I need a little help...some time ago, maybe two or three years ago I saw somewhere on the internet some pictures and a schematic where this guy added a single MFR-455 or a 2sc2290 transistor to the back of a cb radio to give it some added power...the cb may have been a Cobra 25 or a 29,I just can't remember much about it but I was thinking maybe someone on this forum had seen it and can point me in the right direction.....I know that I bookmarked it on another computer but I no longer have that computer...another thing,I know that AM Power is building some one pill amps using some toroid transformers but I am looking for the schemaitc/parts list for a one pill amp using regular air wound coils in the output section instead of the toroid transformers...I found one called a "Mosquito" which gives the schematic and parts list but it doesn't say what the ID or OD or number of turns or turns spacing for the output coils are,has anyone made any of these one pill drivers ? I don't want to build one using toroid ferite coils because of the height of the toroid transformers....can anyone help with any info or links or pictures ? thanks
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50 watt CB mod
- Thread starter robogator
- Start date
look at the datasheets for the transistors they usually have a test circuit with all component values, you would need to add a relay and keying circuit, another option is look at the schematics on cbtricks, there are plenty of 1 transistor cbamps around that that use lc network impedance transformers rather than the binocular ferrite that the custom guys use :wink
http://www.rmitaly.com/Download/Download_M.asp
check out the kl200, the same board is used in a half dozen different brands and could be made significantly smaller
http://www.rmitaly.com/Download/Download_M.asp
check out the kl200, the same board is used in a half dozen different brands and could be made significantly smaller
cbtricks.com/Amp/blackcat/graphics/jb_one_ss.jpg
cbtricks.com/Amp/messenger/graphics/messenger_class_ab_model_125.pdf
cbtricks.com/Amp/pace/graphics/pace_px100.gif
cbtricks.com/Amp/txstar/mod_v_plus_mod_plus/graphics/ts_mod_plus_sch.pdf
cbtricks.com/Amp/miscellanous/graphics/pocket_rocket.gif
cbtricks.com/Amp/miscellanous/graphics/twist100.gif
cbtricks.com/Amp/miscellanous/graphics/mosquito.jpg
cbtricks.com/Amp/messenger/graphics/messenger_class_ab_model_125.pdf
cbtricks.com/Amp/pace/graphics/pace_px100.gif
cbtricks.com/Amp/txstar/mod_v_plus_mod_plus/graphics/ts_mod_plus_sch.pdf
cbtricks.com/Amp/miscellanous/graphics/pocket_rocket.gif
cbtricks.com/Amp/miscellanous/graphics/twist100.gif
cbtricks.com/Amp/miscellanous/graphics/mosquito.jpg
[I found one called a "Mosquito" which gives the schematic and parts list but it doesn't say what the ID or OD or number of turns or turns spacing for the output coils are,has anyone made any of these one pill drivers ? I don't want to build one using toroid ferite coils because of the height of the toroid transformers....can anyone help with any info or links or pictures ? thanks[/quote]
I build a few of these from time to time-- I have the cap values and form diameters-- the spacing between the coils is not too critical-- since thats how you tune the inductance-- once you get the number of wraps right and the diameter close its just a matter of compressing or expaning the coil spacing to tune the inductance-- LC cicuit-- you just tune for resonence at the input-- just do the wrap with the right diameter form pull the coils apart some and check it out-- just space them so they are not touching-- make the space about the same as the thickness of the wire you use to start- usualy about an 1/8 of an inch apart-- you can fine tune from there by expanding or compressing the coil-- the thing about these inputs is the inductnce relly is dependant on the size cap thats used-- so you really need the cap value and inductance-- I personally like using compression caps for this, it aids in fine tuning the input and output
Diameter for the input coil is 5 turns over a 1/4 inch form- 16 guage wire-- space the coil out just so the coils are not touching- output is 4 turns with 10 guage wire on about a 3/8 form-- this will get you in the right nieghbourhood and those are the values I use-- especially if you use variable caps-- from there you just stretch or compress the coils to tune the inductance
If you had an LC meter it would be easier because then you can make a coil with the exact right amount of inductance-- butthis way you have to get the form and wraps close then tune from there
