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Alternative(s) to 200 Hz CW Filter
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I have another suggestion but it may not be doable. This comes out of all the things I love about the QCX and the one thing I don't like about it :-)
So it is not at all a cricitism but I'm just interested how most people feel about it and whether it would be in fact something that could be provided at ordering time, just like the BPF kits included, one could choose either 200Hz or 500Hz filter components, and while we're at it, choose the "zero-beat" frequency. For avid CW operators, to be honest, these are to me the only main downfalls of the QCX in terms of operating pleasure: -- inability to change the 700Hz offset and filter centre, if this could be chosen even at time of ordering with the corresponding component values so that a mod isn't needed, one chooses at build time. -- Likewise the inability to change to 200Hz filter, many CW ops like to have a wider bandwidth for a more natural sound and don't mind the additional QRM preferring the ears to do the filtering. Myself as a CW afficionado I'm quite OK even with 3000Hz, provided there is no AGC to wipe out weaker signals. Again, choosing this at time of kit, e.g. 200Hz, 500Hz, 1kHz, 2.3kHz for example, would be really nice. I know these are things that can be modded, and plan to get around to doing so, but for those who are less comfortable modifying things they build via a fool-proof manual, such as myself... -- Love 30m and CW? http://www.30cw.net
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By the way for those not having a QCX and thinking of it, the 200Hz filter has no ringing exactly as claimed, and signals just boom in the sensitivity is amazing. Would I like wide filter options? Yes for some bands, but don't let the narrow filter put you off. Certainly makes it easier for CW beginners or those more easily distracted and for /P operations. So far it has prevented me listening to only one Chinese commerical ship-shore station that has a huge 2kHz wide chirp, a joy to listen too, but not possible in 200Hz filter :-D
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On 17 Jul 2021, at 09:28, VK5EEE <vk5eee@vkcw.net> wrote:
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I don't understand your point here. The 700Hz offset is changed via the sidetone frequency in the menu. The filter is easily re-scalable for bandwidth and center frequency. There is even documentation on the QRPLabs website explaining how to do this. There are spreadsheets available to calculate the filter components that are readily available. I did this myself on all my builds because I prefer 550Hz for the center frequency. The only real drawback to that is that the internal goertzel filter used for alignment and CW decoding is fixed in the firmware for 700 Hz but you can still do an alignment though the alignment peaking numbers are generally lower and you have to crank the gain more. Hans has a request on the back burner to make the goertzel filter coefficients change along with the menu item for sidetone frequency but it is a challenge due to being out of resources on the processor. I wouldn't be surprised if the man eventually finds a way to make it happen too.
Joe
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Yes thanks Joe
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I guess it is the convenience of ordering the kit with the components, than having to source them seperately, I'm not thinking here of those who are really good at this stuff but those of us who are LIDS when it comes to electronics and even components, hence the ease with which to order a QCX kit already all parts are there and an incredible manual where even us electronics LIDS can't go wrong. But yes it is something we can eventually order the parts and modify. Just nice if it could be ordered the same way we order a particular band. But we can't have everything! Just wondering if those of us wanting wider filter are really such a minority. 77 de Lou
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Love 30m and CW? http://www.30cw.net
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Oh, sorry I didn't understand you post that way. I get it now. Maybe, but might be a kitting headache for somebody?
Joe
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Yes indeed it must be hard enough already to make sure all the right pieces are in there!
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-- Love 30m and CW? http://www.30cw.net
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Mont Pierce KM6WT
On Sat, Jul 17, 2021 at 02:46 AM, VK5EEE wrote:
By the way for those not having a QCX and thinking of it, the 200Hz filter has no ringing exactly as claimed, and signals just boom in the sensitivity is amazing.I agree. QCX is a great radio, and an exceptional value for the price tag, which I'm sure has allowed many many hams the joy of building and operating. Thanks Hans !! There have been some in the group that have played around with component values for wider cw filter width. I wonder if their findings, ( and/or your thoughts Hans ) could be compiled into a QCX Mods document and added to the QCX webpage? Just a thought... :) OH, WAIT... On the QCX Classic, there is a link for QCX Mods, click here to see mod to move the cw filter center frequency. It does not (yet) have a section though on how to modify the cw filter width... Note: This webpage has a number of mods for the QCX Classic, which Hans has incorporated into the QCX+ and Mini. And, with QCX-mini, the filter width mod mentioned above will require ability to rework SMDs. 73 km6wt
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Arv Evans <arvid.evans@...>
Making major changes after the design has been stabilized for several years may be contrary to what most other users would like. It would make it necessary to differentiate which model and which software load you have when talking about problems or modifications. Hans is presently working very intently on the QSX product. Having him go back to redesign older products would possibly take time away from his work on this next product. Arv _._
On Sat, Jul 17, 2021 at 3:29 AM VK5EEE <vk5eee@...> wrote: I have another suggestion but it may not be doable. This comes out of all the things I love about the QCX and the one thing I don't like about it :-)
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Yes very good points indeed, and I see of course (as I should have) that with the mini much of it is SMD resistors so no easy thing, I'd say scrap this idea!
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For the larger QCX we can do those mods if we need/want.
