Sync detection

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Re: Sync detection

Postby Klaas Robers » Sat Mar 04, 2017 9:13 pm

Harry, you should make the vertical scan somewhat larger, resistor lower or the potentiometer in the oscillator called "size". You might need to change the vertical position as well, that is the circuit going to -12 V. Then the circle becomes a real circle, which it should be. But I can imagine that you are happy because at least you can see things.

I also saw that the definition lines are fine and the grey blocks are all visible. Well done.

As you might know, there are two standards, a 50 Hz standard with line frequency 16 2/3 Hz (50 / 3) and an 60 Hz standard with a line frequency of 15 Hz (60/4). This is because som hum in the deflection is unavoidable. If you get SSTV from the other standard you have to readjust the scanning speeds. This is something you might want at the front panel. I coupled both, so this became a kind of "picture size" control. The oscillators should have a provision for that, which I designed in from the beginning.
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Re: Sync detection

Postby Harry Dalek » Sat Mar 04, 2017 10:58 pm

Klaas Robers wrote:Harry, you should make the vertical scan somewhat larger, resistor lower or the potentiometer in the oscillator called "size". You might need to change the vertical position as well, that is the circuit going to -12 V. Then the circle becomes a real circle, which it should be. But I can imagine that you are happy because at least you can see things.


Hi Klass Yes i tried today to do this but i think adjusting the sawtooth oscillator my size control is not as responsive i will have readjust the yoke coil resistor ...oh i am very happy with the monitor more little tweaking which is ok good to learn .

I also saw that the definition lines are fine and the gray blocks are all visible. Well done.


Thanks there lucky i am ok at copying and following instructions :wink: ...i think to the eye more so it gives pretty good results i can see why it took off as a hobby 50 or so years ago .

As you might know, there are two standards, a 50 Hz standard with line frequency 16 2/3 Hz (50 / 3) and an 60 Hz standard with a line frequency of 15 Hz (60/4). This is because som hum in the deflection is unavoidable. If you get SSTV from the other standard you have to readjust the scanning speeds. This is something you might want at the front panel. I coupled both, so this became a kind of "picture size" control. The oscillators should have a provision for that, which I designed in from the beginning.


OH yes i forgot about this that is a very good reason for a panel control for that ...I have a shareware version of the old dos Mscan that has original 7.2 sec and 8 sec transmit to test this out ..i really don't have any thing else that does the original standards to test the monitor apart from yours and Steves wav file posts .
I will work on the size control for the vertical the Horizontal might need tweaking again as well but its position control still works ,might not have to much time tomorrow perhaps in the afternoon with luck .
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Re: Sync detection

Postby Harry Dalek » Sun Mar 05, 2017 9:29 am

I lowered the vertical deflection yoke resistor a touch which gives a longer scan to adjust the aspect ratio trying for a square i think i am a touch long now ...did a few more display test runs this morning not as much light so better to take video.have to get my ruler out !

youtu.be/H867h2zZbJI

youtu.be/lyRVHplMEUg

youtu.be/46h5UJIRHJ0
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: Sync detection

Postby Klaas Robers » Sun Mar 05, 2017 7:37 pm

Harry, if you watch the testbeeld, then you see that the line sync is not always correct. This has to do with the setting of the potentiometer in the sync separator. May be also that it is wise to make the 1M resistor higher, 2M2 or even 4M7. That makes the hysteresis smaller. But the setting of the potentiometer is important and should be done carefully. It is one of the many controls that I have on my front panel and it is called "SYNC LEVEL". Sometimes it needs a small adjustment.
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Re: Sync detection

Postby Harry Dalek » Sun Mar 05, 2017 8:18 pm

Klaas Robers wrote:Harry, if you watch the testbeeld, then you see that the line sync is not always correct. This has to do with the setting of the potentiometer in the sync separator. May be also that it is wise to make the 1M resistor higher, 2M2 or even 4M7. That makes the hysteresis smaller. But the setting of the potentiometer is important and should be done carefully. It is one of the many controls that I have on my front panel and it is called "SYNC LEVEL". Sometimes it needs a small adjustment.


