I was 90% sure, this is how it worked. I'm slowly learning and helping friends with their equipment. This is the final piece of info i needed confirmed to finish this up. Thank you! Refreshing to see someone besides me get to the point and focus on the job at hand instead of trying to make extra long videos on purpose.
Thank you so much I appreciate all your help and videos As well as many others do. I like to personally thank you for your dedication and helping others keep the hobby going 73S
cool video. definitely something that people need to be shown. just a quick tip to add on. Make sure you are watching your output watts while you are tuning your input SWR. you want to find the sweet spot where the input SWR is minimum and the output watts are maximum. it is possible to choke the input watts so far down that the SWR appears to be going down but what you are doing is turning down the power going into the amp. its a resonance thing!
@@tramdr you know i just re-read my comment and i realize it sounds like i was trying to give the advice to you. It is obvious from your videos that you know what you are doing. My tip is meant for those who find this video. thanks for all the great content!
Also never use metallic screwdrivers when adjusting trim capacitors. Even if the screw side of the trimmer is at Ground potential. You want to use plastic tuning tools you will add extra capacitance to the Circuit which will throw off the tuning. Also there's a chance you might accidentally slip and short something. The right way to do the tune up that you're trying to do. You can use the SWR meter on the input and output that will work. You also need a amp meter and voltmeter looking at the current draw of the amplifier you want to adjust the input tuning for minimum reflected power and maximum output power you want to adjust the output tuning so that you have maximum output power with the lowest possible current consumption. So you would adjust that trimmer while looking at the amp meter and the output wattmeters essentially maximum output power minimum amount of current necessary to generate it. That is the most efficient operation of the amplifier at that point. When you multiply volts times amps it'll tell you roughly how many watts of energy you have going into the amplifier those transistors tend to run around 60% maybe 70 at best. So if you can have something in that neighborhood your amplifier is operating at Peak efficiency. Also try reducing the drive power and see if you can keep the same amount of output power. Most amplifiers don't need a whole lot of drive if they're tuned up correctly.
That's easy just take out your mica capacitors on your input and output transformers and replace them with variable capacitors then you will need to retune your input and output swr for the lowest reading which lowers the reflect back to your radio and the output swr with the amp on will be lower at the antenna or dummy load like he did in the video he did not tune the output transformer in this video
Just to be clear man....this only applies to the INPUT swr bud. If its on the output....you have different issues. In other words....if your swr is high....with the swr meter between the radio and the amp....then this or similar is the issue. Of the swr is high woth the meter between the amp and the antenna.....its another issue. Most likely harmonics,poor output tune , bad components causing oscillations or all of the above. Just to clarify the difference between input and output swr
Just found your video...tram Dr. Enjoyed it and your information. I have subscribed and will be looking for more of your expertise in the near future. By the way, where can a person get these trimmers and value of trimmers are needed, that were mentioned for the input ? Thanks, Billy
different amps and configurations will have different values. Many amps don't have them at all. Hence there is not an answer to that that I know of. Maybe someone else can help?
So this is a variable capacitor hooked in parallel with the input lead to the transformer and ground? My little 1 pill amp seems to be resonant on 28.500 MHz in the10 meter ham band checking it with an antenna analyzer. With the relay off it bypasses the amp and I have to hold the relay on to check it. What turns the relay on keying up the mic? The power button is not turning it on.
its called a keying circuit, a small transistor like 2n2222a or 2n3906 puts a ground on the relay when it sniffs the radio signal input coming in. Those transistors go bad, usually from someone putting too much drive into the amp.
I recall reading that Capacitance should precede the Inductance on Input but follow the Inductance on output. I realize your trimmers were on the Transformer cores. I'm trying to determine trimmer placement on a homebrew 4 pill so I have a combiner preceding and following the T's. I want an L-C on both ends of my amp. For Trimmer placement I plan on deeming the Combiners as the Inductance for Trimmer placement. At least for my first Power On try. IDK about trimmers on the T core I was going to keep the mica's. What sort of volt rating should I use Minimum on trimmer caps?
hi dr i have a palomar hd450 with 4 sd1446 pills. 2 pills on one side run real hot. i swap them over with the 2 pills on the other side. then those ones run real hot. pills test ok on the diode meter and are a close match. it has a single bias tranny and the pills recieve .56v. the swr back to the radio is 2:1. i cant see any caps or resistors blown. it is pre tuned, so no vaiable caps. the output of the amp is 320w. it used to be 400w. when disconecting 2 pills from either of the 2 sides . running 2 pills only it puts out 130w.. even on the side that runs cool.. any ideas as to the unbalanced condition
Then you take the trimmers out and then you check the capacitance with a multi meter and get some metal clad capacitors that read the same capacitance of the trimmer and solder it where the variable capacitor was soldered you can use cheaper Micah capacitors on the rf transformers but metal clad type are better
I've got an old 667v that has variable caps on the input and output xformers. Would it be ok to tune it for best SWR and best forward power, remove the tuner caps, get their capacitance then stick on the closest non adjustable cap in their place? I've found the adjustable ones wander with time in a mobile.
