开云体育

  1. BITX20
  2. Topics

#ubitx. Increasing power output

Bo Barry
 

?I know this is an old topic, but I want to do some SIMPLE tinkering & learning.
I put 'socket pins' in for the 6 3904s thinking I could simply find some 'hotter' replacements. ?

Well I tried some 5109 and 2369s found on eBay. No noticeable improvements noted.

Then I tried my hand with LTSPICE, having used in since the 60's and taught it until '06. ?One of the transistors was in their library and I think I added the model for the 5109 correctly.
Not sure my setup is 100%, but I did get similar dismal results.
Anyone have some transistor types that may work.?
Not interested in other mods YET.?
I used to be addicted (and very skilled) in several versions if SPICE. Still have the MicroSim version somewhere.
Bo W4GHV?
??
 

开云体育

Bo have you tried the 2N2222A or 2N2219’s yet? Although I haven’t added sockets I did replace all 2N3904s with 2N2222A starting with Q90. My output has increased on the upper bands.?

Skip Davis, NC9O

On Aug 17, 2018, at 11:59, Bo Barry <bobarr@...> wrote:

?I know this is an old topic, but I want to do some SIMPLE tinkering & learning.
I put 'socket pins' in for the 6 3904s thinking I could simply find some 'hotter' replacements. ?

Well I tried some 5109 and 2369s found on eBay. No noticeable improvements noted.

Then I tried my hand with LTSPICE, having used in since the 60's and taught it until '06. ?One of the transistors was in their library and I think I added the model for the 5109 correctly.
Not sure my setup is 100%, but I did get similar dismal results.
Anyone have some transistor types that may work.?
Not interested in other mods YET.?
I used to be addicted (and very skilled) in several versions if SPICE. Still have the MicroSim version somewhere.
Bo W4GHV?
??

 

开云体育

2N3866’s work even better…

?

?

From: [email protected] [mailto:[email protected]] On Behalf Of Skip Davis via Groups.Io
Sent: Friday, August 17, 2018 1:35 PM
To: [email protected]
Subject: Re: [BITX20] #ubitx. Increasing power output

?

Bo have you tried the 2N2222A or 2N2219’s yet? Although I haven’t added sockets I did replace all 2N3904s with 2N2222A starting with Q90. My output has increased on the upper bands.?

Skip Davis, NC9O


On Aug 17, 2018, at 11:59, Bo Barry <bobarr@...> wrote:

?I know this is an old topic, but I want to do some SIMPLE tinkering & learning.
I put 'socket pins' in for the 6 3904s thinking I could simply find some 'hotter' replacements. ?

Well I tried some 5109 and 2369s found on eBay. No noticeable improvements noted.

Then I tried my hand with LTSPICE, having used in since the 60's and taught it until '06. ?One of the transistors was in their library and I think I added the model for the 5109 correctly.
Not sure my setup is 100%, but I did get similar dismal results.
Anyone have some transistor types that may work.?
Not interested in other mods YET.?
I used to be addicted (and very skilled) in several versions if SPICE. Still have the MicroSim version somewhere.
Bo W4GHV?
??


Virus-free.

--

…_. _._
Timothy Fidler
 

I have not got one to play with but the? BSX-20s work better on small signals than 2N2222 because of lower input capacitance and have no VHF roll off? until well above? 300 Mhz - pull up? a datasheet.? Futurelec.com list them but say no stock. Send Futurlec and email .. often they can find stuff? . BEWARE the 15V VCE max.? Beware destroying the PAs Too. Beware the small size of the output transformer on the PAs .? there should be a D sheet uploading with this post for the BSX
Timothy Fidler
 

bsx 20 this time

BSX20Data.pdf
BSX20Data.pdf

Bo Barry
 

Thanks for the inputs! ?I'll try them.
I'll ?not just check power out, but also the voltages ?/signals with my scope. And for heat too.?
I'll put info on the nice socket pins in the files section.
Bo W4GHV?
Bo Barry
 

Photos section
 

Bo you got a place holder but no photo? kc2ipx

On Sat, Aug 18, 2018 at 11:07 AM, Bo Barry <bobarr@...> wrote:
Photos section


Bo Barry
 

On Sat, Aug 18, 2018 at 08:58 AM, David Nelson wrote:
Bo you got a place holder but no photo? kc2ipx

On Sat, Aug 18, 2018 at 11:07 AM, Bo Barry <bobarr@...> wrote:
Photos section

?

?
Bo Barry
 

Picture added. ?
 

Not as good as it has low peak current capability.

the BSX20 is better suited for the earlier stages.? For? Driver the 2n2222A or 2n2219
has vastly higher peak current and the capacitance is insignificant in a properly
designed circuit.

As to the VHF roll off... ITs a 300mhz FT transistor.? The BSX20 is a 500 mhz device
so its not that much better compared to the 600mhz old standby 2n2963 or the
2n5179 1.2ghz device and if you need real performance the BFR106 at 5ghz.

Allison
 

开云体育

I’m glad you brought these parts up.? I’ve been designing commercially with the BFR106 and BFR182 lately and they are wonderful devices to work with.? In a uBITx design they would work very well for all stages except the PA driver/ PA (and there are better devices for the audio stage).? If someone eventually releases block design boards for the uBITx, these parts would make excellent choices for the build.

?

?

From: [email protected] [mailto:[email protected]] On Behalf Of ajparent1/KB1GMX
Sent: Sunday, August 19, 2018 9:28 AM
To: [email protected]
Subject: Re: [BITX20] #ubitx. Increasing power output

?

Not as good as it has low peak current capability.

the BSX20 is better suited for the earlier stages.? For? Driver the 2n2222A or 2n2219
has vastly higher peak current and the capacitance is insignificant in a properly
designed circuit.

As to the VHF roll off... ITs a 300mhz FT transistor.? The BSX20 is a 500 mhz device
so its not that much better compared to the 600mhz old standby 2n2963 or the
2n5179 1.2ghz device and if you need real performance the BFR106 at 5ghz.

Allison


Virus-free.

--

…_. _._
 

MadRadioModder,

I did a lot of work months ago for the uBITX.

Q90 BFR106, way better.? For the drivers 2N2222A was a good improvement
as a drop in?though 20MHZ.? For 17M and up 2n5109 or similar is still marching on.

However once you get to that point you find other things that need to be improved.
Gain is then no longer an issue but the wide excursion in gain over the 3-30mhz range.
Part of that is what devices, much of its is related to transformers used and
subtleties of circuit layout.? Long legged devices, skinny traces, and high frequencies
at even low power are incompatible with good performance.

Allison

1 - 13 of 13