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Alsworld
| | Posted on Wednesday, March 27, 2002 - 10:13 am: | 
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I don't know whether I have a problem or not but figured I'll get some advise. Long distant DXing (Florida to western Washington) last night and got a report my signal was cutting out, and as he described it, just like keying/unkeying rapidly while talking. He said I had a good signal but breaking up. This is not the first time I've been told this, both happened LSB long distance. I try it here local and all sounds great, solid modulation, all connections are tight, new D104 handheld mic, battery about 1 1/2 months old, no squeals, etc. I realize it could just be the signal degration but we had a pretty solid QSO going pushing through the QRM. I'm suspecting and inadequate power supply but lets put it to the forum.
I run a President Lincoln, new Astatic D104 M6 mic, KLV Mod 351 mobil amp, IMAX 2000, all new coax and connections.
I run the radio off a 4 amp power supply. I had been running the amp off an old 10 amp power supply but it died. Honestly now until I get a correct size power supply it's running off a marine battery with a 10 amp charger attached. Crappy setup yes but works on lower settings. I mistakenly had the amp set on a power setting of 4. I run 1 watt into the amp from the radio. Power mic is set on about 2 on SSB. Now, would the inadequate power supply cause this to cut out like this? I was unable to ask whether my signal cut out or just modulation so being I cannot duplicate this locally, I'm kind of lost. I did not see a loss on my end (meter or amp were not flickering). Ideas? |
Taz
| | Posted on Wednesday, March 27, 2002 - 1:38 pm: |
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yes the power supply could cause that. maybe its the otherguys station. |
Alsworld
| | Posted on Thursday, March 28, 2002 - 10:26 am: |
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Thanks Taz. The only thing else I've notice is with the amp preamp. It will "pulse" sometimes. Where instead of seeing my meter signal increases so many "s" units, it bounces like I was keying and unkeying but this is in the receive mode. If I unplug the charger and run it off the battery alone, it rapidly flickers (receive only with the preamp). This may not be the answer but that power source is affecting it for sure. I have finished a wiring harness for my truck and will test it friday with all the correct setup being both the radio and amp are really mobiles anyway. I had installed it temporarily before to check swr's and it's good in there. Now the setup will be correct. Still need to get a good power supply to use as a base. Is it possible to over power this amp? What I mean is if I were to hook it up to say a 40 amp power supply, will that hurt it or will it only take what it wants/needs to run. I want to get a large power supply in case I ever move up in wattage but without smoke checking what I have now. Thanks |
Taz
| | Posted on Thursday, March 28, 2002 - 6:45 pm: |
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It was probly your power supply. Its bot a whole lot to worry about. Those thing happen. I knew a freing who did the same thing.
What are you powering with the power supply? |
409
| | Posted on Friday, March 29, 2002 - 3:04 am: |
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No, the amp and radio will only draw the current it requires to operate even if you have a hundred amp. supply. Think about it.....auto batteries are capable of currents in excess of 500 amps. |
Taz
| | Posted on Friday, March 29, 2002 - 2:14 pm: |
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The reason I asked is because you want to put a fuse inline. |
Alsworld
| | Posted on Friday, March 29, 2002 - 3:34 pm: |
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409, that's what i hoped for as a larger power supply planning for future items. If I'm gonna spend the bucks, what's another $30 hurt?
Taz, I currently have a fuse inline with the radio (a 3 Amp fuse). I have a dedicated little 4 amp power supply running the radio only.
I do not have a fuse inline on the amp itself. It runs off a marine deep cycle battery with a 10 amp charger attached. I have a new inline 30 amp fuse and fuseholder laying around I thought about installing but wasn't sure if that was the correct size so it's in the drawer. Same wonder as before that if my truck alternator is putting out 100+ amps, will I blow it? I think 409 answered that too. What do you think?
For what it's worth, at the time I broke up, my battery was 90% fully charged and the meter only showed it getting about 2 amps. Hence one reason I suspected the power supply, just not pushing the right amount of power to satisfy the amp. It's a ugly way to work it but it never did this on my old 10 power supply that died so just another clue.
I'm going mobile tonight properly rigged up and I will verify if it doesn't happen when hooked up correctly.
