For my VHF/UHF setup I am using a dual band Yagi antenna mounted with 20 deg elevation, beaming SSW (225 deg). The signal is fed to a dual band amplifier (DBA) from SSB electronics and split into the VHF and UHF path.
VHF goes to my Icom IC-9700. If not used otherwise, it is running on the 144.39 MHz APRS frequency. Signals are processed via LAN using the remote Wfview program on a Linux PC routing the AF signal to the Direwolf modem for digipeating.
The UHF signal is fed through a band pass filter to an Airspy Mini SDR. Signals are processed on a Raspberry Pi 4 running a SATNOGS client.
To check in to the gateway press MEM 1 for your full call and then MEM 2 to report your location. Afterwards you might change location, QRG, status or symbol using the keypad.
On the Yaesu FT-60 HT you have nine available DTMF memories with max. 16 chars each. Two DTMF modes can be selected: MEM and CODE. Press F/W DTMF to toggle between both.
In MEM mode you simply press the PTT and one of the keys 1 to 9 to transmit the predefined DTMF sequence of the respective DTMF memory.
In CODE mode you press PTT and each key 1 … 9 and A … D, *, # will send the corresponding DTMF tone.
How to program the DTMF memories? F/W SET sel 17 -> DT WRT F/W sel d1 … d9 DTMF memory F/W Press keys 1 … 9 or sel A … F followed by F/W for your DTMF tone sequence. E corresponds to “*” and F to “#”. Press F/W > 1 sec to store.
You can also send DTMF sequences from your home station. For example, the Icom IC-0700 has DTMF capabilities with 16 DTMF memories.
Select MENU, then 2 and DTMF. EDIT d0 (MEM 1) to enter ACmy10digitcallsign# and d1 (MEM 2) to enter C9*xxBmy5digitsuffix# – xx your home location.
Select Direct Input or d0 … d* to send manual input or predefined sequences.
Determine your 10 digit call sign number
Example: 9V1KG_ is the key sequence “981540“. The last “0” stands for space, as the call sign only has 5 characters. Next we need to add a check sum based on the position of individual letters. “9”: no letter = 0. “V”: 3rd letter of TUV = 3. “1”: no letter = 0. “K”: 2nd pos of JKL = 2. “G” 1st pos of GHI = 1. “Space” 1st pos of _ = 1. The resulting number is 030211. Taken as a base 4 number we need to convert it to a base 10 number:
The resulting 10 digit number for 9V1KG is 9815400805.
Store ACyour10digitnumber# in your 1st DTMF memory.
Shortcut: For Singapore hams (9V1) with a 2 letter suffix just add the position of the first suffix letter (1…3) multiplied by 16 to the second suffix letter (1…3) multiplied by 4 to 769.
Example: 9V1LH_ = 981540, checksum 769 + 48 + 8 = 825 (L: pos 3*16 + H: pos 2*4 ), the result is 9815400825.
Abbreviated 5 digit call sign
Once your full call sign is known to the gateway, it can be abbreviated to the 3 character suffix only. For 9V1KG the suffix is 1KG. Calculation is analogue to the 10 digit call sign. Key sequence for 1KG is “154“. “1” no letter = 0, “5” 2nd letter = 2, “4” 1st letter = 1, i.e. resulting in 021. Converting to a base 10 number:
0 * 16 + 2 * 4 + 1 * 1 = 8 + 1 = 09
The resulting abbreviated 5 digit call sign number is 15409. My full call sign can be abbreviated with 15409 or even shorter 154.
Shortcut: For Singapore hams (9V1) with a 2 letter suffix just add the position of the first suffix letter (1…3) multiplied by 4 to the position of the second suffix letter (1…3).
Example: 1LH = 154, checksum 12+ 2 = 14 (L: pos 3*4 + H: pos 2 ), the result is 15414.
Terminate any tone sequence with ACzzzzz# – in my case AC15409# – the gateway will complement it to your full call sign. You just need to remember a 5 digit number.
After check in with your call sign ACtttttttttt# (MEM1) and home location C9*xxBzzzzz# (MEM2), you can change to a new location by entering the DTMF sequence xxByyyyy# with xx your location number – as shown in the tables below – and yyyyy your abbreviated call sign (see above). Example: Pressing 30B15409# on the keypad in CODE mode will set my location to Bedok.
A couple of weeks ago I started to gather my first experiences with software defined radios (SDR) and active antennas. I started with low investment, using the RTL SDR dongle, but I quickly realized that using the direct sampling mode for HF is not an ideal solution and added the Spyverter HF up-converter.
For my first trials I used a Mini Whip from RA0SMS as antenna, but the results were quite disappointing.
Finally, I ended up with an active loop antenna (see featured image), using the Cross-country Wireless Loop antenna pre-amplifier (10 kHz to 30 MHz version). The pre-amplifier is powered with 13.8 V via a bias-tee. Common mode chokes on the antenna line and all power lines helped to reduce noise, especially on the low bands. This is final hardware setup setup:
The setup is now running 24/7 on a Raspberry Pi 3B+ using GQRX and WSJT-X. I was surprised, how many stations and countries can be decoded down to 80 and 160 m.
Last weekend I participated in the CQWW DX contest SSB part under the call sign 4E1A. Propagation was miserable on 40 m and 80 m; with my 100 W low power I was seldom heard by DX stations in EU or NA. On 20 m and 15 m propagation was acceptable, and I got even some openings on 10 m. Finally, I could exceed my points from 2018 and made 852 contacts with 62 DXCC entities and in 30 zones.
Raw score: 2287 QSOs x 191 multipliers = 436817 points.