|600MHz Frequency Counter|
This cheap but high performance frequency counter was originally developed as a project for the members of the Adelaide Hills Amateur Radio Society to construct, but proved massively popular with around 110 units being built by members of both AHARS and SCARC (South Coast Amateur Radio Club). The counter is available in two styles, with a cheap but adequate quartz crystal oscillator being used as the time base in the most basic realisation. In the second version, the time base used is a precision 10MHz TCXO, which lifts the performance of the counter to truly professional standards.
An article describing the construction of the basic version was published in Amateur radio magazine in November 2015.
The project is thus offered to hobbyists only, at near cost, in two ways. (a) A complete set of printed circuit boards and a programmed microprocessor -for those who have extensive junkboxes and/or would like to order their own parts. (b) The 10MHz TCXO upgrade comprising 10MHz TCXO (2.5ppm -30 to +75C)and pcb.
BEFORE YOU SEND ME YOUR MONEY, check that items are in stock by emailing me (Jim) at the following address, then click on the Paypal button. Please do this as I really don't want to issue Paypal refunds!!
PLEASE NOTE THAT ORDINARY AIRMAIL IS USED FOR SHIPMENT. THIS MEANS THAT ALL FORWARDING OCCURS AT YOUR RISK UNLESS YOU SPECIFICALLY REQUEST (AND PAY EXTRA FOR) FORWARDING BY REGISTERED MAIL.
600MHz Counter Printed Circuit Board Set and programmed 16F628A........$A16.00 plus post and packing
600MHz Counter TCXO Upgrade.........$A10.00 plus post and packing
Download the files for the 600MHz Counter here by right clicking on the appropriate link and using the "SAVE TARGET AS" Windows feature.
Displays.... If you are using a WeathAlert unit as the source of your case and LCD, power it up first with a 9 volt battery to check the display contrast available. Some of the LCDs in these units are just old and/or have been exposed to a lot of sunlight and are simply not worth using because their contrast is very low. For Australian builders, a replacement for this LCD can be found in the Aztronics catalogue. Type Z7000A is a direct replacement, and if you want backlighting, then use Z7011A. Other types of LCDs with different pinouts can be used provided they have driver chips compatible with Toshiba type HD44780, but care must be taken with the interconnections between the counter main pcb and display. To prevent the long interconnecting leads possibly radiating extraneous signals back into the high impedance counter input circuits, carefully shield the input lead to the main board, and preferably place the LCD on the right side of the main pcb, as far away from the input circuits as possible.
WeatherAlert Units..... I have a very limited number of these units available on a first come first served basis at around $15 per unit depending on condition. Email me at the above address to check whether I have any left and what the postage costs are to your location. If you are not in Australia, the postal costs are probably simply uneconomic. As an indication, Australia Post charges around $40 to ship this 700 gram package to the U.K. by standard uninsured air mail. :-(
If you are scratch building and wish to use a conventional on/off switch, rather than the touch switches on the front of the Weathalert unit, then simply omit all circuitry between the 3.5mm input power connector and the input of the series regulator IC4. C16 must remain in circuit. Then connect your on/off switch between the pads normally used by the collector and emitter of T6.