predistortion, you have to connect the 7610 to a dummy load and go through a calibration process for each band.
In the photo below the blue graph represents energy without predistortiion and the pink graph shows a cleaner signal with predistortion. Notice the pink graph has less energy away from the center test tone.
Thought you might be interested, 73, Al, K7AR
<FLgMmPe5ca0PzGmI.png>
Good deal Mike. This is a big deal in my book Mike and just what our League should be pursuing. I do have an IC-7610, BTW. I doubt they are not already clean as a whistle, but improvement is always worthwhile. And then there are some contest stations that prefer to be, well, wider to keep “their” frequency clear on both sides. How we deal with that is a question for the future. Bob Famiglio, K3RF ARRL Atlantic Division Director 610-359-7300 www.QRZ.com/db/K3RF From: arrl-odv <arrl-odv-bounces@reflector.arrl.org> On Behalf Of Mike Ritz Sent: Monday, November 27, 2023 12:02 PM To: arrl-odv@reflector.arrl.org Subject: [arrl-odv:35362] Fwd: Icom "Dynamic Predistortion" Changes to IC-7610 Some positive news. (See below.) I’d like to think this is a result of ARRL’s CSI efforts! It does show that manufacturers are taking the effort seriously though, and that ARRL can make an impact in the technical space as a benefit for members. Lots of bad clicks and chirpy signals in the CW test last weekend, including one from EU that sounded like an old spark set! Hope everybody had a great Thanksgiving. 73; Mike W7VO Sent from my iPhone, utilizing a very tiny keyboard fed from very fat fingers Begin forwarded message: From: Mike Ritz <w7vo@comcast.net<mailto:w7vo@comcast.net>> Date: November 27, 2023 at 8:40:31 AM PST To: Alan Rovner <k7ar@comcast.net<mailto:k7ar@comcast.net>> Subject: Re: Icom "Dynamic Predistortion" Changes to IC-7610 Thanks, Al! Another ham sent me a note on this also. Icom is one of the JA manufacturers involved with the CSI. Ray Novak, N9JA is a committee member. I don’t know if this was a direct result of CSI, but I’d like to think so! This is exactly what we were hoping would happen. 73; Mike W7VO Sent from my iPhone, utilizing a very tiny keyboard fed from very fat fingers On Nov 27, 2023, at 8:14 AM, Alan Rovner <k7ar@comcast.net<mailto:k7ar@comcast.net>> wrote: Hi Mike I thought you might be interested this news as part of your Clean Signal Initiative. Icom has released new firmware for the IC-7610 that implements something called dynamic predistortion. As far as I can tell it generates a cleaner SSB signal when enabled. I'll include a photo below. While this is a good thing, it looks like it only works with their upcoming PW2 amplifier. There is ongoing discussion about whether non-Icom amps will be supported. Also this only applies to normal SSB voice signals. CW, RTTY, FT8 or other audio tone modes have no need for this feature. In order to use predistortion, you have to connect the 7610 to a dummy load and go through a calibration process for each band. In the photo below the blue graph represents energy without predistortiion and the pink graph shows a cleaner signal with predistortion. Notice the pink graph has less energy away from the center test tone. Thought you might be interested, 73, Al, K7AR <FLgMmPe5ca0PzGmI.png>
There is a lot of chatter about this on the IC-7610 IOgroup, and multiple screenshots of the IC-7610 with and without DPD enabled are in the files section. Most of this testing has been done by Adam Farson VA7OJ. Although this was released in anticipation of the IC-PW2 amplifier, a question came up as to whether this would be of any use without an amplifier. A quote from Adam “Even in the stand-alone mode, DPD will linearise the 7610's SSB output signal, improving TX IMD performance by 20 - 30 dB. This makes for a cleaner signal and reduces the likelihood of adjacent-channel interference.” I’m sure this was in direct response to the Clean Signal Initiative. Bravo! As Bob F. noted, several contest stations would rather work in the opposite direction and be as wide as possible to give them an advantage. I don’t know how this will be addressed in the future. Interestingly, as some of the Yaesu rigs were touted as having key clicks, Yaesu responded by an upgraded firmware that has a minimal limit on CW rise time. Of course, that requires rig owner intervention. ‘73 de Jim N2ZZ Director – Roanoke Division Representing ARRL members in North Carolina, South Carolina, Virginia and West Virginia ARRL – the national association for Amateur Radio Facebook Page: ARRL Roanoke Division Website: www.arrl-roanoke.org<http://www.arrl-roanoke.org/> [Text, logo Description automatically generated] From: arrl-odv <arrl-odv-bounces@reflector.arrl.org> On Behalf Of Mike Ritz Sent: Monday, November 27, 2023 12:02 PM To: arrl-odv@reflector.arrl.org Subject: [arrl-odv:35362] Fwd: Icom "Dynamic Predistortion" Changes to IC-7610 Some positive news. (See below.) I’d like to think this is a result of ARRL’s CSI efforts! It does show that manufacturers are taking the effort seriously though, and that ARRL can make an impact in the technical space as a benefit for members. Lots of bad clicks and chirpy signals in the CW test last weekend, including one from EU that sounded like an old spark set! Hope everybody had a great Thanksgiving. 