The summary from emails is:

1: Fet will be overloaded and generate lots of intermodulation.
2: I have to choose the fet very carefully (I have thousands to select
through).
3: Need bandpass filters.

I think I still to build a box and give it a test.

Won't take much time.

Steve.

(Jim) writes:

steven, i dont know the answer to your question but i am sure that if
you show us the details on your JFET in a box gadget then several of us
will run to build one. lots of testing will follow with much discussion
and maybe even a flamefest! lots of fun will be had by all.

--
Steven D. Swift, , http://www.novatech-instr.com
NOVATECH INSTRUMENTS, INC. P.O. Box 55997
206.301.8986, fax 206.363.4367 Seattle, Washington 98155 USA

"Steven Swift" wrote in message
...

The summary from emails is:

1: Fet will be overloaded and generate lots of intermodulation.
2: I have to choose the fet very carefully (I have thousands to select
through).
3: Need bandpass filters.

I think I still to build a box and give it a test.

Won't take much time.

Steve.
The problem with filters in front of the FET (and this is where they must
be in order to tame the IM), is that their input Z will load the wire
defeating the purpose of having a hi Z FET in the 1st place. A single
parallel L-C trap might afford some protection from the worst offender- but
seems like a lot of trouble.

Dale W4OP

Looks pretty ugly. I put a scope on the antenna and saw about 4 volts of
signal + noise. It would be really hard to make a FET follower that didn't
get messed up with this. And then-- can the radio really take this much noise.

Looks like the 9:1 with low noise methods is still a pretty good idea.

Thanks, newsgroup R.R.S.

Steve.


"Dale Parfitt" writes:

"Steven Swift" wrote in message
...

The summary from emails is:

1: Fet will be overloaded and generate lots of intermodulation.
2: I have to choose the fet very carefully (I have thousands to select
through).
3: Need bandpass filters.

I think I still to build a box and give it a test.

Won't take much time.

Steve.
The problem with filters in front of the FET (and this is where they must
be in order to tame the IM), is that their input Z will load the wire
defeating the purpose of having a hi Z FET in the 1st place. A single
parallel L-C trap might afford some protection from the worst offender- but
seems like a lot of trouble.

Dale W4OP


--
Steven D. Swift, , http://www.novatech-instr.com
NOVATECH INSTRUMENTS, INC. P.O. Box 55997
206.301.8986, fax 206.363.4367 Seattle, Washington 98155 USA