It might work, but for how long. Also detuning the cavity might upset the loading making the exciter unhappy. This can cause many RF problems including spurious generation.
I would consider building a 16 db antenuator. 73, ron, n9ee/r >From: Jesse Lloyd <[EMAIL PROTECTED]> >Date: 2007/08/24 Fri AM 12:13:00 CDT >To: Repeater-Builder@yahoogroups.com >Subject: Re: [Repeater-Builder] Re: Micor Repeater Low Current Mods > >How about this then: in the micor there is a 4 cavity filter on theoutput of >the exciter. If I tuned 3 of those cavities properlyand detuned the last so >it acts as an -16 dB attenuator would that workin obtaining my 10 mW input >into my mobile amp without creating anyproblems? > > > >On 8/23/07, Kevin Custer <[EMAIL PROTECTED]> wrote: >Jesse, > >While your method may work, it likely won't be clean; not ever a goodthing, >especially where a repeater transmitter is concerned. The MicorVHF >transmitter, like most FM transmitters, uses Class C RFamplification. When a >Class C amplifier is under-driven, or turneddown below about 50 or 60% of its >capability, it can become unstable -spurious. It is much better to select >the number of stages, andproperly drive them to create the amount of power >output required. This also results in the best efficiency, and since you >won't haveexcess power to burn in a solar situation, the method I suggest >islikely better. > >Jesse Lloyd wrote:That PA mod is awesome. I was considering knocking downthe >power outof the exciter to 20 mW by increasing the value of a couple >resistors,and then feeding it into a 40 Watt M100 PA. From there I have >theability to vary the output power from 5-40 watts (ish). > >Jesse > > > > On 8/22/07, Kevin Custer <[EMAIL PROTECTED]> wrote: >Jesse, > >You can put a toggle switch on the B+ line going to the Audio PA, thiswill cut >several hundred mA of current draw from the Class AB audiosection, and allow >it to be connected/turned on when service isrequired. > >Since you are working on a VHF unit, you can review the mods on thissite where >I took a 110 watt PA, hack-sawed it in half, and made a 5 to12 watt PA that is >very power efficient: > http://www.kuggie.com/ahra/hmftinfo.html > >I've also been successful in doing the same with only one transistor(the >controlled stage) and created a .5 to 2 watt PA. > > > Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 repeater Tampa Bay, FL No tone, all are welcome.
