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Anyone know if clipping d129 on a HR 2510 will open up the am limiter
- Thread starter hacksaw
- Start date
PLEASE don't clip the limiter on any radio! You only succeed in making the radio sound like crap, and making your meter dance...
Blindly repeating what you hear/read is more annoying then clipping the limiter.
The act of disabling/modifying a modulation limiter circuit does NOT automatically mean the radio is going to sound like shit. If you think I'm wrong explain, and DO be prepared technicaly, or its just another "parroted rant"
This chassis is definitely one which CAN benefit from Modification to the audio train.
Probably the biggest reason to "PREACH" don't remove the limiter is because so many individuals don't have a clue how to properly run a radio.
Actually it is stated Different Strokes for Different folks Ok so he does not like clipping limiters and yet you do but do you have the right to trash the person for what he believes in ?? Oh BTW this person know how to run an open mod radio and make it sound CLEAN
LOL, It has nothing to do with trashing anyone, I spoke my belief based upon knowledge, seems to me your as guilty as anyone of exactly what your accusing me of. I at least did comment on the OP. Oh and where the hell did you read "I LIKE CLIPPING LIMITERS"? or even that I endorse such a thing
Try not to read so much into a post and get your undies out of the bundle...
Since this person in no way supports the claims made it is damn annoying. I do have a right to be annoyed. But go ahead, play KISA, if it makes you feel good.
BTW: the only thing you've managed to do is troll a thread, nothing useful was added, at least I took the time to quantify my opinion about the radio in question. Certainly more then I can say for you.
Mr Fatty writes;
By modifying you're posts in a small amount you may not insite the comebacks that you do. :glare:
By modifying you're posts in a small amount you may not insite the comebacks that you do. :glare:
So what you want me to candy coat my posts? the radio can benefit greatly from modification, whether someone chooses to do so is up to him/her A generic post using the stereotype that all limiters are spawn from hell IMO is not useful at all. It reminds me of a poodle nipping at the heels, And I find it annoying, probably like many find my posting annoying.
If I step/ped over the line of the forums rules then please make me aware of it. If you just don't like what I have to say, YOU have every right to be "annoyed".
I guess my question to you... Is this a suggestion, or more?
I wouldnt clip it but try it. Have someone on the other end on a radio and listen or record you so you have some evidence to work by. first test on AM with the radio unclipped, then second test with the radio clipped. Ask the recieving end how it sounds unclipped and how it sounds clipped. Then if you prefer it clipped then just leave it clipped, if not just leave it in tact...
Most people like to clip while others dont. The way I view this, it is like the NPC mod. Some people like it and some dont.
Just my 2¢....
Most people like to clip while others dont. The way I view this, it is like the NPC mod. Some people like it and some dont.
Just my 2¢....
If you want to sound better do following:
1. C61 - 82pF
2. Remove R120 - hard to find
3. R85 - 470k>180k
4. R86 - 100>330
Adjust your audio with AMC PR.
Audio will be bright and clear, no more muffled modulation.
If you want have broadcast sound:
5. C63, C57, C59 - 4.7uF
6. C58 - swap with 10k resistor.
7. C133 - 1uF - readjust FM deviation after that.
Good luck.
Mike
Someone suggested having another operator listen to give you an audio report. That's a very good idea. Also have him/her listen one channel up and one channel down to see if there's any bit if your audio when you're talking your loudest. If there's adjacent channel noise after the diode mod, you're exceeding the bandwidth (or your buddy's receiver is too broad).
A more precise way to do it is to put an oscilloscope (doesn't have to be expensive) on the output of your radio and watch the waveform. Overmodulation is easy to recognize, and means the extra power you're putting out (the "extra swing") is falling outside the channel you're trying to talk on. I can post a link to scope screen caps if that would help anyone.
HTH,
-- Zygoma --
GROL Holder, Extra Class ham, Inept Old CBer from the Days of Comstat 19s
A more precise way to do it is to put an oscilloscope (doesn't have to be expensive) on the output of your radio and watch the waveform. Overmodulation is easy to recognize, and means the extra power you're putting out (the "extra swing") is falling outside the channel you're trying to talk on. I can post a link to scope screen caps if that would help anyone.
