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What kind of power should I expect?

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Bobcat
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What kind of power should I expect?

Post by Bobcat » Monday, 02 April 2018, 8:50 AM

I understand that this is a "wide open" question but I really am looking for just a ball park answer.

A local CB tech passed away a few months and my son put together a huge fund raiser that got her enough money to make a move in housing to something she can afford.

To thank Tim, she wound up giving him a lot of Skip's old equipment. She didn't know what it all was and would not take "no" for an answer and would not take money from him.

One of the things he wound up with was what LOOKED LIKE a small PC case with to SO-239's on the back, along with 3 fuse holders, a fan on top, and a fan on the back... and a stout line cord. I was guessing it was an amp.... Tim took the covers off of it yesterday just looking.....and found a pair of MRF428 transistors. So in a way... that answers that.

The one question I have.....

WHen an amp has 2 of those, MRF428's , what kind of power would one be expecting? 100 w ? a couple of hundred????

I looked up the sheets on the transistor and each shows 150 w @ 30 MHz but I don't think that tells the whole story on what you might expect out of an amp MADE with them.

Any guesses?


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Re: What kind of power should I expect?

Post by MDYoungblood » Monday, 02 April 2018, 10:11 AM

Looking at the spec sheet 150W is at 50v with 4 watt input is for just one transistor, 2 should in theory should make 300w. Is it a base amp? Snap a couple pics of the inside, I would like to see what it exactly does.

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Re: What kind of power should I expect?

Post by Bobcat » Monday, 02 April 2018, 16:06 PM

I would but Tim already took it home. It's a weird looking thing...at least to me.... like I say it looks like a really small desktop PC case but with PLENTY of holes for ventilation/cooling. Very very heavy transformer inside....quite a chunk. And the funny thing.... not a name tag or plate anywhere on it or in it that we could find. No branding at all.

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Re: What kind of power should I expect?

Post by jessejamesdallas » Monday, 02 April 2018, 18:09 PM

Bobcat wrote:
Monday, 02 April 2018, 16:06 PM
I would but Tim already took it home. It's a weird looking thing...at least to me.... like I say it looks like a really small desktop PC case but with PLENTY of holes for ventilation/cooling. Very very heavy transformer inside....quite a chunk. And the funny thing.... not a name tag or plate anywhere on it or in it that we could find. No branding at all.
Allot of CB type Amps have no name on them or where they are made. (China, Japan, USA, etc...) Sounds like a two-pill base amp, i'm guessing it should swing in the 300-400w dept, depending on the radio...more if the transformer has adjustable voltage.
Last edited by jessejamesdallas on Monday, 02 April 2018, 18:11 PM, edited 1 time in total.
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Re: What kind of power should I expect?

Post by jessejamesdallas » Monday, 02 April 2018, 18:10 PM

oop's duplicate.
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Re: What kind of power should I expect?

Post by nk14zp » Friday, 06 April 2018, 11:09 AM

Hard to say without knowing the transformer output.

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Re: What kind of power should I expect?

Post by Bobcat » Thursday, 19 April 2018, 12:11 PM

He actually got around to trying it out into a good dummy load. With 3W in.... he was getting about 350W out......


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