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Locked Transmit Spike on JT65b

Thomas Riccio
 

I am running a flex6700 with a beko power amp on 2m directly. My new microham peak power meter is showing a power output spike occurring with WJST -X JT65b just at the beginning of the transmit sequence. No power spike if I hit the tune button on WJST. Seems like there is an audio spike that is generated by WJST just at the beginning of the transmission which occurs on JT65 and occasionally on FT8 but none of the other modes. The transmit spike is 30% or so higher and lasts for about 500ms. I can eliminate the spike by setting a 1200ms or greater transmit delay on the flex 6700 and setting the transmit delay on WJST to 0 seconds.
Interestingly I get the same transmit spike using the JTDX program.
Anyone else notice this phenomenom?
neil_zampella <neilz@...>
 

Its not surprising that you see the same issue on the clone, as it uses much of the same code base.

This has been reported previously, I know I've been Bill comment that it shouldn't affect anything, but I forget when I read that.

Neil, KN3ILZ

On 1/16/2020 12:14 PM, Thomas Riccio wrote:

I am running a flex6700 with a beko power amp on 2m directly. My new microham peak power meter is showing a power output spike occurring with WJST -X JT65b just at the beginning of the transmit sequence. No power spike if I hit the tune button on WJST. Seems like there is an audio spike that is generated by WJST just at the beginning of the transmission which occurs on JT65 and occasionally on FT8 but none of the other modes. The transmit spike is 30% or so higher and lasts for about 500ms. I can eliminate the spike by setting a 1200ms or greater transmit delay on the flex 6700 and setting the transmit delay on WJST to 0 seconds.
Interestingly I get the same transmit spike using the JTDX program.
Anyone else notice this phenomenom? 

    

  


					


				
				
				
			

			
			

				
	

	

	
	

		
			

				
					

					

				
				

					

						
						
					

				

			

			

				

					

				

			

			
			
				

	



			
		
			
				
	

		
			
			

			
			
			

				

					


						
							
								
	
		
			
		
		
  
	
    Thomas Riccio
	

	

							
						
					

					

						
							


						
						 
						
							
							
						
						
					

				

			

			

			


Good to know that this has been reported before.
As for it not affecting anything, well if I run 1.5kw on EME, the power spike is 1950 w.
Amazingly, the beko amp can handle that ok but it's pushing it. 
My T/R preamp relays probably don't like it either.
I am effectively cutting off the spike by delaying the start of JT65b transmission by 1500ms.
Fortunately, the transmit 1500ms delay does not seem to effect the decoding on the receiving end .
Having fun on EME just running a 1kw to keep things cool.
Regards & Thanks.
NX3B

				
				
				
			

			
			

				
	

	

	
	

		
			

				
					

					

				
				

					

						
						
					

				

			

			

				

					

				

			

			
			
				

	



			
		
	

	

		
		
		
		
		
	

	

		
		
		
		
		
	

	
	

		
		
		
		
	



	

		
		
		
		
		
		
	

	

	

		

			
	
		

			

				

					
						
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