HTH,
-- Zygoma --
GROL Holder, Extra Class ham, Inept Old CBer from the Days of Comstat 19s
DO NOT CLIP THE LIMITER!!!! There are several reasons why not to clip the limiter.
1# ALL audio will be uncontrolable AM SSB FM deviation
2# The gain you see in increased audio power will bring ALOT of harmonics because the signal is flat topping and clipping, there are better ways to modify the AM amp chain and retain the ability to limit the gain.
3#In most cases you will lose avg power out. You have to have REAL test equipment to see this not a Dosy meter and your friends ear.
I have only seen a few A VERY FEW radios that when the limiter was removed the radio did not show any distortion. The reason being is because those radios had such an anemic Audio amp, it wasnt capable of driving the amplitude to %100.
And just for your information, anything over %100 IS A FALSE /unrealistic number.
'
Some more technical information:
The reason most meters (i.e. dosy, workman etc..) read a higher power output after the limiter has been disabled is because the meter is unable to diferentiate between the target freq. of 27 Mhz and the 2nd and 3rd harmonics of 54 and 81 Mhz.
What happens is, those harmonics leave the radio and travel down the coax to the antenna, the main or "target" frequency leaves the antenna because that is where the antenna is resonate and has the lowest resistance. however the 54 and 81 MHz signals are stopped at the antenna and try returning back to your radio since the antenna has no or little resonance at those frequencies. Well when those signals get back to you dosy watt meter, the zener diode that drives your meter movement doesnt see them as SWR(because its tuned/designed to only check the swr at 27MHz. So those harmonics are read as forward current by the zener diode and therefore shows as more forward power, when in fact if you view this on a spectrum analyzer, you will notice the power has dropped on 27MHz and risen on the Harmonics.
Alot of people dont understand this, and there is ALOT more to it then what I have just explained. But this is about the most simple explanation I can give.
1# ALL audio will be uncontrolable AM SSB FM deviation
2# The gain you see in increased audio power will bring ALOT of harmonics because the signal is flat topping and clipping, there are better ways to modify the AM amp chain and retain the ability to limit the gain.
3#In most cases you will lose avg power out. You have to have REAL test equipment to see this not a Dosy meter and your friends ear.
I have only seen a few A VERY FEW radios that when the limiter was removed the radio did not show any distortion. The reason being is because those radios had such an anemic Audio amp, it wasnt capable of driving the amplitude to %100.
And just for your information, anything over %100 IS A FALSE /unrealistic number.
'
Some more technical information:
The reason most meters (i.e. dosy, workman etc..) read a higher power output after the limiter has been disabled is because the meter is unable to diferentiate between the target freq. of 27 Mhz and the 2nd and 3rd harmonics of 54 and 81 Mhz.
What happens is, those harmonics leave the radio and travel down the coax to the antenna, the main or "target" frequency leaves the antenna because that is where the antenna is resonate and has the lowest resistance. however the 54 and 81 MHz signals are stopped at the antenna and try returning back to your radio since the antenna has no or little resonance at those frequencies. Well when those signals get back to you dosy watt meter, the zener diode that drives your meter movement doesnt see them as SWR(because its tuned/designed to only check the swr at 27MHz. So those harmonics are read as forward current by the zener diode and therefore shows as more forward power, when in fact if you view this on a spectrum analyzer, you will notice the power has dropped on 27MHz and risen on the Harmonics.
Alot of people dont understand this, and there is ALOT more to it then what I have just explained. But this is about the most simple explanation I can give.
This is probably the funniest supposed technical statement I've EVER read on a forum.... Hats off to you for the Chuckle!
Thats where I stopped reading
This is probably the funniest supposed technical statement I've EVER read on a forum.... Hats off to you for the Chuckle!
Thats where I stopped reading
So lets see...... what happens at 101%
Oh I know, clipping /flat topping of the signal AND NOT the kind of clipping used in a quality speech processor where you can alter the % of amplitude on the negative or positive portion of the inteligence signal
Start here http://www.privateline.com/PCS/Weisman.pdf
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