Hello Kevin, It sounds to me like the Extender "noise blanker" is cutting back on your I.F. gain; it is probably set to your new L.O. frequency. In repeater service, you do not want to use the Extender. So make sure that jumper 301 is across the primary of T300 and jumpers 3A, 3B, and 3C are not installed on the interconnect board. The way to test to make sure that the extender is not cutting back your I.F. gain is to measure the voltage on the plus terminal of the C324. If it is around 6V the Extender is not cutting back the I.F. gain, but if it is around 4V the extender is cutting back the I.F. gain.
A word of warning: the heatsink on the Mitrek is woefully undersized for 100% duty cycle and needs lots of forced air flowing over it. There is a lot of good information on Repeater Builders about cooling a Mitrek. Gregory AC6VJ --- In Repeater-Builder@yahoogroups.com, "Gmail - Home" <[EMAIL PROTECTED]> wrote: > > Hi All, > > I am now in need a some big HELP. > > I have been trying to get our groups 10mtr repeater up and running, and it > seems to want to block me at each point. > I am very grateful for the help that has been given so far, and this has got > us to the point where we have 50% of the repeater running. > But as I said above, it appears that I have hit a block again. > I can not get the RX to tune anywhere down to the specs the radio says of > .3uV. The best I can do is 1.9uV. And this is the same for all 3 radios I > have. > > The radio were originally fitted with 33Mhz ICOMS, and I have now fitted > them with 29.540 ICOMS. They are tuning up, but not as good as I would > expect. > Our work radio techinian is even baffled as to the problem, and he has 3 > decades+ experiance. > > Checking the schmatic I notice there is no pre-amp on the RF input. I could > add a pre-amp here, and this would help. But before I go this route I am > asking if there is anything else I can do to get it (them) working better. > > FYI, I am using our companies radio workshop which has all the required > tuning and testing equipment for the aligniment. Be it not the Motorola > gear, but it does the job. > > I can't remember the model numbers, radios are still at work, but they > correspond to 60w, single channel, with extender fitted. > > My understanding from others within this group, these radios will tune down > to 29.540 without any trouble. > So, am I doing something wrong? (Not famillar with Mitreks here in NZ, never > made it this far downunder). > Are all 3 radios faulty? I can't see why, but maybe. > > Are there mods that are required that I have overlooked in all the > information I have onhand, from the many web-pages? > > Do I need to go to another type of radio? And if so, which one/s? Then does > anyone have one available? Or come to that, does someone have a tuned Mitrek > they can spare to sell (or donate). > > I will also post this on the repeater-builders user group just in case they > can help also. > > Thanks for any input, and if you wish to contact me directly, please e-mail > me at [EMAIL PROTECTED] Please remove the "-" in the gmail account, I try > and limit the spam I get. > > With the increase of 10mtr activity down here, have a listen for "ZL1HK" on > 29.64Mhz > > Regards > > Kevin, ZL1KFM. >
