Harold, I used 2 cans in my initial post for simplicity. What I'm working on is a 2037, 3 pass and one notch and I need 3 dB, so 1 dB per can. I'm not moving them very far from the original setup, but I want to verify the IL. Is there a published chart for these settings?
Indeed, still in VY0 land... lh On Wed, Apr 21, 2010 at 7:54 PM, hfarrenkopf <[email protected]> wrote: > > > Just looked up the settings in my files. 9dB notch at 160MHz produces > 1.4dB. 11 to 11.5 will produce your desired 0.9dB Insertion Loss. > 14 to 15 dB produces the 0.40dB IL. > > The cable adds 0.2dB. The settings of 2 cans from Sinclair are typically > 1.0, 2.0 or 3.0dB. > > Larry, are you still up in Iqaluit? > > Harold, VA3HF > > > --- In [email protected]<Repeater-Builder%40yahoogroups.com>, > "hfarrenkopf" <hfarrenk...@...> wrote: > > > > No, using a T connector on the loop, you have a notch cavity although it > is a non symmetrical notch - doesn't matter. You adjust the loop for a notch > depth of say 9dB using the T one loop at a time and that balances the > impedances of the loops in and out so that they are the same. The notch > depths will vary on the frequency of the cavity for a given insertion loss. > This is how the cavities are set up at Sinclair. They know what depth of > notch to set the loop at to give a particular pass response. Quick, > repeatable and reliable. > > > > --- In [email protected]<Repeater-Builder%40yahoogroups.com>, > Larry Horlick <llhorlick@> wrote: > > > > > > So you actually come up with an RL value and equate to an IL value? > > > > > > lh > > > > > > On Wed, Apr 21, 2010 at 9:08 AM, hfarrenkopf <hfarrenkopf@> wrote: > > > > > > > > > > > > > > > Here is how you do it...... > > > > Take a T connector and put it on one of the pass loops. Leave the > other > > > > loop unterminated. Adjust the loop position so that the notch depth > is about > > > > 9dB for 0.9dB IL through if I remember correctly - this is done like > > > > measuring a notch cavity with the spectrum analyzer and tracking > generator > > > > on the T. Adjust the other loop the same way but ensure that the > loops are > > > > rotated the same way from the maximum coupling position as observed > by the > > > > weld mark on the loop (rotated clockwise or counterclockwise). > Recheck the > > > > first loop's depth and adjust so it is the same. This process makes > the in > > > > and out loops symmetrically tuned. Measure the pass insertion loss to > ensure > > > > you have the desired insertion loss. If not, readjust the loop's > notch again > > > > to a slightly different depth - more for less pass loss and less > depth for > > > > more insertion loss. > > > > > > > > Once both cavities are tuned to frequency, the cable length between > them is > > > > somewhat critical in length. With the correct length, the individual > pass > > > > curves add without the need to retune the frequency and the return > loss > > > > curve will show 2 dips approximately equal and above and below the > pass > > > > frequency. If you don't get 2.0dB IL with the 2 cans at 0.9dB, then > the > > > > cable is incorrect. > > > > > > > > Enjoy! > > > > > > > > > > > > > > > > > > > >
