BITX40 Project Progress
A week ago I showed you the BITX40, a 40 Meter SSB radio for $45 from hfsigs.com in India. The kit arrived, and we’ve managed to put it together without letting the magic smoke out! Let us look at how the kit arrived and a minor challenge that was overcome.
Unboxing the BITX40 was quite interesting. I don’t think I’ve ever received a parcel from India before! Upon cutting the envelope, I pulled out the papers and a beautiful shipping protection box. Upon opening that I was greeted with a bag with all the cables and parts needed to get on the air, with the exception of a speaker. The BITX40 board was covered by 1/4″ foam board for protection of the board itself. I cut the tape and lifted that off, and was greeted with a beautifully assembled board.
The only glitch was that a couple of toroids were loose. I was advised to use clear nail polish to glue down the loose toroid, but to leave L4 (the one next to the VFO, which is in the middle of the board) alone in case I needed to change that one to get the radio to tune the range I want.
Next was to figure out tuning. The 3/4 turn potentiometer covers the entire range of
frequencies rather quickly, and since I plan to use a DDS (digital VFO) in the future, I decided not to spend the cash on a 10-turn potentiometer. So, I used some parts I salvaged from a laser printer/fax to make this reduction drive. The Altoids tin is empty, and simply serves as a spacer for the rather long shaft, and also gives me a solid place to bolt down the intermediate gear shaft. The 3/4 turn potentiometer now has 6 turns from lock to lock. A huge improvement! I can now tune much easier.
The speaker is from the Garage Sale Find ATS 505 radio. I’d repaired it, but the corrosion went into a main board, rendering it dead and useless. I raided it for parts, and got this fine 8 ohm speaker. The BITX40 drives it nice and loudly. You can also see the included mic in the above picture. Not shown is the PTT switch, which is a salvaged micro switch from the aforementioned printer.
Now I’ve got to get used to using the BITX40- it’s my first HF rig ever, and I have lots of learning to do. More next time!