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Thursday, May 31, 2012


Last night i worked 9M2AR on CW mode with 29 wpm. It was fast and yet quite difficult to copy. There are some words that i could not copy on the fly, i need to practice more especially Malay words. 9M2AR was a good CW operator, but i am not. When i go DXing (contacting long path station) on 20 meter band, i work on CW mode. CW made me reached USA, Germany, Italy, Russia and Japan stations easily. Not like SSB mode which is my preferable mode for ragchewing on 40 meter band.

Ragchewing on CW mode is not easy, it takes time to learn. For the first time, i was very afraid. I think i will make lot of mistakes. I went to IRC, on #ubuntu-hams i chatted with Fabian DJ1YFK (IARU HST Winner). He told me that many people afraid to work on CW for the first time, but when you are familiar to that mode, it will be fun. I agreed with everything he said. Most of the QSL cards or eQSL that i receive was in CW mode. Some of them are SSB's.

I went to Kota Bharu and met Azman 9M2MT. Looking to his shack, i saw unplugged ICOM desktop mic far away from his desk, only a Begali iambic key connected to the ICOM pro III transceiver. He showed me his keys collection. In my mind, i was thinking that maybe his preferable mode for QSO is CW mode.

I saw many ham's shack. I went to 9M2AR, 9M2SX, 9M2MT and saw at least one morse key on their shack. CW and hams could not be separate, although CW is not all hams preferable mode. I am not a good CW operator, never was.

from 9m2ar.com

Monday, May 28, 2012



The official website of the DXpedition is http://9m0l.legendchew.com/. the team: 9M2TO, 9M2/JE1SCJ, 9M2CLN, G3TXF, 9M2PX, 7K4QOK, 9M8YY, JK1FNL, JA1LZR, JE1CKA, JP1TRJ, JQ2GYU, JE1KUC.

Wednesday, May 23, 2012

Helical Antenna Calculator For Amateur Radio

Helical antenna calculator by R.J. Edwards G4FGQ.

The main reason for using a helically wound antenna is to obtain a low height at a given frequency. Ideally, it should be self-supporting - not too slender. It is mounted immediately above a ground plane in an unobstructed environment. This program inputs helix length, diameter and the 1/4-wave resonant frequency. It then calculates the number of turns on the helix for resonance. Also input is the ratio of wire diameter to winding pitch. Various other characteristics of interest are calculated including wire gauge and efficiency. Within the range of validity, the set of output data always corresponds to the condition of a 1/4-wave resonant antenna. Data is valid provided helix dimensions and wire gauge allow close-wound practical antenna construction. Accuracy is satisfactory provided helix length/diameter ratio is in the range 5 to 100. Most designs will be in the Velocity Factor range of .01 to 0.2, where VF is a measure of miniaturization. The program's arithmetic applies from MF to VHF. Close-wound or fairly close coil turns are required. Don't use wire thinner than needed to fill the helical length. Enamel or PTFE insulated copper wire is appropriate. If spaced bare wire is used because of high power, make the ratio (wire-diameter)/(winding pitch) = 0.71. But winding many spaced turns is a tedious job. With high power, ionization will eventually occur at the extreme top. Most of the transmitter power will be dissipated in the helical winding anyway due to poor efficiency. The antenna is a high-frequency Tesla coil. The resonant frequency of a helical antenna is sensitive to the difficult to control diameter. Q is high. So it may be necessary to prune helix height after deliberately making it too long. Helical antennas are single-frequency, narrow-bandwidth devices. For example, to shift the resonant frequency of a 160m band antenna, with a 3dB bandwidth of 7 kHz, by 3 kHz, requires the removal of only 2 turns from a total of 1160 turns. It is probably more convenient to remove a small number of turns and add a very short straight rod or wire which can be more easily pruned. The extra rod or wire need not be vertical. It can extend sideways. The primary reason for using a helical antenna is to obtain a low overall height. While learning to use the program get familiar with 14 AWG enameled wire by adjusting for 580 turns-per-metre and Ratio = 0.95 Or 460 TPM for 12 AWG. Accuracy may fall off when helix length is less than about 5 times its diameter. When length is greater than 100 times diameter the antenna can become non-self-supporting and is probably too high anyway. It can be guyed. Radiating efficiency increases rapidly with height but when low height is an objective radiating efficiency must be sacrificed. The number of turns on the 50-ohm link coupling coil is approximate. It should be of insulated wire and wound over the bottom end of the helix. Use an antenna analyzer. For 75-ohms increase the number of link turns by about 22 percent. Remember, helix diameter is equal to the diameter of the former on which the wire is wound plus wire diameter. It is usual to choose former diameter first. Don't forget to add wire diameter to former diameter to obtain actual diameter. Basic Operating Procedure Enter frequency, helix diameter, helix height, ratio, ground loss. Then vary helix diameter until a suitable wire gauge is found. Vary diameter to fit to size of nearest standard former. Then trim height for exact wire gauge. The formula for the relationships between helix length, diameter, resonant frequency and turns-per-metre has been adapted and improved from an article in "Reference Data For Radio Engineers" of unknown author and issue date. I copied some data into my notebooks about twenty-five years ago. How the arithmetic was derived I have never understood. The derivation was not properly explained. Recently I have compared results with my own programs and found them to be in the same ball park. My own programs, which have an altogether different mathematical starting point, have been checked at HF on the 160 and 80 metre bands by practical helical antenna construction. The advantage of using the "Reference Data" is that an explicit expression for the number of turns on the helix can be derived from it: Number of Turns = Function( Helix Length, Helix Diameter, Frequency ) It is too complicated to reproduce here. If it is correct at one frequency then it is also likely to be correct over a wide range of frequencies such as MF to VHF. It also means similar explicit expressions can be derived for each of the other three variables. Which makes it easy to incorporate the arithmetic in a practical computer program. Run this Program from the Web or Download and Run it from Your Computer This program is self-contained and ready to use. It does not require installation. Click this link Helix_2 then click Open to run from the web or Save to save the program to your hard drive. If you save it to your hard drive, double-click the file name from Windows Explorer (Right-click Start then left-click Explore to start Windows Explorer) and it will run. 

