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Re: Bitx40 varactor tuning/tuning dial?

Jack Purdum
 

See below:


From: "expatrick@... [BITX20]" To: BITX20@...
Sent: Monday, December 5, 2016 11:40 PM
Subject: Re: [BITX20] Bitx40 varactor tuning/tuning dial?

?
Jack,
I have your DDS VFO kit connected to my BitX 40 at the DDS jack and it is definitely tuning the radio. ?

Two questions:

1) I understand the VFO needs to output between 4.7-5.0MHz to tune the BitX40 ?between 7.0-7.3 MHz. ?Is that correct? ?I disabled the band checking routines in the Arduino sketch in order to tune the VFO that low. ?I have heard some CW signals but no SSB, tuning blind. ?I know your Arduino sketch has a RIT offset, but does it have an IF offset?

I thought it was a 12MHz IF, so you needed to subtract 5Mhz from the IF to get to the tuning range. You need to check that, however, as I have not got that far yet...I have a project I have to finish first. The code does not have an IF offset, but I don't see why there can't be one. Take a look at the code from some other AD9850 VFO's and see how they did it.

2) Should I use the output from J2 or J3 to tune the BitX? ?The J2 output jack is unbuffered, which means its signal is lower than on J3. J3 is meant for older (e.g., tube-type) rigs that need a lot of drive power from the VFO. I would use the output from J2 first.

I can tell, I am so close to having this working! ?I will share the sketch when it is working properly.

Thanks!!

73 de AC3K




---In BITX20@..., wrote :

The SoftwareControlledHamRadio group was formed in response to our March, 2016, QST article on the Forty-9er, a rig that was originally designed by Wayne Burdick (now Elecraft) and Doug Hendricks (QRPGuys.com) as a project for the NorCal group back in the 1990's. You can download details on the PCB, assembly manual, and software at:





I don't know if Farrukh still has boards left, but this really isn't an ad as I don't make enough from this to let the XYL SuperSize her meal once a month. We really did it to try and get more hams using microcontrollers in their projects.

You can get more info on the Users Group at:




Jack, W8TEE

From: "Will Kimber zl1tao@... [BITX20]"
To: BITX20@...
Sent: Friday, December 2, 2016 12:58 AM
Subject: Re: [BITX20] Bitx40 varactor tuning/tuning dial?

?
There is a yahoo group:
SoftwareControlledHamRadio
Which is doing an almost identical transceiver idea using AD9850 and Nano? but based on cheap chinese 49'er kits.? You can use their software for your Arduino of what ever type you use.

Cheers,
Will


On 12/02/2016 06:43 PM, Arv Evans arvid.evans@... [BITX20] wrote:
?
Rich

Re.? making your own Arduino based digital dial.

A good place to start is with on-line documentation for the Arduino boards and
for the IDE (Integrated Development Environment) or code editor.






Code for Arduino is written in C++ with a built-in arduino.h abstraction layer that
provides mostly universal pin designators and built-in functions between most
of the several Arduino boards.? Code for Arduino systems is called "sketches"
with many already built applications being available via on-line searches as
C++ source code with file name suffixes of ".ino".

My own preference is the Arduino NANO Mega-328 from any of several Ebay
vendors. Its size is small for the performance it provides.? Yes, Ebay imparts
some level of caution but to-date my boards seem to work as advertised.?
I have changed the 16 MHz crystal resonator to a 20 MHz crystal with positive
results.?





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