Does my D4D need some maintenance?


Conor Farrell
 

Hi Adam and friends,

I own two D4D transceivers, one each for 20m and 40m. I've really enjoyed using them.

Recently I noticed that I haven't been making any QSOs, and I am not being spotted much on pskreporter.info. At first I suspected it may simply be due to adverse propagation conditions, but when I listen to broadcast stations on shortwave I get very good reception.

When I first constructed the kits and was making lots of QSOs, I noticed that a component in the set emits an audible noise (the FT8 tones) during transmit - maybe one of the coils vibrating as an alternating current passed through it. It was faint but if I listened carefully I could hear it quite easily. Recently, however, when I'm not making QSOs, this noise has stopped. I may be incorrect, but my guess is that the noise-emitting component is part of the TX amplifier section, and it has become faulty, resulting in a weakened transmission.

This evening I did quick test: I tuned a shortwave receiver to 14.074 MHz and used the "Tune" function in WSJT-X to test the transceiver. I could hear the tone easily, but there was also some noise in the signal. I also tested the other D4D transceiver on 7.074 MHz and that signal was much cleaner, with no noise.

So, in summary:
- I am not being spotted a lot and I'm not making any QSOs, with both transceivers
- Both of my transceivers are no longer emitting any audible sound from the PCB
- The signal on the 14.074 MHz D4D seems a bit noisy
- Receive seems to be working well in both transceivers

Do you think I might need to replace any parts on my transceivers?

Best wishes and 73,
Conor EI6GSB


Conor Farrell
 

A brief update: On the 40m D4D, I resoldered the joints for the coils and made sure they were positioned so that they were not too close to or touching other components. I powered up the radio and the characteristic sound from the PCB has returned! Radio propagation conditions aren't good right now but I'll test the set and see how it performs now.

Why did I do this? Well, last year when I first built the 40m kit, there was no sound from the board and I was not being spotted. (I had already built another kit for 20m which was working well so I knew what to expect.) I then resoldered the coils, got the sound, and was making QSOs immediately.

I will report back with results over the weekend in case this information is useful to others.

Conor

On Fri 20 Mar 2020, 19:33 Conor Farrell via Groups.Io, <conchobhair.ofearghail=gmail.com@groups.io> wrote:
Hi Adam and friends,

I own two D4D transceivers, one each for 20m and 40m. I've really enjoyed using them.

Recently I noticed that I haven't been making any QSOs, and I am not being spotted much on pskreporter.info. At first I suspected it may simply be due to adverse propagation conditions, but when I listen to broadcast stations on shortwave I get very good reception.

When I first constructed the kits and was making lots of QSOs, I noticed that a component in the set emits an audible noise (the FT8 tones) during transmit - maybe one of the coils vibrating as an alternating current passed through it. It was faint but if I listened carefully I could hear it quite easily. Recently, however, when I'm not making QSOs, this noise has stopped. I may be incorrect, but my guess is that the noise-emitting component is part of the TX amplifier section, and it has become faulty, resulting in a weakened transmission.

This evening I did quick test: I tuned a shortwave receiver to 14.074 MHz and used the "Tune" function in WSJT-X to test the transceiver. I could hear the tone easily, but there was also some noise in the signal. I also tested the other D4D transceiver on 7.074 MHz and that signal was much cleaner, with no noise.

So, in summary:
- I am not being spotted a lot and I'm not making any QSOs, with both transceivers
- Both of my transceivers are no longer emitting any audible sound from the PCB
- The signal on the 14.074 MHz D4D seems a bit noisy
- Receive seems to be working well in both transceivers

Do you think I might need to replace any parts on my transceivers?

Best wishes and 73,
Conor EI6GSB


Adam Rong
 

Conor,

The enameled wire ends must be treated well. Although the enamel can be removed by solder iron heat, it is still recommended that you scratch them off before soldering.

Thanks,
Adam

在 2020年3月21日,上午5:05,Conor Farrell <conchobhair.ofearghail@...> 写道:


A brief update: On the 40m D4D, I resoldered the joints for the coils and made sure they were positioned so that they were not too close to or touching other components. I powered up the radio and the characteristic sound from the PCB has returned! Radio propagation conditions aren't good right now but I'll test the set and see how it performs now.

Why did I do this? Well, last year when I first built the 40m kit, there was no sound from the board and I was not being spotted. (I had already built another kit for 20m which was working well so I knew what to expect.) I then resoldered the coils, got the sound, and was making QSOs immediately.

I will report back with results over the weekend in case this information is useful to others.

Conor

On Fri 20 Mar 2020, 19:33 Conor Farrell via Groups.Io, <conchobhair.ofearghail=gmail.com@groups.io> wrote:
Hi Adam and friends,

I own two D4D transceivers, one each for 20m and 40m. I've really enjoyed using them.

Recently I noticed that I haven't been making any QSOs, and I am not being spotted much on pskreporter.info. At first I suspected it may simply be due to adverse propagation conditions, but when I listen to broadcast stations on shortwave I get very good reception.

When I first constructed the kits and was making lots of QSOs, I noticed that a component in the set emits an audible noise (the FT8 tones) during transmit - maybe one of the coils vibrating as an alternating current passed through it. It was faint but if I listened carefully I could hear it quite easily. Recently, however, when I'm not making QSOs, this noise has stopped. I may be incorrect, but my guess is that the noise-emitting component is part of the TX amplifier section, and it has become faulty, resulting in a weakened transmission.

This evening I did quick test: I tuned a shortwave receiver to 14.074 MHz and used the "Tune" function in WSJT-X to test the transceiver. I could hear the tone easily, but there was also some noise in the signal. I also tested the other D4D transceiver on 7.074 MHz and that signal was much cleaner, with no noise.

So, in summary:
- I am not being spotted a lot and I'm not making any QSOs, with both transceivers
- Both of my transceivers are no longer emitting any audible sound from the PCB
- The signal on the 14.074 MHz D4D seems a bit noisy
- Receive seems to be working well in both transceivers

Do you think I might need to replace any parts on my transceivers?

Best wishes and 73,
Conor EI6GSB