Presented at the Ontario VHF Association "Do" 2009
Antenna Heights for 6m Sporadic E
Presented at the Central States VHF Society Conference, Mississauga, ON, 2004
222 MHz Yagis with Direct 50 Ohm Feed
Presented at the Ontario VHF Association "Do" 2008
Introduction to Microwave Ham Radio
Presented (mostly in conjunction with VE3EZP (SK) or VE3RKS) to several southern Ontario amateur radio clubs, 2005-2008
20 Plus Years of Ontario SHF Activity
Presented (with VE3RKS) at a Rochester (New York) VHF Group meeting in 2009
A simple antenna for 2304 MHz
Presented (with VE3OIK) at the Ontario VHF Association "Do" 2003
Also in the Proceeedings of the 38th Conference of the Central States VHF Society, 2004
How to build it....
Power Dissipation in Ferrite Bead Baluns at VHF (Draft 3 - Revised Dec 2011 - new 6m example)
My initial thinking on this subject. Feedback and critiques, as well as real life examples of what works and what doesn't, are welcome.
Method for correcting Yagi element lengths from simulations to account for solid elements
(modelling software usually assumes tubing elements)
50 and 75 ohm cable lengths to match 22-45 ohm load to 50 ohms
Solution shown in graphical form
A folding 432 MHz 11-element Yagi for portable use
Fits in any car
A folding 144 MHz 5-element Yagi for portable use
Horizontally polarized for 2m SSB/CW/WSJT
The K2 is a nice IF radio, but there is no way to prevent it from transmitting in CW when the key is pressed. With a standard sequencer this means that RF drive may be present at the transverter input while the antenna relay is switching, which could damage the transverter. This sequencer interrupts the RF input to the transverter to prevent this problem. Note that it is intended for transverter transmit IF power of not more than a few milliwatts. W3FPR has a different approach to this problem at PTT input for the Elecraft K2.
28 MHz Transmit IF Filter for K2
Another challenge when using the K2 with transverters is the sensitivity of the transmit IF output of the K60XV to RF. This filter solves most of the problems. Here are some discussions on the Elecraft reflector on this subject: RFI Susceptibility Unadvertised feature Solution found EMC Issues
Emulating the FT-290R 2 m transceiver using a K2
How I installed a low power 144 MHz transverter in an Elecraft K2 transceiver so it can be used as an IF radio for the microwave bands
Emulating the FT-290R 2 m transceiver using an FT-817/818
An interface circuit that makes the FT-817/818 behave like an FT-290R in low power setting
2 MHz Crystal Calibrator for VHF
Schematic only !
Approximate Methods for Calculating Zo and V.F. of "Wire Microstrip"
Approximate impedance and velocity factor for a wire on the surface of a PC board
Suitable for low power transceivers and transverters up to a few tens of watts
Schematics only - for tone modulated CW gear using a cheap laser pointer
12-LED Optical Transmitter Schematic
Easier to aim than a laser pointer !
Experiments on an LED-Based Optical Transceiver
Notes on a full transceiver design for easy pointing and Morse communication over a few km. Includes data from former preamp and fine-pointing mechanism files
Using 1N5711 diode
A Simple Microwave Noise Source
Uncalibrated, but still a useful and cheap piece of test equipment, good up to at least 10 GHz
Also uncalibrated, but useful for receiver alignment, etc. at HF
A design for a 100 watt class dummy load for HF
Uses lots of ordinary 2 watt resistors
Table of 50 ohm pi attenuator designs using standard value resistors
1-50 dB attenuation, VSWR < 1.20, 10% resistors
Includes details of a 20m 1 watt design - old stuff with dubious copy quality
A Junkbox Switching Power Supply for 28 Volt Relays
Not very elegant or efficient, but uses common parts and it works
An Iambic Morse Keyer with No Clock
An unusual keyer design (from the days before I had a computer to document stuff with)
Increasing Headphone Volume from Realistic DSP-40
I found the output at the headphone jack of this old Radio Shack audio filter to be too low
Photo of Elecraft K2 Mod to Bypass Headphones Jack Speaker Switch
The most common failure in the K2 is the switch (inside the headphone jack) which disconnects the speaker when headphones are inserted. Usually it fails open (speaker never works). By jumpering two of the three pads at the rear of the headphone jack the speaker functionality can be regained, but now it isn't disconnected by inserting headphones. Inserting a plug in the external speaker jack will disconnect the internal speaker, however. The photo shows which pads are to be connected together. Thanks to Don, W3FPR, for identifying the correct pads.
Modified build of the Elecraft KAF2 audio filter for the K2, with wider bandwidth.
Reduces hiss, and provides some rather gentler bandpass filtering for CW than the standard KAF2 kit, while maintaining bandwidth for SSB and digital modes when the KAF2 is "off".
Spartan Sprint Special 40m CW Transceiver
A very small rig!
Notes on some common issues with the Yaesu FTDX10 Transceiver
Deals with receiver hiss on CW, computer keys rig with BK-IN OFF, disappearing band/mode selections,WSJT-X mode setup, no low power tune button
more to come.....