from http://www.qsl.net/va3iul/Antenna/Wire%20Antennas%20for%20Ham%20Radio/111-Helix_Antenna.jpg

Friday, May 18, 2012

Magnetic Loop Antenna Design Software

This software is very useful for designing a magnetic loop antenna, just enter the desired value and it will calculate it for you.

This software is made by Reg, G4FGQ.


Monday, May 14, 2012

DotDash Keyboard - CW Keyboard For Android

Are you looking for an on-screen keyboard that will work with your phone's small screen and slow CPU? Do you know or are you willing to learn Morse code? If you answered "yes" to both of these questions, then this may be the keyboard for you!

IMPORTANT: This is an "Input Method", also known as a "soft keyboard" or IME. It acts as a replacement for the default Android on-screen keyboard. As such, it doesn't show up in your applications list. Instead, after installing it you will need to go to your phone's "Language & keyboard" settings screen and tick the checkbox next to "DotDash Keyboard" to activate it. Then, long-press in any text field (such as the "To" field of a text message), and in the menu that pops up select "Input method". Then choose "DotDash Keyboard" from the list.

DotDash Keyboard is an Input Method, a drop-in replacement for Android's on-screen keyboard. It allows you to enter text via Morse code, using three main buttons: Dot, Dash, and Space (as well as Shift and Delete).
- Type a letter by entering its series of dots and dashes
- Press Space to end a letter and move on to the next one
- Press Space twice to insert a space between words
- Press Delete to clear the letter in progress, or delete the last letter typed if there is no letter in progress
- Type the symbol ".-.-" for the Enter key
- Swipe up off the keyboard for a Morse code cheat sheet

Q: Isn't this an awful lot like that "Gmail Tap" April Fool's Day joke?
A: It is quite similar, but it's no joke. This is a real, working on-screen keyboard which I've been using full time on my cheapo phone for the past two months. Imagine my surprise when my personal software project was perfectly replicated in Google's April Fool's Day video, right down to my rationale for designing it! I was planning to add a few more features before releasing it, but the video made me decide to publish this sparse but fully functional version ahead of schedule.

Q: This is nothing like the setup I use for ham radio.
A: No it isn't. Sorry! I'm planning to add some more ham-friendly features, such as audio feedback, and timing-based input using one paddle, two paddles, and/or iambic, but I haven't gotten there yet.

Q: But really, why three buttons instead of just one?
A: This was actually a design decision. Not only does my phone have a tiny screen, it also has a very slow CPU. I found that input methods based on drawing on screen (or other usage of timing) frequently screwed up when my phone's CPU would bog down. By having a separate button for dot, dash, and space, it doesn't matter how slow the phone processes things, as long as it eventually registers each screen tap in the correct sequence.

Q: Can I switch back and forth between this and my original keyboard?
A: Sure! Just go to your phone's "Language & keyboard" screen and make sure both keyboards are ticked. Then, long-press in any text field and bring up the "Input method" menu again. This will let you switch back and forth as much as you want.

Q: I still don't like it!
A: Well, if you search Google Play for "morse code keyboard" or "morse code IME", you'll find three or four other Morse code soft keyboards. They're each slightly different, so one of them might suit you. If you don't want to learn Morse code but like the idea of reducing the number of buttons on your keyboard, consider trying a T9 keyboard. That's the numeric keypad old cell phones had. There are several on-screen versions of T9 in Google Play, or your phone may even have shipped with one.

