TX Frequency

[sanramonrover]

I've read that there are two diferent freq's used, depending whether North America and Europe. The ones I've heard are 433MHz and 868MHz.

So from these two photos of TX units taken from the threads on this forum, it looks like the freq may be written on the PCB: and
.

Upon opening my own unit, a 265NC, I see this PCB:
.

Would this perhaps indicate the frequency for this unit is 1160MHz? The unit was bought in Canada through National Geographic.

I note that every photo of the PCB inside the transmitter is slightly different. Interesting, no?

[Super-T]

Long aerial is 433....short is 868. Higher frequency, shorter wavelength.
NZ is 433.

[sanramonrover]

So in the bottom photo, you can just see the tip of the aerial. Therefore it looks about the same length as the 868MHz photo.

Just wondered if the 1160 printed on the PCB had any significance.

[Super-T]

The 868 is shorter but not by half according to my measuring on the screen.
Wavelength for 433MHz is apparently 693 mm so 1/4 wave is 173 mm according to this site :- http://www.csgnetwork.com/freqwavelengthcalc.html.
868 would be 86.5mm for 1/4 wave
If anyone has a transmitter open, how about measuring the aerial length?

Wireless Buffs might want to confirm or deny the wavelength?

Dunno about 1160.

[beteljuice]

.... but if they kept the PCB track the same length for ease of manufacture, it would simply mean 1/4 or 1/2 wavelength aerial dependent upon the crytstal

[Charlie]

To add to the confusion, My National Geographic 265NC, bought in Canada, is clearly branded on the back of the receiver as 915 MHz. I have not looked at the board, since it's printed on the outside.

[wd40]

Here is what we have in the USA.