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Timenxs
New member
Username: Timenxs
Post Number: 6
Registered: 6-2011
| | Posted on Monday, August 08, 2011 - 7:03 pm: | 
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I am using an RCI 6900F150 for SSB mostly. It is a mobile install, but the power supply category seemed best suited for the question....
Since this type of transmission has spikes to its current draw, would a 1 farad cap like used for big stereo amps be of use??? I can get them cheap enough. OH, also wouldn't this help take some line/engine noise out of my radio?
Thanks for any help, TimeNXS |
Moonraker
Intermediate Member
Username: Moonraker
Post Number: 281
Registered: 3-2005
| | Posted on Monday, August 08, 2011 - 8:24 pm: |
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The cap won't help you in the power department. It will be fine as long as you don't use wire that is too small. 8 or 10 awg is what I would use.
It might be useful to reduce receiver noise if it is coming through the power wires. Turn the radio on and disconnect the antenna. If the noise goes away the noise isn't coming from the power source. Smaller capacitors can be useful for filtering a/c line noise too...and cheaper. |
Timenxs
New member
Username: Timenxs
Post Number: 7
Registered: 6-2011
| | Posted on Sunday, August 14, 2011 - 1:21 pm: |
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OK, thanks for the info.
What I am also noticing is that the lights dim on the transceiver when I talk on it. Seems to go with the current draw. I am using a 550 cranking amp battery in the car with an 80 minute reserve. My question is whether a 1000 cranking amp battery with a 150 minute reserve will help??? Seems I would be less likely to drain a battery when on a long QSO. ???? Thanks for you help, 524 |
Moonraker
Intermediate Member
Username: Moonraker
Post Number: 282
Registered: 3-2005
| | Posted on Sunday, August 14, 2011 - 9:58 pm: |
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I've saw a few radio that the meter light would dim a little at full output and I know they were getting plenty of power. Maybe the manufacturer cheeped out on the voltage regulator.
Use a volt meter (engine running) to measure the voltage going into the back of the radio and see how much it drops when you key up at full output. You'll see a slight drop but nothing major. I wouldn't worry about it unless it's over 1/4 volt drop. Then you can measure voltage drop at the battery. If you have a lot of voltage drop at the radio and little to none at the battery you need larger wire.
That radio shouldn't draw much more than 30 amps max so I don't think you need a bigger battery. If the engine is running your electronics are running off the alternator. The battery is just a reserve supply. |
Dirty_diaper
New member
Username: Dirty_diaper
Post Number: 3
Registered: 8-2011
| | Posted on Sunday, August 14, 2011 - 11:31 pm: |
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You need bigger wire, larger alt. Go on Youtube, and look up Big stereo amp hook up. Also look in the Auto Audio section on Ebay at the High current Batteries. I used to run 3- 200 amp Powerlines, for my driver, and comp. 16 pill Dave Made Special.I don't have the room in my new truck for all that now, just a radio, driver, and 8 pill. Hope that helps, and again that is just my opinion, there are a million other answers that will come in, it is just what I have done. Good Luck Friend. BTW, this IS NOT MINE!! |
Timenxs
New member
Username: Timenxs
Post Number: 8
Registered: 6-2011
| | Posted on Monday, August 15, 2011 - 7:28 pm: |
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OK, Thanks for the help. I am going to get the larger battery because my radio room is my car. I do a lot of talking with the engine off. I keep my power turned all the way down and still get good reports. Just don't want to get stranded on top of some darn mountain where I go to transmit because I had too long a QSO. So the bigger battery should help with that. Still thinking of adding a 1 to 2 farad cap just to help out. They are cheap enough on eBay.
Battery will be installed this Friday so look for me on 27.375 LSB Friday night. Thanks again, 524/Robert |
Onelasttime
Junior Member
Username: Onelasttime
Post Number: 31
Registered: 8-2011
| | Posted on Wednesday, August 17, 2011 - 2:01 am: |
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First big caps in car audio only help with hard hitting bass excursions. They do not make up for lack of battery reverse capacity or too small of an alternator. The battery in your car is an electrolytic capacitor but it can not discharge as fast as 1/2-1 Farad 16 Volt Cap can. So the cap is their to discharge insanely fast at the start of a sudden and powerful bass hit.
I had 10 12 inch woofer's in my trunk and did a lot of car audio work install's, custom enclouser's, contest prep. etc......In fact when I sold all my gear that I had stockpiled in my bed room before I left for college I made enough to pay for my first year of college. Fixing car amp's is what got me in CB radio's and got me into an Apprenticeship for 2 years before deciding to go to college for something other then electronics.That was 20 years ago but the car audio technology has gone backwards not forwards in that time frame!
