[AMRadio] RE: receiver info needed...

[Gary Schafer]

Hi Brett,

Single conversion to 455 kc if will work ok on 80 meters but unless you have
several tuned circuits in the front end you will probably have some image
problems on 40. On way to do it is to make an 80 meter to 455 kc receiver
and put a crystal controlled converter ahead of it for the other bands. That
would give you an 80 meter tunable IF. Or select a tunable IF frequency
around 2 to 3 mhz. Then you could use the pto that you have. You would then
convert all the bands to the 2 - 3 mhz range. That would probably be cleaner
than trying to use harmonics of the pto. That can get messy getting rid of
images and unwanted responses from the harmonics.

I built a receiver many years ago around a BC453 as the tunable IF. It tunes
200 to 550 kc. I have a crystal control converter for 80 meters. For the
higher bands it converts everything to 80 meters. It has some image problems
though as the 200 kc that the first IF has to pass has the image at 400 kc
away. I have a fixed band pass filter for the first 80 meter (300 kc pass
band range). Some day I need to double that up with another filter so that
the response drops off more to help get rid of the images. Other than that
it is a great little receiver. Every couple of years I drag it out and do a
little more work on it.
By the way it only uses one 3.5 mhz crystal for triple conversion on all
bands.

73
Gary  K4FMX


Brett Gazdzinski wrote:

> Hello all Am,ers!
> I am planning some sort of simple AM receiver for AM reception.
> My requirements/specs are....
>