Nope. Parameters change. Examples, you change coax, radio, antenna etc. Yep, antenna because yes its the output stage, but even output tuning has some effect on the input. One guy on Facebook kept arguing with me that the driver output tune cap was the input tune cap because it effected the input SWR. He didn't know that the after (or before) tuning will effect the next stage.
Ive been given a 1 pill Mini Ball TL-60. It has 1 MRF453 Transistor rated for 60 watts. My Stryker 955 will do on low a little over .5 watts on high about 3.8 watts dead key. Do you have any idea where to set dead key on this thing man? Also it has high SWR between the amp and antenna with the amp turned on.
Someone who actually walks you through the steps, wow 😲 nice job.
Thanks.
I like that myself
I was 90% sure, this is how it worked.
I'm slowly learning and helping friends with their equipment.
This is the final piece of info i needed confirmed to finish this up.
Thank you!
Refreshing to see someone besides me get to the point and focus on the job at hand instead of trying to make extra long videos on purpose.
Glad it helped!
Thank you so much I appreciate all your help and videos As well as many others do. I like to personally thank you for your dedication and helping others keep the hobby going 73S
You're welcome!
Very articulate video. I appreciate you taking the time to fully explain, and actually show, input amp tuning. Have a great holiday season.
Thanks, you too!
cool video. definitely something that people need to be shown. just a quick tip to add on. Make sure you are watching your output watts while you are tuning your input SWR.
you want to find the sweet spot where the input SWR is minimum and the output watts are maximum.
it is possible to choke the input watts so far down that the SWR appears to be going down but what you are doing is turning down the power going into the amp. its a resonance thing!
Agreed, and I do that, but for this video, wanted to keep it very simple. I may add that if I do a followup one day.
@@tramdr you know i just re-read my comment and i realize it sounds like i was trying to give the advice to you. It is obvious from your videos that you know what you are doing.
My tip is meant for those who find this video. thanks for all the great content!
Fantastic, thanks for the lesson. Happy Father's Day.
Good job very helpful.....Didn't expect amp out power to Double..... Amazing !! ....Thx for posting....
Glad it helped
Also never use metallic screwdrivers when adjusting trim capacitors. Even if the screw side of the trimmer is at Ground potential. You want to use plastic tuning tools you will add extra capacitance to the Circuit which will throw off the tuning. Also there's a chance you might accidentally slip and short something. The right way to do the tune up that you're trying to do. You can use the SWR meter on the input and output that will work. You also need a amp meter and voltmeter looking at the current draw of the amplifier you want to adjust the input tuning for minimum reflected power and maximum output power you want to adjust the output tuning so that you have maximum output power with the lowest possible current consumption. So you would adjust that trimmer while looking at the amp meter and the output wattmeters essentially maximum output power minimum amount of current necessary to generate it. That is the most efficient operation of the amplifier at that point. When you multiply volts times amps it'll tell you roughly how many watts of energy you have going into the amplifier those transistors tend to run around 60% maybe 70 at best. So if you can have something in that neighborhood your amplifier is operating at Peak efficiency. Also try reducing the drive power and see if you can keep the same amount of output power. Most amplifiers don't need a whole lot of drive if they're tuned up correctly.
Great video it would be nice to see a modification how to add an input trimmer to add that doesn’t have one.....
I wish all abs had an input tuner..
That's easy just take out your mica capacitors on your input and output transformers and replace them with variable capacitors then you will need to retune your input and output swr for the lowest reading which lowers the reflect back to your radio and the output swr with the amp on will be lower at the antenna or dummy load like he did in the video he did not tune the output transformer in this video
Now I know why my SWRs are high when I use my amp. I've been trying to figure this out for awhile. thank you.
Just to be clear man....this only applies to the INPUT swr bud. If its on the output....you have different issues. In other words....if your swr is high....with the swr meter between the radio and the amp....then this or similar is the issue. Of the swr is high woth the meter between the amp and the antenna.....its another issue. Most likely harmonics,poor output tune , bad components causing oscillations or all of the above. Just to clarify the difference between input and output swr
Just found your video...tram Dr. Enjoyed it and your information. I have subscribed and will be looking for more of your expertise in the near future. By the way, where can a person get these trimmers and value of trimmers are needed, that were mentioned for the input ? Thanks, Billy
different amps and configurations will have different values. Many amps don't have them at all. Hence there is not an answer to that that I know of. Maybe someone else can help?
