Were one to put together a high performance RX with a
9MHz IF (Filters easily available from GQRP club),
how to deal with AM and FM resolution and the BW
over and above that needed for CW and SSB?

Down convert to, say 455 kHz?

Also, with the dream of an Eddystone-like tuning dial,
I wonder if any had thought of using the linear
digital measuring instruments, available up to about
a foot long for lathes, and providing a resolution
of 1/10th of a thou, the idea being that your
Arduino would read off the length of the dial to
determine the frequency of the digital VFO.

Perhaps a better approach would be to have a
rotary pulser with flywheel attached as the tuning
element to drive the digital VFO, with the tuning
dial being driven with a stepper-controlled screw
thread, to also drive the RF stage preselectors.

(Just musing about the 50+ years dream to build
my own comms RX :-) )

In my seemingly forlorn hope of stimulating
relevant and civilised discussion in these NGs.

Gareth's Downstairs Computer wrote:
Were one to put together a high performance RX with a
9MHz IF (Filters easily available from GQRP club),
how to deal with AM and FM resolution and the BW
over and above that needed for CW and SSB?

Filters are becoming more and more a thing of the past.
Reputable companies that once made filters do not make them anymore.

To make a high performance RX today, you would use SDR.

On 08/07/2017 17:17, Rob wrote:
Gareth's Downstairs Computer wrote:
Were one to put together a high performance RX with a
9MHz IF (Filters easily available from GQRP club),
how to deal with AM and FM resolution and the BW
over and above that needed for CW and SSB?

Filters are becoming more and more a thing of the past.
Reputable companies that once made filters do not make them anymore.

To make a high performance RX today, you would use SDR.



.... I've 50 years' of accumulated junk just dying to be used!

(and have SDRs in the Icom 7300 and Yaesu FT450D, but not
impressed with the human interface of either)

Gareth's Downstairs Computer wrote:
On 08/07/2017 17:17, Rob wrote:
Gareth's Downstairs Computer wrote:
Were one to put together a high performance RX with a
9MHz IF (Filters easily available from GQRP club),
how to deal with AM and FM resolution and the BW
over and above that needed for CW and SSB?

Filters are becoming more and more a thing of the past.
Reputable companies that once made filters do not make them anymore.

To make a high performance RX today, you would use SDR.



... I've 50 years' of accumulated junk just dying to be used!

(and have SDRs in the Icom 7300 and Yaesu FT450D, but not
impressed with the human interface of either)

The Yaesu FT450D is not an SDR. The Icom 7300 is.

When you are not impressed with the human interface design our
wellknown Japanese companies can make (neither am I, not specifically
related to SDR transceivers but to transceivers in general!) I would
recommend shopping elsewhere.

My most recent Yaesu transceiver is an FT-817nd and its human interface
really sucks. Not only is it kind of difficult to find the control
you want to set in the function list or menu setting number, but even
worse: they have mapped the functions of the available buttons
(CLAR, HOME, F, V/M, LOCK) in about the worst possible way!

E.g. F which brings up the function list which you then need to scroll
using the SEL knob is located close to the main dial, should have been
with the SEL knob (CLAR or HOME) where you would not accidentally
rotate the main dial when pressing it.
The F button would be more intuively to have the LOCK function.
Etc etc etc.