[600MRG] MF kenwood sensitivity question on QRP-L

[sbjohnston at aol.com]

 On a related note...

Last spring I made a review of the ham transceivers and shortwave receivers manufactured in recent amateur memory.  While nearly all of them included a basic specification showing receive coverage going deep into the MF range (some into LF), nearly all of them had reduced performance down there. This was true of even the current "communications receivers". 

Some digging usually revealed these units had a high pass filter or attenuator that engaged around the top of the broadcast band and reduced sensitivity from that point on down.  

To buy a receiver that could gain my shack an improvement over the BC-453 it seemed like I was going to spend thousands even for a used unit.  That's one of the reasons I splurged on a new TS-990S transceiver - it's receiver design considered the LF and MF ranges worth hearing.  On transmit it covers the 137 and 475 kHz bands for output from the DRV port (so the rig can act as an exciter for low and medium frequency amplifier).  

The default configuration of the TS-990S includes an attenuator that engages in the broadcast band but comes back out of line as you tune lower.  And there is a jumper plug that can be moved to inhibit this action and keep the attenuator out even in the AM band.  

These tx and rx characteristics look to be true of the TS-590S transceiver as well, judging by the info in the manual.  I haven't tried that rig but it looks to be a good choice for use on 630m.



Steve WD8DAS / WH2XHY

sbjohnston at aol.com
http://www.wd8das.net/
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