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Antenna analyzer vs feedline type Sep 21st 2012, 14:37 1 1,869 on 21/9/12
USB to Serial Port problems--Prolific Drivers Aug 3rd 2012, 18:27 1 2,111 on 3/8/12
Italian Phishing emails! Dec 13th 2011, 14:20 1 1,717 on 13/12/11
John K0GMO needs help designing SS Amp Nov 17th 2011, 15:53 1 1,584 on 17/11/11
1 Farad Capacitor to Eliminate Headlight Flicker? Oct 19th 2011, 13:14 4 2,673 on 9/11/11
History of Relay Rack Dimensions? Oct 17th 2011, 12:58 2 1,831 on 25/10/11
Miswired Selsyn Oct 13th 2011, 17:51 1 1,637 on 13/10/11
Stealth Antenna wire Sep 12th 2011, 12:51 2 2,308 on 13/9/11
Designing a ham bench Aug 29th 2011, 12:38 2 2,601 on 29/8/11
Can't find recent Hint and Kink Aug 26th 2011, 13:01 1 2,321 on 26/8/11

Latest Posts

Topic Author Posted On
Homebrew multiband amplifier KC9HTC 1 day, 3 hours ago
As the amplifier building page on this page suggests, the cost to build an amplifier varies tremendously. Perhaps the most cost effective way to get an amplifier is to get an old sweep tube amplifier that needs new tubes and modify it for cheap surplus tubes--perhaps an old Russian tube. Homebrew amps are also very cheap, but I'd only recommend this approach to advanced hams with experience is building projects.

The best approach for a lot of hams may be to save up your money to buy an old Heathkit amplifier--they were made in huge quantities so there is huge knowledge base on how to fix them if anything goes wrong. You may be able to get a really good deal from an elderly ham who no longer needs an amp and wants to find a good home for it.

Zack Lau W1VT

dual band glass mount ant KB2OCW 1 day, 3 hours ago
According to this discussion, the newer Larson dual band antennas use inductive instead of capacitive coupling to reduce the adverse affects of defroster wires. K2QB says they work OK despite the wires.

Wrong driver selection N1GKE 5 days ago
The system restore function may be able to fix your computer.

Zack Lau W1VT
ARRL Senior Lab Engineer
RF Ground question KB9YOJ 6 days, 20 hours ago
It is difficult to predict whether or not you will need a counterpoise. Most hams just experiment, and add one if there is evidence of excessive common mode current in the station. In the old days, one might get an RF bite from the microphone. These days, one may see evidence of problems on your video monitor when you transmit.

In theory, one could model you station using an antenna modeling program to predict common mode currents, but in many cases, details like the actual electrical wiring around a home are a hidden mystery, unless you have photos of the actual wiring.during construction.

Zack Lau W1VT
RF Ground question KB9YOJ 6 days, 21 hours ago
The article first article reference by Rudy N6LF's page suggests that a balun may not be desirable, as it may take a beating when used with a transmatch. This would be indicated by SWR drift.

In theory, a ground plane is a half wavelength on each side, or about 34 feet, which is clearly impractical, which is why it is more common to use radials. Typically, you attach the radial to the point you which you want to be a low impedance. You may need to experiment with what works best for your particular situation. You have more flexibility or options if you run low power versus high power.

Zack Lau W1VT

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