The side mounted loop stub Q202s had different loops based on frequency and spacings for a given a given isolation. Most cavities were designed for 0.6dB Insertion Loss so 4 cans produced 1.5dB or less per side. You could distort it to change the insertion loss.
You can rotate the loops on the top mounted cans for both the stub and capacitor types of Q cavities to change the insertion loss and notch depth but you should have the proper test equipment to see the effects of those changes. Distorting the loop will also affect the can's insertion loss and notch depth and locations. Opening up the loop to have more area inside or rotating the loop so that it becomes more in line with the radial line out from the center gives the cavity less insertion loss but when the notch is adjusted for the desired separation, the notch depth is less and it becomes narrower. The notch might not come in close enough either. Conversely, if the loop is squished smaller or rotated away from the radial line, the insertion loss increases at the pass frequency and the notches move closer to the pass. Adjusting the notch to the desired spacing will produce a deeper wider notch than before. Doing this to a duplexer, improves the midband isolation between the TX and RX ports. Note, when a loop is rotated or distorted, the pass frequency of the cavity will move and will have to be adjusted before adjusting the notch frequency. You should not distort the loop of a loop with a capacitor since they are extremely fragile and will break if there is force applied. Also, soldering the loop on the capacitors is tricky as well and must be done quickly and so that it doesn't unsolder apart. Harold --- In [email protected], "Paul Holm" <[EMAIL PROTECTED]> wrote: > > Does this mean that this vintage of the Q-202G's are only capable of working > at one insertion loss point for any given offset? > > 73 Paul > > > ----- Original Message ----- > > From: "Harold Farrenkopf" > > > Rotating the loop would change the insertion loss and the pass to > > reject spacing. > > > Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
