New England QRP Club : The Excitement is Building....

Thanks for the initial report on your new rig George. First runs of some of these kits often could use some manual tweaking, but I know you've built enough radios to figure out what is meant.

I am curious about the current version of the digital dial used on this radio. Do you see any "dithering" of the last digit, or does it tend to stay on one number. Earlier versions tended to switch fairly radiply back and forth between, for instance 0 and 1. Some averaging in the firmware would eliminate this. I am interested to hear your impression of how the current dial performs.

Thanks again for the report!
72/73,
Bruce N1RX

Hello to all QRPers. I finished last night one of the first units of the dual bander sold in Europe. The rig runs a solid 5 watts in 17 and 40 m. The receiver has a very good selectivity but perhaps the pass band is to narrow for my taste. I have to test it more. I have made some interesting contacts while the process of alignement. Now the problem: I notice a slight bf noise probably coming from the processor. Putting the pin 20 of the chip to earth trough a 1000 Mf capacitor it dissapear.
Geo, did you notice this?
Thanks in advance.
Juan
EA5BLP

Hello to all QRPers. After a couple of mods, the little toy is working quite
well. Here are the problems in my particular case: I found a noticeable noise
probably produced by the low frequency pulses of the display.(It could be also
an internal oscillation of the processor) On the scope, it appears as a
perturbation over the 5 vcc voltage wich modifyes it´s shape according to some
display numeric changes. I found a free hole (ground point) closed to the
processor. I filtered the 5 volts on the pin 20 of the chip with a 8.000 Mf
electrolitic capacitor connected between this pin and the ground hole. The
capacitor is big, and it loocks like an elephant on a poppy flowers field,
but..it works. I know this is not to act over the origen of the problem, but
it´s a possible solution. Now the noise is almost unnoticeable and always below
the noise of the band.
I´m sure Mr. Hendricks and Weber will find a better "visually design" and
electronic solution if the problem is common to more kits.
Second problem: I have also noticed some erratic behaviour of the processor. My
dual bander is for 17 and 40m. Sometimes, when transmitting in 40, the rig
changed by itself quikly to 17m and then suddenly again to 40m producing a short
interruption of the transmission. I thought it could be some RF peak perturbing
the band voltage input pins of the chip. The solution has been dissacoupling the
conmutation voltage wich tells the processor chip what band we choose to
transmit. It´s very easy. I soldered a 47 pf disc capacitor in paralell to R 41
in the display board. It´s not necessary to remove the board, it can be made on
the visible rear side of this board. The solution has worked very well and now
everything is ok. The receiver has a very good and impressive selectivity and I
have made nice contacts receiving also good sigs. This is - I think- one of the
first units build here in Europe.If someone has found the same problems than
myself, perhaps this post could be useful. In relation to the solution of the
first problem I would suggest to wait a little bit and see what the designer of
the kit says. But, for sure, it works. The second solution is very easy and
works fine.
73 dx!
EA5BLP
Juan.

Juan
EA5BLP

Thanks for the information, George. By the moment, and after a heavy job on 17 and 40m, the dual bander is working very well with my own mods. In any case, I would change the processor with the new program if the band jumps again.Fortunately, since I added the condenser, it works fine.
I think the next steep will be to add a switched wider cw filter. Any experience abt this mod?
72, dx!
Juan
EA5BLP