29 swing kit

[stingray]

some instructions i read say to use a 220uf cap. it says some people have also used 470 and 1000uf caps. which should i use and what difference will these 3 different caps make???

 

[Robb]

Experiment.....Buy all three and change them out and look at what your meter says. Couldn't cost more that a couple of dollars for all three. That way you can tailor it to the radio. I'm no tech - but that is what I would do...

 

[Moleculo]

If it works with less capacitance, there's no reason to add more. I think most people probably use the 470uF because it's easy to find at radio shack. I'm just speculating about that, btw.

 

[Robb]

I'm playing around right now with the same swing kit mod on an old 84' Cobra 29LTD. I tried both resistors one at a time on my radio - both the 33 ohm and 100 ohm and read them on my meter. The 33 ohm gives it a stock 4 watt deadkey and the 100 ohm puts it down to 1.5 watt deadkey. Nice - if you have a linear that needs to see a low deadkey to work well.

I can't see any difference with either the 220mf or the 470mf cap on the meter/radio output. If anything, the modulation with the 470mf reacted faster. Is that better? So, I put the 220mf back in and left it. I don't know what advantage - if any - would be had with the 1000mf cap. I didn't buy any, so I can't say what change would be seen on the meter.

Why bother with clipping the D11 diode either? One must remember that a lot of these 'diode hacks' - are just that. Just turn VR4 all the way up instead - and let the 'Dynamike' control on the front panel of the radio be the control point. Makes it far more sensitive that way. A little bit will now go a long way...

I wouldnt mess with the tuning coils either. Unless you really wanted to throw off bad harmonics and think that is better because it moved the meter up only very slightly. Forgetaboutit. After all, you are doing this swing mod so that you can have a clean sound into your amp. Why amplify harmonics and waste amp power?
Keeping your signal sqeaky clean, and let the amp do the swinging makes the most sense at this point to me.

If you are going to run the radio without a amp - or the amp you have has a higher input requirement, then get a ERF2030 and a EN1230 - or make your own EN1230 from the schematic on this page:
CBTricks MOSFET Experimenter's Information Notes
Putting in the ERF2039/EN1230 mod is here:
http://www.cbtricks.com/miscellaneous/fet_papers/ekl/graphics/erf2030_cobra_29_mod.jpg

These are my honest observations as a 'wannabie/newbie' radio tech.
I'm having fun and learning.
I haven't blown up anything yet; and I thank God for it.

 

[Switch Kit]

That's why many "techs" call swing kits "JUNK" ! weather or not you cut the limiter or not . Although you can keep things down to a roar with your mic gain , they still will not look very good on the scope But hey ! we don't talk to machines , right ? we talk to people.

pep swing from a low DK is a class c AM amplifier users dream. Are those numbers really for real ? No ! it really doesn't matter to "them". Does it or can it sound good ? Yes ! Is it truly a clean signal ? No !

I like swing kits concerning AM operations with amplifers. My bad. Bottom truthful line is this , lets use a Texas Star 250 for exsample here , 2 x 2290s at 80 watts per device = 160 pep watts

Will use your 29 for the radio used , now a scoped out clean signal from that radio into that amp would look something like a 2 watt DK to 8 watt pep swing at a 100% (no more) modulation from the radio. (Thats no clips , resistors , caps or anything else) just the radio tuned to the amp.

Of course , these are just ballpark numbers to get my point across.On high on the TS 250 I'd bet to say the readings would read something along the lines of a 60 watt DK to 160 ballpark watts pep swing in a clean
healthy environment. (Clean in is clean out)

Now I take this 29 and swing kit it , now IM doing 2 with a 20 watt pep swing and my audio is down the road and around the corner and down the street !! I now have a 60 watt DK swinging just about 250 on that TS 250 of mine ! is it clean ? Not on your life or of this life ! Does it work ? Yep ! Can it sound good ? Yep ! Can you be so damned loud that it can rattle fillings in ones mouth ? Yep !

OK then , but we want to sound good with our swing kits Right ? So what is one to do ? , first off , you are going to have to turn the mic gain down down down , and chances are you will need to use a stock mic or NC mic for the best audio your going to get out of the situation in the first place.

What does this mean ? What happens when we turn the audio down with our mighty swing kits ? Our pep swings majorly DROP because we turned it down to sound the best that we could What happens to the swing on the amplifier now ? Yep ! it goes down down down as well

So we are now actually getting closer to the truth of mother natures radio and signal qualities as we did when we just tuned the radio to the amp in a clean scoped out environment .

We are now simply cleaning up the mess that was put in there in the first place.(to a certain degree anyway) Dirt in is dirt out . (signal and audio) The good techs of the world know this and that's why a few good ones wouldn't waste there time on those. But at the same time , money is money and some times it's about what the customer wants.

I suppose many of us are comfortable living the lies of cb radio and amplifiers but when the truth matters , it matters. So in the end I always say , (to cover my own lies to a degree) We don't talk to machines , we talk to people. And that's usually all that really matters in the end .

Clean in , clean out.
Dirt in , dirt out. (and the truth of the matter here is this , dirt can be cleaned up to sound good enough for given users) although it still doesn't change the fact that it's dirty all the same.

I remember years ago when given Internet Forum techs' talked the truth about all of this , There's still a few but I don't read from them to much anymore. I often wonder if they found out that telling the truth could be bad for there business ? Nothing worse then being caught talking with forked tongue

 

[Robb]

OK Switch Kit - I think I understand your point...I think...
As I have recently become a Ham, the influence of Ham thinking has filtered into my CB thinking. Hams are down on the splatter box crowd and poke fun at CB'ers at their leisure - and often. I like CB's as much or more than Ham equipment - but Ham stuff is pretty cool too.
So, I guess I'm trying to make my CB something that it isn't...

I wouldn't want a base station with a class C amp in the urban sprawl where I live. Bleeding over onto someone's toaster is sure to get more attention than I want or need - and more than I am willing to risk my license for. Having/getting a General class license was tough enough - with all of the rules and expectations that are imposed with those privileges.

However, having a class C amp in my mobile isn't much of a risk - especially if I use a small one and stay rolling. But I still want it to be as high fidelity as I can without sacrificing efficiency. I want to keep it clean sounding as I can and make it as loud as I can too. If I must make certain compromises to do that, then I must consider just what is being given up for the advantage gained...

 

[Switch Kit]

I think you can enjoy the best of both worlds Rob. Sounds like your just weighing out the pros and cons and wanting what will work best for you . I've personally been cb now for getting on 25 years.

I don't get into the Ham/CB controversey . (been there done that)I do what I do within reason. I let Ham's be the Hams that they are. They do what they have to do and I do what I have to do. Respect can work both ways.

 

[74IN]

Just turn VR4 all the way up instead - and let the 'Dynamike' control on the front panel of the radio be the control point.

That's no different than clipping.

 

[Robb]

That's no different than clipping.

Exactly.
This way, the Dynamike control doesn't have to be turned up all of the way on the front of the radio. Turning it lower than 12 o'clock will work for power mics, and beyond 12 o'clock for using a stock mic.
At least you will have all of the control where you can draw upon it - instead of needing more control. That is what Imeant to say if it didn't come out that way as I first wrote it up.
That's all...