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February 17, 2017

     I am getting this information on short notice, so don't blame me, but the Georgia Defense Force and Georgia ARES Mutual Assistance Team are working together to test two antennas tomorrow. Yeah, I told you it was short notice.

     The tests will take place from Kennesaw State University from 10AM-4PM on 75, 60, 40 and 20m. That's 3975kHz, 7287.5kHz, 5330.5khz, 14,265kHz, apparently all in voice mode. Also they will try PSK125 on 3583kHz. You can check them out here: http://www.facebook.com/groups/1106032292834574/

     Obviously they'll be starting on the lower frequency bands first. As always, listen first, then talk. The testers are especially looking for stations in central and southen counties, but maybe they'll talk to you if you are a little more local. 

February 16, 2017

     Digital practice continued last night with some CW practice afterwards. Our knowledge of FLDigi and how it works keeps growing. There are many other programs available for use in digital modes, but FLDigi is the one specified by ARES leadership for use by us. It helps for us all to be on the same page. Not that you cannot use other programs, but you should at least be familiar with FLDgi because you are most likely to encounter it in an ARES environment. If you use someone else's station, or if someone else uses your station, then there needs to be continuity, so a single program is specified.

     The ARRL has published its report for activity in 2016 here: http://www.arrl.org/news/amateur-radio-emergency-service-posts-its-2016-annual-report

     The monthly meeting is now scheduled for February 23rd. See you there. 

February 10, 2017

     The Georgia Statewide Tornado Drill was held today rather than this past Wednesday as originally planned. The possibility of violent weather precipitated (no pun intended) the change. There was quite a bit of activity on the HF bands as well as on D-Rats.

     K4GK who hosted the voice net on 3975 kHz, had well over 100 check-ins. The PSK net, which was listed as being PSK-125 was actually in PSK-31. Check-ins streamed continuously for quite some time. The D-Rats page scrolled on by with many check-ins as well. It appeared to be a good turnout.

     No one answered my calls on 147.21 so no local VHF net was established. HF voice check-ins ended around 9:50AM. I do not know how long the other nets lasted. Surely we will get some feedback from Georgia ARES soon on the results. 

     Appartently the monthly meeting has been re-scheduled for February 16th at 7:30PM. 

February 2, 2017

     The SE Metro ATL digital practice net continued with simplex practice after the regular net last night. The furthest apart two stations were that were able to communicate (at least most of the time) was 36 miles. This is actually a pretty far distance for simplex amateur stations in this part of the country and shows what a high antenna and good feedline can do for you. 

     We tried BPSK-125 and MT63-2000L once again. Murphy slipped in and left a monkey wrench, but we threw him out and made it work anyway. Not all stations were able to copy each other directly, but relays were certainly possible that allowed all stations to get all the information. 

     Hopefully we will be testing slow scan TV and Winlink Peer-To-Peer soon. Join the fun on Wednesday nights if you can. We start on MT63-2KL at 9PM on the 146.925 WA4ASI repeater in Covington. 

January 26, 2017

     Practice last night on the digital practice net brought in some new folks and provided some interesting experience. The basic take-away from all the simplex practice has been that we will need higher antennas and more power if we are to communicate simplex. However, we have not yet given up on the idea of finding a digital mode that will allow us to communicate directly with each other.

     The distances are high...maybe as much as 36 miles, but we intend to find our limits by trial and error. In any case, we want to know now what is and what is not possible. We know we can communicate through the 146.925 repeater, but what if it is not available? What then?

     So far we have experimented with MT63-2000L, BPSK-125 and Olivia 8-500. I want to try FeldHell next. It is important to remove all restrictions to an incoming signal, such as turning off any attenuators and also turning the squelch completely off. Of course, you will see artifacts on your screen then, but hopefully any signals will be stronger and will overcome the random noise. 

     I believe we will also soon try some of the Winlink Peer-To-Peer modes. Should be fun! Join us!

January 24, 2017

     Net totals from last night were eleven voice, five Winlink and six D-Rats check-ins. Thanks to all who took the time to participate. Participation remains good. ARES is alive and well in SE Metro Atlanta. Inter-county cooperation is good too and would  likely be the key to a successful response in our area. Let's share the wealth!

     Here atop the repeater room we are awaiting several shipments of C4FM equipment. The second repeater has been sent for a physical upgrade so it can handle the latest firmware. A new battery and charger cord for one HT is on the way as is another HT and charger and battery. Probably all of that stuff will come at one time and bowl me over!

     In case you are interested in how C4FM performs vs. analog FM, here is my experience: It depends. How's that for a crappy answer? Well, it's the truth. Sometimes it works better and sometimes it works worse, which means: I doubt digital FM will ever replace analog FM.

     If you look at the 'area of improved performance' charts provided by the sellers of digital FM equipment, you will see a small area on the chart, and that is accurate. There is a small area of improvement but that doesn't tell the whole story. Only on-the-air testing does that and here's my experience: Mobile digital signals are hard for the vocoder to handle. However, if the mobile stops and stands still, all of a sudden things get better. Our personal experience was that sometimes the digital signal will get through better and sometines the analog signal will get through better. Not much more can be said about it. 

