Just a suggestion,but I have not had good experience using simple "up the frequency" methods for 220 conversions. I have had better luck and less stability problems with the "change the multiplier" methods.
I have had problems with: Stability -- Crystal manufacturer's have problems cutting crystals that operate on frequencies other than the range the oscillator was meant to run in. I.E. a 18Mhz crystal running in an element where a 12Mhz crystal would have been. I know it shouldn't cause problems, but it does. It seems like the change in frequency range changes the behavior of the element and makes things go weird. Crystal won't net -- Same as above the series capacitance seems to mess with the element so the crystal will not net properly. Can't get adequate deviation -- Again due to the change in frequency range the crystal is not "rubbery" enough to make good modulation. If the crystal is made to be more rubbery, the stability is degraded. This is less of a problem with a phase exciter. Changing the multiplier to multiply more times ALWAYS yields more deviation. Not only is the frequency multiplied more times, the deviation is multiplied as well. If you change multiplication factors it keeps the crystal manufacturer's happy. They will know what they are doing to make your crystal if you simply tell them to make it for 148.xxx and don't tell them that you are actually going to use it in the 220 band. Since it's their rock that is going to keep your transmitter stable, I would keep them happy and deal with the non-stock issues on your end. Sure the crystal might not be marked correctly for the frequency your transmitter is actually on, but I don't think that's a REAL problem. If you talk to them nicely, they might even mark it correctly for you. (I know Bomar will) I would give serious consideration to this conversion: http://www.condor-connection.org/mods/mastr2.htm I have used the MVP version of this and it worked GREAT!! I would definitely NOT use ANY conversion dealing with the PA. I would simply scrap the VHF PA and use a power module: http://www.repeater-builder.com/products/ampbd.html Do as you will, but if I were putting time and money into converting a radio to 220, I would want it to be right the first time. YMMV Scott Scott Zimmerman Amateur Radio Call N3XCC 612 Barnett Rd Boswell, PA 15531 ----- Original Message ----- From: "wd0ekr" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Tuesday, March 20, 2007 9:44 AM Subject: [Repeater-Builder] 220 conversion >I am looking at the W4UWH M2 conversion on the repeater-builder site > but I am not seeing the info for the crystal freqs, I would hate to > order the wrong crystals > > > > > > > Yahoo! Groups Links > > > > > > -- > No virus found in this incoming message. > Checked by AVG Free Edition. > Version: 7.5.446 / Virus Database: 268.18.14/727 - Release Date: 3/19/2007 > 11:49 AM > >
