Tuesday, December 27, 2016

The Bitx40 Project

The Bitx40 Project --a good rig for just a few dollars!

12/28/2016 ~ First QSO on the new Bitx40. Now at Four Contacts Total!

Listen to the 1st QSO on my new Bitx40. Click the link below. General impressions are that it is a good value for $45 but get the digital VFO add on for another $14. Now that a successful build has been achieved time to move on to another project. Oh for the microphone enclosure (seeing as the electret cartridge is included) I took a defunct microphone and adapted it to the simple cartridge. It seems to work OK. I missed my by Christmas QSO goal by a couple of days but it is working none the less.

Found out why you need the coupling cap out of the DDS! Initially I was advised to disconnect L4 from the pin header. Don't do that! Leave everything as built. The reason I needed a blocking cap was that the hot side of the Pin Header goes right into the base --any RF signal must have the blocking cap. In VU2ESE's Digi VFO there are blocking caps coming off of the clocks. So don't make that mistake.

Additional contacts include K7JUK, KE7LK and KJ6IX. These include stations in Nevada and Arizona. Most signal reports were Q5, Punchy Audio but not even moving the S Meter. What do you expect from 5 watts?

Pete N6QW


I have been working on building the Bitx40, a neat rig from VU2ESE see www.hfsigs.com. Finally got my unit receiving today using the AD9850 for the LO. Below is a still shot and below that a you tube video. I initially had a problem that the DDS wouldn't work and so I shifted to the varactor VFO and that worked so I knew the board was OK. Man talk about drift. Worthless is a good word. Then  I put a cap in series with the DDS and it worked. Without the 10NF cap the DDS output was being shunted to ground.
I would strongly recommend not using the on board VFO for anything other than testing the rig. Either build a solid Analog VFO like N2CQR or just jump to Farhan's add on kit that for $14 additional which gives you the digital capability. Don't waste your time with the on board VFO other than for test purposes.

On par a good value for the cost!

Pete N6QW



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