ottavio said:
I still haven't decided if I want to start with a straight key or a paddle or something in the middle (sideswiper/cootie, bug). This will be the topic of maybe a further thread.
I know there are capacitive paddle keys. Is there a kind of "quiet" straight key? I'd have to practice in shared environment and I don't want to upset other people or attract attention. Or can it be homebrewed?
This might end up being an epic post!
The 'noise' from straight keys is created or propagated by three things I would say.
1) Contact noise (the clicking and clanking of the front and rear contacts closing).
2) Mechanical amplification of those noises caused by the material/s and design of the keys' frame and base.
3) Further mechanical amplification caused by the 'sounds' from the key itself being transmitted through the table or desk etc. that the key is mounted on.
The noisiest keys tend to have hollow plastic bases or bases made from wood, which are in turn in direct contact with the table surface beneath. Also, some of the larger straight keys produce noise because of the weight or mass of the arm being suddenly stopped by hitting the fixed contact.
So based on the above quiet straight keys tend to have lightweight arms, with maybe a solid metal base, which is in turn placed on a soft, sound absorbing mat (some of the thicker foam mouse mats are great for this and cheap too).
The old telegraph keys from the late 1800's are OK, as are the modern equivalent (like the Altai High Speed Key). Others would include Junkers Morse keys (these have a quiet clonk sound to them with their cover closed, but if you open the cover or remove it completely they are surprisingly quiet).
The RAF-D keys are quiet if you use a small gap, and also place them on a mouse pad.
A lot of the miniature military keys from Russia and Serbia etc, are quiet, as are a lot of the military keys. Many of the leg mounted keys are quiet because they are small, and because you leg will not amplify the sound like a table would!
If you want a really modern quiet straight key then the Palm Radio straight key is quiet, but they are no longer made so you need to look for second hand ones. Essentially they are modern equivalents of the miniature military keys, but more expensive generally.
A miniature military key can be obtained for maybe £10-£20, whereas the Palm Radio one will cost perhaps £100-£150...
With pretty well all of the straight keys, if you use them with a very tiny gap, they will be quiet.
The cheaper ones have thin pressed metal arms, and you can use that to your advantage. They allow you to close the gap right down until it is permanently closed, then you increase the tension which causes the arm to bend back up and reopen the contact. Used like that the back contact will never move, and you are in effect turning the key in to a torsion suspension one instead of its original pivoted action. So instead of the arm rocking back and forth it is instead flexing or bending when you apply pressure.
You mentioned touch paddles, well you can use those as straight keys by tipping them on their side and just using the dit or dah output trigger. I've also used mine with the paddles as they should be, and just 'pressed' sideways instead of downwards for straight keying.
There are a lot of designs on the web for 'moisture detectors', and these can be adapted to produce a touch sensitive straight key (actually a touch sensitive pad area), so that again can give you a totally silent 'key'.
https://www.google.co.uk/search?q=moisture+detector+circuit&source=lnms&tbm=isch&sa=X&ved=2ahUKEwih0cXsruzsAhVOQEEAHZPbA-4Q_AUoAXoECAwQAw&biw=1366&bih=626
For the keyed area you can use some Vero (matrix) board, and wire alternate tracks together. This allows you to make a contact 'pad' pretty well any size or shape you wish. Two wires from that to one of the above moisture/rain detectors, and you have a touch straight 'key'.
73, Mark...
