I finally had a chance to play with the Mitrek and radio again. I took the advice and tuned the Mitrek per Motorola spec, 120W out if I remember correctly. This made all the difference! There is no longer any difference between antenna or 50 Ohm load connected to the radio.
There is no longer any significant difference in duplexer tuning any longer. Once the duplexer has been tuend for maximum pass using the signal analyzer I cannot improve upon it once the transmitter has been connected. It seems that a cable length of 61 inches is almost ideal between the radio and the duplexer. It results in about 1.5 dB loss thru the cans. The 1.5 dB were calculated by comapring the power into a 50 Ohm load with the transmitter connected directly versus power into a 50 Ohm load with the duplexer connected. PA current changes by only 100mA when the transmitter is connected to the duplexer. There is no longer any difference whether the system is terminated in a dummy load or the antenna. I cannot measure any desense at all. Once the Z-Matcher arrives I will see if I can tweak it a touch more. All I can say is a "BIG THANK YOU!" to the group and Eric Lemmon in particular for the valuable advise given. One last question, in the VHF Mitrek manual I cannot find any difference between a 75W radio and a 110W radio other than the tuning instructions. I retuned the radio to 85W output per the 75W tuning instructions. The above results are true for 85W out just the same. Can anyone tell me if there is any difference between a 75W and 110W Mitrek other than tuning? Thanks, Adi -- Adi Linden | va3adi | [EMAIL PROTECTED] | http://adis.ca +-----------------------------------------------------------------+ IRLP Node 2590 in Sioux Lookout, Ontario 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/
