| Author |
Message |
    
Phineas
| | Posted on Tuesday, May 14, 2002 - 10:58 am: | 
|
I was wondering. I am in the process of building a 6meter amplifier. I noticed that alot of CB amps have the SD1446 Transistor in them. When I read the specs on these transisters, it showed that these transistors can work up to 90 mhz. I have some questions.
1. If I update the matching circuit, and add a good voltage regulator, could I just convert on of the CB amps that already has those Transistors in them?
2. In the spec, the are shown to be Class C. Does this mean I cant you them for a class AB amplifier?
Thanks for your feedback
Phineas |
Tech671
| | Posted on Friday, May 17, 2002 - 11:40 pm: |
|
I don't see why you couldn't re-tune and bias a 10-11m amp for use on 6m with 1446's. |
Ss8541
| | Posted on Saturday, May 18, 2002 - 11:24 pm: |
|
you probably can get by with it at a reduced power level. the main problem is that the transformers are ferrite material rated for up to 30mhz. around 50mhz, they will become easily saturated. so you may blow your transistors at normal output.
as for the ab part, there are many amps using the 1446 that are ab. if not, you can convert them fairly easily. |
Znut
| | Posted on Sunday, May 19, 2002 - 11:35 am: |
|
Hello,
I myself would like to see someone post the mods for a palomar/shooting star 225 for 6! I have one with two 1446's and have used it on 6 as-is and obviously it has the symptoms of losing input and/or output match when trying to get it over 30-40 watts on ssb. I think the transistors have a pretty flat impedance curve from 27 to 50 mhz so the match should not be that bad.
So, if anybody has any idea:
1. How do I bias the amp?
2. What transformers can I use and should I change the # of turns (there are no trimmer caps on mine)?
3. How do I set it up to handle the SSB power of my radio, ranger 5054DX (same as 2950)? Is using the low power setting on the amp enough? Is that actually the same as reducing the drive?
I'm glad I'm not the only one interested in this type of project!
Take care,
Znut |
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