So do not waste you time with a big cap all the caps in your CB or Export radio prob. do not add up to 1 farad.....LOL
You could change all the caps in the radio to higher voltage caps. Toss in a beefier voltage regulator for the radio. Turn up the voltage a tad coming out of the transformers in the radio to take advantage of the usualy higher then 13.8 volts in a running car. Beef up the wire and socket feeding the radio. Then after have done all that rebias the transistors now that you have more stable and slightly higher voltage and current comeing in.
Usually on RCI the pre SMD designs if the face was flashing and you where already running direct to the battery with 8 gauge or larger wire your voltage regulator was bad or going.
Most old Toyota's had voltages of 14.8 to 15.8 in the late 1980's and early 1990's with the engine running. I always ran 1 guage or over sized old welding cables from the battery to the trunk. I would run that a copper power distrubtion bus one for positive one for negative right to the battery. This ensured that I never had power issue I then used sockets for radios that came apart and would run 6-8 gauge to them. I would twist them tight and tin them. But I have to say that I have not seen those type of connectors that come apart in like the last 10 years everythign today is pre-molded. FOrcing you to go to a larger socket that can support larger wire like what the 400 watt radio's use or the connectors like molex and 6-8 pin and such that amateur radios use.
Why did that guy not just use Lexidyne like the big disel electric trains use 1-2 of those would do what his 8 alternators are doing......I saw a guy once that had a 454 with super charger and nitrous on youtube to power his generators........ For a key down contest!!! IT was a Suburban if I recall.
Never did key down contest's I think they are stupid and dangerious but I ran a sweet 16 then a 32 latter on......I sold all of that when I went off to college. We would see the key down guys though about once a year about a month prior to the contest they would roll in one at a time wanting little tweaks here and their an amp repaired huge broadcast grade and sized coax etc.....We had a huge spool of it in the back room it was the size of my wrist. |
Timenxs
New member
Username: Timenxs
Post Number: 9
Registered: 6-2011
| | Posted on Friday, August 19, 2011 - 3:30 am: |
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Thanks again for the info. Too late for the experiment though. I bought a bigger battery last night (a 1000 amp over the 550 I had) and ordered/received the 2 Farad cap already. So, since I am hard headed (LOL)and already have the stuff I will do an experiment to see if it does any good.
The cap I can sell locally for more than I paid for it, so no loss there. The radio came with a 10 ga wiring harness to the battery post. So if the cap makes no difference, I will re wire with the 8 ga fine strand wire and go from there. The bigger battery will let me talk longer without too much worry of draining the battery and being stranded.
Let you know what I find. And Yes I know the 2 Farad was way larger than I needed even if it would help. The 2 farad cost the same as a 1 farad. So I got that instead.... Thanks, 524 |
Timenxs
Junior Member
Username: Timenxs
Post Number: 10
Registered: 6-2011
| | Posted on Thursday, September 01, 2011 - 6:32 pm: |
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So finally to tally up results from this test. I hooked the cap across the Positive and Negative leads into the radio. The voltage meter on the cap shows 14.3 volts when the car is running and 12.6 when the car is off. When I transmit on AM the discharge light comes on and the caps works only once or twice in a transmission. On SSB with the power all the way down, my normal way of transmitting, the voltage drops from 12.6 to 11.9 and the cap discharge light is blinking all the time in a transmission. Lights on the radio do dim less but outward signs show little gain.
The radio is wired direct to the battery via the cable included with the radio, 10 ga wire.
I don't know what the peaking procedure is for this radio or how much I put out for power.
Anybody with any experience with these radios? |
Timenxs
Junior Member
Username: Timenxs
Post Number: 19
Registered: 6-2011
| | Posted on Friday, July 20, 2012 - 5:04 pm: |
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Update:
I have rewired the radio direct to the battery with 6 GA fine silver wire. Expensive but worth the effort. Voltage drop is very small now. Discharge light on the cap still flashes on SSB transmissions but not as much.
Thanks for all the input... |
Press_man
Advanced Member
Username: Press_man
Post Number: 568
Registered: 5-2008
| | Posted on Saturday, July 21, 2012 - 4:39 pm: |
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Timenxs:
I had a Nissan PU in 1986 that was noisey on recieve so I made a bank of caps (6) to get a farad as well as chokes. The end result was no drop with 350w out and quiet with the preamp on. Got the idea out of Hints and Kinks.
Great idea you used there, that's what radio is about, what you can do as a project to make your base or mobile working better and enjoying the hobby.
73 Pressman
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