Awesome Information, Please Explain The Other Variable Capacitor On The Output.
Maybe make a followup one day, but the other one is just a tuner on the output side. Tune for most watts out.
Good ol positive ground .. isolation...old school
Hey brother , I enjoy your videos, thanks
I appreciate that
Do you know the value of these variable capacitors? I think i would like to add dual tuning to all of my amps.
So this is a variable capacitor hooked in parallel with the input lead to the transformer and ground?
My little 1 pill amp seems to be resonant on 28.500 MHz in the10 meter ham band checking it with an antenna analyzer.
With the relay off it bypasses the amp and I have to hold the relay on to check it.
What turns the relay on keying up the mic? The power button is not turning it on.
its called a keying circuit, a small transistor like 2n2222a or 2n3906 puts a ground on the relay when it sniffs the radio signal input coming in. Those transistors go bad, usually from someone putting too much drive into the amp.
Boy o boy I gotta try this on my 2 tube elkin mobile that would be the screw on the side right the input tune???
Yes, the one on the side by itself is the input SWR tune.
I recall reading that Capacitance should precede the Inductance on Input but follow the Inductance on output. I realize your trimmers were on the Transformer cores. I'm trying to determine trimmer placement on a homebrew 4 pill so I have a combiner preceding and following the T's. I want an L-C on both ends of my amp. For Trimmer placement I plan on deeming the Combiners as the Inductance for Trimmer placement. At least for my first Power On try. IDK about trimmers on the T core I was going to keep the mica's. What sort of volt rating should I use Minimum on trimmer caps?
I don't mess with pills, good luck.
hi dr i have a palomar hd450 with 4 sd1446 pills. 2 pills on one side run real hot. i swap them over with the 2 pills on the other side. then those ones run real hot. pills test ok on the diode meter and are a close match. it has a single bias tranny and the pills recieve .56v. the swr back to the radio is 2:1. i cant see any caps or resistors blown. it is pre tuned, so no vaiable caps. the output of the amp is 320w. it used to be 400w. when disconecting 2 pills from either of the 2 sides . running 2 pills only it puts out 130w.. even on the side that runs cool.. any ideas as to the unbalanced condition
I would guess something is wrong with the output circuit on the side that runs hot. Bad coil or cap.
Nice... I tune every amp I get even if they don't have a trimmer cap
External Tuner?
Yes sir.. And the pill amps if they have bad input or output caps
I have a boomer 600 Deluxe would that work in my Case?
I'm not familiar with it, would have to see pics. If it has an input tuner similar to whats in the vid it should work.
Then you take the trimmers out and then you check the capacitance with a multi meter and get some metal clad capacitors that read the same capacitance of the trimmer and solder it where the variable capacitor was soldered you can use cheaper Micah capacitors on the rf transformers but metal clad type are better
I've got an old 667v that has variable caps on the input and output xformers. Would it be ok to tune it for best SWR and best forward power, remove the tuner caps, get their capacitance then stick on the closest non adjustable cap in their place? I've found the adjustable ones wander with time in a mobile.
Nope. Parameters change. Examples, you change coax, radio, antenna etc. Yep, antenna because yes its the output stage, but even output tuning has some effect on the input. One guy on Facebook kept arguing with me that the driver output tune cap was the input tune cap because it effected the input SWR. He didn't know that the after (or before) tuning will effect the next stage.
Thanks for sharing great information!
My pleasure!
So what if we can't do this on out amp is the high swr gonna hurt anything I have a palomar 250 in my car
Swr is 1.2 on barefoot but 2.5 plus on amp on
thats not too bad. You should be ok.
Ive been given a 1 pill Mini Ball TL-60.
It has 1 MRF453 Transistor rated for 60 watts.
My Stryker 955 will do on low a little over .5 watts on high about 3.8 watts dead key.
Do you have any idea where to set dead key on this thing man?
Also it has high SWR between the amp and antenna with the amp turned on.
more like personal preference.
I found my trimmer but the lowest I got was 1.5 couldn't get it lower
Sounds about right.
Thank you, thank you, thank you!!!
Happy to help!
Thank you my friend very much
who made the transistors? mine are different than those. blw60cf6 with a A inside a little diamond
Heck if I know, I'm a tube man. Maybe someone else can help.
Thx .! Dan.
What is the rating on the trimmer caps
Not sure but my guess is 100pf at 300v. Anybody?
Nice to know
Good info'
Great job.
Thanks.