Archive for MSK144

Update to MSK144 on FT-991a

Posted in Digital Modes with tags , , , on November 13, 2018 by KE0PBR

So you may have read the post on how I was testing different settings on the FT-991a for FT-8 (you can read that here). The whole purpose of that testing was to figure out why I was so deaf when doing Meteor Scatter (MS) on MSK144.

Well, I used the settings in that article to do a mini rove (EN26/36 and EN25/35) last weekend. I wish I could say it was all about my rove, but I also knew that @AC0RA was doing a major rove through much of the south, and if Wyatt is roving, he will also send out some power. I also knew that his rove would get lots of MS guys out there and there would be plenty of people out there that I could make contacts with.

After some, experimentation, I went with AGC of Slow, and IPO of AMP2. I did notice that the DNR turned off, did help with the decodes. Any DNR seemed to slow things down a little.

Did it help?

Yes. Sorry for the poor picture quality, but all those decodes on the left are in the span of a few minutes. In the past I couldn’t get that many in 4 hours.

On the other hand, in about 5 hours I had over 30 QSOs. My previous best was 8 in about 5 hours. Overall it was a good morning, lots of contacts, that is until the wind picked up and blew my antenna over…. But that is a story for another day.

I now feel confident that I can hear, I can decode and I can rove to other areas, and be able to get QSOs!!

Testing the FT-991A on FT-8

Posted in Digital Modes with tags , , , on November 5, 2018 by KE0PBR

As some  of you may know I have been having an issue with “hearing” people while using MSK144 on  6 Meters for Meteor Scatter. The number of decodes I would get was lower then whale crap at the bottom of the ocean. After many different people gave me many different, often conflicting (but helpful) words  of advice I took matters into my own hands.  I knew that on my FT991a there were three main areas that was affecting my ability to hear:

The AGC: Automatic Gain Control. This has X settings: AUTO, FAST, MED, SLOW. There is also an OFF setting, you choose this by pressing and holding the AGC box. The others you choose by just tapping the box.

The IPO: Intercept Point Optimization: I’m not sure that this really is, but I think it is some sort of PreAmp. The possible settings are: IPO, AMP1 and AMP2

The DNR: Digital Noise Reduction: Settings are from OFF to 1 though 15.

There isn’t enough MSK144 traffic to do some standardized testing, so I went with the FT8 protocol on 20 meters. I assumed that this would at least give me a baseline that the settings would be close to the MSK144 protocol. I also understand that antenna I am using is terrible to say the least. That is the reason for the terrible DB levels, even on the best results.

I spent one Sunday afternoon figuring out what was best from the AGC and the IPO. What I came up with was that the AGC = AUTO, and the IPO =AMP2 was the best combination. This was based on decodes per minute and best average DB level. See this chart.




The following weekend I decided to test which DNR (Digital Noise Reduction) would be best or if it was even helpful. I was surprised to learn that in some cases the DB went way up and the decodes per minutes also went up. But I also learned that some of the options on the DNR were less then helpful. As you can see from the attached chart. The DNR options 9 and 10 seem to be the best for FT8.




I understand that there is a bunch of variables that I may have missed or not thought about, but I was only going for a place to start on MSK144. The results that I see here, were similar to what my gut (not including the DNR) was telling me.