{"id":44297,"date":"2020-07-12T08:04:09","date_gmt":"2020-07-12T12:04:09","guid":{"rendered":"https:\/\/swling.com\/blog\/?p=44297"},"modified":"2020-07-12T08:26:38","modified_gmt":"2020-07-12T12:26:38","slug":"adding-cw-mode-to-the-ea3gcy-db4020-dual-band-40-and-20m-qrp-transceiver-kit-part-2","status":"publish","type":"post","link":"https:\/\/swling.com\/blog\/2020\/07\/adding-cw-mode-to-the-ea3gcy-db4020-dual-band-40-and-20m-qrp-transceiver-kit-part-2\/","title":{"rendered":"Adding CW mode to the EA3GCY DB4020 Dual-band 40 and 20M QRP Transceiver Kit (Part 2)"},"content":{"rendered":"

\"\"<\/a>Many thanks to SWLing Post contributor, Frank (ON6UU), who shares the following guest post which expands upon his previous DB4020 article<\/a>:<\/strong><\/em><\/p>\n

\n

The EA3GCY DB4020 transceiver now has CW mode<\/h1>\n

by Frank Lagaet (ON6UU)<\/strong><\/p>\n

After telling you all about the DB4020 SSB build<\/a> I\u2019m here with the CW part of the kit,\u00a0 let\u2019s say this is part 2.\u00a0 At a certain moment Javier let me know the CW interface kit was ready for shipment and some week later it was delivered to my QTH.<\/p>\n

Again, a well packed kit arrived in a brown envelope, components and boards well packed in bubblewrap.\u00a0 I found even a board I did not expect which can hold a push button,\u00a0 a switch and the connector for your morse key.\u00a0 Javier thinks of everything it seems!<\/p>\n

\"\"<\/a><\/p>\n

Unpacking the bubblewrap gave me this result,\u00a0 all components in 2 bags.\u00a0 In the bigger bag another 2 bags with 2 printboards,\u00a0 one for the CW interface,\u00a0 one for the CW filter.\u00a0 Great !!\u00a0 Checking the material bill resulted in all components there,\u00a0 another thumbs up.<\/p>\n

\"\"<\/a><\/p>\n

I started, of course, immediately building it because I wanted CW in the transceiver as soon as possible.\u00a0 I don\u2019t do much in SSB mode anymore and I already started missing CW on the DB4020,\u00a0 so I started my KX3 to listen to while I was populating the boards.\u00a0 I never thought CW was going to have this impact on me! \u2026. ..<\/p>\n

I started building the CW interface,\u00a0 again starting with all small items.\u00a0 I soon saw that the 2 relays which need to be soldered in were ideal to protect all components when the board is upside down, so I soldered them in very quickly.\u00a0 I then soldered in all other components ending with the elco\u2019s.<\/p>\n

Next phase was the CW filter.\u00a0 This board is small and came together in a blink of an eye, no problems there, the long legs of the 3 and 4 pin headers went in last.<\/p>\n

The following day, I made all wire connections and soldered a 13pin connector,\u00a0 leaving one pin out since I want to have the option to choose the width of the CW signal I\u2019m listening to.\u00a0 By cutting the FL CW + pin and adding an additional switch, I have now 500Hz or 2400Hz.\u00a0 Great option, for very little effort and simple.\u00a0 Another thumbs up here.<\/p>\n

Now it was simply a matter of inserting the sub boards in the main board and all should be working.\u00a0 And it did!\u00a0 Hurray!\u00a0 The 500Hz filter works perfectly,\u00a0 filtering away all above or below stations nearby my operating frequency.<\/p>\n

This is the result of the soldering work,\u00a0 2 small boards which need to be inserted in the main board:<\/p>\n

\"\"<\/a><\/p>\n

The CW interface still needs the 13pin header of which I cut one pin and mounted a switch to have the 2400Hz width.<\/p>\n

The IC you see in the middle of the CW interface is the KB2 keyer which gives you several functions like 4 memories and beacon mode.\u00a0 The 4 potmeters are used to set the level on 40 and 20 meters,\u00a0 to set the delay between TX and RX switchover and to set side tone monitor level. \u00a0 The keyer also provides functions as keyer mode A or B,\u00a0 straight key function and can be set for speeds between 1 and 50WPM. \u00a0 WPM speed can be set in 2 different ways.\u00a0 Handy!<\/p>\n

Here a picture of the CW filter inserted on the main DB4020 board.<\/p>\n

\"\"<\/a><\/p>\n

The CW interface is inserted at the side of the main board,\u00a0 notice the 2 wires which go to the switch to allow switch-over between 500 and 2400Hz.<\/p>\n

\"\"<\/a><\/p>\n

(Wiring still needs to be cleaned up in this picture.)<\/p>\n

Finally, the result:\u00a0 a good working multimode QRP transceiver with 2 bands.\u00a0 It should be possible to make close to medium range with it as well as DX,\u00a0 even with QRP power.<\/p>\n

\"\"<\/a><\/p>\n

And while I was building I also made a new key for this radio,\u00a0 it is made out of a relay and cost nearly nothing,\u00a0 looks good doesn\u2019t it ?\u00a0 hihi.<\/p>\n

Homebrew key<\/h2>\n

\"\"<\/a><\/p>\n

The key, when in practiced hands (fingers hi), can do 50 WPM without a problem. My friend HA3HK does without blinking an eye at 40WPM with this kind of key and tells me that he can go faster if needed.\u00a0 Me? I\u2019m going it a bit slower.<\/p>\n

Battery pack<\/h2>\n

As this radio is only using little power (0.4A in RX,\u00a0 1 to 2A in TX depending the power you set it) I thought,\u00a0 let\u2019s make a battery pack for the radio.<\/p>\n

The first plan was installing it in the box.\u00a0 I did not do that because the batterypack is also powerful enough to feed my KX2 and other QRP transceivers. Since I can use it with all of them, a loose battery works out better for me.<\/p>\n

I started with an old laptop which had a broken screen and some other malfunctions,\u00a0 but still had a good battery,\u00a0 although I needed the battery connector of course.\u00a0 A piece of wood to mount the connector on was my next goal.\u00a0 And since I still have another laptop using the same batteries, I can charge the battery without problems.\u00a0 Simple, but good and it weighs much less than a gel cell battery.<\/p>\n

The battery provides me with 12.5V and some 5Ah.\u00a0 Enough to last for hours<\/em> on RX and for sure good enough to activate 2 SOTA sites in one day. \u00a0 It doesn\u2019t look great but works great– that is what matters and to test it was more then good.\u00a0 Next will be getting the battery pack in a nice box.\u00a0 Better to re-use stuff than throwing it away I\u2019m thinking.<\/p>\n

\"\"<\/a><\/p>\n

I need to do something about the cover of the OLED display,\u00a0 there is still some work there to make it look nicer.<\/p>\n

Some video can be seen on YouTube :<\/p>\n