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question about davemade amps

FREECELL PLEASE READ THIS POST!!! FREECELL PLEASE READ THIS POST!!!
FREECELL PLEASE READ THIS POST!!! FREECELL PLEASE READ THIS POST!!!

FREECELL PLEASE READ THIS POST


Hello Freecell,

this is Loosecannon, the guy who wrote the original question about having computer problems with his car, and i am the guy who started this thread asking questions.

i am also the guy who posted recently wondering why you would come here and laugh at my attempts to learn something when i couldnt get you to explain your post in greater detail.
If i am mistaken, and this was not the intent of your post, then please disregard my previous post to you.
my goal is to learn more about this subject, specifically about my situation, not to banter back and forth.

please pay attention to whose post you are responding to, as it seems you are confusing who is posting what.

i repeat, this is Loosecannon.

i am the one who needs help, and i have but two goals.
those are to get this problem resolved, and hopefully to learn something along the way.

i realized when you first posted it that your contention was probably right, i just dont understand the statement enough to know how to apply it.

if your reason for following this thread is to help me, then i will ask any question i can think of to get it answered.

i asked some questions in the thread where you posted your initial response, but you never answered.
that is why i am still trying to get those answers on my own.

if you are looking for someone to ask the "right" questions, then i hope these questions qualify:

1. does the shield of the coax going from my amp to my antenna which is grounded to the vehicle body constitute a multiple ground path when the negative wire of the power cord is also connected to the vehicle body?

2. if the answer to question 1 is YES, how do i correct that situation?

3. does your post about eliminating multiple ground paths apply to the radio/amp/antenna setup, the vehicles computer/electronics, or both?

4. where should i run the negative wire from my amp to?

5. where should i run the negative wire from my uniden PC78XL to?


if you choose to answer these questions, then thank you in advance,
LC
 
LC,

I think you all ready found your answers. Mack made it simpler to understand.

If I am not mistaken what it means is each piece needs its own ground, whether it be to the vehicle body or the battery, not to be daisy chained. Daisy chaining will effectively run them in series which would create multiple ground paths for on piece of equipment and as Mack said then if one piece, say your amps ground goes bad it will try to use the other equipment as a ground which will cause all sorts of problems.

So in other words dont tie it all to one ground cable then tie that cable to the ground. Give each piece its own direct cable to the grounding point.
 
back in my car stereo days we all used one grounding point for all electronic power connections to avoid ground loop problems . i always run both hot and ground direct from the battery into the vehicle and do all my power connections to them inside ( 4 guage in spliting 8 guage to my 2 pill and stock wires to the radio and power meter ) . how ever we wern't transmitting a RF signal with an antenna system . its my understanding (and i certianly could be wrong) that RF and electrical grounds are similar but different animals . so if that applies to RF transmitting i dont know , but it works for me on CB .
i do know that on a mobile there needs to be continuity between the vehicels electrical ground and what ever location (roof,trunk.mirrormount,bumper) the antenna is mounted too .
 
The biggest difference between grounding to a vehicle's chassis, or to it's battery, is the length and size of the required cable to do it. That battery is connected to the vehicle's ground too, right? An 'extra' ground cable going there just seems a bit redundant to me. The 'size' of that ground cable is determined by how much current it has to handle and the distance it has to run. I've yet to see a vehicle chassis that wouldn't carry more current than any practical sized wire/cable. Wanna use a separate ground line to the battery? Knock your self out, do it! Then try it the other way, see if there's really any big difference.
- 'Doc
 
i really do appreciate everyone's input on this.

ground loops ARE my problem! they have to be; i have tried everything else! LOL


that being said, i think i need to start a new thread for this discussion, as it seems to be a very good topic to discuss in an attempt to learn something.

we are now referencing two threads and discussing something that is not even in the title of either thread. LOL

i am going to start a new thread right now, and call it "GROUND LOOPS IN MOBILE INTALLS".

i am going to put it in the "INSTALLATION AND STATION SETUP" section, so anyone who is interested in continuing this discussion on groundloops please follow me there.

hey FREECELL, please join us!

(regardless of what we may think about the man's porcupine like demeanor, he does have the answer in there somewhere LOL)

i will start the topic by stating my situation, and what i have learned so far.

the main reason i want to do this is to help someone in the future who has this issue to find a solution through the search function.

thanks guys!
LC
 
Also LOOSE,

You can contact Dave(who's name is not Dave) via e mail on his site, you will get an automatic response with the number and hours to call him he will always fix the amp to exactly how you want it-he stands by his stuff and is a great guy. I know this post is way late in the game but I just joined.
 
I'm not going to re-read this entire 14 year old thread but. The term "keying" usually means you keyed up over someone. If you have say 5 local stations talking on AM and they want to see who the biggest dog is they turn on their amps, key up, and start talking. Then a base station say 15 miles away will say who they heard. The winner or biggest station can say he "keyed" on everyone. It helps when each person says the same unique thing over and over. When we mess around local her I key the mic and say butcher butcher butcher butcher. Some say one one one one. Someone else might say tiger tiger tiger. This way the 15 mile judge can report back all I heard was tiger tiger. So that station keyed on everyone.
 
I'm not going to re-read this entire 14 year old thread but. The term "keying" usually means you keyed up over someone.
Really! There are actually organized shouting matches?

Thanks for your response. I should have been more explicit. The original post spoke of "there is no RF keying circuit in the amp". The further I read the dimmer the light became.

Ive a 2 pill (M80) Dave Made with a variable. I presume one SC2290 is controlling the output of the other SC2290. This is an outstanding driver for the FatBoy 8X (FB8X).
I've a 3 pill (M200) Dave Made with variable. In this case I know 1 SC2290 is driving 2 SC2879. Too much driver for FB8X without it performing wonky. At some time in the past the M200 was 3x SC2879. I believe it was Hellen who asked for her unit to have a SC2290 driver pill. I presume that was the start of the later constructions.

I've always wondered what is the full potential of the FatBoy 8X 2SC2879. Might consider joining onto a shouting match :) , not! The M80 would only enable ~ 1200W PEP from the FB8X.. The M200, capable of ~400 PEP alone, though I've never pushed > 225W DK into the FB8X without it going wonky; such as 1200W dead key and producing no modulation.

Is the "RF keying circuit" the driver circuit, such as in the case of the first SC2290s in the M80 and M200?
I don't know whether the FB8X has a RF keying circuit or not. It is my only linear with SSB capability.
Surprisingly I can get ~400W+ PEP from the FB8X with the Cobra 2000 dead key at 1.5W. The two driver amps operate best at this low input.
 
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