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- Newsgroups: rec.models.rc
- Path: sparky!uunet!comp.vuw.ac.nz!canterbury.ac.nz!betelgeux!kaiser
- From: kaiser@elec.canterbury.ac.nz (Chris Kaiser)
- Subject: Re: Transmitter/Receiver Mods
- Message-ID: <C1J94M.6ww@cantua.canterbury.ac.nz>
- Nntp-Posting-Host: betelgeux.canterbury.ac.nz
- Organization: Electrical Engineering, University of Canterbury, New Zealand
- References: <C1G1zn.5Fq@cantua.canterbury.ac.nz> <C1HAr2.L7G@hpchase.rose.hp.com>
- Date: Wed, 27 Jan 1993 22:00:22 GMT
- Lines: 32
-
- In article <C1HAr2.L7G@hpchase.rose.hp.com>, jahr@hprnd.rose.hp.com (Steve Jahr) writes:
- > Chris Kaiser (kaiser@elec.canterbury.ac.nz) wrote:
- >
- > Well...... this sounds good on paper. The problem is that the inside
- > of a Tx is a very hostile environment for electronic thing-ies. Seems
- > that there is a great deal of EM garbage/noise being generated from
- > that long metal thing sticking out (:
- >
- > Seriously, I tried a little op-amp adder for a dual rate circuit once
- > and it didn't work anything like I expected. As I recall it worked on
- > the voltmeter *until* I reconnected the RF module and then it went nuts.
- > Seems that the op-amp tried to follow the RF signal noise as well as
- > the control pot signal. Nothing that I tried would clean up the signal
- > enough (filter capacitors and RF chokes).
- >
- > Perhaps if you use a *really* slow op-amp though...
-
- Hmmm. I did say that I hadn't got around to actually trying it...
- One could take the brut force approach and stick the circuit inside
- a fully enclosed metal box with shielded connecting wires. Otherwise
- a bit (lot?) of knowledge and experimentation with noise reduction
- techniques would be required. Considering the amount of electronic
- thing-ies inside a modern radio it must be possible to suppress the
- RF, but probably not easy.... :-(
- A PCB (not veroboard) with ground plane would probably be essential.
-
- Chris Kaiser
-
- Postgrad, Elec. Eng. Dept.
- University of Canterbury
- Christchurch, NEW ZEALAND
-
-