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madmark1 Profile
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Accomplished DX-er

Registered: 10-2009
Location: Abertillery
Posts: 454
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Re: Zetagi B300P amp.


this doubling-up off power output from linears when using ssb as apposed to fm or am is, usually most multimode cb radios will have a power output of around 12 watts SSB and 5/6 watts AM/FM, now 12w is slightly more than double 5w 'obviously'.... so if you have a linear amp and i loosely mean linear.... hi . lets say 100 watts max output with 12 watts input, if you only put 5/6 watts input you should see around 50 watts output. now if you put 5/6 watts input on AM/FM or 5/6 watts input on SSB you will still only have 50 watts output, therefore irrispective of what mode you use when driving your AMP, if you put the maximum input to the amp you will get the maximum output be it on AM FM or SSB, AM can have high peaks on the carrier this is why the carrier power is usually set low and the fact most modulators in modern cb radios use low level modulation as apposed to high level ..... but this is for another day......
mark 163fb20

Last edited by madmark1, 23/Apr/2010, 4:23 pm


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24/Jan/2010, 8:35 pm Link to this post Send Email to madmark1   Send PM to madmark1 Blog
 
madmark1 Profile
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Accomplished DX-er

Registered: 10-2009
Location: Abertillery
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posticon Re: Zetagi B300P amp.


go for the biggest amp you can get, and dont overdrive it, is the best. you can always reduce power from a BIG amp, but you CANT increase power from a small amp. always go BIG

 


mark 163fb20

Last edited by madmark1, 23/Apr/2010, 4:28 pm


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24/Jan/2010, 8:42 pm Link to this post Send Email to madmark1   Send PM to madmark1 Blog
 
Hot Fusion Profile
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Management

Registered: 03-2008
Location: South West England
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Re: Zetagi B300P amp.


Don't forget, guys, that these amps are cheaply built with no harmonic supression such as you would get in an amateur radio, so they will emit harmonics all over the place especially if over-driven - there is nothing built in to stop that. I'm unsure whether they would even be legal to use as part of an amateur station - I would suspect not as they wouldn't be able to produce adequate harmonic supression on their own and would require external low-pass filtering to be acceptable, and how many use that?

About power - these amps are 'rated' according to their power input, not their power output, and the output could be less than half the power input due to inefficiencies.

Sorry if that bursts any bubbles, but that's the way it is I'm afraid. emoticon

Watts are watts, there is no difference between SSB watts and AM/FM watts. This misconception arose because an SSB transmitter can run more efficiently than an AM one, as with SSB there is only a transmitted signal when a voice is present, unlike AM where a carrier is output at all times irrespective. Therefore it was found that an AM output stage could be run harder in SSB and not fail, because of the intermittent nature of the output. The notion of half the bandwidth has some bearing on the S/N ratio at the receiving end, but not the transmitter. It is a more efficient method of transmitting, but doesn't generate any magical extra watts.

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maybach52 Profile
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Freebander

Registered: 01-2010
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Re: Zetagi B300P amp.


Thank you all for a compressive lesson in amplifier specifications and manufacturer bull****!

I've been told some time ago that the Zetagi is "dirty" due to harmonic's caused by over driving which has been clarified here.

It is also clear that the "CB" market is very easy to please! One born every minute comes to mind.

Once again, thanks.

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24/Jan/2010, 9:33 pm Link to this post Send PM to maybach52
 
NumbNut Profile
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Registered: 08-2008
Location: Cirencester, Glos
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Re: Zetagi B300P amp.


quote:

maybach52 wrote:

Thank you all for a compressive lesson in amplifier specifications and manufacturer bull****!

I've been told some time ago that the Zetagi is "dirty" due to harmonic's caused by over driving which has been clarified here.

It is also clear that the "CB" market is very easy to please! One born every minute comes to mind.

Once again, thanks.



If you don't like CB Fine but there's know need to to Slag it off on this Forum like you do on others...



