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My old friend President Jackson.
- Thread starter Grogan
- Start date
rob,
low beta means lower gain, if you swap a high beta for a low beta transistor you would have low idle current unless you turned the bias pot up,
the 477 datasheet specs 40ma idle current, the old rig manuals used 100ma which is what i use as it works well, never tried it @ 50ma or lower in 477 final rigs, i use 50ma for the driver on all uniden exports,
we don't pull the jackson limiter here, we stick a 575 teardrop on
low beta means lower gain, if you swap a high beta for a low beta transistor you would have low idle current unless you turned the bias pot up,
the 477 datasheet specs 40ma idle current, the old rig manuals used 100ma which is what i use as it works well, never tried it @ 50ma or lower in 477 final rigs, i use 50ma for the driver on all uniden exports,
we don't pull the jackson limiter here, we stick a 575 teardrop on
It's a shame they don't relaunch a proper Jackson 1 or Lincoln (Uniden 2830) as in the UK originals are highly sought after and fetch mega money , not uncommon to make £250+ for the Jackson and £300+ plus for perfect boxed Lincolns (but these are President branded)
Surely Superstar must make a statement at some point, if to confirm their involvement or none involvement in this radios existance and coming to market.
If somebody has knocked them up in their shed and sold them as a new product and then put them into the Distributor network, surely it needs addressing for all parties involved.
Radio Hobbyists Worldwide dont miss a trick, on one hand old engineering tends to be prefered in CB Radio circles, but a 29 year old board?.
I can quite clearly see by your photos ths is an old radio.
What worries me is some of the "School Boy Errors" like fitting coarse thread pitch case screws in metric fine threads.
Surely it has stripped the threads in the chassis too?
On one hand it is a classic radio, but it is too much of "Bittsa" in my eyes.
I read a link from our UK based TM1 Forum.....it certainly has been a most interesting read and story.
Surely Superstar must make a statement at some point, if to confirm their involvement or none involvement in this radios existance and coming to market.
If somebody has knocked them up in their shed and sold them as a new product and then put them into the Distributor network, surely it needs addressing for all parties involved.
Radio Hobbyists Worldwide dont miss a trick, on one hand old engineering tends to be prefered in CB Radio circles, but a 29 year old board?.
I can quite clearly see by your photos ths is an old radio.
What worries me is some of the "School Boy Errors" like fitting coarse thread pitch case screws in metric fine threads.
Surely it has stripped the threads in the chassis too?
On one hand it is a classic radio, but it is too much of "Bittsa" in my eyes.
I read a link from our UK based TM1 Forum.....it certainly has been a most interesting read and story.
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You may be waiting along time if not indefinetely for that to happen.
"On one hand it is a classic radio, but it is too much of "Bittsa" in my eyes."
I would agree. I do beleive that if this "classic" radio had come out at the time it was apposed to it would have ruined the names assoaciated with it.
"On one hand it is a classic radio, but it is too much of "Bittsa" in my eyes."
I would agree. I do beleive that if this "classic" radio had come out at the time it was apposed to it would have ruined the names assoaciated with it.
I tried the radio with and w/o the limiter. When I bought it, it came with the limiter already pulled out. So I put in a new one. Then I took it out and added a 1.5k ohm resistor to the collector and put it back in. That works far better on AM w/o affecting SSB. I can get +100% modulation now (checked on a scope), and set the radio's mod meter to correspond to that. Set the dk to 7w for AM/FM. PEP on AM is just below 20w; that is the best I can get out of it short of pulling the limiter out again. Used a real peak reading meter; not a Dosy.
Not big on using AM, as I use SSB 95% of the time anyway. Use a Astatic Silver Eagle; gets really xlnt reports on SSB all the time. However, I'd like to improve the AM performance if I could.
Is it possible to put an electrolytic cap on the audio chip in order to get some negative peak compression on AM TX? I want to turn up the modulation/squeeze some more positive peak modulation % out of it. Is that possible? Where would the negative leg of the cap go to? Which pin on the IC for the '+'/cap recommendation? Pin 5? Yes; I am trying to draw a parallel to the Cobra 2000GTL board & the NPC mod. The difference is the Jacko doesn't have a AM Regulator like the 2000 does.
Pic:
SuperStar JA and a Blue Dot MRF477
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if you want to play with the jacko have a look what people do with the lincoln,
its a similar low level mod radio set out differently,
we don't use AM so no need for npc mods, i used to do tx/rx tone mods and filter mods for friends but nothing for AM.
its a similar low level mod radio set out differently,
we don't use AM so no need for npc mods, i used to do tx/rx tone mods and filter mods for friends but nothing for AM.
I just got a brain storm Rob. How about a switch to switch and unswitch the limiter. Also there is a very simple mod on Cb. tricks for a controlled carrier mod for this radio that has good results. There has been a schematic posted on how to do it in the last couple weeks under one of the Superstar JA threads. Pretty much what you are talking about but with no capacitor. If you try this I would like to know how it works.
How about a switch to switch and unswitch the limiter. Also there is a very simple mod on Cb. tricks for a controlled carrier mod for this radio that has good results. There has been a schematic posted on how to do it in the last couple weeks under one of the Superstar JA threads. Pretty much what you are talking about but with no capacitor. If you try this I would like to know how it works.
I have seen a couple on there and have seen a couple sell for more that they get at the dealers.
am I looking at the pic of the 477 final without a screw and heat sink grease and a insulator on it.
I just ordered one of these to see how it does. I am going to see if AM can wake up a little by changing a couple resisters.
R258 to a 1.5k
R261 to a 3.9k or 4.7k to see if ether will pick up the modulation.
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