Silver faced President Jackson

[jazzsinger]

+1 on cut the alc a bit.
and if you do kill the mrf477 there is a mitsubishi sub with the same bec basing.

the mitsubishi 2sc1945 has the same pinout as the mrf 477,it is best set for around 4-5 w carrier and around 12w pep on ssb.not quite what the original did but ideal to get your radio back on air and sounding clean.

eleflow also make a replacement 2sc1945 if you can't source the mitsubishi original and is available on uk e bay from seller weazle66.Mark weazle 66 is a decent guy to deal with.Mark also has a video on youtube showng how to replace the mrf477 with the 2sc1945 on the president lincoln.

in my opinion the president jackson is THE best ssb radio ever made for 11m,designed solely for dx'ing,many say the early silver versions are the best of the lot,but i've found them all to be excellent,only minor drawback is the agc problem which is easily rectified as previously mention by my learned friend bob 85 and others.Granted its not a great AM performer with its low level modulation but on ssb there are few that compare,its also reasonably good on FM which made it so popular in europe where FM is preferred over AM for its reduced incidence of tvi/rfi.

 

[heavyD]

president Jackson Agc mod

Will the agc mod fix the same issue on am? . I have to keep my hand on the RF gain if I'm talking to 2 people. ITS REALLY BAD. ?

 

[Meglotron]

Wow. This post got dug up from the archives? That's kinda funny.


I sold this radio to a friend of mine a while back, he loves it. Still has the original MRF477 in it, still does 50W on my Bird 43A into a dummy load. He shoots skip a lot with it. The AGC mod I did on it was amazing though. Thanks to all who helped me with that mod. Cheers!


-Exit

Does your midland 79-893 have the same rf gain issue? mine does.

 

[BJ radionut]

To increase transmit power of 5 watts from S-6 to S-7 you need to increase transmit power 4X.
To multiply it once - that would be 10 watts, to multiply it twice it would be 20 watts, to multiply it three times would be 40 watts and to multiply it four times would be 80 watts.
Getting 50 watts out of it - doesn't even move the needle one S unit.

I have been under some wrong impressions, so I am asking you for an update please.
CJ, are you calculating the increase of 1 "S" unit being a 6db rise in signal strength?
I must be calculating incorrectly, as and increase of 5 watts to 10 watts I thought would equal 3db.Then the additional increase of 10 watts to 20 watts would equate to 3 db, thus a 6db increase in signal strength would be achieved by increasing power output from 5 watts to 20 watts.
Please explain your calculations and standards relating to how 5 watts to 80 watts equates to 6db increase in signal strength, I have been totally mis-lead.

So if you had 100 watts of transmit power - you would need 10,000 watts of transmit power - just to move the needle from 10 / S-9 to 20/S-9

I will be interested in revising my thoughts to this "NEW" math as this old calculation must totally misrepresent the "NEW" standards.
Please explain again how a transmitter with output of 100 watts and to raise the receive signal 10db (from 10 / S-9 to 20/S-9) equates to 10,000 watts
This new calculation far exceeds the standard I have been mis-lead to use, as the "old goat" math states a 10db increase using 100 watts as the base figure equates to 1008 watts output(rounded figure).
I look forward to your reply. We are all here to be enlightened.
All the Best
BJ

 

[jazzsinger]

To increase transmit power of 5 watts from S-6 to S-7 you need to increase transmit power 4X.
To multiply it once - that would be 10 watts, to multiply it twice it would be 20 watts, to multiply it three times would be 40 watts and to multiply it four times would be 80 watts.
Getting 50 watts out of it - doesn't even move the needle one S unit.

I have been under some wrong impressions, so I am asking you for an update please.
CJ, are you calculating the increase of 1 "S" unit being a 6db rise in signal strength?
I must be calculating incorrectly, as and increase of 5 watts to 10 watts I thought would equal 3db.Then the additional increase of 10 watts to 20 watts would equate to 3 db, thus a 6db increase in signal strength would be achieved by increasing power output from 5 watts to 20 watts.
Please explain your calculations and standards relating to how 5 watts to 80 watts equates to 6db increase in signal strength, I have been totally mis-lead.

