Monochrome wrote:Hi Harry,
Thanks for the reply and also for the additional youtube links, it seems kargaroc386 had been quite busy experimenting with recording video on cassette.
Yes he also did a bit of 64 line as well but as with 128 used he's own software /
Re the PXL2000, I have one here though I have only ever fired it up briefly. The drive belts had perished due to old age and need replacement but otherwise its fully functional and just waiting for me to fit the new belts. I dont think the PXL was ever released here in the UK but a few turn up on ebay from people who brought them back from the USA which is how mine turned-up. I really must get around to restoring full operation of the PXL.
Reading the labguy's report on these even a broken one is still very collectible ,yes you should get it going its an interesting little gadget ..not many things video camera wise go up in price with time .
I got the PXL hoping it would help me understand how they managed to record the video signal and FM sub-carrier to cassete tape so well and more than anything I wanted to see what was "special" about the heads and tape transport mechanism. In my own 32 line NBTV cassette recording experiments I ran the tape at 10 times normal speed (about 20 ips) and used an FM sub-carrier but I could only get it to work with very small deviation (NBFM) with noisy results though the video response was quite good.
I like your idea on the 10 times speed for recording play back that should of given you more bandwidth ,i would of like to have seen it in action !
In the early 90s i used to record noaa and meteor weather satellites on audio tape . The signal is an analog signal consisting of an amplitude-modulated 2400-Hz subcarrier frequency modulating the RF carrier.
Now due to trying to record this unassisted to tape the frequency changes so play back its way off sync ,i used a Pll to fix this on play back to pc ,i still have the gadget it used to also lock on the the 2400hz signal and switch the recorder on and switch it off when the satellite signal was out of range ..
I would think NBTV would have syncing problems as well on audio tape that 400hz sync would be off frequency around a bit depending on how well the play back speed is kept perhaps another way would be control of the motor speed with a Pll .
It all depends on the quality of the machine ,a vcr used as a sound recorder should work its already made for correct motor speed control .
BTW i read also the PXl used a high quality type of audio tape which helped with the band width ...
Thanks for pointing me to the new generation NBTV software which looks exciting,
Yes its very useful you could make your own system if you liked ..the big problem with this is playback unless you use some thing that is standard in the NBTV viewers out there you have to make a monitor ,a scope tv would be easiest ,i wanted to make my own monitor but .
viewtopic.php?f=15&t=2481&hilit=scope+tv I have downloaded the most recent package and look forward to trying it out. BTW your new CRT monitor, does it use electrostatic or magnetic deflection? Just curious.
Thanks again
73,s
Des.
It will just do photos i think ? if so i should try a animated gif and see if i can cheat but yes its easy when you know read my posts in that link to the software as you have to press the default and set format buttons before hitting the start button but once you work that out its easy and you will start changing the other settings.
The monitor idea started out as a electrostatic (The devil A for Andrew) that seems to work fine to 64 line ...and it has sent me on a road project journey as you see in this construction diary !
viewforum.php?f=31Reading Steve Anderson's advice when he tried 72 line that these small crts can't have a fine enough raster spot for higher line rates so i scrapped 625 line small magnetic crt i have called (The Thylacine) and i am reverse engineering the CRT for a higher line NBTV rates or at least 128 line ...it is also a journey ! it stated out to just be a view finder for the PMT camera so i didn't have to sync it it would be a slave to the camera you will see in the construction diary ....
Now i want to make it also a stand alone medium definition tv monitor and perhaps the higher standards depending on if i have the skills to do that ..so far only displayed very out of sync 32 line as a quick test,i have constructed circuits to sync it now should do 64 and 128 line ...
viewtopic.php?f=10&t=2432viewtopic.php?f=15&t=2436
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.