Thanks Tony,
Agreed the 2N5109 will be around for a long time however as you point out
they are or will be very expensive. At present I use 100's of 2N3866
transistors which are very close to the same die if not selected from the
2N5109 process. My cost in 100 quantity has gone from about $1.60 each to
currently $4.00 each in about 2 years' time for 2N3866's. The 5109 is currently
priced less at $2.22 where the 3866 used to be less. From all this I conclude
that the 2N5109 will follow the huge price increases. I could be wrong but I
will not plan on using the 5109 especially where most things are going to
surface mount also. Even J-310 FETs have gone from <$.20 to $2.41 at 100 level.
Worst thing is 20% of the off brand j-310s don’t meet spec. The only way to
solve this is to go to surface mount where you can still get the good J-310 and
other great devices. One can often use more than one SMD device in an amplifier
having it cost less than one expensive leaded device. For the hams building a
single amplifier the 5109 makes a lot of sense right now. Semiconductor times
are changing rapidly. I make lots of top-band antenna systems using lots of
already expensive electronics. For this reason I have to do as well as I can to
predict the future for my products. My observation is that leaded parts are
disappearing rapidly and this will continue.
Lee K7TJR
Hi-Z Antennas
-----Original Message-----
From: N2TK, Tony <tony.kaz@verizon.net>
Sent: Sunday, July 1, 2018 2:03 PM
To: 'Lee STRAHAN' <k7tjr@msn.com>; martin@ok1rr.com; topband@contesting.com
Subject: RE: Topband: Any experience with 2N3553?
The 2N5109 will be around for many years. It is widely used in the military and
space community. It is listed as a JAN part. But it ain't cheap.
73,
N2TK, Tony
-----Original Message-----
From: Topband [mailto:topband-bounces@contesting.com] On Behalf Of Lee STRAHAN
Sent: Sunday, July 01, 2018 2:15 PM
To: martin@ok1rr.com; topband@contesting.com
Subject: Re: Topband: Any experience with 2N3553?
Hello Martin and all,
The 2N3553 device was plagued with a low Ft (high at its introduction)
making it mostly a low frequency device with questionable high gain high
frequency use in typical ham preamps. It is no longer available through the
original manufacturers. Also perhaps you are thinking of the BFQ18A and not the
BFQ19A device. The BFQ19 is at end of its life cycle and in addition the 18A is
widely used now in the MATV industry for wideband amplifiers. I have some
experience with the 18A using it in a wideband Norton style amplifier where it
is providing 10+dB of gain with a measured noise figure of 2 dB on 160 meters.
Its typical IMD is at least listed at UHF on the data sheet. My IMD testing
setup is not adequate to test the range of this device but I can say that it
exceeds any other amplifiers I have built to date. I typically use the 2N3866
which unfortunately is pricing itself out of the market now. I suspect the
2N5109 will follow as inventories shrink.. A pair of the 18A devices at ~$1.00
USD each single price in a push pull Norton configuration would in my opinion
make it worth trying as a killer wideband amp.
Just my $.02 USD.
Lee K7TJR OR
-----Original Message-----
From: Topband <topband-bounces@contesting.com> On Behalf Of Martin Kratoska
Sent: Sunday, July 1, 2018 9:51 AM
To: topband@contesting.com
Subject: Topband: Any experience with 2N3553?
The 2N3553 is a brutal 7 watt device in a TO-39 metal package. Chris Trask,
N7ZMY mentioned some unparalleled IM characterics
'... The BFQ19 (made by NXP née Philips) and the NE46134 (made by NEC) are both
highly popular within the CATV industry, and are virtually identical in terms
of linearity. They compare favorably to the 2N5109 in terms of linearity,
though they pale in camparison with the 2N3553 (as do all the others)...'.
See
http://www.home.earthlink.net/~christrask/Bipolar%20Transistor%20Evaluation.pdf
2N3553 is often mentioned in transmitting applications but I was unable to find
some other details like IM, noise and gain characteristics in high DR preamps
for receiving purposes. Any experience?
73,
Martin, OK1RR
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