Repeater Builder ----- Original Message ----- From: Jack Davis To: No Reply Sent: Friday, December 07, 2007 9:34 PM Subject: Re: [Repeater-Builder] Digest Number 5925
I did remove a full turn off both helical resonators on the output of the receiver oscillator, they do have a big peak in the center and a smaller peak all the way out. The test set meter readings are in the ballpark of what the manual calls for but it just does not make it. I used the instructions on the RB wed site for the conversion, if there are some optimized values I would sure like to hear about them. I put a GASFET preamp on it and it may be usable but I have a nagging feeling it is just not right. Low drive could sure be a factor, if there was a dead device somewhere in the path it would be a bigger problem than what I have. Jack K6YC Re: MII Receiver Posted by: "Doug Bade" [EMAIL PROTECTED] kd8b2005 Fri Dec 7, 2007 5:29 am (PST) While I have never seen or heard of a case, it may be possible.. However, it is most likely not the case. I suspect insufficient drive from the oscillator chain through to the mixer.. The copper helical bandpass filter at the end of the L.O. chain will not tune without mods, getting them into the correct range was a lot of trial and error for me, and is suspect in my opinion. Insufficient injection level after a L.O. mod on any Mastr II conversion is normally the culprit of low sensitivity, OR you have something tuned to a wrong lobe.....in one of the helicals right now... There are more than one "peak" in some cases... Doug KD8B At 01:56 AM 12/7/2007, you wrote: >Do the Mastr II 800 MHz receivers have the "tin whisker" problems >that some of the other bands do? I have one I converted to 900 MHz >and the sensitivity will not go below 2.2 microvolt's for 12 db of >SINAD. I have tuned it right by the book and it never gets any >better. I have not opened up the helical resonators, but that will >be the next step. > >Thanks >Jack >K6YC > Back to top Reply to sender | Reply to group | Reply via web post Messages in this topic (3)
