T&L Publications

A friend of mine wants a tracking transmitter to track His cat so We both found a circuit on the I-Net. I built the circuit but it doesn't work.The crystal osc. barely works. Here is the circuit description: 3volt battery is bypassed with c2[.001uf],battery neg goes to q1 emitter,r1[220k]and r2[1.5k] are in series to base of q1[a415]ecg107,c3 [2uf] + to junction of r1,r2 - to emitter.high side of r1 to battery +. also L2[4.5t,#32,1/8"d]from battery + in series with L1[12.5t,#36,1/8"d]
and c1[15pf}tank circuit to collector q1.crystal is across coll-base[used 162.55mhz scanner crystal,third overtone?] antenna from bottom L1. animal wire from + of battery. I even redesigned L1 and c1 [2.1pf] I would appreciate any help.

This is Timothy Rasch.I forgot to give my juno email address: [email protected]

Your circuit description is indecipherable. Why don't you post the URL of the schematic?

This URL may be useful: http://www.electronics-tutorials.com/os ... lators.htm

Finding schematic is easy. Just type in Google: animal tracking transmitter. M15 prepared by William W. Cochran,Dec.1,1967 copyright by Jerry Baumeister 1995 . Look for free tracking transmitter plans.Any help would be appreciated. I can't get the circuit to operate properly. Timothy Rasch [email protected]

Looked at the circuit, deceptively simple. Hard to say what's wrong without hands on but there are a few things I noticed.<p>1. Construction counts, especially in RF circuits. Not so much a quality issue but for example you don't want the inductors to be too close together or they could share a B field and mutually induct. <p>2. I noticed in other similar FM circuits C1 is often variable (5 to 60pf in one ckt). In your case this could allow you to compensate for variances in making your own coils.<p>3. Try simulating it. You can download a demo copy of a schematc capture/simulation program and experiment with variables to get a better idea of which parameters are more important and which you can be sloppy with. Multisim is really cool and powerful you just can't save or print with the demo version.<p>4. Try putting an R and C in parallel with the xtal, use a large R and calculate RC to resonate at the broadcast freq. (see #3)<p>5. Buy the $3 plans and construction notes if you have not already done so. There is probably a clue to the problem in there if not a solution. Look at the photo of the beeping transmitter on the same site for ideas.<p>How do you plan to recieve the beacon signal this makes, I'm just curious. <p>Well, thats my nickel

You might try cannibalizing a "Sona-Bouy" [?] transmitter. <p>They are cheap and some are tiny.<p>Surplus stores have them at around 5 bucks each?

CHRIS SMITH--------
You wrote a reply about animal trackers:<p>You might try cannibalizing a "Sona-Bouy" [?] transmitter.
They are cheap and some are tiny.
Surplus stores have them at around 5 bucks each? <p>What is a "Sona-Bouy" and what type of 'surplus stores' have them? Do you know what the range of transmission is?<p>Mr. Glen

A sona-bouy is a submarine detection device. I contains a microphone, transmitter, and salt water battery. It is thrown out of a plane and when it lands in the water it starts transmitting.

Yes to the above, and the transmitter is usually high frequency, and it transmits quite far. <p>Some 20 or more miles, some just a few miles. The transmitter section could be clipped out and as mentioned above, a salt water battery drives the thing meaning it requires very little power.[amperage]<p>Electronic surplus stores carry them and Depending on what state your from, East coast or west, I know at least two that might still carry them. <p>C&S in California and Fair radio sales in OHIO, both are mentioned in N&V. Last time I saw a barrel of them at C&S but that was years back, and all were 5 bucks or less. <p>C&S is California, not Illinois, and isn't in the later N&V. I'll try to find in a back copy if yo cant find any local surplus stores in your area?

CHRIS SMITH<p>I can't find an outlet for electronic surplus in the Puget Sound area. Can you tell more about C&S and Fair radio sales in Ohio?
My project is falling behind without the electronics bay outfitted.

Fair Radio Sales is in Lima Ohio. They have been selling Milatary surplus for about fifty years?<p> They are listed in N&V but you might want to call them up as Im not sure they have listed Sona buoys for a while? <p>I haven't looked up any old NV yet for the C&S in the LA area but I have them all the way back to 92 or 93.<p>They were down in La a few miles from where I was in Pasadena, San Gabriel or Altadena area.

I'll have a look soon. <p>Another one might be "halted specialties" in the bay Area. [In N&V]<p>
Sorry, It was C&H Pasadena 1 800 325 9465 which has also been in business for over 50 years. <p>They have 148 page catalog available. <p>Hope this helps?<p>[ September 21, 2002: Message edited by: Chris Smith ]</p>

There are alot of small qrp designs that run efficiently on batteries for extended periods. The late W1FB Doug Demaw was fond of building little transmitters and good at explaining how and why different components are preferred for RF His interest in the subject shows in his writing and for some who like more depth he includes other projects on inexpensive test equipment. He wrote an arrl book that is excellant for a progressive RF tech called "W1FB's QRP notebook"
For someone that needs a more lengthy discussion to understand this field. An apply it hands-on.<p>If you don't care how it works but want a good kit. Ramsey electronics sells a foxhunt (cathunt)transmitters. Doing an internet search on QRP kits would likely bring up a few. I have read alot of misinformation by amatuer radio techs (codeless techs many are really techless radio buffs that get a Tech license and talk CB on 2 meters, they are a menace to electronics but they pay dues to the club)

ramsey electronics sells a model rocket tracking transmitter. good luck