Thats why variable caps aid in tuning-- if there is any variance in induactance to can almost balance out the tank circuit by adjusting the cap
The wrong value fixed value cap and it won't work, the wrong inductance and it wont work
What your building at the input is basically a "tank circuit" for tuning the input--
For some of these circuits you also have to use inductance where the power comes into the colector- one of those small chokes with the holes in them with 2 full wraps will do
Good luck and shoot me an email -- starting full time at the shop this week---YES!!!--so I might not be able to get back to you too fast-- I can take a few pics of the design your trying to copy
Take care
I build a few of these from time to time-- I have the cap values and form diameters-- the spacing between the coils is not too critical-- since thats how you tune the inductance-- once you get the number of wraps right and the diameter close its just a matter of compressing or expaning the coil spacing to tune the inductance-- LC cicuit-- you just tune for resonence at the input-- just do the wrap with the right diameter form pull the coils apart some and check it out-- just space them so they are not touching-- make the space about the same as the thickness of the wire you use to start- usualy about an 1/8 of an inch apart-- you can fine tune from there by expanding or compressing the coil-- the thing about these inputs is the inductnce relly is dependant on the size cap thats used-- so you really need the cap value and inductance-- I personally like using compression caps for this, it aids in fine tuning the input and output
Diameter for the input coil is 5 turns over a 1/4 inch form- 16 guage wire-- space the coil out just so the coils are not touching- output is 4 turns with 10 guage wire on about a 3/8 form-- this will get you in the right nieghbourhood and those are the values I use-- especially if you use variable caps-- from there you just stretch or compress the coils to tune the inductance
If you had an LC meter it would be easier because then you can make a coil with the exact right amount of inductance-- butthis way you have to get the form and wraps close then tune from there
Thats why variable caps aid in tuning-- if there is any variance in induactance to can almost balance out the tank circuit by adjusting the cap
The wrong value fixed value cap and it won't work, the wrong inductance and it wont work
What your building at the input is basically a "tank circuit" for tuning the input--
For some of these circuits you also have to use inductance where the power comes into the colector- one of those small chokes with the holes in them with 2 full wraps will do
Good luck and shoot me an email -- starting full time at the shop this week---YES!!!--so I might not be able to get back to you too fast-- I can take a few pics of the design your trying to copy
Take care
why not get instead..
something like a ranger/rci radio
they do 50 watts no moding needed
just a thought
Later
something like a ranger/rci radio
they do 50 watts no moding needed
just a thought
Later
You guys are right-- thats the only real way to get good clean power out of a radio-- get a radio that will do it--- get the power externally or like in this case, add in a new rf power stage and that isn't the better of the 3
I've talked to robo a few times, great guy, I think this is something he is interested in doing-- much easier to pick up another radio or get an amp-- but I think its cool that there are guys interested in homebrewing, learning about different circuits ect ect
Robogator--- try doing that Rat75 design that you sent me-- looks solid and the same thing pretty much that I do
Its a heck of alot easier with an LC meter, but thats the pain in the a$$ about this design-- not having the lc meter and having to tune in the resonent circuits-- your set when you get the input done
I've talked to robo a few times, great guy, I think this is something he is interested in doing-- much easier to pick up another radio or get an amp-- but I think its cool that there are guys interested in homebrewing, learning about different circuits ect ect
Robogator--- try doing that Rat75 design that you sent me-- looks solid and the same thing pretty much that I do
Its a heck of alot easier with an LC meter, but thats the pain in the a$$ about this design-- not having the lc meter and having to tune in the resonent circuits-- your set when you get the input done
These guys are correct..that would be the best way to go...just buy a high powered radio in the first place or just add an external linear.
