ka5piu
03-22-2008, 01:40 AM
Hello.
Several people have talked about the Texas Star conversion.
This is the basis for this conversion.
First, the original schematic.
http://texasstar.com/350HDVschematic.gif
Next, one of the conversions, based on Motorola technical notes.
http://www.cqham.ru/projects/100w_hf_qro/hf_qro1.jpg
Next, the completed circuits, with the low pass filtering.
http://www.cqham.ru/projects/100w_hf_qro/hf_qro1.jpg
Note that Texas Star amplifiers can be supplied as class C, or, as AB.
http://www.texasstar.com/export/specifications.html
Note also, that the 350HDV is supplied as a TRANSMITTER, and not an AMPLIFIER, this is to skirt around the laws.
http://www.copper.com/cart/index.php?cPath=61&osCsid=de291ee4cadc92847637dd04e0ab1717
I see nothing wrong whatsoever in using such a unit as the basis of a linear amp, but the original design does need rework.
So, why do it?
Take a close look at the prices, and that is New!
I can sometimes get a fully functional Texas Star 667HDV for under $100, that is less than I could ever buy the parts for, AND, it comes in a box with a board and heatsink.
And, remember, this is a CONVERSION, the units are not used as is.
I am the same kind of person who will take an old AM only car radio, convert it to do 160 meters, build a companion transmitter from discarded TV parts, put the whole thing, including power supply, microphone, and speaker, inside a wooden box, and make it look like an old AC/DC radio.
I find the radios from GM cars work best, as the tuning cap can take a few watts.
Nothing like chatting on 160 with the radio out of a vega!
But, this is one part of the hobby, building things out of stuff that was never intended to do this.
Several people have talked about the Texas Star conversion.
This is the basis for this conversion.
First, the original schematic.
http://texasstar.com/350HDVschematic.gif
Next, one of the conversions, based on Motorola technical notes.
http://www.cqham.ru/projects/100w_hf_qro/hf_qro1.jpg
Next, the completed circuits, with the low pass filtering.
http://www.cqham.ru/projects/100w_hf_qro/hf_qro1.jpg
Note that Texas Star amplifiers can be supplied as class C, or, as AB.
http://www.texasstar.com/export/specifications.html
Note also, that the 350HDV is supplied as a TRANSMITTER, and not an AMPLIFIER, this is to skirt around the laws.
http://www.copper.com/cart/index.php?cPath=61&osCsid=de291ee4cadc92847637dd04e0ab1717
I see nothing wrong whatsoever in using such a unit as the basis of a linear amp, but the original design does need rework.
So, why do it?
Take a close look at the prices, and that is New!
I can sometimes get a fully functional Texas Star 667HDV for under $100, that is less than I could ever buy the parts for, AND, it comes in a box with a board and heatsink.
And, remember, this is a CONVERSION, the units are not used as is.
I am the same kind of person who will take an old AM only car radio, convert it to do 160 meters, build a companion transmitter from discarded TV parts, put the whole thing, including power supply, microphone, and speaker, inside a wooden box, and make it look like an old AC/DC radio.
I find the radios from GM cars work best, as the tuning cap can take a few watts.
Nothing like chatting on 160 with the radio out of a vega!
But, this is one part of the hobby, building things out of stuff that was never intended to do this.