     The story above is one reason I run my System Fusion repeaters in 'Mixed Mode' or 'Automatic Mode Select'. This allows you to use either the digital or analog mode without having to manually switch anything. The repeater determines what mode it hears and re-transmits in kind. If you have your mobile or handheld System Fusion radio in AMS, it will change your radio to the mode the repeater is using. That's pretty handy in this case. I believe the same thing should happen if you are transmitting HT-to-HT or HT-to-mobile or even mobile-to-mobile....all provided you are in the AMS mode. 

     One clarification: System Fusion is a proprietary name that indicates a 'fusion', or 'coming together' of different modes. There are actually four in this particular case: DIGITAL NARROW, DIGITAL WIDE, DATA and ANALOG. I won't go into all that here though. C4FM refers to the actual method of modulation which is also known as 4FSK. This is really APCO P25 Phase I stuff with a slightly different vocoder.

     Confusing? Yes, it is in my opinion. Necessary? That's up to you to decide. Am I pushing this technology? Not at all. I am only reporting on my experience and letting you know what to expect if you access the K1KC 146.61 repeater. What else can you expect? If you do not run CTCSS, you may hear the whooshing noise of digital transmissions. If your squelch is open for any reason you may hear this. 

     In addition I can tell you this: Digital Narrow mode runs your voice through in a compressed channel as compared to analog FM. It's not too bad if the signal is strong and received well, but to my old ears, it can sound pretty terrible if not strong. In fact, if it's weak enough, you won't hear it at all. This is where analog shines. Remember how the original digital cellphones sounded? Well, that should give you an idea of what to expect with a crappy digital signal.

     Sure, there will be situations where digital will outperform analog. Bottom line: It's six of one and half a dozen of the other.

     In other news, we received reports from the GA State ARES Convention held Saturday the 21st. It seems there were two main areas of discussion: Weather and digital operating modes. You should all know that GA ARES has certain digital protocols all GA ARES members should be familiar with and be able to operate on. There has to be some standard so that we are not fishing around at the wrong time. The gaares.org wbsite has more information if you need it. If you need practice, why not try the Wednesday night SE Metro digital practice net. It occurs at 9PM local on the WA4ASI 146.925 repeater...currently starting in MT63-2KL. 

January 21, 2017

     This Saturday afternoon we are having some weather worth watching. To our southwest there was a tornado warning in Lamar County. The rain fell heavily here about 90 minutes later, then the wind picked up and is still blowing strongly. Of course, there were the obligatory power interruptions that we have during high winds.

     Going outside after the rain, I could see the 2m receive antenna taking a beating. I happened to be in the repeater room when the power went off but, the backup system worked beautifully! Only the room lights went off. All the radios and servers, routers and modems stayed alive. Don't you just love it when a plan works like it is supposed to?

January 19, 2017

     I did it, but only for a second: I put down '2016' instead of '2017'. I immediately made it right though. Please don't say a word. I wouldn't want anyone to know.

     Area digital practice took a big step last night by moving off a repeater into the simplex world and, boy, what a difference! The main idea is to simulate emergency conditions. Suppose your favorite repeater was not available in an emergency, or suppose it was tied up with other traffic. What would you do? Well, we wanted to know just how well different modes would serve us if we needed them to perform in simplex.

     The group that tried it out last night was scattered with the closest station at 15 miles and the furthest at 36 miles (from me). As you might expect, some stations could hear each other and some could not, but the funny part was that it was not necessarily the closest stations that could hear each other. Actually, the middle distance station and I heard each other better than me to any other station. 

     What this did for us immediately, was to show that ALL stations could be reached, by relay. It is very useful to know this in advance. You don't want to go fishing for important information like this when the chips are down. You want to know this NOW! I encourage all ARES members and interested parties to get your practice in now and perform like a professional later. 

     What we need now is more practice to learn which modes will work the best in weak signal conditions on VHF. In fact, if you possess that information, please inform W4DEL at w4del@arrl.net. Many stations aso decided their antennas need to be higher and so forth. Let me tell you: that is ALWAYS a benefit. If you were able to get your antennas above the trees, and if you had a very good feedline to that antenna, you'd be surprised at how it will perform.

     Experiments have been performed that show that tree trunks are what block signals. Yes, it seems leaves block signals too, particularly when they are wet. but amaze yourself. Get above the trees. We all know that doing so can be doggone difficult, especially if you live on a small lot, have neighbors and have 100' tall pine trees around. Well, I can't change those factors and digital modes can only make up for so much. All I can do is to tell you from experience, there is a whole new world above the trees.

      Want to know how bad the trees affect your signal? One station I know can barely get into a 460-something MHz repeater 2.13 miles away with 4 watts on a handie-talkie, with the antenna nearly 400' up on a tower. Why not? That stations is buried in tall trees. 

     Want a tip? One station I know in another state could not reach stations in the southern part of his county due to terrain. So, the one station got a directional antenna, pointed it AWAY from the intended stations, towards a large metal local landmark, and bounced his signal off the landmark. It was successful. Okay, so you want o go to New York from Atlanta. Maybe you have to go by way of Omaha first. Whatever works!

  

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