I like building stuff..I have been on the CB since 1958....I was building tube amps in the late 60's...I used 807's,813's,6146's,6je6's,6lq6's,3-500Z's,4-400's,4-1000's and in the last 6 months or so,I built about 65 2 and 3 pill boxes....as I said..I like to build! ...in this area there are no 1 pill boxes because everyone wants more power...but think of all the 23 and 40 ch. radio's there are out there that by adding one or two large final transistors inside the radio,would make someone a lot of extra money...cb radios at the flea markets here are a dime a dozen....stinger boards inside the radio is out of the question because when you add echo boards and noise toys there is no extra room for a stinger board but 1 or 2 pills mounted inside the radio on the back of the case is possible..a lot of people like the old cb radio's...and if you could add an extra 1 or 2 pill final to the inside of the radio and get it to work as good as adding an external linear,you would have a gold mine.....just think...no switching relays,no toroid transformers,no lot of extra parts needed.....a lot of radio's out there that could be modded with this HP final upgrade.......BTW some trucking companies here won't let the drivers have high powered CB radios or external linears and the drivers are checked at random so if they are caught using a hp radio or an external amp it is grounds to be fired......so extra power inside what looks like a low powered cb radio would be a money maker.......
I like building stuff..I have been on the CB since 1958....I was building tube amps in the late 60's...I used 807's,813's,6146's,6je6's,6lq6's,3-500Z's,4-400's,4-1000's and in the last 6 months or so,I built about 65 2 and 3 pill boxes....as I said..I like to build! ...in this area there are no 1 pill boxes because everyone wants more power...but think of all the 23 and 40 ch. radio's there are out there that by adding one or two large final transistors inside the radio,would make someone a lot of extra money...cb radios at the flea markets here are a dime a dozen....stinger boards inside the radio is out of the question because when you add echo boards and noise toys there is no extra room for a stinger board but 1 or 2 pills mounted inside the radio on the back of the case is possible..a lot of people like the old cb radio's...and if you could add an extra 1 or 2 pill final to the inside of the radio and get it to work as good as adding an external linear,you would have a gold mine.....just think...no switching relays,no toroid transformers,no lot of extra parts needed.....a lot of radio's out there that could be modded with this HP final upgrade.......BTW some trucking companies here won't let the drivers have high powered CB radios or external linears and the drivers are checked at random so if they are caught using a hp radio or an external amp it is grounds to be fired......so extra power inside what looks like a low powered cb radio would be a money maker.......
"and if you could add an extra 1 or 2 pill final to the inside of the radio and get it to work as good as adding an external linear,you would have a gold mine.....just think...no switching relays,no toroid transformers,no lot of extra parts needed]"
True-- but you also have alot of extra rf interfernce to deal with -- thats the big problem --
Regardless, I say go for it.... as long as you know a bit about resonent circuits and get used to tuning them your all set
Nothing is really prefect when making your own chokes and coils without a meter to measure it --it the reasson why the spacing between the coils is variable-- for tuning-- so its hard to say exactly what the space between the coils will be since you will have to increase and decrease this to tune the circuit-- just start with the coils not touching
Main thing is to get the guage of wire close and the form size close-- so the inductance will be very close to whats needed-- then you tune it in from there by expanding or compressing
The only other thing I can do is send you some pics of the design
True-- but you also have alot of extra rf interfernce to deal with -- thats the big problem --
Regardless, I say go for it.... as long as you know a bit about resonent circuits and get used to tuning them your all set
Nothing is really prefect when making your own chokes and coils without a meter to measure it --it the reasson why the spacing between the coils is variable-- for tuning-- so its hard to say exactly what the space between the coils will be since you will have to increase and decrease this to tune the circuit-- just start with the coils not touching
Main thing is to get the guage of wire close and the form size close-- so the inductance will be very close to whats needed-- then you tune it in from there by expanding or compressing
The only other thing I can do is send you some pics of the design
Maybey take a look at an amp called a "deer Hunter" it uses a different design for the inductance-- no torrids- but it uses small wire wraps that actually wrap through the board to save space-- this kind of design can also be used in back of a radio or on a small board inside
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