During our recent open house at the 404 wing, many hams that attended were very curious about a display that was set up by Joe Street VE3VXO.

It consisted of an area of ham communications that not many of us have experimented with, but for Joe, its his pride and joy, and something that he enjoys building. I have asked Joe to provide us with a bit of a description of his display and of the hobby. Here is VE3VXO's report. 

       Ben VA3BNY Program Director 

Well the rigs I had there consisted of a 40 m VXO controlled direct conversion transceiver which is not finished yet. A 20m superhet and a couple of home brew keys. One straight key made from a micro switch shrink wrapped to a piece of tubing so that it can be keyed on any hard surface while wearing gloves. The other is a combination keyer and touch sensitive paddle. I also had a lightweight lithium battery pack with built in supervisory circuit to protect the sensitive cells from over charge or discharge. Then there was the hilltop gear. The VHF portion uses a regular 2m mobile and a home brew collapsible 5 element quad of my own design. This is used for talk back to coordinate aiming the dishes and tuning. Since the microwave gear can drift several MHz with temperature and the link only happens when both dishes are pointed directly at each other AND tuned to the right frequency, it takes a bit of fiddling to get it set, and the VHF COM's are vital to this process. Now for the microwave gear.

This consists of a tripod and surplus military dish which started out its life as targeting X-band radar in a CF-100 fighter plane. It now resides on top of my tripod and is fed with a switchable feed 10 or 24 GHZ. The feed assy. also contains a low noise preamp for the receiver home brewed from a microwave transistor which delivers about 30 dB of gain and a noise figure better than 1 dB at the IF. The receiver has IF shift capability and is home brewed from a TDA7000 FM IC and has a sensitivity of about 2 microvolts without the preamp. The modulator is optimized for low noise and has a deviation control to allow compatibility with other equipment which may have different receiver bandwidths. There is also tone modulation available for when the path gets tough and CW is the only way to make the QSO. 

I have taken pains to match the preamp to the video impedance of the microwave mixer and extra shielding and input filtering to keep out the nasty RF's that live on the hilltops we typically operate from. So all told the system has an overall noise figure of about 12 dB which is good for a wideband FM rig and the dish offers 30 dB gain on 10 and over 40 dB on 24 Ghz so it is looking like a high performance WBFM rig now. My hope is to break the Canadian DX record on both of these bands this year which is long over due and perhaps 200 km will be possible with 5 mW on 10 Ghz. With 24 Ghz I have a whopping 10 mW but the atmosphere absorbs roughly 0.1 dB per kilometer so it is much more challenging, and the antenna beam widths get down around 2 degrees further increasing the difficulty on 24, but my equipment is considerably better than equipment which was used previously to establish the records so we shall see.

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Vy 72 de ve3vxo