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I did my first mod today!

A

ajw2685

Guest
Well, I went to Rat Shack and got an El Cheapo soldering iron with 15w and 30w power levels. I bought a package of resistors, some solder and a package of tuning tools. I removed one leg of the modulation limiter diode and removed the internal speaker on my Uniden Pro 520XL. I plan on testing it this weekend without the limiter and with a resistor in line with it.

I feel like a rocket scientist! Some more hands on training and I will be modding all of my own radios. :D
 

start by resoldering the mod limiter diode. hacks clip limiters, dont be a hack.
 
I am only going to try it out once. Then, I will be putting a resistor back inline with it.
 
That is what I plan on doing. DTB on here said to try 10k-15k. I am starting with a 10K tomorrow morning when I get to my parents house after I try it in no limiter all splatter mode to see what it does. :LOL:
 
in the past i usually grab a small pot from radio shack and adjust that for 100% modulation. after i find what it takes i check the resistance and find a simular value resistor(s) and solder them in for good.

its handy if you are dooing a few different radios or tring to set the perfect amount of talkback.
 
Well, I had it all tuned up, then I ruined pot L1. :roll: I had a dk of 4 and swing of 14-15. At first it was a dk of 6 and swing of 15 and bleedover/splatter LIKE CRAZY!!!! It was kinda neat to play with and hear myself on every speaker in my parents house and in the garage. Well, I found pot L1 somehow adjusted my audio. So, my dad was listening on the other radio as I was adjusting L1 down, and my cheap tuning tool thing-a-ma-jig from Rat Shack rounded off and broke without me noticing. :roll: I thought the tool came out of the slot so I gave a little push, well, the pot popped and the tuning slug would not adjust up or down, just turned in place. So, now the radio works, but I have REALLY low audio on the other end. I got my receive tuned WAY UP. I was pretty proud of that part. I also spread the copper coils to see what it did, and did not notice much as I lowered my DK at this same time and the splatter stopped. So, I don't know if the lower DK stopped the splatter or spreading the coils did.

When I first started, with just one leg of the mod limiting diode removed from the board, it was 6 watt dk and 15 watt swing. Well after conversing with a member on here, I learned I was tuning it wrong. I was indoors with a mobile antenna. I know, I know! I knew better but it was all I had. I had my wilson 1000 mounted in my parents garage on our big wood stove. I had a flat SWR, but apparently my power levels were all harmonics.

So, I will be buying another Pro520XL and starting over. I have a list a mile long of things I need from Sparky's and I will be heading over there in 2-3 weeks and I will continue this experiment then.

Thoughts/Comments/Constructive Criticism?
 
Anything labeled as "L" is NOT a pot. A pot is a variable resistor like a volume control or a small board mounted mod level control. Those "L" components are inductor coils and the slug is VERY brittle as you found out. Never, and I mean NEVER, use a metal tuning stick to adjust them.They will break.In fact,unless you know what you are doing it is generally a bad idea to adjust them anyway. The output coils in a radio are generally tuned for harmonic supression and adjusting them may show more on a meter but the harmonics are much worse as well.I have seen guys think they have the RX peaked to the ultimate only to see the S- meter higher but the received splatter faaaar worse than ever before.Even had one guy swear he could hear much better since he adjusted his S-meter level control. :LOL: Everyone was 20 over 9 :roll: It's good that you want to learn and experiment but it is better if you have an idea of what should happen before you make an adjustment.
 
those copper coils you spread are the traps. that makes your radio splatter. it allows more harmonic distortion to your signal, it makes the watt meter show an improvment but its just fake wattage.
 
Carl said:
those copper coils you spread are the traps. that makes your radio splatter. it allows more harmonic distortion to your signal, it makes the watt meter show an improvment but its just fake wattage.
Click to expand...

do you mean in the same way i spreaded the coil in my 68xl mod???
finalpicinboardedited.jpg
 
werent we all newbies at one time or another? hehe. Oh the things i would have done to that little thing now. Carl you should have seen it man. My 68xl Had a Chameleon paint job.(changed colors in the sun) it was very awseome.
 

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