Fall 2018 6m APRS and Misc Update

November 2, 2018

Figured I’d take this “downtime” evening in 4-land and toss together a quick update on the 6m APRS system and a status report. Note that I have several draft blog postings that I’ll try to finalize in the coming weeks. Sorry for the lack of posts, but get used to that being the new normal on here due to other priorities. Hey, you get what you pay for 😉

Well hopefully everyone had a good summer. I wound up being back-n-forth bi-coastal more than originally planned but it’s all good. It stresses the XYL at times, but like I remind her “we’re healthy, we have a roof over our heads, clothes on our backs, we can pay our bills, job security is not a concern, and we’re ahead of the game on retirement plans so let us realize just how blessed we are.” We recently got in from a nice Fall trip up in New England. We were a bit late for peak Fall foliage color in the inland areas, but there was some spectacular color along the coastal areas.

We stopped in 4-land for a quick work project and I needed to absentee vote this year. A longtime friend and former co-worker is running for Judge Exec and his Chief Deputy is running to fill his shoes as Sheriff. We also have a somewhat interesting statehouse race.

So I just cast what may be my last vote as a Kentuckian. The other half is an official Wyomingite so we’re heading back west this week so she can vote there. Plus we both need to get a pile of work done before holiday hustle and bustle arrives.

Hey where the heck did 2018 go to? Current plans are Thanksgiving in 4-land, then another extended family Christmas in the Idaho mountains, followed by New Years Eve in Wyoming. Hey the snow is piling up on the mountains so holiday mountain grandeur and fresh powder to play in = yes please!

Hopefully during some of the holiday downtime I can get the blog and some other ham radio documentation projects caught up for the locals. No guarantees though LOL.

Okay, moving on to some status reports….

6m APRS:

K4KPN-6/-4 was moved from the Jonesville tower site to the Jonesville “East” tower site (my personal tower) in early September after some coverage testing. The east site has a lower noise floor (better receive performance) and still meets coverage needs into the three tough to cover EMCOMM relevant locations we keep that port around for.

The K4KPN-6 6m APRS Digi/I-gate remains on the air 24×7 on 50.6200 MHz using 1200 baud AFSK and no changes are currently planned.

KI4WEF recently got his home Outpost PMM terminal on the air again from the new home he is building. He’s on a temporary 6m antenna till he finalizes how he’s going to setup his new station. His station is also beaconing an APRS compatible beacon so we have another 6m APRS station on the air.

I haven’t had time to confirm the details but scuttlebutt is 6m APRS is being used in some of the Marine Corps Marathon events. Cool eh?

 

Packet and Repeaters:

Most all the packet gear has been shifted over to the club callsign.  I just got the coordination for 444.4250+ repeater switched over to the club callsign and will reprogram it’s ID when time allows. This is all part of an evolving plan to move things over to the JFD tower site and let Greg, Lonnie, and Mark manage it once we fully retire out west.

There has been some talk about making 425 dual-mode analog/FUSION or analog/P25. The reasoning will be explained later on. It’s currently on the air from Williamstown in low profile test mode as I need to finish tweaking it. Current plans are to relocate it back to its primary site at JFD once some antenna and feedline repairs are completed there. ETA on that move = good question, probably going to be next Spring.

 

Node/BBS/RMS Shutdown plans:

Several have understandably asked if these systems will still be around in a few years. First off I’m not going to guarantee anything. I have plans but I can’t predict the future. It is just just a hobby, we don’t charge a dime in dues, we do what we do for the love of packet radio. Several silent keys and folks moving off for work/retirement reasons have left KYPN and packet activity in N. Kentucky at a fraction of what it used to be. It is what it is.

Actual local utilization will drive choices on what remains. Rack space and site integration issues at the future site will also play a role. There’s not going to be room for everything there so if I was to hazard a guess? The 10m RP, 220 1.2k, and 441 9.6k ports will be what remains. For those wondering what packet gear to invest in? There’s your answer 😉

 

2m APRS:

The K4KPN-15 2m APRS Digi/I-Gate is scheduled to be turned off January 2020. It is at a location where I lease space for my day job. I’m slowly extricating myself from my KY obligations and will not need that space come 2020.

I don’t have any free site that would accommodate K4KPN-15. Hopefully some others will step up and run some of the local 2m APRS infrastructure.

K4KPN-15’s days are numbered. Plenty of notice has been provided.

