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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 1 1,109 on 19/2/16
March 2016 QST Compact Multiband Dipole Feb 19th 2016, 15:23 1 896 on 19/2/16
Antenna analyzer vs feedline type Sep 21st 2012, 14:37 1 2,764 on 21/9/12
USB to Serial Port problems--Prolific Drivers Aug 3rd 2012, 18:27 2 3,326 on 26/12/15
Italian Phishing emails! Dec 13th 2011, 14:20 1 2,414 on 13/12/11
John K0GMO needs help designing SS Amp Nov 17th 2011, 15:53 1 2,274 on 17/11/11
1 Farad Capacitor to Eliminate Headlight Flicker? Oct 19th 2011, 13:14 4 3,854 on 9/11/11
History of Relay Rack Dimensions? Oct 17th 2011, 12:58 2 2,509 on 25/10/11
Miswired Selsyn Oct 13th 2011, 17:51 1 2,435 on 13/10/11
Stealth Antenna wire Sep 12th 2011, 12:51 2 3,098 on 13/9/11

Latest Posts

Topic Author Posted On
New to Ham Radio WoodguyCO 1 day, 19 hours ago
https://www.fmca.com/motorhome/basics/372-internet-to-go.html
There are non-amateur services that may meet your needs. The author of this article mentions 10 minutes as being an eternity. It is unlikely you will get that sort of reliability with ham radio.

You may have difficulty getting good answers to your question as this isn't a typical ham radio activity.

HF can be very unreliable from Alaska. While beautiful to some, aurora borealis will block radio signals, preventing HF propagation.

Zack Lau W1VT
ARRL Senior Lab Engineer
Power line transformer interference? jmayer180 3 days, 19 hours ago
http://www.tdworld.com/overhead-transmission/smarter-approach-resolving-power-line-noise
Note that transformers are not listed among the most common power-line noise culprits. Despite their reputation, only a small percentage of transformers are actually found to be the cause of an RTVI complaints. Many times transformers are replaced because they are believed to be RTVI sources, when in reality, the transformers' loose hardware merely needs to be tightened.
Home made mast for inverted 40-80 meter dipole k9zzp 4 days, 15 hours ago
http://forums.qrz.com/index.php?threads/35-pvc-antenna-mast-tower-ideas.286123/
Discussion of this on qrz.com
AM broadcast on 80 meters? KO0Y 4 days, 16 hours ago
Yes sometimes the filter can help. But, Rigs like the K3 with ham band bandpass filters are much less likely to have difficulty with a clean transmitter than receivers that use the same filters for ham band and general coverage reception.

Perhaps the first thing to do is to take out any preamplifiers and put in some front end attenuation to see if that helps--it could just be a preamp or front end mixer overloading.

http://www.arrl.org/broadcast-station

One clue is to whether everyone is hearing the interference--it is possible, though rare, to have a misadjusted broadcast transmitter.

Zack Lau W1VT
ARRL Senior Lab Engieer
Gain of a Quarter Wave Ground Plane Antenna? WA6EJO 5 days, 17 hours ago
The wide variety of opinions suggest the answer is not so simple.

Traditionally, it took three years of engineering school to learn how to calculate the impedance of a highly simplified dipole. First year you learned single variable calculus. Second year you got to handle real engineering problems with two variable calculus. Third year you took the hardest classes, which included solving antenna problems with calculus. Senior classes were typically easier, as they expected you to to be pre-occupied with finding a job.

The first edition of Antennas by Kraus, W8JK is now a free download.
https://www.scribd.com/document/8688310/Kraus-Antennas It is well worth studying if you want to understand the tradeoffs made to calculate antenna gain from first principles. For instance, the antenna element is usually infinitely thin with zero conductor loss, something that is impossible with real antennas. But, nobody has been able to solve the equations if you try to solve for a real conductor diameter.
Fortunately for hams, method of moments computer programs can give good answers provided care is taken in setting up the proper models. A distinct advantage of computer models is that they specify exactly what is being modeled--what exactly is a "ground plane antenna"?
One approach is to consider it half of an ideal dipole above an infinite perfect ground. This is useful because it provides a clever way to get an answer. The difficulty with this approach is answer is that it is often misleading. You can argue that the answer is pretty good for tiny little atolls in the Pacific surrounded by salt water, but most hams have ground conditions that are significantly worse than this "best case" scenario. And getting from an idealistic best case to what you really want can be hard to understand if you insist on solving calculus problems to get there.

So, for most hams, the most useful answer they can get is to learn how to use modeling programs to best approximate the antennas and ground conditions they actually have. While it is nice to know what you could get if you moved to beach front property, most hams would benefit more if they could obtain comparisons between more realistic antenna options.

Zack Lau W1VT
ARRL Senior Lab Engineer

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