Thanks for your help. |
Taz
| | Posted on Friday, March 29, 2002 - 4:09 pm: |
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sounds good. if its just off the battery hen there is no sense in putting a fuse on it. But if your going to put that on a 100 amp altenator then put a fuse inline that is a good 5 amps higher than what the thing is your hooking up to it. |
409
| | Posted on Saturday, March 30, 2002 - 12:34 am: |
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If you were running ssb, chances are you were using more current than your little power supply could handle. 4 amps is pretty close for many side-band rigs. Many require more. Could be why you were cutting out. |
Powermad
| | Posted on Saturday, March 30, 2002 - 9:06 am: |
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Get at least a 25 amp pwr supply and you will be fine I had the same problem and went and got a 35 amp and never happened again. |
Alsworld
| | Posted on Saturday, March 30, 2002 - 11:45 am: |
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Thanks to all that responded. That is what I was looking at was a minimum 25 amp power supply, but even larger was tempting for a few more bucks (although 25 amp is more than enough for my little amp). Ahhhh the future power dreams... Anyway, installed in my truck, it works like a charm. I kind of figured my power supply setup was the culprit. Ironically, I prefer to run barefoot but the extra ooomph is nice talking DX. The preamp comes in handy when the noise levels are low.
Now onto TVI problems. Bleeding on the neighbors computer speakers and some video thing. No TV's or phones. I already think I've caused my own problems by running dual ground wires from the base of my antenna to grounding rods. They are about 36 feet long each. Gosh, come to think of it that's just about the same length as the 11 meter wavelength! After reading all of Taz's post on "no ground wires over 8' long, they radiate", I think I'll remove them. I'm thinking about just spending the cash on some Belden 9913 but I'm gonna check out what Copper has here. This just gives me an excuse to run better coax (I've got Radio Shack RG 8/U mini) and throw a better low pass filter inline. Man, I want a good meter, better coax, power supply, new inline filter....better go buy my lotto tickets or get a second job!
There is enough information and links on this board already about TVI problems so I'll do the homework. Thanks for everyones inputs on my problem. |
Alsworld
| | Posted on Friday, May 10, 2002 - 1:30 pm: |
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I just wanted to post a follow-up to this with the answer. The problem came back while barefoot and I thought my radio was going bad. Tech 181 walked me through many steps and it turns out that 409 hit the nail on the head. My little power supply is dying. I could no longer even talk SSB without breaking up. AM I could turn the variable power knob to about 6 watt deadkey and be okay but after that it got a bad hum and broke up badly. Got a temporary setup going and works like a charm. At least I know what my next piece of equipment will be, a real nice, more than adequate power supply. This problem had progressively gotten worse until I could duplicate it on am. Thanks Tech 181 and everyone else who replied. |
Highlander
| | Posted on Friday, May 10, 2002 - 8:07 pm: |
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I know that switching-type power supplies are not always appropriate for RF, but Samlex has a 23 amp switching power supply model SEC1223 that sells for about 100 dollars that will run a 100 watt ssb rig with no problem. It is about the size of a mobile cb radio! I love mine. I have no problems with RF noise from it, it is well filtered. |
Alsworld
| | Posted on Friday, May 10, 2002 - 9:16 pm: |
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Thanks Highlander,
I am now aggresively shopping for a power supply that can push both the Lincoln and my little amp. Currently looking at the Alinco DM-330MVT, 30 amp continuous. It's overkill but my mind is not made up yet. I'll look into the one you've mentioned. By the way, my next purchase was going to be a Dosy meter from Copper until this problem cropped up. I do not have a good meter (yet), and especially want one that can show me modulation on both am and SSB. I saw on another post from you about using the mic gain button when going to SSB. Can you explain further please. Is that only with power? My profile tells my equipment although I try to run barefoot on SSB but sometimes turn it up. Whenever I get the meter, I'll be able to see for myself but for now, I'm intrigued. I want to sound CLEAN. Sounds like you may have some knowledge I'd like to learn. I'm all ears...
