• 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.

tuner before amp

552fl

Active Member
Mar 29, 2018
239
61
38
61
2-pill driver into heathkit sb-220...someone suggested putting a antenna tuner inbetween driver and sb-220??
 

I wouldn't. What radio are you running? A 2 pill driver for that amp seems a bit much. I'm guessing 80-100 watts would be all that amp needs to do 1000-1200 watts. Might even coast along at 700 watts with only 50 watts of drive.
 
They said that it would tune the input of the 2 pill going into the Heathkit tricking it to 50 ohms was just wondering if anybody has tried it.. I have the variable turn down on the two pill so is that it is doing about 90 Watts Peak. When you're talking about 100 Watts what are you talkin average or Peak Watts going into it curious.. what should be the a good dead key with the 2 pill key down on the Heathkit SB 220
 
Why do you think you need a tuner between the driver and the sb220? If the input swr is high something is wrong with one of the amps or the tubes in the sb220 are soft.

I wouldn't run the sb220 at more than 100 to 150 watts carrier. The cooling system and hv power supply aren't good enough to handle much more. Run it in cw mode on AM.
 
Is that 50w bird or or is at 50 Watts Peak into the sb220

No offense but God I hate seeing things like this. There are no such things as Bird watts. That is something CB'ers came up with. A Bird meter can read average watts or if it is a pep Bird meter it can read peak watts so saying Bird watts or peak watts is completely wrong and meaningless. The SB220 was designed to be run with a typical 100 watt transmitter. If you drive it on SSB with 100 watts pep then that is fine. if you want to hit it with a 100 watts UNMODULATED carrier as in CW mode that is fine. just don't hit it with a 100 watt AM carrier and then expect to modulate that carrier.
 
In the book it says it 100 Watts but that was back in the day average power..

Again that is not quite right. That 100 watt input rating is as I described above. Peak versus average has nothing to do with "back in the day". The only thing about back in the day is input power versus output power. Old amps were rated in input power whereas today they are rated for output power. I cringe every time someone says they can't understand why their Yaesu FL-1200 won't make any more than 800 watts output when it is rated for 1200 watts. That is 1200 watts INPUT and it will make about 600 watt OUTPUT so their 800 watts is driving the crap out of an amp that they expect even more out of.
 
As for a tuner between the driver and the amp.....you should not need it. The SB220 has a tuned input and should present an SWR of 1.5:1 or thereabouts. I wonder if the person that suggested that idea was thinking that the amp did NOT have a tuned input. Many of the older amps of that era or earlier did not have tuned inputs and back then pretty much all radios had tube finals which did not need a perfect SWR so the tuned inputs on amps were not really needed until solid state drivers came into play.
 
  • Like
Reactions: Shadetree Mechanic
No offense taken but I Am a cber .. somebody on the radio the other night was saying that's how they ran their sb220.. I'm always willing to learn something is why I'm on this forum. I purchase a bird meter and installed the pep kit in it. Was just trying to figure out the wattage to Drive the sb220 with the right way... Everyone has a different Theory on this
 
No offense taken but I Am a cber .. somebody on the radio the other night was saying that's how they ran their sb220.. I'm always willing to learn something is why I'm on this forum. I purchase a bird meter and installed the pep kit in it. Was just trying to figure out the wattage to Drive the sb220 with the right way... Everyone has a different Theory on this

Don't hit the amp with more than 100 watts peak and that should be fine. If you want to run it on AM I suggest you follow the info presented in post #6 of this thread. AM is high duty cycle and that amp's power supply was never designed for severe duty cycle like AM at full output. It will overheat and too as the fan cannot remove that kind of heat.
 

dxChat
Help Users
  • No one is chatting at the moment.
  • dxBot:
    Tucker442 has left the room.
  • @ BJ radionut:
    LIVE 10:00 AM EST :cool:
  • @ Charles Edwards:
    I'm looking for factory settings 1 through 59 for a AT 5555 n2 or AT500 M2 I only wrote down half the values feel like a idiot I need help will be appreciated