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Receiver alignment question

groundwire

Sr. Member
Jul 19, 2014
1,370
1,829
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If the receiver alignment is not done correctly, is it possible to have alot more sensitivity and noise on the upper channels compared to the lower channels? Or more on the low end than the top end, either way. Basically uneven receive throughout the whole 40 channel spread
 
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Ok. I got a brand new 29ltd right out of the box with this sympton. Guess i have to do a receiver alignment.
 
Wow, what a piece of crap radio. I put it on the bench, open it up and all the slugs have that white powdery look, wtf!. I know from experience that means they are brittle and are gonna crack and of course they did. Every single rx can cracked and all the other cans look the same. Pshh, what a joke. Oh well another brand new radio went in the dumpster. Unbelievable
 
You or anyone else - if interested, can learn more here...


It's a long thread but might help others from making the same mistakes...

In the older days, Cobra knew of this issue, talked about it in their 29WST series by having RX peaked on channel 40 - then the BANDSPREAD the radio has, versus the IF being picky and desiring of only one frequency to develop the highest transfer, was checked from channel 1 to Channel 40 - adjusting L22 - when you tuned one of these radios - you have to remember to "peak out on channel XX" but when in RX mode, you set Channel to XX and tune LX, Lx and so on - to peak - then Change channel to XX and BALANCE signal generator output to read XX equally on Channel 1 and Channel 40 using the S/RF-meter...

1671314430482.png


And even in their more elaborate SSB radios they actually wanted you to turn down the IF to peak the RX coils more for general coverage and equalize the performance across the band.

I'm sure you've seen this...Pro 810e on CB Tricks...
1671316089868.png
L5 was the "coupling" coil that buffered the PLL's IF out of the VCO. So you wanted to lessen any artifacts and remixing by turning down the IF out and let the RX signal in to maximize the ability to "hear" - doesn't mean "select" - so to "discern" you had to lessen the IF mixer to obtain the peak RF signals to even work with that boards mixing system.

Realistic TRC-453 says...(see STEP 3)
1671315878762.png

Sharp radios also talked about this but wanted you to "scope it" instead.

1671315296006.png.
So really, it's any hybrid-ized method you can use from any and all the radio manufacturing systems factories used to develop a method and means to obtain any sort of performance - and is subjective - based upon the tuning methods you decide to use.

Whether it is to follow the 29 exactly - which if you did, you must not have liked those results because you're posting more questions here.

You have to find a method - using several tips and tricks that other radios makers have stated in their own service manuals - and develop your own.

So, when it comes to the 29 PC-122 or a Cobra 2000 - you have to know the ways and means of the company that built these chassis and the way they did their tune-ups, so ALL their techs can follow thru the process throughout the facilities they were built in, to standardize the results and make their quality goals and keep their reputation - secured.

So I can't prevent the problems you had, any used radio is Caveat Emptor for anyone - but I see I got here too late to help.
 
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