858 PLL Mods and stuff

[2RT307]

Hi folks, I stumbled across this site while looking for some information for my friend HomerBB. I'm not even sure the site owner is still alive, but the information is interesting. It is hard to navigate, but there is a lot of different information there for the 858 PLL board found on the TRC-458, Cobra 138XLR, 139XLR, and many others. Some of the stuff I have never seen, especially the continuous tuning dial with frequency counter. It seems similar to the mods I have seen for the Cobra 2000GTL with the 3 segment readout, but I am not sure if it is related.

EFJ Devices
N9EFJ PIC Micro - CB Radio code
EFJ Devices

Anyone have any thoughts on this stuff? ExitThirteen??? Your input would be greatly appreciated!

73,
RT307

 

[IMD262]

Hi folks, I stumbled across this site while looking for some information for my friend HomerBB. I'm not even sure the site owner is still alive, but the information is interesting. It is hard to navigate, but there is a lot of different information there for the 858 PLL board found on the TRC-458, Cobra 138XLR, 139XLR, and many others. Some of the stuff I have never seen, especially the continuous tuning dial with frequency counter. It seems similar to the mods I have seen for the Cobra 2000GTL with the 3 segment readout, but I am not sure if it is related.

EFJ Devices
N9EFJ PIC Micro - CB Radio code
EFJ Devices

Anyone have any thoughts on this stuff? ExitThirteen??? Your input would be greatly appreciated!

73,
RT307

Carl is active on Bennie's forum.

 

[2RT307]

I don't know who Bennie is! I probably should have looked up his call on QRZ to see if he was "active" or not. Thanks for the info.

73,
RT307

 

[tecnicoloco]

I don't know who Bennie is! I probably should have looked up his call on QRZ to see if he was "active" or not. Thanks for the info.

73,
RT307

Bennie is the owner of CB Tricks website and Carl is the owner of EFJ Devices and goes by 2x4,also sells a very good software to troubleshoot cb radios called QF4.0

 

[2RT307]

Hi technicoloco! Thanks for the info. I really thought this thread would have been interesting to more people. I know there are a lot of good 858 PLL rigs still operational out there. I have a base station 139XLR, and it is one of my favorite rigs to this day. I have not modded it though, as it is about the only rig that I have that is perfectly stock. :laugh:

73,
RT307

 

[HomerBB]

Say, Brett, thanks for the info. The tech had the 458 going, and then it quit modulating again. Too many hands in it over time. He has been fixing screwdriver screw ups as he goes trying to put it back together for me.

 

[2RT307]

Hi Homer, I had a problem with my 139XLR where the modulation quit working. Mostly on AM, but it wouldn't put any power out. Seemed to be a common problem, as Mike at Kilgore's (the shop I mentioned to you when we visited) was able to fix it cheap.

Next time I talk to him, I'll ask him about your Realistic rig, and the Digiscan issue, too!

73,
Brett

ps the end fed dipole is working great, many contacts today while on the flat side hanging from the side of my house!

 

[HomerBB]

Thanks for the help with the Navaho.
That one isn't an end fed dipole, but an end fed half wave wire antenna.
I am glad you are getting some fun use from it. It was just hanging on my pegboard as you saw.

 

[unit_399]

Anyone have any thoughts on this stuff?
73,
RT307

Some good info...some BS. The picture of the 458 with a frequency display looks photoshopped to me. Also, his description of the speech clipper circuit as an "equalizer" is pretty lame, and his saying to remove it to increase performance is dead wrong. I would take his self-serving, " If you don't know your radio, know your technician," statement with a grain of salt.
- 399

 

[2RT307]

Noted, 399. I have heard of folks taking the speech processor out of line in these rigs. I have to say that my 139XLR is one of the only rigs that I have used that sounds really good with a stock mic. LOUD modulation, and crystal clear on ssb. I always wondered why it would work so well with even a RK56, until I found out the radio had a type of processor.

73,
RT307

 

[tecnicoloco]

Diode clipper followed by a bandpass filter banned by the FCC

 

[unit_399]

Diode clipper followed by a bandpass filter banned by the FCC

It wasn't actually "banned." It was more like the FCC saying, " If you want us to continue to type-accept your radios, then don't send us one like this again."

- 399

 

[2RT307]

It wasn't actually "banned." It was more like the FCC saying, " If you want us to continue to type-accept your radios, then don't send us one like this again."

- 399

Why was this method bad? Can you explain a little more?

My local tech has told me that the 139XLR was "over engineered" and actually more complicated than it had to be. Still, he tells me to hang onto it as it is a great SSB rig. He doesn't say that about many of the rigs I take to him... just the President Lincoln, the Uniden Grant XL's, and my 139XLR base. And that is NOT because he is constantly repairing them for me, haha.

73,
RT307

 

[Zman]

The funny thing is there are actually 2 different SSB 858 chassis and they DO NOT mod the same.. The regular board that is used in the Cobra 139XLR, Robyn 520D, 510D, TRC 458, 457. Then the other board that is used in the Teaberry Stalker 1 40 CH mobile, Midland 79-893, Courier Spartan 40H mobile, Courier Centurion PLL 40 and the 40D and a few other rigs.... Both board have the 858 PLL but both boards are laid out totally different!

 

[unit_399]

Both board have the 858 PLL but both boards are laid out totally different!

Correct. The 139XLR, TRC 457, 458, etc. is the second generation 858SSB board, and is by far the better of the two. Both had speech clipping circuits, but the AMC on the 139XLR board is light years better. Uniden put the speech clipper in their AM sets too (Cobra 29XLR for instance) but it was a much less sophisticated design and not nearly as effective. This same design was used in the 1st generation 858SSB boards in the Teaberry and Courier rigs, and their audio wasn't even close to that from a 139XLR. There are other subtle differences that improved the gen 2 board's receiver too.

RT307 -
I wouldn't call the 139XLR board "over-engineered." Back then (1977) the CB craze was going full-tilt, and there was a lot of competition between high end manufacturers like SBE, Stoner, CPI, etc. to make the "ultimate" CB. Uniden was the new boy on the block, so to speak, and wanted to strut their stuff. So they updated their existing 858SSB sets which proceeded to kick ass on-the-air, and, at 1/3 of the price of the high end guys' equipment.

The FCC didn't like the direction that the manufacturers were taking, and decided to rein things in. They directed that any new models had to have less expandability and power potential. By this time the CB craze was winding down, and SBE, Stoner, CPI, Teaberry, etal had already closed shop. With CB sales way down, Uniden redesigned their CB line with the emphasis on low cost rather than max performance. So speech processing and other frills were a no-no. This is pretty much where we stand today. To me, the gen2 Uniden 858SSB was the best mass-produced type-accepted cb ever made.

- 399

Sorry this was so long-winded.