 

30m RP APRS / K4KPN-10:

While there are no current plans to shut down K4KPN-10 I am looking at moving it to a site near the VA/KY border. This is where one of my day job clients has a spare HF antenna and some rack space.

I’ve had the VA site patched into the WAN loop since July. I’ve been playing with both IP and stream feeding a spare modem on the remote radio there into K4KPN-10. Results show very little difference in NOAM and S. EU coverage and a slight improvement on the N. EU path. So that’s looking like an option I may explore further when time allows for me to run more tests from out west.

 

Well I’m beat and we want to hit the road early so that’s enough for now.

WA4ZKO


K4KPN-10 Robust Packet I-Gate / Digipeater Update and APRS-IS Gotchas

May 26, 2018

K4KPN-10 has clearly benefited from the combination of antenna system repairs and noise floor (NF) reduction work at the site last Fall. Performance is back to what one would expect from it.

For those that ask why Robust Packet? One word….performance. Below is a screencap of what the 30m RP APRS world looks like from the Kentucky gate’s perspective over a few days.

RPR_K4KPN-10_20180519

K4KPN-10’s view of the 30m Robust Packet APRS world. Why RP? One word….Performance.

Around 25 to 30 of those stations on there have been heard direct on RF at some point. Single hop stateside coverage is easy. Europe is in to some degree nearly every evening and EU mobiles are often heard. Even the challenging polar path over to RT9K-15 is in there at times.

I’m hesitant to use APRS-IS for serious coverage analysis since it doesn’t begin to reflect everything heard on RF, especially on HF. Regardless K4KPN-10’s “heard” and “heard by” data is interesting:

RPR_K4KPN-10_heard_201805

APRS-IS perspective on RP HF APRS stations heard by K4KPN-10 so far this month.

RPR_K4KPN-10_heard_by_201805

APRS-IS perspective on RP HF APRS stations that have heard K4KPN-10 direct so far this month.

Yes some of the soundcard modems will do good work on 300 baud AFSK for single hop HF APRS and some occasional DX can get through. Some can do even better with bit fixing. The problem with bit fixing (guessing) is it breaks spec and can easily cause corruption if done too aggressively even on APRS. Thus why we so often trace corruption on the VHF APRS feeds back to soundcard modem equipped gates. Even with bit fixing the limitations of 300 baud AFSK become apparent over long haul DX paths.

Where Robust Packet shines is it uses Pactor-III like modulation that allows error correction without breaking spec. RP offers good noise immunity and deals with the multi-path on long haul DX packets better than a typical AFSK modem can.  Since RP uses space and power efficient dedicated hardware it is also well suited to stand-alone portable/mobile tracker uses without the need for a PC/laptop.

Robust packet is a mode and hardware built from the ground up for improved performance on HF and well suited to HF APRS. DX reception is not occasional, it is commonplace. I admit to sort of taking 4,000+ mile APRS DX as NBD till one of the HF AFSK guys sent me a “holy $#@$ what are you using that hears across the pond nightly” email LOL.

For those asking “where is K4KPN-10 hearing RT9K-15? Oh it is in there on RF, but due to his gate configuration it’s going to be difficult for stations other than a few lucky EU gates to ever get credit (APRS-IS perspective) for hearing him.

RT9K-15_at_K4KPN-10

RT9K-15 being heard direct at K4KPN-10.

Well here is an opportunity for a good lesson on the flaws of assuming APRS-IS gives a complete picture of what is going on at the RF level.

It is important to realize that APRS-IS does dupe checking. If I-Gate A and I-Gate B hear the same packet only one of them can get credit for it from the APRS-IS perspective. Which one gets credit? The first one that gets that packet to APRS-IS. The one with the lowest latency to the APRS-IS system.

If you run an I-Gate or home APRS system on both IP and RF you can easily screw yourself with bad timing values. The RT9K-15 I-gate is doing something that will make it very hard for coverage analysis via APRS-IS. It appears to be aggressively beaconing to APRS-IS every few minutes? I’m told that it is heard often in EU, but rarely does an EU gate get credit for it in the eyes of APRS-IS. This tells me it is probably making the 2nd mistake of beaconing to APRS-IS and RF at the same time. This means even if another gate hears his packet on RF then it’s unlikely outside of internet congestion on his link that another gate can decode that packet off RF and inject it into APRS-IS before his internet beacon gets into APRS-IS.

