W1VT
| Joined: | Sat, Apr 4th 1998, 00:00 | Roles: | N/A | Moderates: | N/A |
Latest Topics
| Topic | Created | Posts | Views | Last Activity |
|---|---|---|---|---|
| QST Downloads | Feb 19th 2016, 16:34 | 3 | 2,335 | on 19/3/18 |
| March 2016 QST Compact Multiband Dipole | Feb 19th 2016, 15:23 | 1 | 1,596 | on 19/2/16 |
| Antenna analyzer vs feedline type | Sep 21st 2012, 14:37 | 1 | 3,460 | on 21/9/12 |
| USB to Serial Port problems--Prolific Drivers | Aug 3rd 2012, 18:27 | 2 | 4,129 | on 26/12/15 |
| Italian Phishing emails! | Dec 13th 2011, 14:20 | 1 | 3,067 | on 13/12/11 |
| John K0GMO needs help designing SS Amp | Nov 17th 2011, 15:53 | 1 | 2,934 | on 17/11/11 |
| 1 Farad Capacitor to Eliminate Headlight Flicker? | Oct 19th 2011, 13:14 | 4 | 4,629 | on 9/11/11 |
| History of Relay Rack Dimensions? | Oct 17th 2011, 12:58 | 2 | 3,126 | on 25/10/11 |
| Miswired Selsyn | Oct 13th 2011, 17:51 | 1 | 3,129 | on 13/10/11 |
| Stealth Antenna wire | Sep 12th 2011, 12:51 | 2 | 3,762 | on 13/9/11 |
Latest Posts
| Topic | Author | Posted On |
|---|---|---|
| RST (Readability, Strength, Tone) | AI6OZ | 4 days, 3 hours ago |
| http://www.arrl.org/quick-reference-operating-aids The RST System- Readability 1--Unreadable 2--Barely readable, occasional words distinguishable. 3--Readable with considerable difficulty. 4--Readable with practically no difficulty. 5--Perfectly readable. Signal Strength 1--Faint signals, barely perceptible. 2--Very weak signals. 3--Weak signals. 4--Fair signals. 5--Fairly good signals. 6--Good signals. 7--Moderately strong signals. 8--Strong signals. 9--Extremely strong signals. The page has additional information on reporting tone for CW. |
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| How to determine the Beta of a Transistor | WB5EMX | 4 days, 3 hours ago |
| https://www.instructables.com/id/Transistor-Curve-Tracer/ The best approach is to measure it with a transistor curve tracer. Zak Lau W1VT ARRL Senior Lab Engineer |
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| Is "balanced" (as in baluns, etc.) a myth? | ag7ov | 1 week, 6 days ago |
| I use ununs for impedance matching. The 80M vertical has a step up transformer to provide a 200 kHz SWR bandwidth (below 2:1). It worked well enough to get 80M DXCC with a 100 watt solid state rig without a transmatch or ATU in a couple months. A 4:1 voltage balun can often be wired to provide a DC short to ground. This can be very useful for getting rid of static charge that would otherwise build up on an antenna. But, many 1:1 current baluns don't provide this useful feature. Zak Lau W1VT ARRL Senior Lab Engineer |
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| Is "balanced" (as in baluns, etc.) a myth? | ag7ov | 1 week, 6 days ago |
| Yes, this distinction is actually quite useful, based on actual amateur practice. For instance, I chose to wind an unun for my 80M vertical on an iron powder core, which can't practically be re-designed for a high common mode rejection. But, unlike ferrite cores, iron power cores handle a lot of power, so I don't have to worry about it burning up while running an amplifier. Speaking of amplifiers, hams used to build amplifiers with separate high voltage power supplies. Which meant that it was best to bond everything together securely for electrical safety. Safety first! An effective way of getting rid of common mode currents with verticals is to use an extensive radial system. I think it is quite useful to describe an off center fed dipole as on unbalanced antenna. With a conventional dipole, you can eliminate shield currents by using a balun and properly routing the transmission line away from the antenna. But, with an OCFD, even a perfect balun won't eliminate shield currents caused by the asymmetry between the antenna and the way the feedline is routed. This can be easily shown with computer modeling, which allows you to insert a perfect balun between antenna and the feedline. I've had the opportunity to get plenty of feedback on what type of articles people like by publishing a hundred of them. Back around 1996 I wrote some rather math intensive articles for QEX, and found that EEs in the industry preferred that I do construction projects instead. Now that I have other hobbies, such as growing two hundred rose bushes, and cooking for myself, I only have time to do the occasional article in my free time. Zak Lau W1VT ARRL Senior Lab Engineer |
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| Want to Etch my own Circuit Boards | WB5EMX | 2 weeks, 1 day ago |
| No ARRL bibliography. A Google or YouTube search is more effective these days. This is a popular topic among the Maker Crowd. Among hams, many have opted for services like ExpressPCB, to solve the secondary problem of how do I provide boards for people who wish to copy my projects. It is relatively easy to make boards at home. It is much harder to make boards for picky customers. Zak Lau W1VT ARRL Senior Lab Engineer |
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