I had a call from the Radio Society of Great Britain. BBC Television were looking for someone to make a replica of the Great Seal Bug found in the US Ambassador’s residence in Moscow in 1952. It had been there for SEVEN YEARS. I made some Youtube videos about the initial stages of the project under the code name Project Swordfish, but then after the programme was broadcast, I was able to create a series of videos about the whole project.
It’s a story of spycraft, cutting edge tech, celebrities, gulags, sharaskas and some extremely clever PsyOps work. This was one of the first really clever bugging operations, known as JUNE, although GUNMAN, Buran, EASY CHAIR, SATYR and many others were to follow.
I made a video on Youtube about making a lantern chuck which I needed to grip a batch of M5 cap screws so I could machine a domed end to the threaded shaft, then polish them. A few folks have asked for the drawings. If I made another of these, I’d probably make the brass collar 10mm longer and the openings 15mm longer, and maybe make the collets slightly smaller. I don’t have a drawing of the insides of the shaft, it is just a simple magnetic hex-socket fitting as used to hold screwdriver bits, in a hole reamed to be a sliding fit. I milled a slot in the side and fitted a dog-point grub screw to prevent rotation, then used another grub screw in an M6 tapped hole at the rear end to fix the position of the bit-holder. Finally, I made a pointed locking grub screw to clamp the other grubs screw in place. Details are on https://youtube.com/ and drawings are here. I can send the DXF on request, I can’t upload it here
I ran a quick test in Fusion360 to look at the stresses around holes in a 1 metre aluminium boom with a large hole in the top and a cross-hole, with one end of the boom fixed and 200N on the other end. Just testing the facility to see how it works.
I’ve been trying out some ideas for a feedhorn that uses the dielectric-horn POTY approach with a 22mm circular guide for 10GHz suspended in the mouth of a 9cm horn. Quick video of the idea shows some issues, like it only works with the coax feed to the 10GHz horn when it is cross-polarized. Needs a lot more thought, but I needed to do this sketch to get it clear in my head. The outer tube is almost transparent in this rendering. It is 180mm long and 68mm OD. The open end of the 22mm tube will have an HB9PZK dielectric lens and the 68mm tube will have a thin dielectric plastic disk with a hole to support the 22mm tube. Hopeless like this though because of the cross-polarisation issue. More thought needed.
I needed a spider to support long workpieces out of the back of the headstock spindle. I had a bit of EN8 round bar so I used that. Bored to 42mm to match the spindle ID, then counterbored to fit the spindle OD. I used a 1mm slitting saw to form a clamp and milled out pockets for a couple of M3 caphead bolts. Bored out a hole in the end of three M8 cap bolts and made brass inserts. Works a treat.
This project is being implemented by the Goole Radio and Electronics Society. The antenna uses the modified PA0RDT Mini-Whip design. The PCB and component kit was put together as a kit by the late Dave Powis G4HUP and now sold by the UK Radio Astronomy Association. The kit only includes the electronics. I decided to make a proper enclosure, couplers and fittings to make a decent mechanical solution.
I made up another batch of my variant of the VK3CV model choked Chaparral®-style feedhorns. Chokes are 7mm diameter, bore is 2mm, Body is 30.75 x 15mm, with an adjustable 4mm diameter coupling cavity. These are made from brass.
Grooves are 0.5mm wide by 0.75mm deep, made with a toolpost spindle at 14,000 rpm using a two-flute carbide end mill in the lathe at 8rpm
Machining and Ham Radio experimentation from VLF to SHF