Opinion of use of a part for replacement

[L.]

I have a component - part number - NE76038 - made by "NEC". I bought it with
the "slight" hope it can replace a part I was told is unavailable. The part
it is replacing is a GaAs Fet RF amp from a Pre-amp operating in the 144 MHz
band (experimentally).

The original part was smoked - and I am "trying" to repair the pre-amp -
there isn't much to it - being the (GaAs Fet RF amp is pretty much the heart
of it.

The paperwork I have shows it as a "minimum" frequency of .5 GHz. These were
not too bad price wise, so if not able to be used for that - I'm sure I can
find more appropriate uses for them - being I do homebrew.

THIS part is the closest I've seen to what I need to replace. I don't have
the exact part number needing to be replaced, but again - it "IS" a GaAs Fet
in a "receive" preamp in the 144 MHz range. So, I'm asking your opinion
(those who may be familiar with this device) - will it bow down that low and
do a decent job? The original part has a 20 dB gain. This boasts -> 21.67 dB
at .5 GHz. 13 dB gain at 4 Ghz. 7.5 dB at 12 GHz. It "states" best for 2nd
or 3rd stage RF or DC Amplification. This preamp is single stage.

If need be, I can pull up the part number actually needed - but have to do
some digging to do so.

I know I could just plug this thing in and "try" it, but I have to dig it
out too - so I could probably have an answer here - a hell of a lot faster.

Thanks in advance. IF this is able to do the job, then I've now got a
handful of replacements to keep this thing going for a long time. If not -
as I said, I'll do some homebrewing - no big deal.

L.

 

[Graham W]

I have a component - part number - NE76038 - made by "NEC". I bought it
with the "slight" hope it can replace a part I was told is unavailable.
The part it is replacing is a GaAs Fet RF amp from a Pre-amp operating
in the 144 MHz band (experimentally).

The original part was smoked - and I am "trying" to repair the pre-amp -
there isn't much to it - being the (GaAs Fet RF amp is pretty much the
heart of it.

The paperwork I have shows it as a "minimum" frequency of .5 GHz. These
were not too bad price wise, so if not able to be used for that - I'm
sure I can find more appropriate uses for them - being I do homebrew.

THIS part is the closest I've seen to what I need to replace. I don't
have the exact part number needing to be replaced, but again - it "IS"
a GaAs Fet in a "receive" preamp in the 144 MHz range. So, I'm asking
your opinion (those who may be familiar with this device) - will it bow
down that low and do a decent job? The original part has a 20 dB gain.
This boasts -> 21.67 dB at .5 GHz. 13 dB gain at 4 Ghz. 7.5 dB at 12
GHz. It "states" best for 2nd or 3rd stage RF or DC Amplification. This
preamp is single stage.

If need be, I can pull up the part number actually needed - but have to
do some digging to do so.

I know I could just plug this thing in and "try" it, but I have to dig
it out too - so I could probably have an answer here - a hell of a lot
faster.

Thanks in advance. IF this is able to do the job, then I've now got a
handful of replacements to keep this thing going for a long time. If
not - as I said, I'll do some homebrewing - no big deal.

There doesn't seem to be much to stop you trying it. The curves on the
datasheet http://www.alldatasheet.com/view.jsp?Searchword=NE7
(free access and you don't need to register) show gain and noise down
to 100MHz so it should do well but watch out for the very high gain at 2
M.
Do you have a top/bottom screening plate across the source pins?

HTH

73 de G3VPC

 

[Ancient_Hacker]

You might look this over:

http://tinyurl.com/zqvhb


it's a preamp kit with complete instructions. Uses a cheaper xistor I
suspect.

 

[Ancient_Hacker]

You might look this over:

http://tinyurl.com/zqvhb


it's a preamp kit with complete instructions. Uses a cheaper xistor I
suspect.


Or you could try www.digi-key.com, search for "low noise transistor".
Several hits.

 

[L.]

There doesn't seem to be much to stop you trying it. The curves on the
datasheet http://www.alldatasheet.com/view.jsp?Searchword=NE7
(free access and you don't need to register) show gain and noise down
to 100MHz so it should do well but watch out for the very high gain at 2
M.
Do you have a top/bottom screening plate across the source pins?

HTH

73 de G3VPC

--
Graham W http://www.gcw.org.uk/ PGM-FI page updated, Graphics Tutorial
WIMBORNE http://www.wessex-astro.org.uk/ Wessex Astro Society's Website
Dorset UK Info, Meeting Dates, Sites & Maps
Change 'news' to 'sewn' in my Reply address to avoid my spam filter.

Thanks, I'll have to check that out. IF it does work - I may even create a
couple other preamps - since there really isn't much to this thing.

Top and bottom plate - you lost me! Without looking at the preamp - all I
can tell you is the Transistor is soldered to the appropriate tabs provided
for it and they in turn go to the other components as needed.
The design is pretty well laid out - only there is a "shield" with a hole to
allow interstage connections. The Shield separating the sections as needed.

L.

 

[L.]

You might look this over:

http://tinyurl.com/zqvhb


it's a preamp kit with complete instructions. Uses a cheaper xistor I
suspect.


Or you could try www.digi-key.com, search for "low noise transistor".
Several hits.

Thanks, will check that out as well.

L.