[Elecraft] 472KHz/500KHz

[Wayne Burdick]

Matt Maguire wrote:

> Did you read in that article how a KXV3 module is used in the K3 to  
> bypass the high pass filtering used to protect the T/R PIN diodes?  
> The KX3 has the same filtering, but no possibility for a KXV3  
> module. Therefore, the KX3 is not really usable below around 1500kHz.

It is usable for receive, but not for transmit.

The high-pass filter starts rolling things off around 1.3 to 1.5 kHz.  
Sensitivity is certainly reduced at the low end of the band, but  
atmospheric noise is generally very high in this band anyway, and in  
practice the S/N ratio is adequate for casual AM broadcast listening  
over the entire band. If you're interested in weak-signal AM broadcast  
work, a transverter would be useful.


> If you want to get onto the 600m band with a KX3, you'll need to  
> look at building a transverter.

I did an experiment with 600-meter transceive on the KX3 (around 500  
kHz). With the ATU installed, which provides additional filtering for  
the broadcast band, the transmitter put out about 0.5 to 1.0 watts.  
But additional low-pass filtering would be required, and as noted  
above, receiver sensitivity is reduced in this band due to the high- 
pass filtering.

73,
Wayne
N6KR