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Author Topic: BC-1004C Question  (Read 51154 times)
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Steve - WB3HUZ
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« Reply #25 on: May 08, 2010, 01:05:12 PM »

That's mostly a function of your meter. The meter is just not accurately measuing the PEP of the low frequency stuff. Power is power and it doesn't matter what audio frequency is involved.


I didnt say that there was nothing in the rumble area of the spectrum, just nothing useful IMO on the ham bands which is what I meant earlier. Id rather quit wasting power down there and get a lot more power out of old BC iron by rolling the lows off. Then emphasizing high positive peaks.


Even using a series modulator, as I do, it takes a LOT of power away from the capabilities of the station when you have the 'rumble freq's' passed.

I can see about 15 to 20 percent MORE PEP when I turn the subsonic synth OFF in the mobile.


--Shane

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KM1H
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« Reply #26 on: May 09, 2010, 09:29:44 AM »

BUT....if you have a transformer that is spec'ed and has the iron to go down into the nether regions and then limit the audio to say 200 Hz you now have the ability to run more power thru it before reaching the saturation point. Proportionally, it takes a lot of power at the low end which is better utilizied higher in a ham modulator. If you want the rumble then add bass boost to the receiver.

Carl
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Steve - WB3HUZ
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« Reply #27 on: May 09, 2010, 11:31:09 AM »

All true - there will be more power in the audio frequencies that actually do some good. But it shouldn't make a difference on a true RMS power meter.


BUT....if you have a transformer that is spec'ed and has the iron to go down into the nether regions and then limit the audio to say 200 Hz you now have the ability to run more power thru it before reaching the saturation point. Proportionally, it takes a lot of power at the low end which is better utilizied higher in a ham modulator. If you want the rumble then add bass boost to the receiver.

Carl
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KD6VXI
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« Reply #28 on: May 09, 2010, 11:47:32 AM »

All true - there will be more power in the audio frequencies that actually do some good. But it shouldn't make a difference on a true RMS power meter.


Where is this RMS wattmeter?

I've only got AVG and PEP on mine...  Only time I saw RMS on a wattmeter was one designed for the 27 mhz band.

I agree with what you are saying, though, Steve.  It SHOULDN'T make a difference.  I wonder if I have a problem with the transistor(s) I'm using for the series modulator?

Another problem could be this:  Trying to shove the sub freq's into a system that CAN'T pass them.  If the modulator (iron or series or Huh) is only designed to pass freq's above say 200Hz, and you start trying to shove LOTS more power below 200 Hz, then things start getting squirrely.

--Shane
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Steve - WB3HUZ
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« Reply #29 on: May 09, 2010, 03:28:59 PM »

Hewlett-Packard and others made/make them. They are usually called True-RMS Meters (not the so called ones that are cheapo multimeters). I've used one made by Racal to make noise power measurements.



All true - there will be more power in the audio frequencies that actually do some good. But it shouldn't make a difference on a true RMS power meter.


Where is this RMS wattmeter?

I've only got AVG and PEP on mine...  Only time I saw RMS on a wattmeter was one designed for the 27 mhz band.

I agree with what you are saying, though, Steve.  It SHOULDN'T make a difference.  I wonder if I have a problem with the transistor(s) I'm using for the series modulator?

Another problem could be this:  Trying to shove the sub freq's into a system that CAN'T pass them.  If the modulator (iron or series or Huh) is only designed to pass freq's above say 200Hz, and you start trying to shove LOTS more power below 200 Hz, then things start getting squirrely.

--Shane

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