Double Balanced Cross Coupled Product Detector

Back in 1980, Pat Hawker G3VA(SK) spoke about this circuit in his technical topics column for the RSGB Mag. This circuit has surfaced again in the latest issue of SPRAT. I do not have access to the SPRAT article but I do own a copy of the RSGB Technical Topics Scrapbook which comes with a CD of all 50 years of Pat’s column.

Other than that, I do not know all that much about this circuit and I cannot find any other references to it, or the references in the article, though the sprat article does go into its mode of operation. So while I do not know all that much about it, what I do plan to do is to build this circuit on some vero or scrap copper clad board and run it through its paces and see how it performs and then compare that to some known mixers I have here and try and quantify its qualities.

Anyway, i will post more on this once I have done the work and published the results. For now, I am off to LTSpice to simulate it and see what happens.


15m Dead As A Door Nail

Band is open, no one is home. Had a SSB qso for 30mins with a friend of mine, on 15m, good signals both ways, he is on a beam, I am on a vertical, between us we should have been making enough noise to attract someone’s attention somewhere. But no, not a single breaker, no callers at the end, nothing. Just a bunch of crickets.

So i dropped down to CW and called a little just to see where I was being heard. VK, ZL, WANK, I was putting some signal somewhere, after calling for 10mins i gave it up as a waste of time just like I did a few days earlier when I was being heard in JA, EA and HS.

My mate had done the same thing, he was spotted in a few more places and after 30mins made 1 contact. So where the hell is everyone? Drop to FT8 and work a bunch of stations. But SSB and CW, its crickets.


The Gilligan’s Island Desk Mic

Things often change and this is actually a big one for me. For just about forever I have used a headset and would probably use it still for contests, but for daily driving, I have been using my headset as a huge hand mic. Not the best way of doing things, but it was getting the job done.

I did dig out the hand mic and was using it for the last couple of days, but for a while now, I have had the idea to build a desk mic. Yeah you can buy them, yeah they are not all that cheap, but what always got me with them is that you really had no way to adjust them to fit your own unique needs.

So we have the above. The Gilligan is born. Its not the final product, it is just a mock up in wood to get the shape and dimensions just right for what i need. What will come after this is something similar but in steel with either a nice hammer tone finish or polished to a high shine.

The insert is out of a CB mic i bought off ebay, I have had it on the air for a quick test with Steve VK3KTT and from the video he sent back, it sounds just fine to me. Nice, clean and natural sounding. Cant ask for more, now I just need to buy the steel and get welding.