After the debate on the proper capacitor values, some of it caused by my manual and the original schematic calling for 68pfd, I decided to look at the 2 boards I have built and run some tests. Upon examination, I found that 1 board had 33pfd as recommended by Sunil and silk screened on the board, and 1 board with 47pfd capacitors.
A physical look at the cores told me that the 33pfds had far more tuning range than the 47pfds and the 68pfd as called for in my manual probably wouldn't tune properly. ( I will change the manual).
First, the 33pfd picture Quite a bit of tuning range. They are towards the top of the can though.
Next the 47pfd. These are almost topped out in the can. The 68pfds would quite likely not be able to tune.
Next, lets test the filter.
This is a 10MHz sweep from 10MHz to 20MHz. We have an insertion loss of about -4db. Lets increase the frequency resolution.
This is a 3MHz sweep centered on 14.260MHz.
Both boards tuned similarly. 47pfd could be used but the 33pfd gives a wider tuning range.