Hi Skipp Is it possible to share you Micor pa mod to 220 and the LPF circuit.
Thanks milo ----- Original Message ----- From: skipp025 To: [email protected] Sent: Friday, July 13, 2007 3:23 PM Subject: [Repeater-Builder] Micor vhf to 224 MHz conversions Hi Ron, I've tried and completed a number of micor pa mods... it's been a number of years since I did the vhf to 220 conversion. It did work but pretty poor related to what I was expecting or hoping for. Pre modification I measured all stage values & levels. Yes I removed the LPF and built a 224 MHz replacement filter using metal caps and coils in a standard 5 section layout. The conversion up was tried in two forms... a reduction in both L and C values were tried with the L values showing the best practcial performance (pretty much required to make it work), which was still nothing to get excited about when the best we could get was less than 40% of normal rated power. We bailed on more conversions because of the ease of hybrid low drive 224 MHz PA Modules and I started just making 224 two and three stage repeater amplifiers with rated 40 watt output. In a file somewhere I have all the conversion noted recorded... "our results did vary" quite a bit... cheers, skipp > Ron Wright <[EMAIL PROTECTED]> wrote: > skipp025, > On the Micor PA for 220 I assume you disconnected the LPF and > was using a VHF PA. > > Since the Micor PA did have tuning did you modify the variable > caps; lowering their value??? > > 73, ron, n9ee/r > > > > >From: skipp025 <[EMAIL PROTECTED]> > >Date: 2007/07/13 Fri PM 12:36:06 CDT > >To: [email protected] > >Subject: Re: [Repeater-Builder] Hamtronics > > > > >I have converted Micors and it's not even close to a free lunch. > >Best I was able to do with a full on 220 micor pa conversion was > >about 20 to 30% of rated power. I also suspect the transistor/devices > >don't perform very well that far above their spec'd range of > >operation. > >s. > > > >> Ron Wright <mccrpt@> wrote: > >> Eric and all, > >> > >> On the PA problem has anyone on the board tried using PAs from > >> say Micors or GE Mastr line made for 150 or UHF on 220. > >> > >> These often have LPF on their output which can be taken out (don't > >> like to). Since these amps are wide band they just might move > >> up/down to 220. Some do have tuning like in the Micor so would be > >> little harder, but GEs only have a pot for adjusting drive/output > >> and some with SWR shutdown circuit adjustments. > >> > >> 73, ron, n9ee/r > > > > > > > Ron Wright, N9EE > 727-376-6575 > MICRO COMPUTER CONCEPTS > Owner 146.64 repeater Tampa Bay, FL > No tone, all are welcome. >
