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Antenna analyzer vs feedline type Sep 21st 2012, 14:37 1 1,376 on 21/9/12
USB to Serial Port problems--Prolific Drivers Aug 3rd 2012, 18:27 1 1,665 on 3/8/12
Italian Phishing emails! Dec 13th 2011, 14:20 1 1,370 on 13/12/11
John K0GMO needs help designing SS Amp Nov 17th 2011, 15:53 1 1,260 on 17/11/11
1 Farad Capacitor to Eliminate Headlight Flicker? Oct 19th 2011, 13:14 4 2,191 on 9/11/11
History of Relay Rack Dimensions? Oct 17th 2011, 12:58 2 1,478 on 25/10/11
Miswired Selsyn Oct 13th 2011, 17:51 1 1,319 on 13/10/11
Stealth Antenna wire Sep 12th 2011, 12:51 2 1,904 on 13/9/11
Designing a ham bench Aug 29th 2011, 12:38 2 2,007 on 29/8/11
Can't find recent Hint and Kink Aug 26th 2011, 13:01 1 1,921 on 26/8/11

Latest Posts

Topic Author Posted On
meaning of contest exchanges KD2BME 1 day, 10 hours ago
The Sweepstakes contest uses a message header as its exchange. It makes more sense if you know that in the early history of the American Radio Relay League, relaying messages was a really big deal.

Zack W1VT
QRP transmitter PA output and lowpass filter? KA8SYX 3 days, 4 hours ago

If the filter cut off is too low, the most likely answer is that you are using toroidal inductors with too much inductance. It is quite common for folks to miscount the number of turns--each time the wire goes through the hole counts as one turn--one loop is actually two turns.

Zack Lau W1VT
ARRL Senior Lab Engineer
How do I contact W1AW/4 on CW and RTTY? NE8K 3 days, 5 hours ago
Many of the W1AW/p stations use a 1 kHz split on CW and RTTY. This is only approximate--if there are a lot of stations calling it is common for operators to tune around a little and respond to frequency a little up or down from that. A few operators use a wide filter and go back to anyone they can pull out of the pile. If the pileup is large the operator may specify a different frequency split or a range of frequencies.

Often, it helps to listen a bit and tune in the stations he is answering. A highly skilled operator can copy multiple signals at once. There are also programs that can copy multiple signals.

Zack W1VT
ARRL Senior Lab Engineer

Zack W1VT
Q on dBi, dBd & dB(nothing) vendor data? xof7fox 6 days, 10 hours ago

You should not assume anything with regard to antenna gain figures. It is extremely easy to produce misleading gain figures, which is why they aren't allowed in QST unless backed up by computer modeling.

In January, 1998, the ARRL Board of Directors changed the ARRL advertisement-acceptance policy to permit the advertising of antenna gain figures for antennas whose performance can be accurately modeled using either NEC-4 or Yagi Optimizer modeling programs. To do this, advertisers submit their antenna models for verification by the ARRL Laboratory staff. If the Lab is able to verify that the model accurately represents the design of the antenna, the advertiser may then advertise the antenna gain figures in ARRL publications.

Zack Lau W1VT
ARRL Senior Lab Engineer
Recommendations for HF antenna/tuner for a newbie wshartjr 1 week, 2 days ago
If you are in a HOA, it is best to either get permission to put up an antenna or put up a display of the American Flag which is also used as antenna. Either will put you on sound legal footing--the Freedom to Display the American Flag act of 2006 is a law passed by Congress and signed by President Bush.

Zack W1VT

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