Q: Are you sure this isn't a joke? It doesn't show up in my applications list.
A: This is an "Input Method", and so it doesn't show up in your applications list. See the note labelled "IMPORTANT" at the top of this description for setup instructions.

Amateur Radio Call Log For Android

Amateur Radio Call Log is a basic ham radio logging app for Android 1.5 and above. It stores Date, Time, Station, Freq, Mode, RST, and additional comments. Also has the ability to easily look-up callsign information from the FCC database.

Morse Decoder For Android

Morse Decoder decodes Morse code characters through the built-in microphone of your Android device.
Morse Decoder can be used by Ham Radio operators or anyone else interested in decoding Morse code from a Radio or any other device.

Morse Decoder includes a “waterfall” to show a frequency spectrum of about 50Hz to 2300Hz. A narrow band DSP filter can be set for the frequency of the Morse code tones by tapping the waterfall. The DSP filter is followed by an automatic gain control (AGC) to compensate for changing signal strengths.

The detected signal will be shown as a graph and several algorithms will then detect the speed of the Morse code and convert them into readable text. Speeds of less than 4 Wpm (Words per Minute) to more than 50 Wpm can be decoded.


Place your Android device against the speaker of the radio or the device which transmit the Morse code. If there is a tone present the waterfall will display a blue or white vertical line (As stronger the signal as brighter the line) Slide the red rectangular on top of the vertical line. Even though Morse Decoder uses a 200Hz wide AFC (automatic frequency control) it is recommended to move the slider always on top of the vertical line. It may take several initial characters containing both dots and dashes before the WPM speed estimation acquires the actual Wpm and decodes the characters correctly.

Lock Speed:

Morse Decoder will constantly determine the speed of the Morse signs. In very long breaks it is possible that Morse Decoder will detect the wrong speed. The next couple of characters could be decoded wrong. After Morse Decoder detected the right speed it is recommended to push the “lock speed” button. Morse Decoder will lock the speed and will not attempt to change the decoding speed.

Some advice:

To improve the performance it is recommended to place the device directly against the speaker of the radio or the device which transmit the Morse code. Morse Decoder still decodes Morse code when the device is not directly placed at the speaker but several effects like phase interference due to echo’s or background noise can disturb the performance.



Screen lock: Prevents the screen from turning off. CAUTION: this option consumes a lot of battery power.
Waterfall sensitivity: Some Android devices have very sensitive built in microphones others are very deaf. The decoding algorithm uses an AGC but the waterfall sensitivity can be adjusted in the settings.

DX Cluster For Android Phone

DX Cluster for Android  Newer miss a DX spot again.  Get live DX spots on your Android device.      Real time DX spots     Different band and mode filters     A country filter for spotter or the spots     Prefix or call sign alarms   This app is intended to use by ham radio operators only.  You need a ham radio call sign to log into the DX cluster!

DSP Audio Filter For Android

The DSP Audio Filter is a tool that enables you to filter frequencies from an audio spectrum by using your cell phone’s microphone.

This app was originally programmed for Ham Radio (Amateur Radio) operators to remove unwanted background noise and improve SSB and CW signals (Morse Code) but it can be used in different other ways.
For Example:
-Bird watchers can use it to filter out higher frequencies and eliminate street noise or other disturbing low frequencies.
-Musicians can filter out a spectrum of specific instruments.

 The DSP Audio filter uses a freely adjustable lowpass and highpass filter which allows you to select specific filter frequencies and bandwidths. A waterfall visually displays the incoming audio spectrum to better identify the wanted or unwanted frequencies. You must use a headphone to avoid feedback effects.
Ham Radio Operator’s: Just place your phone’s microphone close to your radio’s speaker and listen to clear audio in your headphone.

How to use:

DSP Audio Filter uses a waterfall to display the incoming frequency spectrum. With 2 sliders the cut-off frequencies can be adjust. The areas which are covered by a grey blurry layer are cut out and they will not be passed through to the headphone. All other areas will pass the filter.

The DSP Audio Filter can be used with 4 different sampling rates (22050Hz, 16000Hz, 11025Hz and 8000Hz) which can be set in the settings menu. Unfortunately not all devices support those sampling rates. The DSP Audio Filter will check for the supported sampling rates and only allows the selection of the supported sampling rates.

