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Hi Aaron,

I not used MeSquares, but have done quite a bit of "dead bug" construction (which is just placing parts - upside down or not - over an unetched PCB).? Basically I just follow the schematic as it pretty much already organizes the parts in the place you want them on the board.? Start with the receiver antenna connector (or short piece of coax or twisted line) and just start building out.? The receive bandpass filter is first, then the RF amp, mixer, etc all follow.? The build will probably end up long an narrow, but that is good as it keeps the higher level signals away from the lower level ones.? Reading the description of Farhan's build you will see he did it this way too.? You might want to build the VFO, BFO, and AF amp on separate PCB's.? This will allow you to shield the RF one's and also allow you to keep the build from getting too long.? For sure I would put the PA on a separate board.

When soldering parts to the ground plane, remember that is one big piece of copper that you are heating up.? It will take higher heat and a longer heating time than the parts.? Clean then wet the tip of the iron with fresh solder, place the tip on the board where you want to solder, and wait until solder placed on the PCB near the tip will melt by itself.? Then you can place the part to be soldered to it onto the board.? This will keep the part from over heating.

You can place parts upside down or rightside up -- whatever is easiest and makes connections the simplest.

73,


Mark

PS:? Ferrite core toroids or old TV baluns will work much better than tap washers for transformers and inductors as the designer found out in the end.

PSS: If you can't find Toko type transformers for the bandpass filter, you can use fixed inductors and accomplish the filter adjustment by making the capacitors variable instead (trimmer caps).?

On Apr 7, 2020, at 07:15, Mick <Mgsebele@...> wrote:

?Gavin,
I agree with Scott’s antenna suggestion. Another improvement I discovered was to use a USB dongle sound device (see below, the one I use) The sound volume and quality are greatly improved compared to direct to computer connection.
You will have to make sure the PTT connection from the dongle is disconnected or it will constantly trigger your TX.
I eventually mounted a second set of 3.5mm jacks on the back of my rig (wired to the audio jack) through a selector switch (Dpdt on-off-on) on the front of my rig.

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73
Mick VA3EPM?

Rubens,

Most likely it was heat that fried your finals.? Digital modes have been reported to have this issue on all of the uBiTx models, as they keep the transmitter on for 15 seconds at a time at full power.? Before going back on the air I would suggest that you add a fan, larger heatsinks, or both.? Remember that the stock radio does not have electrical isolation of the heatsinks.? Either keep the new heatsinks isolated, or add the insulators for the IRF510s.? The alternative is to reduce the output power with the RV1 adjustment.??I would adjust RV1 using an RF power meter and keep it under 10 watts for 40 meters.? Monitor your finals temperature to verify that they are not getting too hot.? As long as you can keep your finger on them right after the end of transmission, then they should be OK.? I would send a continuous tune signal for at least 15 seconds into a dummy load, turn off the power and immediately check the finals.? I did learn that if you do not turn off the power, there is a large risk that you will move the heatsink and short it out, usually just blowing the fuse.

As to how to set up the bias values for the new finals, there are instructions on the HF Signals and sights.? I have used HF Signals for the bias adjustment:


You should not need to adjust the BFO or frequency calibration.

The above are just suggestions.? There may be better ways to do the testing, however, the ones that I know of would require an IR measurement device.
73
Evan
AC9TU

I use the HF Signals direction:


Requires an amp meter in the power to the finals, or just look for a difference of 100 ma for each setting.

73
Evan
AC9TU