mcHF Build Progress

 Ive not done much updating on this project, but it is coming along.

I now have the LPF toroids wound and installed, going by the specified number of turns. There is a lot of info out there about these, and much of it seems contradictory. No matter, i'll see how the transmit performs per band and if needed will adjust these coils later.

One problem I had was how to mount the static discharge neon lamp. I didnt like the idea that some had used of milling out the shielding plate and putting it on the 'wrong' side of the board, but also wanted the BNC rather than SMA RF connection. So, I carefully cut away some of the plastic body of the BNC in order to be able to solder the neon bulb in place.

As luck would have it, I discovered that the supplied enameled wire is self-fluxing, which makes it a lot easier to do a reliable joint.

Another trick ive used is to solder the nuts onto the tabs of the TO-220 power transistors and regulators. This makes them captive, and so removes a very tricky step in trying to hold the nut, and transistor, in alignment with a hole inside the case, while the screws are inserted!

And, so far, this below is my progress. All the sockets, switches, encoders, the LEDs, TFT display, latching relays, and LPF toroids are fitted. I decided to solder the display direct. Hopefully that doesnt turn out to be a mistake later!

 I still have the transformers to wind, the VSWR bridge to build, and the power semiconductors to install. I intend installing the temperature sensor for the oscillator, thats on order and should be here in a few days. A small bridge of copper will link it to the oscillator package for best temperature monitoring. I also dont wish to remove metal from the shielding plate, so one of the 220uF 16V SMT electrolytics will have to be replaced, ideally if I can find one on a surplus board or in my SMD stock, with an equivalent in the little square tantalum packages.

Ive already had the ferrite cores out of the bag and given them a good going over with a sanding block to remove any sharp edges, which are notorious for cutting into the enameled wire and causing shorted turns. I also need to look at and if required make the modification to the wiring on the PCB for the VSWR bridge, where I believe one of the windings is connected in the wrong place. This is a design flaw but should be simple to correct.

So far, apart from the lack of a fixed, standard build manual for the version, ive only noticed one gripe - it doesnt have enough LPF and BPF sections! Meaning its lower frequency limit is about 2MHz without excessive harmonics. I appreciate its designed to be very compact, but we have access to 10 amateur bands, so just 4 sets of filters is insufficient really.  5 or 6 sets of filters would have been much better, in my opinion.

Either way though, im looking forward to being in a position to try it out!