Greetings!!!


I plan on building a 500 KC transmitter, 200 watts output. I have
never worked with power FETS before.

What is the selection method used in determining which FET to use??
I see some great FETS
cheap.

Example: IRFP254

250 volt Vdss

RDS on .14

Amps 32 amps

Rise time : 51 NS

Cost; 2.50 each

The data sheet does not spec any freq's ( Ft) like bipolar
transistors?? How do I select the right FET??? freq range

Thanks!!!

The 500 KC transmitter will run at 28 VDC

I can hardly imagine just about any device like this having an Ft so low
that it wouldn't work at 500 KHz. What ham band do we have at 500 KHz?

wrote:
Greetings!!!


I plan on building a 500 KC transmitter, 200 watts output. I have
never worked with power FETS before.

What is the selection method used in determining which FET to use??
I see some great FETS
cheap.

Example: IRFP254

250 volt Vdss

RDS on .14

Amps 32 amps

Rise time : 51 NS

Cost; 2.50 each

The data sheet does not spec any freq's ( Ft) like bipolar
transistors?? How do I select the right FET??? freq range

Thanks!!!

The 500 KC transmitter will run at 28 VDC

--
Scott
http://corbenflyer.tripod.com/
Gotta Fly or Gonna Die
Building RV-4 (Super Slow Build Version)

--
Scotthttp://corbenflyer.tripod.com/
Gotta Fly or Gonna Die
Building RV-4 (Super Slow Build Version)- Hide quoted text -

- Show quoted text -

There are Part 5 licenses recently issued for a 2 year duration 505 to
515 KC to WD2XSH for 20 watts ERP...
I doubt that even 200 watts will get you there with any normal ham
antenna...



denny / k8do

RV7 - even super SLOWER build....

It is a temporary authorization to specific hams or is it for something
completely different and it just happens to be a ham who asked the
original question??

Scott
N0EDV

Denny wrote:
--
Scotthttp://corbenflyer.tripod.com/
Gotta Fly or Gonna Die
Building RV-4 (Super Slow Build Version)- Hide quoted text -

- Show quoted text -


There are Part 5 licenses recently issued for a 2 year duration 505 to
515 KC to WD2XSH for 20 watts ERP...
I doubt that even 200 watts will get you there with any normal ham
antenna...



denny / k8do

RV7 - even super SLOWER build....

--
Scott
http://corbenflyer.tripod.com/
Gotta Fly or Gonna Die
Building RV-4 (Super Slow Build Version)

On Dec 28, 7:03*pm, Scott wrote:
It is a temporary authorization to specific hams or is it for something
completely different and it just happens to be a ham who asked the
original question??

Scott
N0EDV





Denny wrote:
--
Scotthttp://corbenflyer.tripod.com/
Gotta Fly or Gonna Die
Building RV-4 (Super Slow Build Version)- Hide quoted text -

- Show quoted text -

There are Part 5 licenses recently issued for a 2 year duration 505 to
515 KC to WD2XSH for 20 watts ERP...
I doubt that even 200 watts will get you there with any normal ham
antenna...

denny / k8do

RV7 - even super SLOWER build....

--
Scotthttp://corbenflyer.tripod.com/
Gotta Fly or Gonna Die
Building RV-4 (Super Slow Build Version)- Hide quoted text -

- Show quoted text -

It's temporary (for now) and there are 23 licensees authorized... DO a
search on the 500 kc and the call and you should come up with it...

denny

Scott wrote:
I can hardly imagine just about any device like this having an Ft so low
that it wouldn't work at 500 KHz. What ham band do we have at 500 KHz?

wrote:
Greetings!!!


I plan on building a 500 KC transmitter, 200 watts output. I have
never worked with power FETS before.

What is the selection method used in determining which FET to use??
I see some great FETS
cheap.

Example: IRFP254

250 volt Vdss

RDS on .14

Amps 32 amps

Rise time : 51 NS

Cost; 2.50 each

The data sheet does not spec any freq's ( Ft) like bipolar
transistors?? How do I select the right FET??? freq range

Thanks!!!

The 500 KC transmitter will run at 28 VDC

Well a friend of mine once wanted to build a mobile transmitter for
455khz AM and 10.7mhz FM so he could tell the bozo in the car ahead of
him where to go after he cut him off.....

"ken scharf" wrote in message
. ..
Well a friend of mine once wanted to build a mobile transmitter for
455khz AM and 10.7mhz FM so he could tell the bozo in the car ahead of him
where to go after he cut him off.....

I hope you clued him in.. (re. 262 kHz...)

Pete

Uncle Peter wrote:
"ken scharf" wrote in message
. ..
Well a friend of mine once wanted to build a mobile transmitter for
455khz AM and 10.7mhz FM so he could tell the bozo in the car ahead of him
where to go after he cut him off.....

I hope you clued him in.. (re. 262 kHz...)

Pete


I'm not too sure, but I think that today's car radios DO use 455khz.
I think they stopped using 262khz some years back when Detroit started
having the radios made in China and got rid of the RF stages.

But, back then I think Mitch knew better. He never did build that
transmitter, too bad it would have been fun.

ken scharf ) writes:
Uncle Peter wrote:
"ken scharf" wrote in message
. ..
Well a friend of mine once wanted to build a mobile transmitter for
455khz AM and 10.7mhz FM so he could tell the bozo in the car ahead of him
where to go after he cut him off.....

I hope you clued him in.. (re. 262 kHz...)

Pete


I'm not too sure, but I think that today's car radios DO use 455khz.
I think they stopped using 262khz some years back when Detroit started
having the radios made in China and got rid of the RF stages.

Actually, most of them use 450KHz nowadays.

The synthesizer ICs are designed for 450KHz, presumably because of
some fact that makes it easier to design for that IF, such as it
allows an existing common crystal or something.

I can't think of any car radio I've opened up that had digital tuning
and not a 450KHz IF.

It's not so absolute in other types of radios, but it is still a common
IF (which can be a real bother if you've got a shortwave receiver
and thus can't improve selectivity with a good and relatively cheap
used 455KHz mechanical filter).

262KHz IFs in car radios did pretty much disappear with the coming of ceramic
filters. And no car radio is being made without ceramic filters. Though,
I think I did see one car radio, it must have had analog tuning, that did
have a 262KHz ceramic filter.

Michael

LOL!! That might be more fun then using "the finger"

Scott


ken scharf wrote:

Scott wrote:

I can hardly imagine just about any device like this having an Ft so
low that it wouldn't work at 500 KHz. What ham band do we have at 500
KHz?

wrote:

Greetings!!!


I plan on building a 500 KC transmitter, 200 watts output. I have
never worked with power FETS before.

What is the selection method used in determining which FET to use??
I see some great FETS
cheap.

Example: IRFP254

250 volt Vdss

RDS on .14

Amps 32 amps

Rise time : 51 NS

Cost; 2.50 each

The data sheet does not spec any freq's ( Ft) like bipolar
transistors?? How do I select the right FET??? freq range

Thanks!!!

The 500 KC transmitter will run at 28 VDC


Well a friend of mine once wanted to build a mobile transmitter for
455khz AM and 10.7mhz FM so he could tell the bozo in the car ahead of
him where to go after he cut him off.....

--
Scott
http://corbenflyer.tripod.com/
Gotta Fly or Gonna Die
Building RV-4 (Super Slow Build Version)