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26-FB-173 - NumbNut / 26-TM-121 - DingBat / 26-CT-151 - Beelzebub

24/Jan/2010, 11:17 pm Link to this post Send Email to NumbNut   Send PM to NumbNut
 
simon26OD004 Profile
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Registered: 07-2009
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Re: Zetagi B300P amp.


quote:

NumbNut wrote:

quote:

maybach52 wrote:

Thank you all for a compressive lesson in amplifier specifications and manufacturer bull****!

I've been told some time ago that the Zetagi is "dirty" due to harmonic's caused by over driving which has been clarified here.

It is also clear that the "CB" market is very easy to please! One born every minute comes to mind.

Once again, thanks.



If you don't like CB Fine but there's know need to to Slag it off on this Forum like you do on others...




I think that's a bit harsh, but I dunno what may have been said on other forums ect.

The truth is he's right, in my eyes there are 2 types of CBers, some that are interested in radio, and others that just want to use it to chat to people. That is what CB is for, for people who are basically uninterested in how radio works to be able to use a radio for local comms, unfortunately those are the same people who get duped into believing manufacturer bullshit and are smiling at the happy watts on their meter whilst wiping out the rest of the streets TV's. Antron 99 9.9dbi gain for eg.

There are some CBers who are absolutely clueless when it comes to the technical aspect of radio, but the reason CB is there, it's so they don't have to be clued up. When they operate within the law it's no problem, but once they step out of a legal setup, it pays to learn a little bit about what they are actually doing.
24/Jan/2010, 11:56 pm Link to this post Send Email to simon26OD004   Send PM to simon26OD004
 
rich 26fb456 Profile
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Registered: 07-2009
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Re: Zetagi B300P amp.


the only way to test out put is on a good meter!! not cheap crappy meters!! you will also need a pep watt meter ! not average or what ever they want to call it! in to a dummy load as well not across your antenna!! also if you look on sites with the sd1446 device! these are common in rm amps!! it is sometimes rated at 90+ at 12.5 volts! these are low drive devices ! you could almost say for am ie low drive high swing!! i personaly like the 1446s! i think they have the loudest audio from any device!! i have a kl400 with 1446s in it and that rocks! loud clear audio with good numbers!! like any amp if you drive the crap out of it to see every last watt your asking for trouble!! 73s.
25/Jan/2010, 1:36 pm Link to this post Send Email to rich 26fb456   Send PM to rich 26fb456
 
26fb99 Profile
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Accomplished DX-er

Registered: 08-2008
Location: Stoke on Trent North Staffs
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Re: Zetagi B300P amp.


hi rich,1446s in my old kl400 as was 1 trying to explain as an example to bob in the previous posts at 90watts plus as youve researched, at 12.5 volts would perfectly summarise my recorded 230/240 watts driven with 10watts at 14 volt supplied(engine running)12.3 without.
so the b300 uses the other type trannys yes? 70watts rated?
So Bob. Again.your 120watts seems pretty close with losses.

people,people no need for the whole Ham/CB can of worms on this thread.Save it for when you come in from the boozer!!!! LOL.

Congrats for everyones input.This thread has nearly every piece of info on "real life" CB amp issues.it was what i couldnt find 2 years back when i returned to radio and bought a kl400.

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73s
26/Jan/2010, 12:18 pm Link to this post Send Email to 26fb99   Send PM to 26fb99
 
26fb010 Profile
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Registered: 01-2009
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Re: Zetagi B300P amp.


i have to agree though. you could sell the "average" CBer a dying rat, if you added an echo and rated it at 400watts. call it a "sky duster" or some other random astrological shi`ite
3/Mar/2010, 7:31 pm Link to this post Send Email to 26fb010   Send PM to 26fb010
 
porky69 Profile
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Registered: 04-2008
Location: usb & lsb
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Re: Zetagi B300P amp.


quote:

26fb010 wrote:

i have to agree though. you could sell the "average" CBer a dying rat, if you added an echo and rated it at 400watts. call it a "sky duster" or some other random astrological shi`ite



lol emoticon
9/Mar/2010, 1:33 pm Link to this post Send PM to porky69
 


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