They work!! Even into shortwave!!
 

The LM3820's I bought cheap do work just fine. I didn't realize the scope probe was loading down the oscillator, keeping it from going above 5MHZm when that dawned on me, and I switched the probe to X10, I had the chip running at 13 mhz just with junk box coils.
So I have a cheap ass AM/SW radio for use with my ghost receivers. I'm using one yellow IF can, and two ceramic 455 khz filters in the IF chain. I used an FET detector, and there's enough audio straight out of the detector that I connected it to the line input of boom as a quickie audio amp.

The connections in the LM3820 data sheet seem incorrect, and would not work. I used the pin out I found in an app guide AN-174 (I think) for the LM1868. I'll check Monday when I get to work to make sure that app giude is correct. The other app guide was for an AM/FM system using the LM1868, and the LM3820 as the AM receiver. I used just a six foot wire for an antenna, instead of the tuned input as shown in the guides, and it works ok. I can e-mail a schematic of my conncetions if anyone interested.

Frank

They work!! Even into shortwave!!
 

Well done Frank!

Re the CRO loading. I quite often use the loosest coupling I can when
aligning things, even to the point of touching the probe to an insulated
part of the board or attaching a small "antenna" to the probe tip.
Whether this works well depends on the frequency of course!

Cheers Bob VK2YQA

Frank wrote:
The LM3820's I bought cheap do work just fine. I didn't realize the
scope probe was loading down the oscillator, keeping it from going
above 5MHZm when that dawned on me, and I switched the probe to X10,