JT-9 operating tip - TX bandwidth

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Now that JT-65 and JT-9 are gaining in popularity I thought I would pass along a tip to avoid a problem I ran into tonight.

While operating WSJT-X I tried replying to a station running JT-9 @ 2900 Hz. My power out was 1/4 of what it should have been, resulting in poor signal received by DX station and retries.

I noticed I had DIGI-U TX bandpass set to 100 - 2900. I opened it up to 100 - 3100 and made two more contacts tonight @ 2900 Hz with no drop in power from where I have it set. The two stations I contacted at 2900 HZ were -26 and -28 signal while my report was at least 10 higher. They are probably using radios limiting their TX passband (modern Icom is 100 -2900 Hz)

So the tip is to check your TX bandwidth if planning on JT-9 mode.


73

Dave wo2x


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David Decoons wo2x, Elmer

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Posted 1 year ago

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Kent Olsen

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David

Thanks, that is a good tip!

Do you have AGC turned off while using WSJT-X?

Thanks
73
Kent
NC6B
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Ian GM4KLN

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Sorry but I don't agree: I think a far better way is to use the "split" functionality within WSJT-X, which places your TX in the middle of your TX default passband...thereby helping to reduce the opportunity to TX harmonics...and indeed away from the skirts of the TX filters. 
Works like a dream....
As to AGC - I run with that off at all times.
73, Ian GM4KLN
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Ian GM4KLN

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Hi Jay
thanks for the comments and kind offer, but I'm already using v1.71 r7486 which I self compiled - managed to blunder through the process :-)
I was just not sure whether the 6300 code had been included in the release version and as your link to another thread confirmed, not yet, but there's a work-around. I just couldn't remember yesterday when I was away from the shack. 
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Ian GM4KLN

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Hi Jay
thanks for the comments and kind offer, but I'm already using v1.71 r7486 which I self compiled - managed to blunder through the process :-)
I was just not sure whether the 6300 code had been included in the release version and as your link to another thread confirmed, not yet, but there's a work-around. I just couldn't remember yesterday when I was away from the shack. 
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Jay / NO5J

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Ian

The changes for the 6300 model missed the WSJTX v1.7.0 release by a few days.

The 1.7.0 GA release occurred on 12/19/2016 using -r7405.

WSJTX v1.7.1 r7486 should already include the 6300, hamlib3 changes. So it ought to work as is.

 The change in Hamlib3 was committed on 12/24/2016,  Which was Hamlib3 Commit [10eb19] .

So any WSJTX builds done after Christmas, should include TCP/IP CAT for the 6300, any revision past -r7426 actually. 

WSJTX v1.7.1 r7486 was available beginning 1/12/2017. 

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  73, Jay - NO5J

(Edited)
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Ian GM4KLN

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Thanks Jay - good info: that's nice and clear. As I suspected then....
I've just started using DXLabs so will re-configure and try 6300 "native". 
73, Ian GM4KLN
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Jay / NO5J

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Ian

If you haven't already, then be sure and look into the DXLabs-Fldigi-Gateway.

http://www.n2amg.com/software/fldigi-dxlabs-gateway/ .

It will set you up to log Fldigi directly into DXKeepers log.

For WSJTX, JTAlert does the same thing and a lot more.

http://hamapps.com/

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(Edited)
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YV5WZ

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I've been doing JT65 & JT9 with WSJT-X software, actually: 1.7.0 r7405
DIGI-U TX bandpass set to 100 - 5000 and RX 5K, Slip operation: None 



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Rob Fissel

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FWIW, I always use an RX bandwith of 0-5000 hz for JT modes on HF. For example, I've seen stations before where their VFO was at 14.078 for JT9, transmitting at 2500 Hz - that's 4.5kHz up from 14.076. I've worked many stations this way - it's nice to be able to monitor ALL of the JT65 and JT9 occuring at any given time. Also, as others have mentioned, I use fake it to keep the TX around 1500 Hz no matter where the signal lies within the RX passband. 
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Jay / NO5J

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Rob

I have created custom SmartSDR memories for both 4k and 5k filter widths I just save them and then delete the saved frequency field. that way I can quickly use a 4k or 5k width on any slice, no matter where I'm tuned. I have a neighbor fairly close by that operates rtty inside the agreed JT9 assignment, and I can usually exclude his 40 over signal from my AGC passband by dropping back to a 4k passband. I also have separate 2k memories setup for both JT65 at #.076 and JT9 at #.078
That I can switch to when I don't want to operate both 65/9. I also prefer to use fake it. 

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