Circuit Diagrams in "The Screwdrivers Experst Guide"
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- Super Member
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Re: Circuit Diagrams in "The Screwdrivers Experst Guide"
I am assuming the extra capacitance is whats needed, i put out 4 watts and am bang on frequency but when i get to ch23 (Hi band - new band added) the tx power has gone from 4 watts to 1/2watt and 27.635 is all i can get to - any ideas?
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- Super Member
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- Joined: 17 Apr 2015, 18:26
Re: Circuit Diagrams in "The Screwdrivers Experst Guide"
Hi All
With the weekend fading fast I took a punt and put an 82pf cap in parallel with C212(47p) shown above and good news is i have:/-
Mids: 26.965 - 27.405
Hi's: 27.415 - 27.855
All channel frequencies are good now.
However, I know need to work out how to get the radio to cover all the channels withRF output, as I have full 4 watts on the all the mids but still only 4 watts up to ch23 where it drops off and practically 0.1watts on ch40- of the Hi's.
Is there a tip for broadnading the power as well with this type of mod?
Thanks.
With the weekend fading fast I took a punt and put an 82pf cap in parallel with C212(47p) shown above and good news is i have:/-
Mids: 26.965 - 27.405
Hi's: 27.415 - 27.855
All channel frequencies are good now.
However, I know need to work out how to get the radio to cover all the channels withRF output, as I have full 4 watts on the all the mids but still only 4 watts up to ch23 where it drops off and practically 0.1watts on ch40- of the Hi's.
Is there a tip for broadnading the power as well with this type of mod?
Thanks.
- cb4ever104
- Legend
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- Location: España
Re: Circuit Diagrams in "The Screwdrivers Experst Guide"
It's not the same as the VCO . There's a lot more involved in the output stage . From the mixers , all the way through to the antenna . I've never seen that radio , but you might not get the full 80ch range on TX . Or RX for that matter . Sue posted a thread about the 2824 chassis and she used the VCO voltage to track/adjust both the TX and RX stages to broadband it , but it's a lot of work . You might be able to bridge a coil at the mixer stage to dampen it a bit , but it's just a guess . If you have a scope then you should be able to see which stage is dropping off .
30TM060
Paul aka "Sammy". (108) PY60 Old Paisley DX Group (RIP Rab Markie)
Ex GM0 , now EA5 .
Handle "Fortune Hunter" back in "the day"
Radios ....? Anything that says "TAIWAN R.O.C" on the back.
Paul aka "Sammy". (108) PY60 Old Paisley DX Group (RIP Rab Markie)
Ex GM0 , now EA5 .
Handle "Fortune Hunter" back in "the day"
Radios ....? Anything that says "TAIWAN R.O.C" on the back.
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- Super Member
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- Joined: 17 Apr 2015, 18:26
Re: Circuit Diagrams in "The Screwdrivers Experst Guide"
Hi Sammy
Its got the TC9102p PLL in it and from what i read its fine for the 80 ch mod its just when u have me doing it that you run into problems! Haha! i will take your suggestions on the mixers etc and read up on those and see if i can glean anything i can try, many thanks for this much appreciated. .
Its got the TC9102p PLL in it and from what i read its fine for the 80 ch mod its just when u have me doing it that you run into problems! Haha! i will take your suggestions on the mixers etc and read up on those and see if i can glean anything i can try, many thanks for this much appreciated. .
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- Super Member
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Re: Circuit Diagrams in "The Screwdrivers Experst Guide"
Done!!! Working across all 80 channels it just needed a tweak on the tx pots!
My first addition of extra channels and it worked, i am amazed!!
In the words of that great philosopher “Alan Partridge”... Back of the Net!
My first addition of extra channels and it worked, i am amazed!!
In the words of that great philosopher “Alan Partridge”... Back of the Net!
- cb4ever104
- Legend
- Posts: 6562
- Joined: 28 Jul 2011, 21:26
- Location: España
Re: Circuit Diagrams in "The Screwdrivers Experst Guide"
Glad you got it sorted . I thought you'd already tried realigning the output stage , but it looks as if that wasn't the case . Anyway . Well done !
30TM060
Paul aka "Sammy". (108) PY60 Old Paisley DX Group (RIP Rab Markie)
Ex GM0 , now EA5 .
Handle "Fortune Hunter" back in "the day"
Radios ....? Anything that says "TAIWAN R.O.C" on the back.
Paul aka "Sammy". (108) PY60 Old Paisley DX Group (RIP Rab Markie)
Ex GM0 , now EA5 .
Handle "Fortune Hunter" back in "the day"
Radios ....? Anything that says "TAIWAN R.O.C" on the back.
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- Super Member
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- Joined: 17 Apr 2015, 18:26
Re: Circuit Diagrams in "The Screwdrivers Experst Guide"
Thanks for your help again!
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Re: Circuit Diagrams in "The Screwdrivers Experst Guide"
No Oscillation frequency in the circuit you built nothing to inject.
What freq xtals are you using.
A 2n3904 transistor is what you need and the oscillator circuit for it to work.
What freq xtals are you using.
A 2n3904 transistor is what you need and the oscillator circuit for it to work.