Alan
Alsworld |
Highlander
| | Posted on Friday, May 10, 2002 - 11:12 pm: |
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Well, I run an Astatic 575 power mic on it, and to get the best sound out of the rig on AM, I use the mic turned up pretty high with the mic button on the radio on high. I get a good peak to carrier ratio, and it is loud and clear. If I just switch over to SSB and don't adjust it, it is WAY to high with or without the amp----It's just too much. I could take care of this with the control on the mic itself, but I'd rather not do that and it turns out that pushing the radio's mic button to low is the perfect amount of attenuation. Like I said, I am very conservative about how I drive my amps--I sure as heck dont get "351" watts out of my KLV 351p amp, that's for sure. I don't have a meter in the car anymore, but when I set it up, 2 watt deadkey had the amp keyeing at 50 watts, with healthy forward movement on AM, and between 160-180 or so on SSB, with great audio reports in both modes. FM is fabulous, too! Amp makers are jerks for labeling their units with numbers like that. It probably leads to alot more amps getting sold to people who blew them up trying to see those numbers on a PDC or Dosey.
One of the board techs can do better at explaining it, but most amps sound much better, run cooler, last longer, put out less garbage and RFI if you leave them plenty of headroom power-wise. Like I said, the techs can correct me if I'm wrong, but an example might be if you have an amp with two power transistors each rated for 70 watts each, that's 140 watts. I would set my radio's deadkey to get the amp to key around 35 watts on it's highest setting. If my radio modulates that carrier going into the amp(whatever it is, it doesn't matter) to 100 percent, my amp should swing to 140 watts on a true peak reading meter or an O-scope. Dosey's and PDC's usually read pretty close to that, mine a little less (PDC-600). Sideband I would adjust either variable power (which doesn't seem to do much on my lincoln) or mic gain to get the amp to show around 140 watts and that's it. You can get alot more power to show on a meter with that amp, but it won't sound as good, and it will run hotter and be more likely to splatter. Another ("better) way to do the sideband is to say "AHHH" into the mic while observing the output on the meter. You turn it up until the output stops rising, then back it down until it just starts to dip down. Verify all this with on the air checks, and you'll have a blast. |
Tech181
| | Posted on Saturday, May 11, 2002 - 12:07 am: |
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Highlander,
Tech671 is our amp man, but I will inject my .02...
Make sure you have adequate power and ground wires/cables capable of handling the amperage.
Set the amps input (from the radio) so that the carrier of the amp is 1/4 of its total peak power. A class "C" amplifier with (2)1446's will get you around 195 watts peak (give or take depending on meter) at 14.5 VDC (alternator output). At least that's what my tests of the KL300P showed.
Keep modulation at no more that 100%, even a little less is fine, and don't try to tweek every last watt out of your setup. Want more power? Buy more power. Run it conservatively and you will have a powerful, clean sounding setup, that will last a long time.
Steve
Tech181
Tech181@copperelectronics.com |
Tech671
| | Posted on Saturday, May 11, 2002 - 10:01 am: |
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Alan,
The radio alone should have 10a available. Yes that's overkill but on SSB the amperage peaks go higher than you may think. For the 351, it uses (2) 1446's capable of 70w rms ea @ 12v with 4w rms drive. What does that mean in english? Like T181 said, around the 200 range, so a 50-70w AM carrier on highest setting, same for FM. On SSB adjust your radio or mike gain setting so the amp peaks no more than 200w. This will reguire occasional amperage peaks of 25a. Your thoughts of a 30a continuous are right in the ball park.
RM makes some nice power supplies, you may check with Copper to see if they can get you one.
As to the mike gain button ....
Adjust your radio button to "high" on AM, set your mike power level to get the sound you want. When you flip to SSB, set the mike gain button to "low" and that should be about right but you may double check it with operators that hear you on a regular basis. |
Alsworld
| | Posted on Saturday, May 11, 2002 - 10:08 am: |
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Thanks for the replies. I don't push everything to the max because I want it to last. This little amp is more than sufficient for my wants. I currently drive it with a 1 1/2 watt input, but going to sideband I just turned down my power mic (D104 M6B). For the life of me I hadn't even thought of the mic gain button. Duh! I can hardly wait to get me the meter from Copper's but need a power supply first. My entire priority is to to sound very clean, not overmodulate and just run a great sounding station. I never had to worry about that barefoot with the stock mic on SSB, but now the more I'm at it (first ever power mic and amp), the drive for doing it right, and sounding great is my focus. The meter will help me "see" the figures. Most of my local friends run AM only and they like the sound of my mic cranked wide open. I reduce that quite a bit because I know, even if it sounds great to them, it's causing splatter. Thanks. |
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