I use a Dremel tool with a pointy stone bit, to cut the tracks. It works a treat. Thanks for this video! I'm building my first direct conversion 80m receiver.....steep learning curve after 30 yrs away from this!
Like the jig idea for measuring to matched diodes,i learnt something with this as in the pass i just used ohm meter to match diodes ,You do lovely neat work with your construction.Cheers,
Hi Charlie Good video. Couple of questions 1) what material are these wires...doesmt twisting them together "short circuit" them 2)what is the board used to assemble the circuit?
Hi Sameer. This wire had an enamel coating so there is no problems with shorting. It commonly called transformer wire. The board is simple strip board. Just be careful to minimize the negative effects of inter-track capacitance.Charlie
Another superbly done video Charlie. And many thanks for your channel, amazing job! I noticed that, on both, the breadboard schematics and the final product, wire (c) of type A toroid connects to wire (c) of type B toroid, via the bottom-left diode. Similarly, wire (b-dot) of type A toroid connects to its namesake on the B toroid. But the original electrical schematics is slightly different e.g wire (c) on the A toriod connects to wire (b-dot) on B etc.. does it matter?
No it should be correct Luis. They are constructed as per the schematic. It might just be how i drew it out. The bottom trace is also earth. Sorry for any confusion. There is a later video on this too from the Simple SSB series. A week or two ago.
Why is my homebrew downconverter for sdr not working? I am using a diode ring mixer with 10 turns for each transformer and I am using 1N419 diodes. When I adjust my function generator, It does not affect the spectrum at all.
@@CharlieMorrisZL2CTM Thanks Charlie. I need to up the impedance of the circuits to around 800 Ohms to suit my crystal filter and I have increased the winding reactance to 4k using binocular core type 43. Also used 1k pot for the balance setting. I have put the mixers and filter on top of the chassis where I can put a shield can over each of them. 73
I built one from watching alan's w2aew video couple months ago useing 1n5711 diodes. how do you adjust the resistor. Listen to signal or other method. .great video.
Gidday Rasmus. It's more about making sure the signal is coupled to the diodes and reconstructed again. 10T of trifilar windings on a FT37-43 works well for that.
Thank you for the answer. I’m currently designing a Diode ring mixer as a school project and are mixing an 8MHz and a 5MHz signal. How would i determine what toroid and number of turns to use for my transformer in that case?
Hi Emerson. Below is a link which provides a good summary of the advantages and disadvantages of different types of mixers. I've always likes the DBM due to it cancelling out the RF and LO at ther IF output. www.rfwireless-world.com/Terminology/single-balanced-mixer-vs-double-balanced-mixer-vs-triple-balanced-mixer.html
Hi. It's in the video. Measure the forward voltage drop while forward biasing the diode with a 10kohm resistor. Measure a bunch and select those with the closest forward voltage drop to each other.
if this helps someone, i didn't find the correct video about DBM's inductance of 1:1 tranformers lowers cutoff is calculated by => 2 ¶ F L² > 4 R R (impedance) , F (freq.) and the high frequency has to be with the number of conductors twists .