DroidSSTV - SSTV On Your Android Phone

DroidSSTV lets you transmit and receive amateur radio (ham radio)  slow scan TV (SSTV) on your Android Smartphone or Android tablet. This communications app is a great tool for portable amateur radio SSTV operation. Just connect your Android phone or tablet to an HF radio (or even set it next to the radio’s speaker), tune on to an SSTV frequency, and watch the pictures scroll onto the screen. DroidSSTV supports the modes Scottie 1, Scottie 2, Scottie DX, Martin 1, and Martin 2 at this time.
The features in the receiving modes include:
  • Spectrum analyzer for easy tuning
  • Auto synchronization ( auto slant correction)
  • Auto mode detect
  • VIS encoding (detects SSTV header and sets mode automatically)
  • Level bar for adjusting the audio signal
  • Auto save received pictures to SD Card.
  • Share received pictures (Email , Dropbox etc.)
The features in the transmitting modes include:
  • Pre-load up to 9 pictures from the SD Card into DroidSSTV’s gallery
  • Adjust contrast, brightness and saturation
  • Template editor for easily overlaying templates over images
  • Macro’s for use with templates

DroidPSK - PSK On Your Android Phone

DroidPSK is an app for Android to decode and encode Ham Radio BPSK31 with the build in microphone/speaker or wired to your radio.

A waterfall shows the frequency spectrum of 100Hz to 2000Hz. Just slide the waterfall slide on a PSK carrier frequency and DroidPSK and decode the signal. In transmitting mode characters can be entered trough the keyboard. 9 Macros are also available to store standard texts like “name and qth” and “station info”

Starting V2.0 Droid PSK also now includes a logbook. Callsign, Name RST etc can be easily tranfered into the lookbook from the receiving screen.
The logbook also includes ADIF export and import to transfer your logbook data to a PC based logging software.

DroidPSK to FT817 Interface

This is a small interface which makes it possible to connect an Android cell phone or tablet to a FT- 817.  This circuit might work on other radios as well but I was only able to test it on a FT817 and an IC756PROII.  The goal was to build an interface which doesn’t need an external power supply.  Since the Android device doesn’t have a serial port to switch the PTT another solution had to be found. After some research on the internet I found a nice schematic from KH6TY (https://sites.google.com/site/kh6tyinterface/ ) .

I built the board but all the available Android cell phones and tablets (Droid Incredible, Dell Streak 7 and Motorola Xoom) only provided about 200mVss audio output which is not enough to switch a transistor. An audio 16:500 audio transformer was the solution. I got more than 1 Vss out of the transformer. The rectified signal switched the transistor.

The audio input of the Android device was another problem. When connecting the phone directly to the isolation transformer I had the problem that the phone didn’t recognize the external audio signal or the music player all of a sudden started up. I did some measurements on a headset which I sometimes use with my phone and I had conductivity in one direction but not in the other. It looked like a transistor needed to be connected to the audio input. I am not sure about the value of the resistor R9. 5.6K worked very well on all my testing devices. But depending on the voltage the phone provides on the external microphone pin the value might be different.

Here is the schematic I came up with:

Component list
C1 = 4.7µ
C2 = 4.7µ
C3 = 2.2µ
D1 = 1N4148
D2 = 1N4148
J =3.5mm  4 pin (Mouser 171-7435-EX)
R1 = 5.6k
R2 = 1k (variable)
R3 = 1k
R4 = 1k
R5 = 10k
R6 = 1k
R7 = 1k (variable)
R8 = 330k
R9 = 5.6k
T1 = 2N2222
T2 = 2N2222
Tr1 = 16:500 (42TM026-RC)
Tr2 = 600:600

The first prototype looks like this:

Update: I tested the interface with an ICOM IC756PRO II and it worked fine. I think this interface will work with most radio as long as there is a small voltage present at the PTT pin.  I am more concerned that the interface will not work with all Android devices. On my Droid Incredible I need to set the volume to at least the second highest level to get the PTT to switch. If the audio level is to low on the Android device the interface might now work.

If you have any suggestions or questions please email me at info@wolphi.com. I would like to hear from you.

This schematic is without any warranty. It worked on my phones and  my FT817 but I can not guarantee that it will work with all the Android devices. Please test this schematic at your own risk. I can not be held responsible if you damage your phone or radio.

DroidRTTY - RTTY On Your Android Phone

DroidRTTY is available now on Android Market. DroidRTTY is an Android application to decode and encode Ham Radio RTTY with the build in microphone/speaker or wired to your radio. A waterfall shows the frequency spectrum of 100Hz to 2000Hz. Just slide the waterfall slide on a RTTY carrier frequency and DroidRTTY will decode the signal. In transmitting mode characters can be entered trough the keyboard. 9 Macros are also available to store standard texts like “name and qth” and “station info” DroidRTTY also includes a logbook. Callsign, Name RST etc can be easily transfered into the lookbook from the receiving screen. The logbook also includes ADIF export and import to transfer your logbook data to a PC based logging software. If you like to see more information you can take a look at the manual at : http://www.wolphi.com/droidrtty/manual/ 

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