ARRL

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 1,559 on 21/9/12
USB to Serial Port problems--Prolific Drivers Aug 3rd 2012, 18:27 1 1,802 on 3/8/12
Italian Phishing emails! Dec 13th 2011, 14:20 1 1,472 on 13/12/11
John K0GMO needs help designing SS Amp Nov 17th 2011, 15:53 1 1,363 on 17/11/11
1 Farad Capacitor to Eliminate Headlight Flicker? Oct 19th 2011, 13:14 4 2,353 on 9/11/11
History of Relay Rack Dimensions? Oct 17th 2011, 12:58 2 1,588 on 25/10/11
Miswired Selsyn Oct 13th 2011, 17:51 1 1,415 on 13/10/11
Stealth Antenna wire Sep 12th 2011, 12:51 2 2,032 on 13/9/11
Designing a ham bench Aug 29th 2011, 12:38 2 2,207 on 29/8/11
Can't find recent Hint and Kink Aug 26th 2011, 13:01 1 2,042 on 26/8/11

Latest Posts

Topic Author Posted On
KX3 on PSK31 using Signalink & Digipan KZ6B 18 hours, 41 minutes ago
Quote by KC1YC
Hello KC1YC here,

I am new to PSK31. Have an FT-817ND set on full Power. SWR fine into AlexLoop (indoors). Transmits fine with Mike and ssb. SignaLink between rig and computer. Receives fine, On transmit, rig is triggered (transmit led comes on) but power is nil on external meter (normal indication when using Mic).


That indicates that you don't have audio on the headphone or speaker output making its way to the radio. You might try listening for it--disconnect your rig temporarily and use a computer speaker or headphones to hear it. A computer typically has more than one volume control window--you may need to hunt around to find the right window.

Once you get that sorted out, the next step is making sure you have the proper connection from the computer headphone output to the mic input of the rig.

Zack Lau
ARRL Senior Lab Engineer
Return Loss Bridges WB5EMX 3 days, 2 hours ago
The return loss bridge can be used to characterize the impedance transformation of a balun--how much it increases the SWR of the system. In practice, this isn't as important as the loss of the balun, as most hams have a tuner to compensate for a mismatch created by the balun.

http://www.w8ji.com/balun_test.htm
http://karinya.net/g3txq/chokes/
Typically you want something that will accurately measure high impedances to characterize the choking impedance of a balun.

How to Evaluate Your Antenna Tuner - Part 1
QST April 1995, pp. 30-34
With some simple low-power measurements you can learn a lot about your antenna tuner. There may be some real surprises.
How to Evaluate Your Antenna Tuner - Part 2
QST May 1995, pp. 33-37
AI1H shows data taken using a low-power SWR tester and his simple load boxes to evaluate several antenna tuners.
These two QST articles show a clever way to determine tuner loss.

You can certainly use a signal source, detector, and a return loss bridge to characterize an antenna, but most hams find it more useful to use an antenna analyzer, which is a portable box that combines all these functions--the newer ones will even plot out the results on a graph--great for people who need a picture.

When making SWR measurements it is important to filter out harmonics--either at the detector or signal generator. You won't get accurate measurements with a square wave and a diode detector!

Zack Lau W1VT


Heathkit HW-101 and SB-620 KC1DAK 5 days, 21 hours ago

Here is a very informative article on modifying the SB-620 for a 3395kHz IF, if that SB-620 is set up for something else.

http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0CCYQFjAB&url=http%3A%2F%2Fwww.tronola.com%2FConverting_the_Heathkit_SB-620_for_3395kHz_IF_Receivers.pdf&ei=rsPsVOLVGfiOsQSar4CwAw&usg=AFQjCNEFlmeXjlHBGVlp0fyh96ts0if2Tw&sig2=G0OwN7HV-c5UNLuRfyxuZg&bvm=bv.86475890,d.cWc&cad=rja


QRP transmitter PA output and lowpass filter? KA8SYX 1 week ago
If you are trying to match up Chebyshev designs, you need to match up the passband ripple in addition to the cutoff frequencies. As the amateur bands are narrow, it isn't unusual for designs to accept some passband ripple in order to use standard value parts--which typically makes the design less expensive to duplicate. You could also use two capacitors in parallel to obtain non-standard values.

Zack Lau W1VT
ARRL Senior Lab Engineer
kg-uv6d software Idahobob 3 weeks, 4 days ago

http://www.kc8unj.com/kguv6.html
KG-UV6 Commander

Free programming software for the Wouxun KG-UV6D and KG-UV6X.

Back to Top