Hi Gordon,
I bought quite a few (20) of the 10MHz crystals from Tayda, currently they are 10c each (perfect for experimenting with):
I spent quite a while going through them using a couple of different methods to sort them:
The first was using Ashhar Farhan's method as shown below:
specifically page 66:
The other method was the one from the following site:
specifically the 'Crystal parameters calculator' page:
I used these for my first Bitx20 and it works really well, I have listened (I just built the receive sections) to people from many different countries on it. When I built this receiver I did not have a spectrum analyser so I used an oscilloscope and RF generator to set up my circuits. Now I have a spectrum analyser I can look at my circuit blocks in great detail which is really interesting - I really like seeing how they all work and I can also tweak them until I am happy they are tuned exactly how I need them.
My other reason for creating this receiver (other than learning how to design each section from scratch) is learning how to use my new spectrum analyser to look at and adjust the individual circuit blocks (RF amplifiers, filters, mixers etc) - this is very interesting and I am really enjoying learning how it works.
I hope this helps,
Kerr
