Redoing the install(s)...

[The Jerk]

Not that my installs were wrong, but just not perfect...

Start with the car...installed a through-roof mount for the Wilson antenna...that made a good improvement in SWR. Looking forward to seeing if there are any other improvements...

Move to the truck, been loafing my 4-pill on 8ga wire...have 4ga wire to replace it for 6 months. To install the heavier wire, I got to pull the interior...figure this will be a good time to neaten the wiring up and install a 1F capacitor to help on SSB (mainly because I had it left over from a stereo install and my headlights dim with modulation on SSB). Got the 4ga pulled, still got to finish plling th interior for the other stuff.

All to make a better install...

 

[W5LZ]

A word of warning about that 1 F capacitor. Unless the thing is rated for 50 volts or greater, I think I'd be very careful with it. It really won't help much so not using it would be a good idea too.
The problem with any large capacitor that doesn't have a voltage rating at least 3 times the supply voltage is that they are susceptible to catastrophic failure from surges. Not just from what's being drawn past them from the radio/amplifier, but especially from incidental surges for whatever cause. If you ever need a 'jump' to get that truck started you would be very wise to disconnect that cap first. You've probably heard all that before but they can get very, very nasty.
- 'Doc

 

[74IN]

Caps are useless. For an RF amp anywho.

 

[The Jerk]

I believe the cap is rated at around 40 volts...I used it before (in a similar install) without issue, should (hopefully) pose no trouble now.

As for the cap being useless, for straight AM, I agree...they won't help a continuous draw. But for SSB, where the draw is in pulses (which is causing my lights to dim/pulse, just like a stereo amplifier); I can't see the harm in trying one out.

Current draw is current draw, and that cap doesn't know if that's a stereo amplifier or linear, and likewise that linear doesn't know if that's a capacitor or a battery...the price is right, and its not going to hinder the install...be curious to see what, if anything, it does.

Hopefully it cures my "dancing" headlights, which is the reason capacitors are used in the car stereo world.

 

[Cajun Invader]

But for SSB, where the draw is in pulses I can't see the harm in trying one out.

Hopefully it cures my "dancing" headlights, which is the reason capacitors are used in the car stereo world.

I have seen them used before with SSB and it did in fact cure the "dancing" headlights. On AM it didn't do a thing. Seeing that you have the capacitor already it's worth a try.

Most people that try capacitors find that they did not help but some do.

Good luck and let us know what your results are.

 

[W5LZ]

The Jerk,
Capacitors work, if the surges they 'make up for' are fairly short duration and aren't larger than the thing can handle (shaving off the bumps and filling the pot holes, sort of). But they can't make up for an inadequate supply of power, bigger batteries, etc. Which is basically the reason for those lights pulsing. But they help, and that's the nice part.
The not so nice part is that they are dangerous as hell. If a little cap can sting like a bee, you just don't wanna know what the big ones can/will do. Most of the people who work with or install them (and who know what they are doing) fuse them. And there are precautions you should take if you do have one installed. That voltage rating is a 'fudge factor' for safety. It should be large enough to handle any possible surges. I haven't seen that many large capacitors, but I honestly can't remember seeing one rated for 40 volts (I haven't seen them all, so take that for what it's worth). It's your 'neck', treat it like you thing it should be treated.
- 'Doc

 

[Cajun Invader]

But they can't make up for an inadequate supply of power, bigger batteries, etc.

Personally that's the route I would take. More, bigger, better batteries.

 

[Robb]

First of all, I think most auto electrical systems just aren't up to the task of running even a 2-pill/2879 setup. Let alone - running four of them. Your truck will probably handle a 2-pill setup w/o much trouble; but a 4-pill may be the straw that breaks the camel's back - so to speak...
http://www.aa1car.com/library/alternator_highoutput.htm

This situation demands more output power from your alternator. Probably even the alternator output wires/guage as well. A deep cycle battery and your 1 farad cap would then be sufficient to handle the load over a long period of time/usage. Otherwise, the alternator just may take a giant dump on you - if pushed for too long. BTW-what brand/kind of truck is it? I have a Honda CR-V and a Texas Star 350DX (2/2879's); I dread putting it in because that little dinky alternator -I know- won't take it. For that matter, I wonder if a 200 watt linear would be OK. Air conditioning, fuel injection, fuel pump, head lamps, and stereo are already taking their share...

You might get away with what you are running for awhile. But then - it just may take a sudden dump. Not what you want to happen if you are 'out in the sticks'. Remember that the amperage output of most small vehicles - and even some larger ones weren't built to handle large output demands. You will need 50 amps + whatever your vehicle requires. It may need a better output alternator. Might as well go back to the car stereo place where you bought your cap and see if they have any hi performance alternators that will fit your vehicle. A 200 amp output alternator would be about right -IMO. That is - if you want to keep it trouble-free and rolling...

 

[mackmobile43]

I use a 105 amp alt I built myself and 2 schedule 31 batteries for a 2x4 setup for ssb in my car, when using the stand alone car battery I saw alternator overloads with a vom and with the headlights dimming but after reworking the alternator and adding the batteries the voltage suffication issue was resolved and I have tried the large farad cap (3 farad rated at 100 volts) and it did nothing to the ssb issue after the initial 2 or 3 words.

 

[The Jerk]

The truck is a 2500 dodge, twin 1050CCA batteries, 137A alternator...it already has the batteries and alternator...it also has a programmer that keeps the voltage up better.

Its not like a 4-pill is drawing *that* much power.

The cap is fused, and it is 40 volts. I have seen caps in all sorts of voltages...ran them quite a bit.

Will take it out tonight and see, but I had to take my digital watt meter out because I moved the radio...

 

[Cajun Invader]

twin 1050CCA batteries, 137A alternator...it already has the batteries and alternator...it also has a programmer that keeps the voltage up better.

Then you shouldn't be having a problem with your headlights "dancing". A loafing 4 pill will be hard pressed to pull 65 amps on AM and 85 on SSB.

 

[Robb]

Then you shouldn't be having a problem with your headlights "dancing". A loafing 4 pill will be hard pressed to pull 65 amps on AM and 85 on SSB.

The Cajun Invader is right.
Maybe it is time to inspect the parts and check the output with an amp meter - give it a diagnostic run if you can...

Don't overlook the obvious. All of the system depends on the fan belt tension and quality.
No spinee - no ampee...

 

[The Jerk]

Well, you take 85Amps and "pulse" it, and the system will have some lag time to recover...the alternator can't respond that quickn nor push the charge to the batteries that fast..

I'm happy to report, the dancing is gone, but there was no SSB happening to get a feel for quality. Although - did get an excellent report on AM barefoot.

Hopefully the skip starts happening more consistantly.

 

[Cajun Invader]

Well, you take 85Amps and "pulse" it, and the system will have some lag time to recover...the alternator can't respond that quickn nor push the charge to the batteries that fast..

I'm happy to report, the dancing is gone, but there was no SSB happening to get a feel for quality. Although - did get an excellent report on AM barefoot.

Hopefully the skip starts happening more consistantly.

I'm glad it all worked out for you.

 

[The Jerk]

Oh, and my SwR is 1:1 with and without power...which isn't much improvement, but it is noteworthy.