So if you had 100 watts of transmit power - you would need 10,000 watts of transmit power - just to move the needle from 10 / S-9 to 20/S-9

I will be interested in revising my thoughts to this "NEW" math as this old calculation must totally misrepresent the "NEW" standards.
Please explain again how a transmitter with output of 100 watts and to raise the receive signal 10db (from 10 / S-9 to 20/S-9) equates to 10,000 watts
This new calculation far exceeds the standard I have been mis-lead to use, as the "old goat" math states a 10db increase using 100 watts as the base figure equates to 1008 watts output(rounded figure).
I look forward to your reply. We are all here to be enlightened.
All the Best
BJ

BJ radionut,

you are correct in both cases, 6db increase from 5w = 20w, and 10db increase from s9+10db - s9+20db would require the power to be increased from 100w to 1000w, not the 10,000w that was misquoted by channel jumper.

 

[IMD262]

George

Is there any difference between the silverface and the early 5 band black face Jackos?

 

[jazzsinger]

George

Is there any difference between the silverface and the early 5 band black face Jackos?

to be honest i had them both at the same time and never thought to compare them (was more interested in getting a pb010 chassied radio going at the time), both were excellent radios though. i think the early silver taiwan ones may have the board capacitively decoupled, can't mind if the black philippines one i had did. bob 85 might recall better than me, i believe he's had both as well.

 

[ExitThirteen]

No real difference between the black faced Jacksons, and the silver faced Jacksons... the silver faced Jacksons have the PB-042AB revision PCB in them, and the black faced Jacksons had the PB-042AE revision PCB, if memory serves me right. No real difference tho, both are great radios!



~Cheers~

 

[jazzsinger]

No real difference tho, both are great radios!



~Cheers~

A point i would never argue against, in my opinion for 11m ssb work the president jackson is the best of the best. i've had so many off them both silver and black faced 5 banders and numerous black faced 6 banders and all were superb on ssb.

tx audio is sublime even with just the standard dynamic mike supplied, and is even better with an astatic 575-m6.when you have a cb wired to a basic linear and an astatic 575-m6 and people continually ask over years which kenwood,yaesu or icom your running,depending on their preference.you know your running something a bit special.

the jackson is certainly special, a radio designed for only 1 purpose, illegal operation on 11m ssb.pity those friggin outputs are so expensive.

 

[bob85]

i like the early jacko's silver or black over the later 6 banders, the earliest board was tidied up a little with less components tacked on the back like they did with the lincoln but they seem to work the same,
there are more versions than i first realised, now im not sure when the board stopped been decoupled from the frame but they omitted the caps in favour of wire links at some stage in the production, after that came the so called high power version with mrf455 output on a small addon pcb again like they did with the lincoln,

the early jacko with a 575 mic is still one of my favourite cb's for mobile ssb.

 

[psycho]

George

Is there any difference between the silverface and the early 5 band black face Jackos?

None...they are all crappy AM radios and the SSB was fair. The Silverfaced Jacksons were the first versions of the Jackson.
Bought one in 1982 and sold it the next day. $270 was a lot of money back then.
The Jackson was the one of if not the first Export Radio available here.
Worst radio I have ever owned.

 

[Se7en]

 

[rabbiporkchop]

Update...


Performed the mod...simply incredible. No more adjusting the RF gain anymore on close SSB signals! My Jacko is rockin'. Thanks!

Welcome to the club. Guys like bob85 are a Dying Breed.
73's

 

[Fred Spoon]

I have recently bought on old black 5 banded Jackson and want to know what is the best mods for modulating on am

 

[Robb]

If you are looking to find an AM monster in this radio, then I'm afraid that you have struck out.
However, if you were looking THE best SSB radio,; then you hit a grand slam homer.

The AGC mod is a necessary mod for this radio receiver section. It really must be done to it. Read back a few posts on this thread and it is there.