Message	Date	From	Subject
2709	2009-02-19 05:15:17	Eduardo Alonso	Bipolar RF Transistor for FLEA TRX
Thanks Steve for explaining our current activities. For us, is a little difficult to express fluently in English. -- Sorry, it's an big mistake to use old parts. Yesterday I was doing a "internet meta-search" of a high power bipolar transistor. A candidate is the 2SC2166. It's a low cost transistor, I can buy it in a local store for 3 EUR, but I don't know if currently is in production. I can not find it in DIGIKEY or MOUSER. The best reference I have, is that it was used in K2 transceiver. Neither I have spice model, but I will try to make one from the datasheet and some algebra. I can not find another POWER RF bipolar transistor in DIGIKEY or MOUSER. Other parts under consideration are 2SC1969 (high price) and ubiquitous IRF510 (but redesign needed). An "European" solution is to use a BD139 transistor, but the ft (frequency with current gain unity) is unspecified. HIGH BETA is desired, because the current inside XTAL is the limiting variable in the design. -- Yes, FLEA is not very reproducible, you need all the components and EMRFD book to understand what happens when it does not run. This TRX is like the Arecibo Observatory receivers, they are designed and manually tuned for performance, not for reproducibility. -- The 80meters version is on going. I have access to a 80 meters band antenna in the EA4RCT radioclub. 73 from Eduardo EA3GHS/4
2710	2009-02-19 05:48:21	Chris Trask	Re: Bipolar RF Transistor for FLEA TRX
> >A candidate is the 2SC2166. It's a low cost transistor, >I can buy it in a local store for 3 EUR, but I don't know if >currently is in production. I can not find it in >DIGIKEY or MOUSER. The best reference I have, >is that it was used in K2 transceiver. >Neither I have spice model, but I will try to make one >from the datasheet and some algebra. > >I can not find another POWER RF bipolar transistor in DIGIKEY or MOUSER. >Other parts under consideration are 2SC1969 (high price) >and ubiquitous IRF510 (but redesign needed). > > The 2SC2166 is not an exceptionally good choice as it appears to have been discontinued by Mitsubishi. You can still get it as well as legitimate 2N2866 and 2N3553 made by Microsemi through RF Parts: http://www.rfparts.com/ On the other hand, the PZT2222A is a SOT-223 version of the 2N2222A and has twice the power dissipation capability (1W), and you can safely get 0.5W in class A operation. Further, the PZT4401 will handle 1.15W and you can probably get 0.75W out of it if you have an adequate means of heat dissipation. That part only costs $0.40 in single piece quantities from Mouser. Chris ,----------------------. High Performance Mixers and / What's all this \ Amplifiers for RF Communications / extinct stuff, anyhow? / \ _______,--------------' Chris Trask / N7ZWY _

Message

Date

From

Subject

2709

2009-02-19 05:15:17

Eduardo Alonso

Bipolar RF Transistor for FLEA TRX

Thanks Steve for explaining our current activities.
For us, is a little difficult to express
fluently in English.

--

Sorry, it's an big mistake to use old parts.

Yesterday I was doing a "internet meta-search" of a
high power bipolar transistor.

A candidate is the 2SC2166. It's a low cost transistor,
I can buy it in a local store for 3 EUR, but I don't know if
currently is in production. I can not find it in
DIGIKEY or MOUSER. The best reference I have,
is that it was used in K2 transceiver.
Neither I have spice model, but I will try to make one
from the datasheet and some algebra.

I can not find another POWER RF bipolar transistor in DIGIKEY or MOUSER.
Other parts under consideration are 2SC1969 (high price)
and ubiquitous IRF510 (but redesign needed).

An "European" solution is to use a BD139 transistor,
but the ft (frequency with current gain unity) is
unspecified.

HIGH BETA is desired, because the current inside XTAL
is the limiting variable in the design.

--

Yes, FLEA is not very reproducible, you need all the components
and EMRFD book to understand what happens when it does not run.
This TRX is like the Arecibo Observatory receivers,
they are designed and manually tuned for performance,
not for reproducibility.

--

The 80meters version is on going. I have access to
a 80 meters band antenna in the EA4RCT radioclub.

73 from Eduardo
EA3GHS/4

2710

2009-02-19 05:48:21

Chris Trask

Re: Bipolar RF Transistor for FLEA TRX

>
>A candidate is the 2SC2166. It's a low cost transistor,
>I can buy it in a local store for 3 EUR, but I don't know if
>currently is in production. I can not find it in
>DIGIKEY or MOUSER. The best reference I have,
>is that it was used in K2 transceiver.
>Neither I have spice model, but I will try to make one
>from the datasheet and some algebra.
>
>I can not find another POWER RF bipolar transistor in DIGIKEY or MOUSER.
>Other parts under consideration are 2SC1969 (high price)
>and ubiquitous IRF510 (but redesign needed).
>
>

The 2SC2166 is not an exceptionally good choice as it appears to have been discontinued by Mitsubishi. You can still get it as well as legitimate 2N2866 and 2N3553 made by Microsemi through RF Parts:

http://www.rfparts.com/

On the other hand, the PZT2222A is a SOT-223 version of the 2N2222A and has twice the power dissipation capability (1W), and you can safely get 0.5W in class A operation. Further, the PZT4401 will handle 1.15W and you can probably get 0.75W out of it if you have an adequate means of heat dissipation. That part only costs $0.40 in single piece quantities from Mouser.

Chris

,----------------------. High Performance Mixers and
/ What's all this \ Amplifiers for RF Communications
/ extinct stuff, anyhow? /
\ _______,--------------' Chris Trask / N7ZWY
_