73; Mike W7VO Sent from my iPhone, utilizing a very tiny keyboard fed from very fat fingers Begin forwarded message: From: Mike Ritz <w7vo@comcast.net<mailto:w7vo@comcast.net>> Date: November 27, 2023 at 8:40:31 AM PST To: Alan Rovner <k7ar@comcast.net<mailto:k7ar@comcast.net>> Subject: Re: Icom "Dynamic Predistortion" Changes to IC-7610 Thanks, Al! Another ham sent me a note on this also. Icom is one of the JA manufacturers involved with the CSI. Ray Novak, N9JA is a committee member. I don’t know if this was a direct result of CSI, but I’d like to think so! This is exactly what we were hoping would happen. 73; Mike W7VO Sent from my iPhone, utilizing a very tiny keyboard fed from very fat fingers On Nov 27, 2023, at 8:14 AM, Alan Rovner <k7ar@comcast.net<mailto:k7ar@comcast.net>> wrote: Hi Mike I thought you might be interested this news as part of your Clean Signal Initiative. Icom has released new firmware for the IC-7610 that implements something called dynamic predistortion. As far as I can tell it generates a cleaner SSB signal when enabled. I'll include a photo below. While this is a good thing, it looks like it only works with their upcoming PW2 amplifier. There is ongoing discussion about whether non-Icom amps will be supported. Also this only applies to normal SSB voice signals. CW, RTTY, FT8 or other audio tone modes have no need for this feature. In order to use predistortion, you have to connect the 7610 to a dummy load and go through a calibration process for each band. In the photo below the blue graph represents energy without predistortiion and the pink graph shows a cleaner signal with predistortion. Notice the pink graph has less energy away from the center test tone. Thought you might be interested, 73, Al, K7AR <FLgMmPe5ca0PzGmI.png>
This is really nice to see. Pre-distortion is a common technique outside of ham radio and can hide nonlinearities in modern final amplifiers. Many of the PAs in small devices are amazingly efficient because they are nonlinear and corrected in this way. It will be particularly interesting to see what testing reveals about the improvements. On Nov 27, 2023, at 9:02 AM, Mike Ritz <w7vo@comcast.net> wrote: Some positive news. (See below.) I’d like to think this is a result of ARRL’s CSI efforts! It does show that manufacturers are taking the effort seriously though, and that ARRL can make an impact in the technical space as a benefit for members. Lots of bad clicks and chirpy signals in the CW test last weekend, including one from EU that sounded like an old spark set! Hope everybody had a great Thanksgiving. 73; Mike W7VO Sent from my iPhone, utilizing a very tiny keyboard fed from very fat fingers Begin forwarded message: From: Mike Ritz <w7vo@comcast.net> Date: November 27, 2023 at 8:40:31 AM PST To: Alan Rovner <k7ar@comcast.net> Subject: Re: Icom "Dynamic Predistortion" Changes to IC-7610 Thanks, Al! Another ham sent me a note on this also. Icom is one of the JA manufacturers involved with the CSI. Ray Novak, N9JA is a committee member. I don’t know if this was a direct result of CSI, but I’d like to think so! This is exactly what we were hoping would happen. 73; Mike W7VO Sent from my iPhone, utilizing a very tiny keyboard fed from very fat fingers On Nov 27, 2023, at 8:14 AM, Alan Rovner <k7ar@comcast.net> wrote: Hi Mike I thought you might be interested this news as part of your Clean Signal Initiative. Icom has released new firmware for the IC-7610 that implements something called dynamic predistortion. As far as I can tell it generates a cleaner SSB signal when enabled. I'll include a photo below. While this is a good thing, it looks like it only works with their upcoming PW2 amplifier. There is ongoing discussion about whether non-Icom amps will be supported. Also this only applies to normal SSB voice signals. CW, RTTY, FT8 or other audio tone modes have no need for this feature. In order to use predistortion, you have to connect the 7610 to a dummy load and go through a calibration process for each band. In the photo below the blue graph represents energy without predistortiion and the pink graph shows a cleaner signal with predistortion. Notice the pink graph has less energy away from the center test tone. Thought you might be interested, 73, Al, K7AR <FLgMmPe5ca0PzGmI.png> _______________________________________________ arrl-odv mailing list arrl-odv@reflector.arrl.org https://reflector.arrl.org/mailman/listinfo/arrl-odv -Kristen (K6WX) "Your eyes ... it's a day's work just looking into them" Laurie Anderson (--... ...-- -.. . -.- -.... .-- -..-)
