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Telstar Electronics January 3rd 07 12:23 PM

High Power RF Transistors for Sale...
 
These transistors cost $69.95 at RF Parts
This is a fantastic deal...
http://www.telstar-electronics.com/d...sClearance.htm


ray January 3rd 07 09:38 PM

High Power RF Transistors for Sale...
 

"Telstar Electronics" wrote in message
ups.com...
These transistors cost $69.95 at RF Parts
This is a fantastic deal...

You forget they do not work in a CB! That is a MOSFET so a number of
changes would be required to the circuit. You also need to accommodate it
which might be difficult as the rest of the board was designed around a
TO220.
The frequency range is too high so no chance of much gain on 27MHz.
Go and do some research.



Telstar Electronics January 3rd 07 09:53 PM

High Power RF Transistors for Sale...
 
ray wrote:
You forget they do not work in a CB! That is a MOSFET so a number of
changes would be required to the circuit. You also need to accommodate it
which might be difficult as the rest of the board was designed around a
TO220.
The frequency range is too high so no chance of much gain on 27MHz.
Go and do some research.


Never said they worked directly in a CB. They certainly can work at
27MHz though.. with very good gain! They are also 28Vdc. I sure can
tell you're an engineer. Thanks for your input...

www.telstar-electronics.com


james January 4th 07 10:14 PM

High Power RF Transistors for Sale...
 
On Wed, 3 Jan 2007 21:38:14 -0000, "ray" wrote:

+++
+++"Telstar Electronics" wrote in message
egroups.com...
+++ These transistors cost $69.95 at RF Parts
+++ This is a fantastic deal...
+++
+++You forget they do not work in a CB! That is a MOSFET so a number of
+++changes would be required to the circuit. You also need to accommodate it
+++which might be difficult as the rest of the board was designed around a
+++TO220.
+++The frequency range is too high so no chance of much gain on 27MHz.
+++Go and do some research.
+++

**************

Go and do some research. Gain increases as frequency decreases. The
major problem of using this device at 27 MHz is keeping the gain low
enough so that the amp will be stable. Any amp using this part at
27MHz will have to have a lot of feedback to minimize gain.

Also FET large signal impedances are not all th at different from
bipolar devices. With RF power amps you are more interested in the
large signal characteristics of the device and not the small signal
characteristics. This device would make a decent preamp for 27MHz if
you can make it stable. Would have a excellent 3rd order intermod
characteristics also.


james

Telstar Electronics January 5th 07 06:16 PM

High Power RF Transistors for Sale...
 
james wrote:
Go and do some research. Gain increases as frequency decreases. The
major problem of using this device at 27 MHz is keeping the gain low
enough so that the amp will be stable. Any amp using this part at
27MHz will have to have a lot of feedback to minimize gain.


Yes the gain would be high at 27MHz... however... having too much gain
is never really a big problem... you can always throttle it back. It's
having too little gain that comes to get you... LOL

www.telstar-electronics.com


james January 6th 07 02:31 AM

High Power RF Transistors for Sale...
 
On 5 Jan 2007 10:16:50 -0800, "Telstar Electronics"
wrote:

+++james wrote:
+++ Go and do some research. Gain increases as frequency decreases. The
+++ major problem of using this device at 27 MHz is keeping the gain low
+++ enough so that the amp will be stable. Any amp using this part at
+++ 27MHz will have to have a lot of feedback to minimize gain.
+++
+++Yes the gain would be high at 27MHz... however... having too much gain
+++is never really a big problem... you can always throttle it back. It's
+++having too little gain that comes to get you... LOL
+++
+++www.telstar-electronics.com

**********

right, keep on thinking man. Get a unity gain with the right feedback
and you have an oscillator.

james

Frank Gilliland January 6th 07 04:35 AM

High Power RF Transistors for Sale...
 
On Sat, 06 Jan 2007 02:31:08 GMT, james wrote
in :

On 5 Jan 2007 10:16:50 -0800, "Telstar Electronics"
wrote:

+++james wrote:
+++ Go and do some research. Gain increases as frequency decreases. The
+++ major problem of using this device at 27 MHz is keeping the gain low
+++ enough so that the amp will be stable. Any amp using this part at
+++ 27MHz will have to have a lot of feedback to minimize gain.
+++
+++Yes the gain would be high at 27MHz... however... having too much gain
+++is never really a big problem... you can always throttle it back. It's
+++having too little gain that comes to get you... LOL
+++
+++www.telstar-electronics.com

**********

right, keep on thinking man. Get a unity gain with the right feedback
and you have an oscillator.



Especially with a high input impedance and large internal capacitance.
Try to run them puppies hard outside the recommended frequency range
and -=POOF=-!!!





Telstar Electronics January 6th 07 02:23 PM

High Power RF Transistors for Sale...
 
Frank Gilliland wrote:
Especially with a high input impedance and large internal capacitance.
Try to run them puppies hard outside the recommended frequency range
and -=POOF=-!!!


Nonsense Frank... I have built amplifiers at 40MHz with these MRF173s
with no problem.
That's like saying since a 2N3055 has an Ft=2.5MHz... that you couldn't
use for an audio amp... or they would blow up... LOL

www.telstar-electronics.com


Frank Gilliland January 6th 07 04:44 PM

High Power RF Transistors for Sale...
 
On 6 Jan 2007 06:23:18 -0800, "Telstar Electronics"
wrote in
. com:

Frank Gilliland wrote:
Especially with a high input impedance and large internal capacitance.
Try to run them puppies hard outside the recommended frequency range
and -=POOF=-!!!


Nonsense Frank... I have built amplifiers at 40MHz with these MRF173s
with no problem.



Uh-huh. That's why you are unloading them at a fraction of the market
price, right?


That's like saying since a 2N3055 has an Ft=2.5MHz... that you couldn't
use for an audio amp... or they would blow up... LOL



Incredible..... how do you manage to stick your foot so deep into your
mouth? The 2N3055 is bipolar, has a relatively low input impedance,
and is -INTENDED- for frequencies from DC through audio and up. Not
only that, your implication is that the transition frequency (Ft) is
the intended operation frequency when in fact it is the point at which
the transistor exhibits unity gain, making it pracitically useless at
that frequency.

So where's that schematic, Brian?




Telstar Electronics January 6th 07 04:49 PM

High Power RF Transistors for Sale...
 
Frank Gilliland wrote:
Incredible..... how do you manage to stick your foot so deep into your
mouth? The 2N3055 is bipolar, has a relatively low input impedance,
and is -INTENDED- for frequencies from DC through audio and up. Not
only that, your implication is that the transition frequency (Ft) is
the intended operation frequency when in fact it is the point at which
the transistor exhibits unity gain, making it pracitically useless at
that frequency.


Frank, don't know any nice way of saying it... you're just plain
stupid.

www.telstar-electronics.com



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