ESP8266 JT65a beacon up and running

Posted in VHF on 9 May 2018 by iw0ffk

Click qui per la VERSIONE ITALIANA

The old 144 MHz beacon transmitter has been replaced with a brand new one.

The goal was to have a JT65 simple beacon without the need of a dedicated ssb transmitter and at the same time maintaining the very useful control via Telegram.

The WSJT mode in use is JT65 submode A, our band plan limits the bandwidth of a beacon to maximum 500 Hz.

The microcontroller is an ESP8266-12E and the radiofrequency is generated by a DDS AD9959. The AD9959 is a very nice DDS, it has four outputs and, if the internal clock runs at 500MHz, can generate up to 200MHz. The down side is the tuning word limited to “only” 32bit.
The external reference clock can be multiplied up to 20 times by the internal PLL to obtain the needed 500 MHz. The AD9959 demo board comes with an installed 25MHz oscillator but unfortunately it can’t be used to generate a good 144MHz JT65 signal. With Pino IK0SMG we measured too much drift in the short time and the JT65 results not decodable. Now I’m using a 100 MHz OCXO and the PLL multiplier has been set to 5x. The minimum phase noise is obtained disabling the PLL…we must be content with what we have.
Claudio IZ0TYD gave me a surplus 10MHz GPSDO and I will try to catch an higher harmonic in order to further improve the Reference.
The Internet connection is mandatory for the Telegram exchanges, so it’s used also for the time synchronization needed for the JT65 protocol.
The beacon is now installed in our HF contest farm in Ostia Antica, close to the sea.
In that location we already have a wlan, internet access and an headless Raspberry Pi that handles some automations and security tasks.



The microcontroller programs 144.461 MHz on the DDS then the amplitude is gradually shaped to obtain the morse code without clicks. The JT65a modulation is generated programming on the DDS the pre-coded tones in the correct order at the correct time without phase jumps.


The beacon transmits for 2 minutes the message in telegraphy, then 3 minutes of JT65a.

Everyone on the beacon Telegram group can send simple commands to the beacon, like attenuate the output power in steps of 3dB up to 12dB or request a steady carrier.
As example to insert the 6dB attenuator, just write on the group /att6db
For a complete list of commands, write /help




IQ0OS/B moved and enhanced -> Telegram beacon !

Posted in Electronics, VHF on 24 March 2018 by iw0ffk

The 144.461 MHz ARI Ostia beacon changed ID and has been moved in JN61DS. Actually is running with my callsign but I hope it will be a temporary solution to grant the presence on air of this historical beacon active for about 25 years.

Thanks to Pino IK0SMG, Emilio IK0OKY and Fulvio IK0YFK in few hours in a rainy and windy Sunday, the beacon has been installed in our HF contest farm in Ostia Antica. The output power is 3 Watts and the antenna is the same omnidirectional horizontally polarized double hentenna.


The new site has full internet access, this gave me the opportunity to made some changes. The RF section has been realigned, just in case, but was ok.
I replaced the microcontroller Pic 16F84 that worked for the last 10 years (and still works) with a more recent ESP8266 (that has WiFi capability) and wrote a new firmware.

Now the new beacon can be instructed with a smartphone to connect to the WiFi Access Point, then it can be controlled by a Telegram bot.
By writing messages in the IW0FFK/B 144.461 Telegram Group , the beacon’s owner can power it on/off, change the callsign, locator and qth.
Other users can change the morse speed, just for fun, or ask the beacon to transmit a steady carrier for maximum 120 seconds, in order to do some measure like an antenna plot with the G4FHQ’s software.

plotlfaffk beacon_bot

If someone is interested I can share the ESP8266 executable that can be customized easily for every VUSHF beacon.

More improvements will come!

10G DXCC+ODX = 1100+ km !!

Posted in VHF on 30 August 2017 by iw0ffk

In the latest days very good conditions of ducting over the Mediterranean Sea with huge signals from Spain in VHF & Up bands.


Silvano I0LVA has opened the path, then many OM maked skeds with Vicente EA5YB.

I did it in the afternoon (after three attempts at 1 hour interval).



Here the Vicente EA5YB working conditions

Summer works 2017

Posted in Electronics, VHF on 30 August 2017 by iw0ffk

Usually I spent part of my August holidays to do some work that can’t be done during the working days. In the latest months I prepared some parts to be installed on the rooftop. This year has been focused to 23 and 3cm bands.
Stuff list:

The GPSDO has been placed near the antennas and supplied 24/24/365 with POE shared with a WiFi Access Point. It provides the reference signal for the 9936 MHz oscillator and for the ADF4153 inside the LZ5HB’s transverter.


With Pino IK0SMG we measured the DF9NP’s oscillator that works well and has a good phase noise.

Then we measured the 10G power amplifier and after some work the maximum gain of 8+ dB has been centered to 10.368 MHz. My driving power is little more than 30 dBm, the resulting power to the feed is now 37 dBm.


The 23cm amplifier uses a MRF186 device that has a gain of 11 dB @ 960 MHz, when used at 1300 MHz the gain drops around 9-10 dB. The RF power of the transverter is 2 Watts, so the power in antenna is something less than 20 Watts. Not so much but it’s better than before. The transverter, the amplifier and the RX filter (necessary) have been placed in an aluminum box on the mast near the antenna.


