Is there a narrower filtering going on in CW?? 2.4 kHz won't be good

No.

https://www.sotabeams.co.uk/dual-bandwidth-filter-modules-ssb-cw/

I am just trying out a variable bandwidth filter from sota-beams.

I am not sure if the drive level from the preamplifier taken directly? from the audio gain pot will be enough to drive this or if it will need to be fed from the audio output socket. Gain can be pre-set between 1 or 4.

It will run off 5V to 14V so not sure whether or not to run this from a mini buck converter or directly off the 12V supply.

If anyone has got one of these dual band or vari-filters up and running I would like to know how you got on. I will update you when I have tried out a few ideas. Derek G4VWI.

The filter from qrp guys works nicely. Can also give you some adjustable ?gain so you don’t drive the Tda2822 too high.
--
72 and God bless
KD4EPG

Derek :?

Regarding the SOTABEAMS DSP filters.

I have a couple of the dual-bandwith ones. The General filter (2.5Khz/300 Hz) is installed in my BITX40
and the CW filter (1khz/300Hz)? in my uBITX. Both are working very well. To others looking for a CW filter solution you, would be very hard
pressed to find an audio filter that works better than this, especially at this price. Performance far exceeds any analog audio filter I have ever used.

https://www.sotabeams.co.uk/audio-filters-and-more/

On the uBITX I removed the yellow wire from the AF Gain pot and connected that to the input of the filter. The output of the filter
is connected? back to the pot where the yellow wire was, via a series 0.1 uF capacitor (this is to isolate DC voltage present on the filter output).?
What I ended up doing in the end is using a?3PDT switch to switch the filter in and out and a separate SPST switch to toggle between WIDE/NARROW bandwidth.
The three poles on 3PDT are used to switch the filter input, filter output and supply voltage to the filter. BTW the filter is powered from 12V
via a small power-line filter (two 220uF electrolytic caps to ground with a series 12 Ohm resistor between them) to prevent any "garbage"
from getting back into the 12V supply (this is a precaution).??

You will want to install the signal LED as that makes a great tuning indicator. It will flash?on and off with the CW signal when a station
is tuned in close to the center of the filter bandwidth.?


By grounding RB12 on the filter board you can increase the filter gain. This doesn't actually increase the output of the filter, it decreases the
minimum signal required to?get full output from the filter. You might want to play with this to see which you prefer. I went with grounding it, as that allows a lower
setting of the AF Gain control when the filter is engaged and it sounded a lot better to me. This could be wired to yet another SPST switch?
to make it selectable.? It might be desirable to be able to unground RB12 to reduce the internal filter gain on very strong signals.?
I
don't have my uBITX in a permanent enclosure yet so I haven't decided if I will use a switch for RB12.?

Best of luck and let us know how you make out.?

Michael VE3WMB?

P.S. With a "brick-wall" audio filter like the SOTABEAMS DSP,? it is IMHO actually desirable to not have AGC or at least be able to turn AGC off.
Without AGC you don't get "AGC pumping" caused by a strong adjacent signal within the IF filter passband, but outside of the AF filter?
passband.?I have actually used my BITX40 in a few casual contests on CW and it works amazing well with the filter in the 300hz position.?

Farhan gives a hint on the uBitx description to consider adding a second crystal filter at a lower IF. It would involve retuning the bfo and selecting it. I would imagine its been done by someone. 73 curt

Gilles?

MY ubitx is also a V3.

Don't forget the coupling capacitor on the filter output.. I had some very strange behavior in the audio of my Bitx 40 until I figured out that the output of the filter was Dc coupled.

Cheers?
Michael VE3WMB

Please do not answer as if this is a troll.

Why is it that people buy a simple and low cost SSB radio that can do CW with only
one filter and then complain about?CW performance???

It seems inconsistant that if one desires CW a radio optimized for that would be the goal.
I'd like a serious answer please.??

Allison

Allison, I refer to it as the Walmart syndrome. Some people expect more than what they are paying for and then complain when they get what they pay for. Next they want to return it because it doesn't live up to something 5 times the price even when they can see it's specifications before they buy it. I see it every day working in retail. Flame suit on, off soap box.

Roxie -- K1AUS

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Hi Allison,

And why do they buy a ten watt radio and then push it hard into a corner to get it to 15 watts? It makes no difference whatsoever at the distant receiver (where it counts) but shortens rig life and most likely generates all kinds of ill mannered splatter.

Once upon a time I had a Ten Tec Argonaut 509. That fine radio (I'm sorry I let it go) had an SSB bandwidth crystal filter. No CW bandwidth filter of any kind in the I.F. chain. just like the uBitx. It relied on an active filter for it's CW selectivity and it worked very well. So now we all know what we have to do for CW selectivity with our uBitx boxes:) I have NEScaf audio filter that I will be using on CW.

Today I will be installing a pot to adjust the sidetone level and probably installing the CEC software in my own radio. I will also be using low pass filters, one for each band, external to the radio and doing business on the CW bands. Digital comes later. See you on the air uBitx style.

73,

Bill KU8H

--
bark less - wag more

Howard,

It is rhetorical to a point and its also a chance to ask first hand.?

Hey you bought this and then...?

I know I'm probing human nature maybe but its of interest to my inner engineer
who asks how do we fix this?? As we first have to understand what the problem is.

Part of me says build a SSB only radio and sell it as such and watch the fur fly.
I bet a penny the first is can it do CW and the second is can it do FT8.

I say that as I've already seen how to I do hook up PSK31 with a Rockmite!

Allison

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W2CTX,

Well maybe CEC firmware needs to be fixed, or maybe it has and you need a newer version.?
To me that is a legit issue that needs attention and can be fixed.

What is funny to me in AOs are not new, I remember '50s articles and comments in CQ and
QST about them.? The number of SSB? radios with CW are too numerous to list and many
of them are far worse.? Try CW on a HW101 without the CW filter, then with.? Its then you
realize it keys terribly.? ?;)

Switchable or adjustable filters were a big deal and you could have them at significant cost
or the price of a radio that offered that.? I think its forgotten.

Then again I got to know a lot of old time CW ops that used what ever they had and?
Ran nets and QSOs in what sounded like beeping soup.? They could even recognize
a particular fist!? Skill and knowledge.

Allison

I think a lot of the problem stems from the uBitx being perceived as a cheap multi-band SSB/CW radio that is mostly ready to install and use out of the box.? In essence, most people don't perceive it as an experimental kit radio, despite strong evidence to the contrary, but rather see it (wrongly) as a? much more finished product than it is.?

I also know that many purchases in today's world are impulse buys, and people that buy on impulse rarely research things before hand, much less pay attention to specs.?

Perception and impulse buying are hard things to deal with in a practical way, especially when nearly all of today's advertising tries to get you to buy on impulse. :(

73,

Carl, K0MWC