Jim Kortge, K8IQY, uses a cascode amp in his famous 2N2/40. He actually
uses it in the transmitter ... even with a passive mixer you don't need a
lot of gain on 40!

See http://www.qsl.net/k8iqy

...

"Yuri Blanarovich" wrote in message
...
Back from good old tube days, cascoded triode RF preamps were good for
high
gain, stability and low noise.

Anything out there in transistorised version, or there is there better
stuff
available? Looking mainly for preamps on HF to be used with low gain
antennas,
like small loops or beverages.

Yuri, K3BU.us

xpyttl wrote:
Jim Kortge, K8IQY, uses a cascode amp in his famous 2N2/40. He actually
uses it in the transmitter ... even with a passive mixer you don't need a
lot of gain on 40!

See http://www.qsl.net/k8iqy

..
There are two ways of looking at cascade, the devices are in series for
dc and ac, or only ac. The above link shows the latter. I had an idea
for a hybrid cascade amp of the first kind. The input would be a jfet
which sorta becomes the emitter resistor for a bipolar transistor as the
second stage of the cascade amp. The bipolar is run in grounded base
(for ac, normal bias network and base bypassed to ground with a cap).
Would give the advantages of high input impedance of the fet and high
gain from the bipolar.

Ken Scharf ) writes:
xpyttl wrote:
Jim Kortge, K8IQY, uses a cascode amp in his famous 2N2/40. He actually
uses it in the transmitter ... even with a passive mixer you don't need a
lot of gain on 40!

See http://www.qsl.net/k8iqy

..
There are two ways of looking at cascade, the devices are in series for
dc and ac, or only ac. The above link shows the latter. I had an idea
for a hybrid cascade amp of the first kind. The input would be a jfet
which sorta becomes the emitter resistor for a bipolar transistor as the
second stage of the cascade amp. The bipolar is run in grounded base
(for ac, normal bias network and base bypassed to ground with a cap).
Would give the advantages of high input impedance of the fet and high
gain from the bipolar.

It's been done. There was an article in Ham Radio magazine in 1970 or
1971 about a six meter converter. Just as you described, a common source
JFET with a bipolar transistor as the upper element. Used a Vackar oscillator
to make it tuneable. It might be this one:
Six-meter converter, improved K1BQT 50 Aug 70
The date is about when I remember it, though I don't remember K1BQT being
the author.

Michael VE2BVW

Michael Black wrote:
Ken Scharf ) writes:

xpyttl wrote:

Jim Kortge, K8IQY, uses a cascode amp in his famous 2N2/40. He actually
uses it in the transmitter ... even with a passive mixer you don't need a
lot of gain on 40!

See http://www.qsl.net/k8iqy

..

There are two ways of looking at cascade, the devices are in series for
dc and ac, or only ac. The above link shows the latter. I had an idea
for a hybrid cascade amp of the first kind. The input would be a jfet
which sorta becomes the emitter resistor for a bipolar transistor as the
second stage of the cascade amp. The bipolar is run in grounded base
(for ac, normal bias network and base bypassed to ground with a cap).
Would give the advantages of high input impedance of the fet and high
gain from the bipolar.


It's been done. There was an article in Ham Radio magazine in 1970 or
1971 about a six meter converter. Just as you described, a common source
JFET with a bipolar transistor as the upper element. Used a Vackar oscillator
to make it tuneable. It might be this one:
Six-meter converter, improved K1BQT 50 Aug 70
The date is about when I remember it, though I don't remember K1BQT being
the author.

Michael VE2BVW

Nothing new under the sun!
Guess I need to get the HamRadio collection on CRrom.

Michael Black wrote:
Ken Scharf ) writes:

xpyttl wrote:

Jim Kortge, K8IQY, uses a cascode amp in his famous 2N2/40. He actually
uses it in the transmitter ... even with a passive mixer you don't need a
lot of gain on 40!

See http://www.qsl.net/k8iqy

..

There are two ways of looking at cascade, the devices are in series for
dc and ac, or only ac. The above link shows the latter. I had an idea
for a hybrid cascade amp of the first kind. The input would be a jfet
which sorta becomes the emitter resistor for a bipolar transistor as the
second stage of the cascade amp. The bipolar is run in grounded base
(for ac, normal bias network and base bypassed to ground with a cap).
Would give the advantages of high input impedance of the fet and high
gain from the bipolar.


It's been done. There was an article in Ham Radio magazine in 1970 or
1971 about a six meter converter. Just as you described, a common source
JFET with a bipolar transistor as the upper element. Used a Vackar oscillator
to make it tuneable. It might be this one:
Six-meter converter, improved K1BQT 50 Aug 70
The date is about when I remember it, though I don't remember K1BQT being
the author.

Michael VE2BVW

Nothing new under the sun!
Guess I need to get the HamRadio collection on CRrom.

Ken Scharf ) writes:
xpyttl wrote:
Jim Kortge, K8IQY, uses a cascode amp in his famous 2N2/40. He actually
uses it in the transmitter ... even with a passive mixer you don't need a
lot of gain on 40!

See http://www.qsl.net/k8iqy

..
There are two ways of looking at cascade, the devices are in series for
dc and ac, or only ac. The above link shows the latter. I had an idea
for a hybrid cascade amp of the first kind. The input would be a jfet
which sorta becomes the emitter resistor for a bipolar transistor as the
second stage of the cascade amp. The bipolar is run in grounded base
(for ac, normal bias network and base bypassed to ground with a cap).
Would give the advantages of high input impedance of the fet and high
gain from the bipolar.

It's been done. There was an article in Ham Radio magazine in 1970 or
1971 about a six meter converter. Just as you described, a common source
JFET with a bipolar transistor as the upper element. Used a Vackar oscillator
to make it tuneable. It might be this one:
Six-meter converter, improved K1BQT 50 Aug 70
The date is about when I remember it, though I don't remember K1BQT being
the author.

Michael VE2BVW

xpyttl wrote:
Jim Kortge, K8IQY, uses a cascode amp in his famous 2N2/40. He actually
uses it in the transmitter ... even with a passive mixer you don't need a
lot of gain on 40!

See http://www.qsl.net/k8iqy

..
There are two ways of looking at cascade, the devices are in series for
dc and ac, or only ac. The above link shows the latter. I had an idea
for a hybrid cascade amp of the first kind. The input would be a jfet
which sorta becomes the emitter resistor for a bipolar transistor as the
second stage of the cascade amp. The bipolar is run in grounded base
(for ac, normal bias network and base bypassed to ground with a cap).
Would give the advantages of high input impedance of the fet and high
gain from the bipolar.