2017 VUSHF season in JN61

Posted in VHF with tags , , , , , on 17 June 2017 by iw0ffk

This Spring/Summer I have two new bands to play with: 1296 MHz and 10 GHz.

23cm setup for now is a single 55 elements F9FT and a transverter made by LZ5HP

This transverter has a power of 2 Watts and it’s placed on the boom of the Yagi, I’m building a 100 Watts power amplifier based on the project of K5TRA (pcb by IK0EQJ, tnx!). I would place it on top of the mast in the same box of the xverter. It’s still WIP.


Anyway two Watts are enough for a 23cm AirScatter QSO if on the other side there is someone with big ears like IK3GHY.

With Giorgio IK3GHY we had also a nice Rain Scatter QSO on 10 GHz, the first part of this video was recorded by IK3GHY. It’s interesting to note the effect of the scatter on the demodulated telegraphy tone, the single frequency generated is spread in a good part of the rx filter producing a Morse code modulated noise, funny to hear and similar to the Aurora effect on the VHF bands.

The same day, but beaming to a different scatter point, SSB QSO with I6XCK. The effect on the Cesare’s voice is the same as CW.

On 10 GHz a remarkable QSO and my personal ODX was with ED4SHF/6 in JN10wm, QRB 750 km. The QSO has been recorded by Silvano I0LVA.

144 MHz ES worked a new country, 5B4VL in KM64 (Cyprus) and a new square KO37 thanks to YL2OK in Latvia.

On 6m TEP not a single QSO around the equinox days but worked several ES openings mainly toward Asia with good signals from Korea, China, Philippines and two new countries E3 (Eritrea) DXCC #198 and C6 (Bahamas) DXCC #199.

DS4EOI Corea in PM47

C6ATA Bahamas in FL15
The audio file has been recorded by C6ATA

This is the first year of heavy use of the JT65 on 6m for terrestrial QSOs. I think it’s a great tool to promptly detect the openings but it’s too slow to make contacts and several times the dx station is workable only for few tens of seconds, often enough for CW.
The gold rule is, if you hear the JT65 tones on the headphones, you’re wasting time and propagation.


IC-7300: more antenna connectors with Arduino!

Posted in Electronics, VHF with tags , , , , on 12 April 2017 by iw0ffk

I wish to use the IC-7300 on all my bands, but the problem with this rig it’s always the same: too much frequencies for a single antenna connector and I don’t want to swap the coax all the time. On the market there are manual coax switches, but there are not so handy for a remote use…and this one is cheaper.

So, in a rainy Sunday I have built this 1×3 antenna switch controlled by Arduino. I already done something similar in 2009 with a PIC, this time I choose Arduino because it does not need of any programmer to write the code on it, just the USB cable. In the past several OMs have sent their empty PICs to me and I have sent them back programmed. A single project usually don’t worth the cost of a PIC programmer.

This should stops the foot traffic, everyone can load the code in the IDE and write it into the chip with a click.

This 1×3 ant switch is made with few generic electronic components around a “Nano” (ATMEGA328), but the code can be adapted to any ucontroller. It is powered by the transceiver (pins 2 and 8 of the ACC connector) and reads the frequency from the “Remote” jack. It can be fixed directly on the antenna’s connector by using a male-male PL259 adapter. Into the RF box there are three Finder relays model with gold plated contacts. The values of attenuation and isolation between the ports are good:

28 MHz – att. 0.11 dB – isol. 40 dB
50 MHz – att. 0.11 dB – isol.35 dB
70 MHz – att. 0.12 dB – isol. 32 dB

The microcontroller and the rest of the parts are in a separate box to avoid interferences.

The IC-7300’s range of frequency 30-74800 kHz is divided in 24 sub-bands, every sub-band can have associated one of the three antennas output. The right antenna is selected automatically. Simply it remembers the last selection.


Ask me the source code to my address. does not permits to upload zip files.

Icom IC-7300 RX Antenna mod

Posted in Electronics with tags on 11 March 2017 by iw0ffk

I like this transceiver, good receiver, fantastic DSP filtering and NR, excellent GUI and many goodies like the automatic record of QSOs triggered by ptt/key or the RS-BA1 software that shows the waterfall on the PC screen (it works ok also in Linux wine).

Probably Icom has decided to limit some capability of this model for market reasons. The IC-7300 has only one TXRX antenna connector and no RX input, but it’s easy to add a connector on the back and, inside, there is enough room to place a coax relay.

The relay can be mounted on a shaped aluminium bracket fixed to the transceiver by two screws that fix the RF-UNIT board to the chassis.

The adapter has been made with a female TMP connector and a SMA-M to SMA-F transition (used as a wear protection for the connectors of the instruments).

The external ATU supply connector can be moved away, like on the IC-756, and replaced by two pieces of copper pcb board that holds the switch and the coaxial connector.
The orange wire of the ATU is used to energize the relay.

This mod is fully reversible and the transceiver can return in his original status in few minutes.

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Now the IC-7300 can be used also as a second receiver for the 6m or for monitoring the IF of the FT-817, connected to the 3cm transverter.