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Love 30m and CW? http://www.30cw.net
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Arv Evans <arvid.evans@...>
Those wanting a wider filter may very well be in the minority...because this is a CW rig and most CW signals are fairly narrow. _._
On Sat, Jul 17, 2021 at 6:19 AM VK5EEE <vk5eee@...> wrote:
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Curt wb8yyy
Before calling it a 200 or 300 Hz filter, examine the response it detail using an audio spectrum analysis program. It's the overall shape that matters not one number. Compare its response to a filter you prefer in another rig. While being sharp near the top, its skirts may already be wider. It sounds and works to me as is.
Curt
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Yes, I realise that, but old style CW ops we are used to wide band RX and doing ALL the filtering in our ears/brain, it is only in the modern era that people started to believe that CW should be heard only one conversation at a time(*), and without any other signals to be heard. For us old style OPs to be honest, it is very boring to listen to CW at the same pitch in a narrow filter. Bring back chirp, drift, and 3kHz or even 10kHz wide audio and the days of 500kHz.
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Love 30m and CW? http://www.30cw.net
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Measuring it with my ears I call it 200Hz because that is the range within which the volume does not appear reduced, it is usable for many signals to 300 Hz. But of course you are right. And it does work fine as it is. It's just when one does a LOT of CW, and I've had non-stop QSOs lasting 6 hours or more with only short toilet breaks, it is nice to be able to vary pitch and bandwidth, of course this is what the big rigs are for, and we have the most value-for-money compact rig with the QCX. I realised from replies and the mini design, that this is not practical, but it would be nice in a QSX and I suspect this will be there.
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-- Love 30m and CW? http://www.30cw.net
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Arv Evans <arvid.evans@...>
I have to disagree. Older receivers had an internal crystal filter (usually a phasing type) that was used to reject unwanted signal frequencies. Older integrated transmitter-receivers (Collins, etc.) included IF based crystal filters for CW. Many of us poor folk added Heathkit Q-multipliers to our cheaper receivers in order to get very narrow IF passband. Others added audio filters for narrow CW reception. Arv K7HKL _._
On Sat, Jul 17, 2021 at 10:36 AM VK5EEE <vk5eee@...> wrote:
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Dave VE3GSO
Exactly! Let us not forget the 88mH toroids bought at Dayton in the cardboard packs that we turned into all manner of filters. Talk about clunky!
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Dave
On Jul 17, 2021, at 12:43, Arv Evans <arvid.evans@...> wrote:
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So you’re saying you’re looking for a Swan Three-Drifty? ;>)
Mike WM4B
From: QRPLabs@groups.io [mailto:QRPLabs@groups.io] On Behalf Of VK5EEE
Sent: Saturday, July 17, 2021 12:36 PM To: QRPLabs@groups.io Subject: Re: [QRPLabs] Alternative(s) to 200 Hz CW Filter
Yes, I realise that, but old style CW ops we are used to wide band RX and doing ALL the filtering in our ears/brain, it is only in the modern era that people started to believe that CW should be heard only one conversation at a time(*), and without any other signals to be heard. For us old style OPs to be honest, it is very boring to listen to CW at the same pitch in a narrow filter. Bring back chirp, drift, and 3kHz or even 10kHz wide audio and the days of 500kHz.
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On Sat, Jul 17, 2021 at 05:53 PM, Dave VE3GSO wrote:
Exactly! Let us not forget the 88mH toroids bought at Dayton in the cardboard packs that we turned into all manner of filters.I still have a 4 x 88mh passive audio filter here, and it works superbly. I never used any of the published circuits, it was just my own design but it easily achieves a 40Hz bandwidth with no ringing. I wonder if these coils are still use the telecoms people these days ? A few years ago I did come across a company still making them, (more like 10 years, time flies so fast these days!) in the US, but I wouldn't know if they would be prepared to sell some for hobbyist use. Of course, all this bulk is now only some lines of code in a DSP filter these days ;-)
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On Sat, Jul 17, 2021 at 06:08 PM, Jesus Christ on Toast wrote:
A few years ago I did come across a company still making them, (more like 10 years, time flies so fast these days!)88mh coils Found them.. https://www.charlesindustries.com/product/load-coils-line-conditioning-devices/
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Dave VE3GSO
Note that those coils are encapsulated and would be difficult to impossible for the home hobbiest to reuse or disassemble for other uses. Not progress, IMHO.
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Dave
On Jul 17, 2021, at 13:26, Jesus Christ on Toast via groups.io <andyfoad@...> wrote:
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R. Tyson
Hans already supplies an amazing product at a very good price. How is he supposed to stock an extra range of components in order to facilitate probably a miniscule demand. He would then have to ensure that his pickers/packers catered for the odd individual who didn't want the standard components. Not very feasible or reasonable is it ? To keep costs down components are bought in bulk. Is he expected to make bulk orders, and store them, for components that will seldom be asked for ?
Instead of trying to make the packing of kits far more difficult and time consuming it makes more sense for those who want to differ from the standard kit to sort it out themselves. It is easy enough to buy components. Thousands of kits are picked and packed and then the whole process is supposed to stop and pick the different parts for someone's whim. The kit is there, it builds into a brilliant product and is what the majority want. It has also been pointed out, many, many times that there is no capacity left for adding to the programming but still people come up with the request to add things they personally would like. Accept it as it is or go modify it yourself but don't expect to complicate the process of producing these remarkable radios because it doesn't quite do what you would like. Reg G4NFR
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