[Repeater-Builder] Re: Radio conversion to 225MHZ

2009-10-15 Thread skipp025
Sometimes same amplifier used for VHF High-Band and UHF 
can be modified up/down to the 224 MHz band... but the 
conversion project is not for the faint of heart. 

In the case of the Micor PA... they are not an easy 
mod by any means and I was never able to get more 
than about 45% of the original rated power from some 
versions.  The first problem is the frequency limit 
of the transistors, then modifying the substrate 
traces. 

One can retrofit replacement boards for the ceramic 
substrates (circuit boards used in the Micor and MSR-2000 
RF Amplifiers) with the proper parts, but you're really 
building a new amplifier in place of the old. So why 
not start from scratch if it's a ground up project. 

I was able to get the UHF GE MVP amp to work quite well 
on 224 MHz, haven't yet had my hands in the Master 
Series Power Amplifier. That's a winter project... 

For the 224 MHz band... I've been building PA's from 
scratch and modified commercial gear. Lately it's been 
hard trying to find cheap enough power devices (transistors 
and fets) in any type of quantity. But I sometimes get 
luck on Ebay. 

What you end up with is mostly determined by the available 
drive level from your exciter (transmitter). 


cheers, 
s. 



--- In Repeater-Builder@yahoogroups.com, K5IN k...@... wrote:

 Kevin,
 
 
 Any suggestions for a decent quality 220mhz amp for repeater duty?
 
 Micor 20-25 watts drive or pull the PA and exciter in and 50-60 watts
 output?
 
 
 Thanks
 
 -Original Message-
 From: Repeater-Builder@yahoogroups.com
 [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Kevin Custer
 Sent: Wednesday, October 14, 2009 5:57 PM
 To: Repeater-Builder@yahoogroups.com
 Subject: Re: [Repeater-Builder] Radio conversion to 225MHZ
 
   
 
 J wrote:
  Has anyone converted any of the commercial (GE/Motorola) radios to the 220
 band? If so what works and what doesnt. I need several 225 radios and
 thought this might be a route to go.
 
 I have converted MASTR II Mobiles, both multiplier and PLL exciter, with 
 standard receivers to 220 MHz. - they work fine, the PLL is easier. 
 There are preferred instructions on the MASTR II conversion site: 
 http://www.repeater-builder.com/rbtip/geindex.html#220
 http://www.repeater-builder.com/rbtip/geindex.html#220 
 
 For the M2 with a PLL exciter, Scott sells a complete conversion kit:
 http://www.repeater-builder.com/products/MIIconversionkit.html
 http://www.repeater-builder.com/products/MIIconversionkit.html 
 
 The PA's won't convert, but there is an easy fix:
 http://www.repeater-builder.com/products/ampbd.html
 http://www.repeater-builder.com/products/ampbd.html 
 
 I have converted MICOR Mobiles and Stations to 220 MHz. - they also work 
 fine. There are preferred instructions on the MICOR conversion site:
 http://www.repeater-builder.com/rbtip/micor-index.html#220
 http://www.repeater-builder.com/rbtip/micor-index.html#220 
 Helical Resonators modified for 220 operation are available here:
 http://www.repeater-builder.com/products/
 http://www.repeater-builder.com/products/ 
 
 The PA's won't convert, but again - never fear, the amp board is the 
 solution:
 http://www.repeater-builder.com/products/ampbd.html
 http://www.repeater-builder.com/products/ampbd.html 
 
 Any of the above radios can be converted to 220 MHz and achieve book 
 specification sensitivity on the new band. My favorite is the MICOR.
 
 Hope this helps...
 Kevin Custer





[Repeater-Builder] Re: Radio conversion to 225MHZ

2009-10-15 Thread ac6vj
J and the Group,

I have a converted MICOR mobile one 220 with a Toshiba amplifier module in it 
set to 15 W out driving a TE Systems 2206RN amplifier with 65 W out.  In Skipps 
vault on Mt. Vaca and it has been working flawlessly since its installation, 
four years ago.  The TE Systems, amplifier was not cheap, but when you take 
into account that I have not had to go up to the top of the amount in four 
years to work on it, it's a great deal.

Gregory AC6VJ

--- In Repeater-Builder@yahoogroups.com, K5IN k...@... wrote:

 Kevin,
 
 
 Any suggestions for a decent quality 220mhz amp for repeater duty?
 
 Micor 20-25 watts drive or pull the PA and exciter in and 50-60 watts
 output?
 
 
 Thanks
 
 -Original Message-
 From: Repeater-Builder@yahoogroups.com
 [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Kevin Custer
 Sent: Wednesday, October 14, 2009 5:57 PM
 To: Repeater-Builder@yahoogroups.com
 Subject: Re: [Repeater-Builder] Radio conversion to 225MHZ
 
   
 
 J wrote:
  Has anyone converted any of the commercial (GE/Motorola) radios to the 220
 band? If so what works and what doesnt. I need several 225 radios and
 thought this might be a route to go.
 
 I have converted MASTR II Mobiles, both multiplier and PLL exciter, with 
 standard receivers to 220 MHz. - they work fine, the PLL is easier. 
 There are preferred instructions on the MASTR II conversion site: 
 http://www.repeater-builder.com/rbtip/geindex.html#220
 http://www.repeater-builder.com/rbtip/geindex.html#220 
 
 For the M2 with a PLL exciter, Scott sells a complete conversion kit:
 http://www.repeater-builder.com/products/MIIconversionkit.html
 http://www.repeater-builder.com/products/MIIconversionkit.html 
 
 The PA's won't convert, but there is an easy fix:
 http://www.repeater-builder.com/products/ampbd.html
 http://www.repeater-builder.com/products/ampbd.html 
 
 I have converted MICOR Mobiles and Stations to 220 MHz. - they also work 
 fine. There are preferred instructions on the MICOR conversion site:
 http://www.repeater-builder.com/rbtip/micor-index.html#220
 http://www.repeater-builder.com/rbtip/micor-index.html#220 
 Helical Resonators modified for 220 operation are available here:
 http://www.repeater-builder.com/products/
 http://www.repeater-builder.com/products/ 
 
 The PA's won't convert, but again - never fear, the amp board is the 
 solution:
 http://www.repeater-builder.com/products/ampbd.html
 http://www.repeater-builder.com/products/ampbd.html 
 
 Any of the above radios can be converted to 220 MHz and achieve book 
 specification sensitivity on the new band. My favorite is the MICOR.
 
 Hope this helps...
 Kevin Custer