[Elecraft] K3 and Sound Cards

[Joel Black]

No comments are necessary unless I just really screwed something up. This is just some evidence of how a really good sound card can help with weak signal work.

There has been a lot of sound card discussion lately. I’m not wanting to add to that, but Jim (K9YC) has recommended several cards and even given a receive level recommendation of whatever sound card you’re using. I thought I’d give an example.

This morning, I was toodling around on 10 m trying a little JT9. Now, at this moment, my hex beam cannot be rotated. I have it pointed west to work SOTA. Here is a snippet of what I heard (and one I worked). Pay attention to the receive levels (pay no attention to the +26 [WA4MIT]. The guy literally lives about three blocks away). The first column is time (U), receive level at my station, I don’t remember what the third column is, frequency shift, and message. The “@“ denotes JT9.

1534 -23  0.1  677 @ CQ G6UQI IO82        
1534 -10  0.3  598 @ W9MDB F5JQF 73       
1534 -20  0.8  781 @ ON7BL RRR 73         
1534 -22 -2.6  981 @ AB3OF R TU 73        
1535 -16  0.1  785 @ KQ8M ON7BL 73        
1535 -23  0.2 1181 @ CQ N3GTY FM05        
1535 -15  0.1 1296 @ G4CFS KB0PPQ R-12    
1536 -19  0.1  678 @ CQ G6UQI IO82        
1536 -23 -2.8  982 @ CQ 9H1FF JM75        
1537  26  0.2  981 @ 9H1FF WA4MIT EM63    
1538 -21  0.1  677 @ CQ G6UQI IO82        
1538 -23 -2.8  980 @ WA4MIT 9H1FF -05     
1539  Transmitting 28.078 MHz  JT9:  G6UQI W4JBB EM63      
1540 -16  0.1  676 @ W4JBB G6UQI -24      
1541  Transmitting 28.078 MHz  JT9:  G6UQI W4JBB R-21      
1542 -20  0.1  676 @ W4JBB G6UQI -24      
1542 -22  0.8  780 @ N7FN KQ8M -13        
1542 -23 -3.0  982 @ CQ 9H1FF JM75        
1543  Transmitting 28.078 MHz  JT9:  G6UQI W4JBB R-21      
1544 -16  0.1  675 @ W4JBB RRR 73         
1545  Transmitting 28.078 MHz  JT9:  G6UQI W4JBB 73

These are levels I *regularly* see with my K3 and my sound card which is a Creative Labs E-MU 0204 (discontinued). The one I worked from England is long path for me since I’m pointing west and live in Alabama.

When I last tested my SignaLink, the NF was 20 - 30 dB higher than the NF of the 0204. The 0204 only cost about $20 more than the SLUSB not counting cables which are easily made and you’d have to make for the SLUSB anyway.

I have yet to try this with my KX3. Although I’ve done the temp compensation for it, I don’t have an after-market heat sink and am apprehensive to try a high duty cycle mode like JTx or Olivia.

So, take Jim’s advice. Get a nice sound card for about $100 or so (or less in the case of the Numark) if you really want to hear (and work) some weak signal stuff.

73,
Joel - W4JBB