These are supposed to be wadley loop design receivers but after looking
through the manual for the R1530 I just got, that simply is not true !
so don't tell anyone its a wadley loop !

I won't tell if you will tell me what a wadley loop is.
cuhulin

It is very similar to the Wadley loop...................basically, it uses a
1MHz crystal oscillator as a reference. This oscillator is divided down to
500kHz, which is your reference. This 500kHz oscillator is very rich in
harmonics (comb generator). A tracking preselector is used to tune to each
harmonic, which is applied to one input of a mixer..........the VFO signal
is applied to the other input of this mixer in a premixing scheme similar to
the Drake receivers.
This same scheme is used in the Sony 6800 receivers, as in the FRG-7.
Usually, after several years, component drift causes the PLL to
unlock......this is the main reason that people get rid of these receivers.
I've had a couple of them over the years, with the optional AM filter. They
are pretty decent receivers. The main difference between this receiver and
the R1530 is that the 1530 uses FETs in the front end and uses hot carrier
diodes in the 1st mixer. The former owner of one of the 530s that I had
upgraded the mixer to this type of diode. I am not sure what kind of diode
he used, but the receiver had poor sensitivity across the whole tuning
range. It might have been low LO injection.........I don't know. I was new
to receiver topology in those days.
One upgrade would be to replace that 1st mixer with a Mini-Circuits SRA /
TUF / TFM3. Either one of these 3 mixers would work very well in this
application. That would probably solve the problem of the relatively poor MW
performance. I remember that below 2MHz, the receiver sensitivity would
droop. One of these days I will pick up another unit and do the upgrade.
Harry Blessey, the local antique radio person who heads up the antique radio
club in the Chicago had an R1530 about a year ago. He sold it in the 600
dollar range. I would have liked to buy that one!

Pete
wrote in message
...
I won't tell if you will tell me what a wadley loop is.
cuhulin