Back in the saddle again... 40 meters adventures

The last week or two has gotten me back on the air finally.  My goal of having a complete homebrew station is just about done.  At least the HF part of it, for now.

The 40 meter transceiver I'm using is a heavily modified K1SWL SW40+, with redesigned bandpass filters, an arduino-controlled DDS replacing the stock VFO, redesigned RF amp with a MJE-182 final and a headphone amp outboard from the original OPAMP. Other than that, it's a SW40+ built manhattan style on PCB stock. It has a 300 Hz bandpass crystal IF filter and puts out a whopping 1.5 watts.  I could push the MJE182 up to 3.5 watts, but I didn't like how hot the transistor was getting, so I backed the drive down to 1.5W.  At some point, I'll put together a 5W output amp, but I want to see what I can do with what I have first.

To the left of that transceiver is a BITX20 that I hacked together. Again, I've replaced the VFO with an arduino-controlled AD9850 DDS.  The radio appears to work, but it seems I'm never in the shack when 20 Meters is actually open lately, so it hasn't been used on air yet.  More to come on that later.



Here's the BITX20 going into its case

The device with the 4 red buttons is a PIC controlled keyer that started out life as a 4SQRP club style keyer, homebrewed on a piece of stripboard.  I've hacked around so much on the code that it's more my design than the original.  It's not quite as good, I don't think, but at least I tried, right?

Next to that is the audio filter I hacked together a while back.  It originally had a wood case, but I thought better of that and bought a nice little brake from Harbor Freight that I have used to make all the rest of the cases you see pictured.  It makes building equipment boxes really quite simple.

Bending the top cover of the BITX from Galvaneal
 

Not shown in this mess is my homebrew antenna tuner.  It's just an L network for tuning up the only HF antenna that has survived the wind this winter.  The antenna is a 69' end fed wire in an inverted V configuration.  I haven't figured out its pattern yet.  My bet is that the radiation is mostly vertical so it will probably be fairly omnidirectional.  There are lots of trees on my lot though which tends to do funny things.

At any rate, I've made a few QSO's with the 40 meter transceiver.  My biggest disappointment is the high background noise level at my QTH.  I missed a nice QSO into NC last night because of received noise.  I have two strategies that I'm going to try going forward to help deal with the noise.

First, is actually using the active audio filter.  Secondly, I have a receiving loop that I've already put up and a low noise broadband amp built.  I just need to get it boxed up with the appropriate switching scheme and we'll see if that doesn't help with the received noise.