WA0CBW
| Joined: | Sat, Apr 4th 1998, 00:00 | Total Topics: | 0 | Roles: | N/A |
| Last Login: | Never | Total Posts: | 0 | Moderates: | N/A |
Latest Topics
| Topic | Created | Posts | Views | Last Activity |
|---|---|---|---|---|
| Roller Inductor Tuner | Dec 20th 2011, 19:26 | 1 | 289 | on 20/12/11 |
| Using Ladder Line | Jul 27th 2011, 19:43 | 3 | 780 | on 29/7/11 |
Latest Posts
| Topic | Author | Posted On |
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| IC7000 Transmit problems | KW4Z | 1 day, 2 hours ago |
| Ummmm.... I hope you still have fused the radio at least at the battery. The problem you described could be caused because of poor connections in the fuse holder or because there were two fuses in series (i.e. one at the battery and one at the radio). By their very nature fuses have a voltage drop. Depending on the length of the wire to the battery you may need to increase the size of the wire. For a 100 watt radio I wouldn't use anything smaller than #10. Check your voltage drop from the battery to the radio. Bill |
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| Noise Suppression | KB4LLA | 3 weeks ago |
| Knowing if the noise is getting to the radio from the power feeding the radio or from the antenna can be helpful. Disconnect the antenna and see if you still hear the noise. If the noise goes away then it is being radiated from the source (spark plugs, ignition system, etc. Try using the noise blanker on the radio. Most radios have a pretty good noise blanker and should be able to suppress most of the noise. It may be necessary to use shielded spark plug wires, or noise suppressor spark plugs. Also bond the hood and other body panels so that the noise is shielded in the engine compartment. Any electrical motor may need to be bypassed with a capacitor. A common noise producing motor is the fuel pump usually located in the gas tank. This can be especially difficult to get to. If the noise doesn't go away when you remove the antenna it is probably coming in on the power leads to the radio. You can check this by powering the radio from a 12-volt battery separate from the cars electrical system. If the noise goes away with the separate battery you need to check the electrical system. Make sure the power comes directly from the battery, not the cigarette lighter plug. Be sure you fuse the positive power lead near the battery. If you connect the negative lead directly to the battery it should also be fused. Another cause of noise can be the alternator. Working in a 2-way radio shop I have found about 75% of the alternator whine is caused by a bad alternator or battery. Corroded connections for the charging circuit or grounds cause about 25% of the remaining noise. In extreme cases bonding of body parts, doors, trunk lid, hood, and other pieces such as the "A" frames, muffler and tail pipe may be necessary. Hopefully this will give you some places to start looking. Bill - WA0CBW ARRL Technical Coordinator - Kansas Section |
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| Does Paint Affect Braided Ground Line | tas99 | 4 weeks ago |
| Braided ground wire is not allowed at most commercial 2-way radio sites. It has the potential to create intermod and has a higher impedance that solid copper, jacketed copper, or flat copper flashing. Motorola's R56 manual specifically prohibits braided ground wire either outside or inside radio sites. Either solid copper wire or jacketed copper wire should be used (sized for the appropriated distance). BB |
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| rf filters from RadioShack any good? | k7gav | 4 weeks ago |
| I'm not sure what RF filters from Radio Shack you may be talking about. In general today's HF radios don't produce "splatter" (usually caused by excessive drive or ALC) if tuned up properly. It is possible you could interfere with radios and TV's because of the higher power (100 watts) because some of those devices are not manufactured to reject 100 watt transmitters that are close by. In this case filters would not help but reducing the power might. BB |
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| Kenwood TH-79A changed to TH-79E | ahamack | on 12/4/12 |
| I was given a TM-741 that someone had been "moding" for expanded frequency coverage that did the same thing. I was not able to return it to the proper frequencies either. Bill - WA0CBW |
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