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Zetagi B-300P Need advice on amp installation

Miura

Active Member
Feb 7, 2022
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I’ve just got hold of a Zetagi B300P linear + preamp. I’m totally new to amps settings and how it works.
Hence I have a few questions for the knowledgeable chaps around here ;)
What does pre amp mean and what is it used for? Should it be always on?
How many watts should the hosting radio be putting out to the amp on am and ssb?
and now the stupid question: Where should I locate my external SWR meter? in between the amp & the radio or in between the amp and the antenna?
 
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I’ve just got hold of a Zetagi B300P linear + preamp. I’m totally new to amps settings and how it works.
Hence I have a few questions for the knowledgeable chaps around here ;)
What does pre amp mean and what is it used for? Should it be always on?
How many watts should the hosting radio be putting out to the amp on am and ssb?
and now the stupid question: Where should I locate my external SWR meter? in between the amp & the radio or in between the amp and the antenna?
The Preamp increases your receive capability. Allows you to hear weaker signals better. Use as needed.

1 or 1 1/2 watts is ideal. No more than 2.

Pecking Order:
Radio
Amp
SWR Meter
Antenna

That should fix you up. :giggle:
 
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You'll need at least an additional 40A power supply. This is usually not a problem in a mobile installation, but you'll need a big power supply if not.
 
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Best remember if 250 watts OUT...then roughly 500 watts input!!
Plus radio + pre-amp drain = ???
500 / 13.8v = slightly more than 36 amps... x 125% (for headroom) = 45 amps
My 2 cents
All the Best
Gary

20 amp max specs that amp =140 - 160 PEP at best output
20 x 13.8 = 276 watts INPUT x 60% efficiency = 165 watts max output
 
Best remember if 250 watts OUT...then roughly 500 watts input!!
Plus radio + pre-amp drain = ???
500 / 13.8v = slightly more than 36 amps... x 125% (for headroom) = 45 amps
My 2 cents
All the Best
Gary

20 amp max specs that amp =140 - 160 PEP at best output
20 x 13.8 = 276 watts INPUT x 60% efficiency = 165 watts max output
LOL!! OK, let's just go with 60A to be safe. This cannot end well. So I'm out.
 
River man, Thank you very much for all your advice! I now have a much clearer idea of how to operate it. Very useful Info. Power supply is 50 amps so it should do the work. Now my only problem is to get 1 or 1.5 watts out of my radio…it’s minimum being 4W I believe.
Many thanks also to all the chaps who chipped in. I should be sorted now. I will revert and let you know how things went ;)
cheers!
 
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Never ceases to amaze me when "reality" show RF output meets true mathematics, someone's lower posterior always gets bruised.:love::cool:

Gary, you need an “s” on the end of “show”.
Reality is singular. It should read, “. . . when reality shows RF output . . .

Just sayin’. :love::cool:
 
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Motorola shows matched pair rating of 175 watts out...

275 watts input (20-amp x 13.8v)
Zetagi shows 200 watts AM/FM ...Output
This would require amp to be 73% efficient:unsure:

Up to 400 watts SSB.
Hmm on a 20-amp supply. OK



Something interesting here... 275 watts input (20-amp x 13.8v) = 400 watts out. o_O

 
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