TFT 9107A frequency change

Gotta watch those Fresnel zones!
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pajkiwi
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Joined: Wed Nov 12, 2014 6:05 pm

TFT 9107A frequency change

Post by pajkiwi » Wed Nov 12, 2014 6:15 pm

Can anybody help with information regarding frequency changing a TFT 9107A receiver ? I do not have a manual. HELP

jammerdave
Posts: 112
Joined: Tue May 31, 2011 9:03 pm
Location: West Sacramento, CA

Re: TFT 9107A frequency change

Post by jammerdave » Thu Nov 13, 2014 10:25 am

Here's the sheet on doing it on a 9107B model, not sure of any differences.

http://www.tftinc.com/support/STL%20910 ... cedure.pdf

pajkiwi
Posts: 3
Joined: Wed Nov 12, 2014 6:05 pm

Re: TFT 9107A frequency change

Post by pajkiwi » Thu Nov 13, 2014 4:33 pm

Thanks Jammerdave

That information is useful, thanks for providing it. Still, I cannot figure out what the new DIP switch settings are and how they relate to the crystal oscillator currently at 102.4 MHz. We are trying to receive 851.5 MHz . If I could find a block diagram of how all of the 3 VCO's work together I might be crack the code. To my way of thinking, there should be pages in the manual that explain how this all works and how to calculate the settings. Trouble is , I cannot find a manual .

davek
Posts: 145
Joined: Sun Aug 02, 2009 7:28 pm
Location: Sydney, Australia

Re: TFT 9107A frequency change

Post by davek » Fri Nov 14, 2014 5:28 am

Is the info you need not in this document .. ?

http://www.tftinc.com/support/STL%20DIP ... ttings.pdf

pajkiwi
Posts: 3
Joined: Wed Nov 12, 2014 6:05 pm

Re: TFT 9107A frequency change

Post by pajkiwi » Sat Nov 15, 2014 4:39 pm

That document was useful, thanks , and It helped, but somehow I am still not getting the result I need. I must have misunderstood something.....

I feel that I am so close ... but ....not getting the right answer.


The information must be out there somewhere :(

TPT
Posts: 591
Joined: Mon Dec 03, 2007 3:18 pm
Location: St. Marys, WV

Re: TFT 9107A frequency change

Post by TPT » Sun Nov 16, 2014 9:04 am

Sort of simplistic--but I've run into this between different manufacturers.

The dip switches are used to create a short on certain pins on an IC, the binary coding determining the frequency. A binary "1" usually represent on open circuit (voltage) on the IC pin, a "0," then being no voltage or a ground connection.

Some folks consider that when a dip switch is "OFF," the connection is thus a binary "1," and then turning the switch on is a binary "0." So they make up their chart (for frequency changes) accordingly.
Other folks are more literal, hence "0" means the switch is "off," and "1" becomes "ON" (just like the logo on my monitor and a million other devices). So their chart is completely opposite.

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