W1VT
| Joined: | Sat, Apr 4th 1998, 00:00 | Roles: | N/A | Moderates: | N/A |
Latest Topics
| Topic | Created | Posts | Views | Last Activity |
|---|---|---|---|---|
| Antenna analyzer vs feedline type | Sep 21st 2012, 14:37 | 1 | 994 | on 21/9/12 |
| USB to Serial Port problems--Prolific Drivers | Aug 3rd 2012, 18:27 | 1 | 1,214 | on 3/8/12 |
| Italian Phishing emails! | Dec 13th 2011, 14:20 | 1 | 1,137 | on 13/12/11 |
| John K0GMO needs help designing SS Amp | Nov 17th 2011, 15:53 | 1 | 1,014 | on 17/11/11 |
| 1 Farad Capacitor to Eliminate Headlight Flicker? | Oct 19th 2011, 13:14 | 4 | 1,783 | on 9/11/11 |
| History of Relay Rack Dimensions? | Oct 17th 2011, 12:58 | 2 | 1,245 | on 25/10/11 |
| Miswired Selsyn | Oct 13th 2011, 17:51 | 1 | 1,072 | on 13/10/11 |
| Stealth Antenna wire | Sep 12th 2011, 12:51 | 2 | 1,579 | on 13/9/11 |
| Designing a ham bench | Aug 29th 2011, 12:38 | 2 | 1,668 | on 29/8/11 |
| Can't find recent Hint and Kink | Aug 26th 2011, 13:01 | 1 | 1,529 | on 26/8/11 |
Latest Posts
| Topic | Author | Posted On |
|---|---|---|
| What is an accepted range for a DX contact? | WN6WJN | 1 day, 17 hours ago |
| http://www.arrl.org/distance-records As you can see, when you get to the higher amateur bands, even 100 miles is enough to set records. Zack Lau W1VT ARRL Senior Lab Engineer |
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| RF Suppressor Ground System | KK6CXF | 1 day, 22 hours ago |
| The best way to handle the second floor shack grounding issues is to run coax from the antenna to single point ground that is line of sight and bonded to the electrical service entrance, and then bring up the coax to the 2nd floor station. Some antennas, such as verticals and long wires, may require a good radial system for decoupling, as ground rods are typically inadequate. A balanced antenna, like a center fed dipole, will often work with just ground rods. A half wave dipole is likely to be the easiest antenna to get working well from a 2nd floor station. Zack Lau W1VT ARRL Senior Lab Engineer |
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| looking at MFJ 31' vertical /portable antenna | KB9YUT | 3 days, 17 hours ago |
| Instead of leaving a dipole up, perhaps you could install support ropes that can be used for future operations? Zack Lau W1VT ARRL Senior Lab Engineer |
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| Air Conditioner RFI | KD4LN | 3 days, 22 hours ago |
Ideally, there should be a line of sight path from your service entrance to your shack's single point ground--that way, if there is lightning strike on the service wiring, there will be a simple and direct path to the station grounding. Typically, lighting will take a path through the home instead of going around a corner to follow a bad ground path. The service entrance ground and the single point ground can be the same, but you will need to work harder remove electrical noise from the single point ground. Ground rods aren't as effective as a good radial system in decoupling noise from grounds. In terms of overall station performance, it may be worthwhile to sacrifice a little bit of transmit signal if you can significantly reduce the noise on receive--typically, we are talking about a fraction of a dB on transmit and many dB on receive, if there is a low SWR on the transmission lines. Zack Lau W1VT ARRL Senior Lab Engineer |
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| G5RV to Remote Auto Tuner | KD5DRY | 4 days, 15 hours ago |
| As pages 7 and 8 of the instruction manual for that tuner explain, you can and do run into matching issues--you can't really expect this tuner to handle any load you throw at it. A G5RV can be a good antenna on several bands if put up high, but I do run into a lot of hams that are frustrated if they can't get good performance on every band--a G5RV falls short of this expectation. In contrast, while the Inverted-L requires more work to set up properly, it is much more likely to work as an all band antenna. More importantly for a lof of hams, the Inverted-L needs less space. One also has to realize that efficient wire antenna interact with nearby antennas, wires and metal structures--antennas with "problem" bands will vary unpredictably depending on location. In theory, one could swap baluns to optimize performance--using a 4:1 balun for high impedance loads, a 1:4 balun for low impedance loads, and a 1:1 balun for moderate impedance loads. In practice, folks want to use one balun for everything. Zack Lau W1VT ARRL Senior Lab Engineer |
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