This is great news. Adaptive pre-distortion was introduced for general amateur use by Dr. Warren Pratt, NR0V. His “Pure Signal” software works with PowerSDR and OpenSDR. Since 2013 all Anan transceivers have all been designed physically to work with this capability. The Flex PGXL and Elecraft KPA1500 amplifiers have a sampling port for this purpose and should also work with Icom rigs, assuming Icom does not have some non-standard requirement. The concept is to compare two signals and correct for transmit linearity. I don’t know anything about Icom’s implementation, but presumably ANY amplifier could be used with a sampling port, which is an evening project to build or can easily be purchased. I used a Wavenode watt meter with a RF sensor with sampling port (“RF View” option), for example, with an Anan 7000 and Alpha 9500. Back in 2013 Flex said that their Signature line (Flex 6300 – 6700) was designed to implement adaptive pre-distortion as soon as their software could be completed, but to this day it has not been “completed.” More recently Elecraft said the same wrt their K4. Looks like Icom beat them to it. I set out the need for and history of this effort back in 2015/2016 in two columns addressed to contesters in particular, see here if you are interested, especially the January 2016 column wrt Dr. Pratt’s explanation: CQ Contesting K3ZJ Dec 15 Jan 16<https://app.box.com/s/hxeoxo3d5q7saf6v18gewtwgq57r8rbd>. I don’t know if his presentation at the 2014 Friedrichshafen gathering is still available on the web, but it went into more detail than my brief summary. 73, Dave K3ZJ From: arrl-odv <arrl-odv-bounces@reflector.arrl.org> on behalf of Kristen McIntyre <kristen@alum.mit.edu> Date: Monday, November 27, 2023 at 4:14 PM To: Mike Ritz <w7vo@comcast.net> Cc: "arrl-odv@reflector.arrl.org" <arrl-odv@reflector.arrl.org> Subject: [arrl-odv:35366] Re: Icom "Dynamic Predistortion" Changes to IC-7610 This is really nice to see. Pre-distortion is a common technique outside of ham radio and can hide nonlinearities in modern final amplifiers. Many of the PAs in small devices are amazingly efficient because they are nonlinear and corrected in this way. It will be particularly interesting to see what testing reveals about the improvements. On Nov 27, 2023, at 9:02 AM, Mike Ritz <w7vo@comcast.net> wrote: Some positive news. (See below.) I’d like to think this is a result of ARRL’s CSI efforts! It does show that manufacturers are taking the effort seriously though, and that ARRL can make an impact in the technical space as a benefit for members. Lots of bad clicks and chirpy signals in the CW test last weekend, including one from EU that sounded like an old spark set! Hope everybody had a great Thanksgiving. 73; Mike W7VO Sent from my iPhone, utilizing a very tiny keyboard fed from very fat fingers Begin forwarded message: From: Mike Ritz <w7vo@comcast.net> Date: November 27, 2023 at 8:40:31 AM PST To: Alan Rovner <k7ar@comcast.net> Subject: Re: Icom "Dynamic Predistortion" Changes to IC-7610 Thanks, Al! Another ham sent me a note on this also. Icom is one of the JA manufacturers involved with the CSI. Ray Novak, N9JA is a committee member. I don’t know if this was a direct result of CSI, but I’d like to think so! This is exactly what we were hoping would happen. 73; Mike W7VO Sent from my iPhone, utilizing a very tiny keyboard fed from very fat fingers On Nov 27, 2023, at 8:14 AM, Alan Rovner <k7ar@comcast.net> wrote: Hi Mike I thought you might be interested this news as part of your Clean Signal Initiative. Icom has released new firmware for the IC-7610 that implements something called dynamic predistortion. As far as I can tell it generates a cleaner SSB signal when enabled. I'll include a photo below. While this is a good thing, it looks like it only works with their upcoming PW2 amplifier. There is ongoing discussion about whether non-Icom amps will be supported. Also this only applies to normal SSB voice signals. CW, RTTY, FT8 or other audio tone modes have no need for this feature. In order to use predistortion, you have to connect the 7610 to a dummy load and go through a calibration process for each band. In the photo below the blue graph represents energy without predistortiion and the pink graph shows a cleaner signal with predistortion. Notice the pink graph has less energy away from the center test tone. Thought you might be interested, 73, Al, K7AR <FLgMmPe5ca0PzGmI.png> _______________________________________________ arrl-odv mailing list arrl-odv@reflector.arrl.org https://reflector.arrl.org/mailman/listinfo/arrl-odv -Kristen (K6WX) "Your eyes ... it's a day's work just looking into them" Laurie Anderson (--... ...-- -.. . -.- -.... .-- -..-)
participants (5)
-
Boehner, James, N2ZZ (Dir, RK) -
david davidsiddall-law.com -
Famiglio, Bob, K3RF (Dir, AD) -
Kristen McIntyre -
Mike Ritz