I noticed the sync trimmer is critical i will take your advice and upgrade the trimmer to a perhaps a pot ..and increase the 1m resistor to something higher ...good advice for sure ...if you needed or wanted one i will follow...!
I did readjust it today but the tests below are not classic standard they are robot vis coded so manual vertical start only when using this on my monitor just a bit of interest to see what would happen with the mixw3.1 and croma pix programs with this monitor .

youtu.be/Q7-b2q_cYmU

youtu.be/R_TQtZyQWpY
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: Sync detection

Postby Klaas Robers » Sun Mar 05, 2017 9:34 pm

Remarkable that these pictures are narrower than the testbeeld. However there are quite some strange standards out there.

What I mis Harry, is the sound. It is not uncommon to have an audio amplifier to the input signal, a set of computer speakers will do, so you can listen with the SSTV sound. Normally I could hear the differences in 16,6 Hz and 15 Hz signals. It is the repetition of the lines that you hear. In my Heathkit-like monitor I also built in a loudspeaker and a small amplifier.
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Re: Sync detection

Postby Harry Dalek » Sun Mar 05, 2017 10:52 pm

Klaas Robers wrote:Remarkable that these pictures are narrower than the testbeeld. However there are quite some strange standards out there.

Some pictures don't fill the transmit screen i suppose has to do with image size ,,,,i would rather a classic standard program and makes me wonder why i was ignored by most making these programs least i can sync to the horizontal with the window versions .
When i made my first SSTV i only had a cassette tape to sync to lucky for me it was in the correct standard ...

What I mis Harry, is the sound. It is not uncommon to have an audio amplifier to the input signal, a set of computer speakers will do, so you can listen with the SSTV sound. Normally I could hear the differences in 16,6 Hz and 15 Hz signals. It is the repetition of the lines that you hear. In my Heathkit-like monitor I also built in a loudspeaker and a small amplifier.


I was just looking at it in Andrews posts talking about the screen cover and i was looking at your control panel ...a speaker and even a speaker with volume control would not be to hard to add again i will take this on and add it to my monitor ...have to work tomorrow so may not have time to do this but i will some time this week .
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: Sync detection

Postby Harry Dalek » Mon Mar 06, 2017 9:16 pm

I added a little speaker Klass i didn't have time tonight to do more but i will work on those changes to the sync circuit you mentioned a few posts back ...

youtu.be/Oco4MwsFHnQ
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: Sync detection

Postby Klaas Robers » Tue Mar 07, 2017 4:28 am

Yes, this is the kind of sound that I am used of for SSTV. You will see that you are soon familiarized with it.

Good luck with the extensions you are making.
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Re: Sync detection

Postby Harry Dalek » Tue Mar 07, 2017 6:56 pm

Klaas Robers wrote:Yes, this is the kind of sound that I am used of for SSTV. You will see that you are soon familiarized with it.

Good luck with the extensions you are making.


Hello Klass

I had some time this afternoon so the 10k pot is a panel control now and the indicator changed the 1m resistor the sync circuit for a 4.7m after all that i was using your testcard but i forgot to film it /// :roll: got to testing those programs to see if they still worked with the changes .
Old trimmer replaced by that plug socket from an old vcr circuit board ...they come in handy for cabling pots to a circuit board neat .
i will redo test a bit later .

youtu.be/NsAcLGJiauM
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The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: Sync detection

Postby Harry Dalek » Thu Mar 09, 2017 7:33 pm

Only light changes today panel mounted the contrast control and changed the focus to a trimmer i don't want that on the panel .
Trying to neaten up the wiring so i can mount the boards ...as in the last video edited into these tests today .

youtu.be/mhZE9PPb2Mw
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Harry Dalek
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Re: Sync detection

Postby Harry Dalek » Thu Mar 09, 2017 7:37 pm

Only light change today panel mounted the contrast control changed changed the focus to a trimmer i don't want that on the panel .
Trying to neaten up the wiring so i can mount the boards .

youtu.be/mhZE9PPb2Mw
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Harry Dalek
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