[MRCA] [Milsurplus] grc106 low audio

[KA1LHZ]

I modded a HS-159 with a Motorola carbon microphone element and use that
instead of the H-33. The PTT works and you just need to move 1 wire on
the U-77 connector. I think you can use a bell system carbon element in
the HS-159 as well although I don't know how the audio would sound.

Steve

DE KA1LHZ


On 04/17/2018 09:30 AM, Ray Fantini wrote:
> 1A5 the transmitter IF/Audio section takes care of all the audio issues with that transceiver. It has a AGC system that keeps you from overdriving the radio along with a bias network that powers the microphone from the +20 volt bus.  You can use any high output device to drive the audio input being it was designed to receive the high level output of the H-33 that's capable of producing huge levels of audio when working correctly.
> The key thing there is it has to be working correctly and that's the biggest problem because most H-33 handsets I have used have dead microphone elements. 
> The weird thing is that is a SSB only transceiver. In AM mode you are just running USB with a carrier and in USB the audio level controls the carrier level so are the comments from running SSB or AM?  A good microphone will result in good action on the carrier level meter, how is that looking when you transmit? I can loan you another 1A5 to try if you think there is an issue with its audio. There is always a possibility that something like one of the interstage capacitors is going south although I don't think I ever saw one fail. Also you may want to stay away from having too sensitive a microphone with all the noise the amplifier generates!
>
> Ray F/KA3EKH
>
>
> -----Original Message-----
> From: milsurplus-bounces at mailman.qth.net [mailto:milsurplus-bounces at mailman.qth.net] On Behalf Of comcast
> Sent: Monday, April 16, 2018 6:34 PM
> To: mrca at mailman.qth.net; milsurplus at mailman.qth.net
> Subject: [Milsurplus] grc106 low audio
>
> folks i have a grc106 working as a fixed station using ame mode i have been receiving reports of low audio. i made a mike adapter using a motorola mocom70 mic and also the older style base station mike.  compared to the h33 handset ( am ive tried several different h33s) audio no better. any recommendations for a carbon mike with gain?   i have  an electrovoice 602t aviation hand mike which has a built in amp and am thinking about using that. 
> thanks
> jeff
>
> Sent from my iPhone
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