So yesterday I made my first contact using my ET-2 rig. Last night I got an e-mail from Gary, the fellow at the other end of that contact:
Evening
Bill, N2CQR….Yes I did learn about you from the spot on the DX Summit
cluster. I tuned to the freq to see if I could even hear your 80 mW and
you were a good real 569 when calling CQ. You built up to a real 589 on
the later transmissions. I did not have either of the two pre-amp
positions on in the ICOM 756 Pro II. There was not any QRM on the freq
either. Your spot indicating the 80 mW is what really got my attention.
My antenna is a 2 element yagi at about 115 ft and it really works great for me.
Thanks
for the picture of the great little transmitter. Glad to be your first
DX QSO with it. Hi Hi Maybe again soon. My pleasure to work you.
73, Gary, K4MQG
Fort Mill, SC
Farhan commented on yesterday's post, saying that it was hard to tell (from my pictures) where he rig started and ended. He was right. So this morning I have tried to clean up my bench a bit -- I hope these pictures are better.
Above you see the whole rig. The transmitter board is right next to the key that Farhan gave me. You can see the 7040 crystal. A C-Clamp holds to the bench the piece of scrap plywood that serves as the base for this rig. Next to the C-Clamp you see the TR switch -- the just switches the antenna -- both transmitter and receiver are powered at all times. I can hear the transmit signal in the headphones and this serves as my sidetone.
Here is a close-up of the transmitter with the schematic below:
The transmitter is VERY simple. Nine parts, including the low-pass filter. You can barely see the J310 FET to the right of the crystal.
Here is the receiver:
I really like N0WVA's regen. The green diode in the source circuit is the key. This one does not squeal when you go into excessive regeneration (when you think about it, regens should NOT squeal at audio frequencies -- but most do). Also, the green diode dims a bit when you are at the right amount of regeneration. In the picture you can look down the tube of the variometer that Pericles HI8P gave me many years ago. The big variable cap is from the junk box -- I think it may be from a Johnson Viking transmitter. Note the long shaft with the insulating connector -- this is to reduce the hand capacity effect. On the right you see a smaller cap with just one vane -- this is my fine tuning control --- with the smaller cap at mid range, I would just set the big capacitor to put the receiver at 7040 -- with the smaller cap I could tune +/- 12 kc. I also used an insulating shaft on the smaller cap -- the connector for this one is from an old 1930s era regen that I picked up at the Kempton Part rally in London.
Instead of the audio transformer and Radio Shack headphones, I just used some old DLR-1 WWII Headphones. They are very sensitive and work well.
Lots of soul in this new machine: The variometer from Pericles. The WWII headphones. The 1930s era shaft connector. The circuit idea from the Autumn 2001 SPRAT. Farhan's key.
I recently read on Hack-a-Day of a new FPGA chip that has on it 35 BILLION transistors. I'm sure that thing can produce some fascinating results, but can anyone really understand it, or feel that they really BUILT something that has that kind of chip at its center? On the other hand, I did rely on a lot of modern digi technology in this project: The Reverse Beacon Network reported back that my unanswered CQs were in fact getting out (one as far as Kansas to K9PA). And in the end I had to ask -- via the DX Summit Spotting cluster -- for someone to listen for me. So I can't go full Luddite here. And I wouldn't want to have to use a rig this simple every day. No way. It is just too hard to use. But there is a beauty and a challenge in simplicity. There is some virtue in using just two transistors instead of 35 billion.
Thanks to N0WVA, W2UW, VU2ESE, HI8P, K4MQG, The G-QRP club and their inspirational journal SPRAT, the RBN and the DX Summit.