-
You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.
Low drive 2 pill
- Thread starter Staybolt
- Start date
All 2 pills are low drive if you want long life. As to your 2 pill, it should be possible to attenuate the input. ( basically big resistor going to ground to bleed off input drive). Chances are input will have to be retuned.
You can buy an attenuator to put between the radio and amp but that's really a waste of time and money.
The general rule with the 2879 is you want your input watts to produce 20-25 watts per pill carrier. With a 2 pill give it enough drive to produce a 40-50 watt carrier and modulate or swing the rest.
The hg pills are getting better but you still want to be nice to them so id stay closer to the 20 watt/pill if that's the case. If you want more from Toshibas bumping up the voltage i think is better than more input watts but thats subject to opinion.
The hg pills are getting better but you still want to be nice to them so id stay closer to the 20 watt/pill if that's the case. If you want more from Toshibas bumping up the voltage i think is better than more input watts but thats subject to opinion.
2 Pill High Drive?
A simple resistor to "swamp down" (Attenuate) RF input signal across to ground - AFTER the relay.....
Or just keep the Radio on low...
Both live to see another day...
+1 with @Tokin - one question though, do you use MOSFET for Radios' Finals?
IF Yes, then install a feedback loop in the radio more than anything else - gotta' limit peaks else you might wind up with a lot of distortion - an effect you don't want in your amps output - really high peaking effects does more harm than good.
A simple resistor to "swamp down" (Attenuate) RF input signal across to ground - AFTER the relay.....
Or just keep the Radio on low...
Both live to see another day...
+1 with @Tokin - one question though, do you use MOSFET for Radios' Finals?
IF Yes, then install a feedback loop in the radio more than anything else - gotta' limit peaks else you might wind up with a lot of distortion - an effect you don't want in your amps output - really high peaking effects does more harm than good.
Consider what a dummy load does. Turns all your transmit RF into heat, but fools it into thinking an antenna with a low SWR is attached.
Now consider a "partial" dummy load. This is the attenuator they're talking about. All low-drive amplifiers are not created equal. Same goes for 'high drive' radios.
40 years ago we saw a lot of 2-transistor amplifiers that would overdrive at around 9 or 10 Watts PEP. Adding resistors to cut the drive power reaching the transistors in half made them sound a lot better with the single-final radios of the day. Tweren't no radios with two final transistors yet.
Without knowing what kind of transistors the amplifier uses, it's hard to say what the peak power needed to drive it will be.
Equally important to know the peak output of the radio, as well. The attenuator will need to soak up the difference between the two, however much this is.
73
Now consider a "partial" dummy load. This is the attenuator they're talking about. All low-drive amplifiers are not created equal. Same goes for 'high drive' radios.
40 years ago we saw a lot of 2-transistor amplifiers that would overdrive at around 9 or 10 Watts PEP. Adding resistors to cut the drive power reaching the transistors in half made them sound a lot better with the single-final radios of the day. Tweren't no radios with two final transistors yet.
Without knowing what kind of transistors the amplifier uses, it's hard to say what the peak power needed to drive it will be.
Equally important to know the peak output of the radio, as well. The attenuator will need to soak up the difference between the two, however much this is.
73
Ah, would have been two SD1446 or two 3SC2290, depending on when it was built.
Or whatever someone may have installed in the time since it was built.
Probably about right for a single-final 40-channel radio the way it is.
To use a two-final radio I would use a pair of 22-ohm 5-Watt carbon-film resistors and a 100 ohm 5-Watt. The foil trace that leads from the relay to the primary winding of the input transformer gets cut. One 22-ohm resistor gets one end soldered to each side of the cut. The other end of each resistor get twisted together. One side of the 100 ohm also goes here. The other end goes to ground. Called a "T" attenuator. Should cut the drive pretty much in half.
73
Or whatever someone may have installed in the time since it was built.
Probably about right for a single-final 40-channel radio the way it is.
To use a two-final radio I would use a pair of 22-ohm 5-Watt carbon-film resistors and a 100 ohm 5-Watt. The foil trace that leads from the relay to the primary winding of the input transformer gets cut. One 22-ohm resistor gets one end soldered to each side of the cut. The other end of each resistor get twisted together. One side of the 100 ohm also goes here. The other end goes to ground. Called a "T" attenuator. Should cut the drive pretty much in half.
73
Oh it's a sweet little amp. I got it local. I had an m 800 in the 90s I wish I had of never sold. The guy that bought it would get drunk and key it on a local channel and lock it down. He blew the amp up twice, sadky.
That's a shame. I like the success stories where the drunk keys up for hours and everything is OK.
That would be our local Mr. Whiskeyman over in Lakeland. He beats the shit out of a ts 667v with drunken rants and tirades. It gets so hot i bet you could bake potatoes in that amp and it just keeps going. If i tried that it would be instant smoke lol.
That's how it is sometimes. A local used to run a Texas Star 500 playing music for hours and hours. He ran the amp on a 30 amp meanwell or something similar. He was smart enough to keep the output low and use plenty of airflow. I miss that guy. The CB got stale after he moved away.
Its amazing how much the trolls keep radio popping around here and every channel has them lol