Finally, the SW40+ project is over. I did not updated the status for a long time, although a lot of things happened!
After completing the assembly of the kit (toroids and final transistor) I was ready to make all the adjustments. In the mean time, the enclosure had arrived and I chose to install it first and then adjust it. The enclosure kit comes with a BNC antenna connector and at the time, all my other equipment uses PL-259 so I bought some adapters to use until I make a final cable with a BNC plug.
After connecting my main antenna to the SW40 through the adapter I started adjusting the receiver. It sounded a bit deaf, meaning, that there was not quite big difference whether the antenna was connected or not. This puzzled me a lot but I decided to continue with the transmitter part.(This proved later to be a big mistake!).
I connected the transceiver through my power meter to a mini dummy load and started keying the transmitter. There was no output at all! No matter what I did, the transmitter was dead.
It took me about 3 hours of thinking and signal tracing to make the discovery. The BNC to PL-259 adapter was faulty…actually, it was shorted! All the transmitter testing was performed with a shorted output! This resulted in a fried output transistor, and I had to order new ones from Small Wonder Labs!
After replacing the output transistor (and disposed the faulty adapter!) all the adjustments were finished within minutes. The transmitter is capable of delivering something more than 2.5 watts (as displayed on my power meter, with unknown accuracy !) but I set it to about 1.5 Watts for safety.
The SW40+ finished
I have used it a bit, mainly on receiving (yes, my CW skills are still bad…but they are improving fast!) and it is quite a pleasure! The receiver is sensitive enough and can hear almost everything my main rig hears (which means that they are both either very good or very bad!).
There are two thing that someone has to get used to. First, is the tuning pot. The tuning range of the VFO is small but for a single turn pot, it stil feels that it tunes too fast! Also, it is a bit non-linear, because, there is a small range at the beginning and a bit smaller at the end that does not actually changes the VFO frequency. It is not very serious though and there are a lot of mods to fix that as well as the tuning range.
The other thing is the lack of AGC , which for someone that has never used an AGC OFF switch on his transceiver, is a bit strange! On the SW40+, most of the time when tuning and the GAIN is on the max setting, very strong signals appear from nowhere at very “annoying” levels !!! It takes a little practice to learn to tune with both the TUNE and the GAIN control.
Another view of the SW40+
However, none of the above issues can degrade the quality of the transceiver and are not at all annoying. It is just something that take about 2 hours to get used to! The on-the-air performance is very good and it makes a very compact and portable transceiver that I am going to enjoy for a long time!
I hope to meet you on the band, soon!