| Author |
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Pitbull477
| | Posted on Friday, February 01, 2002 - 1:04 am: | 
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i have a question about swr readings on my dx 1600,when i ordered it carl suggested driving it with a palomar 250 which is what im doing together swr is fine but if i use the 1600 by itself the swr goes through the roof.today i decided to try it with a ts mod v.the mod v by itself had a good swr reading but when i used it to drive the 1600 the swr went through the roof.seems as though the palomar 250 lowers the swr (i use it on low).im not new or a seasoned pro at this so i asked a friend who has been at this longer than me and he thinks the 1600 has a swr tuning capability like i said i dont know.other info im using a dx 99 and a wilson 5000 good coax with amphenol ends (i have tried different jumpers same result) all purchased at copper with the exception of the mod v.i am satisfied with the results using the palomar 250 as i have talked all over the country im just puzzeled as to why the swr is only low when driving amp with the palomar 250.any input would be appreciated. |
Taz
| | Posted on Friday, February 01, 2002 - 8:59 am: |
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try tuning the antenna! |
Pitbull477
| | Posted on Friday, February 01, 2002 - 8:57 pm: |
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what i guess im asking is can you get an accurate swr reading while running amps,or is the reading im getting just harmonics.by the way with no amps on im getting a 1.1 swr reading so i dont think the antenna nees to be tuned.thanks for the suggestion taz.hey 307 could you enlighten me on how to take an swr reading properly when running amps.thanks for any help |
Warlock
| | Posted on Saturday, February 02, 2002 - 9:33 am: |
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There's a few keys to running big power. These are essentials.
1. You must have enough current supply to the amp. A S16 needs minimum of 150a supply, and 2ga power wire. Do you have a 200a alternator? If not you need one or need a smaller amp.
2. Equal or moreso to the current supply is ground. 2ga to the battery and an additional ground of at least 4ga DIRECTLY to the frame, not seat bolts. These connections need to be bare metal, then sealed.
3. Antenna System: A Wilson 5k will handle this amp, but needs to be permanent mounted. The coax on a Wilson 5k is the weak link. RG8x will handle around 500w continuous for only intermittent periods. Your amp is capable of 600+ and the coax should be changed to something like Times Microwave LMR240 or CQ lo-loss mini8. These coaxes can handle 1kw continuous power.
4. Additional grounds: When running this type of power, if the various parts of the vehicle are not grounded they can become radiators. Several grounds from the body to frame, the battery, hood, fenders, engine block, all to the frame.
5. Finally on some amps if they are underdriven (ie: 1600 with no driver) can show incredible reflection. Maybe 307 or someone else can expain why exactly, I don't know.
Running big power isn't as easy as some may lead you to believe. Do it right and you'll be very happy. Skimp and you'll be very aggrivated and possibly damage your equipment and possibly your vehicle. |
Tech181
| | Posted on Saturday, February 02, 2002 - 7:36 pm: |
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Excellent post Warlock!
Steve
Tech181
Tech181@copperelectronics.com |
Possum
| | Posted on Thursday, April 18, 2002 - 6:47 pm: |
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I run a 2 amp setup and have swr of 1.3 to 1.7 with boxes on. Do not overly concern yourself with swr at the radio because of minimal power. Measure at the last box using a 2 foot jumper. Most important to keep in mind when running big power 6 pil and up is ground, ground, ground, I use 3 grounds of 10 guage to the antenna mount which is permanent and run those to the frame. big power plays "tricks" with swr. set your dead key to 4 watts or whatever will give you 90% of total amp output and set swr accordingly. I use a big coil antenna to handle the power. But grounding (no paint underneath, enough groundplane, big enough cables, quality coax) marine grade rg213 from ancor. as you increase or decrease rf pwr vswr WILL change. I use more of a reflected power meter because if its not coming back chances are it wont hurt me. good luck Possum |
Rci2990
| | Posted on Friday, May 10, 2002 - 12:19 pm: |
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Try it on a dummy load and see what happens. If it still does it then it might be a problem with the amp itself. At least by doing that way you can start to single out problems.. |
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