lowpasstwo

My Feedback: (127)

Danny:

The JR "grey cap" FM receiver xtals have "three small circles" on the label with one typically "filled" in.

What does this indicate? Does this affect interchangeability or
compatibility receiver to receiver?

thanks,

Terry

dsnyder

The dots indicate where the crystal is cut in relationship to the frequency listed. It is general policy to avoid having opposite dots, that meaning to not have the transmitter crystal with a dot on the left and the receiver crystal from having a dot on the right. With todays level of tuning however it makes very little difference in performance.

sfaust

My Feedback: (11)

What does it indicate in terms of shift. For example, how far off are two crystals if one dot is on the right, and the other crystal has a dot off on the left? Basically, what is the resolution that the dots signify?

Thanks

dsnyder

It has to do with the crystal cut being slightly to the right or to the left of the exact frequency when viewed on a scope. The difference is very minor in the amount of deviation, but it is a way the JR allows users to have the best possible link for extreme conditions and applications. Today it makes very little difference.

sfaust

My Feedback: (11)

I realized that it had to do with the cut being off just a little. I was wondering more if you know what off a little meant in terms of a number. Its easier to compare the differences if a number is specificed, rather than something less descriptive as 'just a little'

Do you know how far off a crystal needs to be off center before it gets the left or right dot? If not, could you ask around? Thanks.

dsnyder

I don't have specific numbers that I can provide.

sfaust

My Feedback: (11)