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D4D: 20m version needs more time

Adam Rong
 

Folks,

As I tested building 20m version one more time and I still found a little bit self-oscillation. As I said this is the nature of this architecture to use only one NE602 for both RX and TX. AA7EE also mentioned about this when he was building his DSB radios:

I had thought I found a perfect fix by muting the front end but it seems not working very stable for 20m as the frequency is higher and the self-oscillation gets easier, I suppose.

What I am going to do, is that I will hold the shipment and announcement for 20m version before the actual shipment starts. I will need about one week to find a proper fix. If it does not happen, I will ask if you would like to switch to 40m or accept refund.

The 40m version is stable and I think you will enjoy this tiny radio to make dozens of QSO’s. 

Thanks,
Adam

Adam Rong
 

Folks,

I am pleased to announce that the issue was found. I will take time to verify the fix and the shipment will be pushed out for about a week. To play safe, I will check 40m as well. Sorry for the delay.

BTW, I got crystals for 3.573 today and 80m version will be in plan.

Thanks,
Adam

在 2019年5月11日,下午11:40,Adam Rong via Groups.Io <rongxh@...> 写道:

Folks,

As I tested building 20m version one more time and I still found a little bit self-oscillation. As I said this is the nature of this architecture to use only one NE602 for both RX and TX. AA7EE also mentioned about this when he was building his DSB radios:

I had thought I found a perfect fix by muting the front end but it seems not working very stable for 20m as the frequency is higher and the self-oscillation gets easier, I suppose.

What I am going to do, is that I will hold the shipment and announcement for 20m version before the actual shipment starts. I will need about one week to find a proper fix. If it does not happen, I will ask if you would like to switch to 40m or accept refund.

The 40m version is stable and I think you will enjoy this tiny radio to make dozens of QSO’s. 

Thanks,
Adam