SSTV problems

[Highlander_821]

Since getting my FT-847 back repaired, I am trying to get SSTV working again. I am using MMSSTV 1.13A (latest), and a Tini-Cat-847 interface which seems to be functioning properly. TX freq is 14.230 into my wire antenna. Running 50 watts.

I had this same setup working a few years ago, and had great fun and success with the mode.

This time around, I am apparently having serious TX slant issues. I calibrated my sound card clock using the MMSSTV options, tuning to WWV. I have verified that the pics I am receiving are at the correct slant (auto-slant is OFF) The pictures come in straight, and my calibration is the same using WWV as well as stations that I know are sending unslanted images.

But when I send, everything looks like it is working properly, but stations are reporting terrible slant issues. None of the cams on the web are picking me up either. I have run the full-duplex loopback test and get a straight image indicating no need for a TX offset value.

I am beginning to think that whatever the problem is, it isn't actually a slant issue, just maybe seems that way to RX stations reporting slant problem. It seems like even with auto-slant turned on, the RX stations don't get any coherent image at all, but they are receiving my signal fairly well.

I tried using a different soundcard, same results. I went up to 10 meters and sent some pics to my other 10 meter rig with an interface and MMSSTV installed, and my pictures are coming through perfectly straight and 595.

All other MMSSTV settings are default.

 

[Highlander_821]

I think I may have got it solved. Because the "Wave" slider on my Windows volume control was a bit twitchy, I was using the TX power knob on the 847 to get the power set to around 45-50 watts for SSTV. That may have been what was producing the garbled images.

I tried leaving the radio power at full power, then used a combination of the Wave and Master volume sliders. Finally a webcam in Texas saw my pic and it was straight and 595. I then got an image reply from a station that also reported straight and 595 with auto-slant off on the RX.

So I think I'm good. Thanks for reading my post!

 

[Road Squawker]

Many people don't understand the difference between the two slant "adjustments" in MMSSTV.

The WWV calibrates the RX only and the TX offset is for the Tx only. sounds like you have them both properly set.

The AUTO SLANT feature should be turned off, its only included by the software developer to assist the casual user. the correct and preferred method is calibration of the soundcard.

after a while, you can tell which webcams have the autoslant turned on and which don't.

http://worldsstv.com/

 

[Highlander_821]

Looks like I spoke too soon. I went back to trying to use the on-board audio, and have the original issue. I went to Best Buy to buy another sound card (the one I was using belongs to another computer that needs it back) and discovered that Best Buy doesn't sell sound cards in stores anymore. GAH!!!

I ordered one from Newegg.