Another problem this creates for APRS-IS analysis is it throws the packet counts off on the above pages. A good example is it shows a monthly total of 5 packets for DF1CHB /AM.  He was in direct on the eastern USA I-gates for hours earlier this morning, but also hitting EU gates so NOAM will only get occasional credit for gating him even after dozens of packets gated in. Tonight he is airborne over Serbia and K4KPN-10 is hearing him direct like clockwork on 30 meters:

DF1CHB_30m_rpr_aprs_20180526

DF1CHB /AM over Serbia and coming in on 30m robust packet almost as if he’s a local on VHF LOL.

Don’t get me wrong, this is not a complaint towards APRS-IS. It’s just how the system works and how it has to work. It’s just important for APRS operators to understand that APRS-IS doesn’t give you the full RF picture due to the necessary dupe checking going on. This is especially true on HF where the same packet can easily be heard by multiple I-Gates hundreds or thousands of miles apart.

Also noteworthy that some stations run beacons marked “RFONLY” or “NOGATE” paths. A properly configured I-Gate will not gate those beacons into APRS-IS. This is another gotcha if you’re trying to get a full picture of RF level activity via APRS-IS based systems and apps.

Recommendations based upon lessons learned here if you are interested in getting decent coverage analysis via APRS-IS?

  1. There is normally no need for an APRS station to position beacon on their internet port (APRS-IS) more than once or twice an hour unless it is moving. Serves no useful purpose for fixed stations and it only adds to the cumulative load on the APRS-IS system.
  2.  I-gates should consider beaconing on their internet port at a rate of just under 60 minutes.
  3.  Avoid beaconing via RF and internet ports at the same time.
  4.  If you are not moving, then you don’t need to be pounding the heck out of the RF side either. 2-3 RF beacons an hour from a fixed station is more than enough to keep you on most maps and fresh in APRS-IS for messaging/gating purposes if you are in range of an I-Gate.

WA4ZKO


Stay Tuned

April 22, 2018

Well after two weekends worth of discussion and debate, some Kentucky Packet Systems will be returning to the airwaves soon. Not everything is returning and a lot of what is returning will only remain if it sees enough usage to justify it. This week’s projects have been tower climbs to re-feed the VHF/UHF antennas on my personal tower and tweaking the microwave links between the sites that will be used.

Our utility company recently replaced a pole next to the Williamstown building where I still maintain a minimal office/storage site. When they scheduled that I pressured for new hardware (vs just swapping it to a new pole) and better grounding. This has helped some with the nasty 6m/2m noise floor at that location. As such I’m going to see if it will be useful to have a low profile APRS I-gate there. With the loss of the KB9GYO digi last Fall, Edgewood’s limited coverage down this way, and the reduction in coverage from the Lexington digi, the area’s local 2m digi coverage is very poor now. I’m not certain how much a low profile I-gate/Wide1-1 digi in Williamstown will help, but we shall see what T&E reveals this week.

Do note that this I-Gate site will not be permanent, it will eventually be turned off.  I’m leasing that site and seriously doubt I’ll still have any need for it in a few years. The proper fix for the APRS network is a much better I-gate location and a local medium profile digipeater. Sorry but I can’t provide either and others are going to have to step up and provide better 2m APRS infrastructure. Sorry, it is what it is.

Yes the local APRS scene is in near shambles. My inbox since last summer makes it clear that I’m not the only one that has noticed. My initial monitoring of the 2m APRS network from a medium profile location quickly revealed many problems.  A lot of stuff with poor signals, misconfigured software, and of course the usual congestion from abuse/silliness on the channel from adjacent areas. My my what a mess the 144.3900 APRS frequency is anymore. I can’t imagine why I prefer the HF APRS network over the 2m APRS network for my needs LOL.

Some have asked about K4KPN-10’s future? Well I just signed a 3 year contract on two very nice fiber runs into that site and invested in a new HF radio for it last Fall. Safe to say KYPN remains committed to keeping that on the air. Plans to eventually move it to Wyoming? No plans to move it out there since it is not wise to place another HF gate there that close to Bill’s excellent gate in Montana. With VE7OI’s new gate coming online and the excellent observed performance of K4KPN-10 out that way by myself and Randy (K7LNR) it seems clear that the N. American 30m RP APRS network is best served by K4KPN-10’s current location.

With the solid internet (both fiber and dialup) at that site now, it’s proving relatively easy to properly monitor, control. and keep secure from afar which has been one of my top control op concerns. When you run stuff under the automated & remote control rules you have an obligation to monitor and keep control over anything putting RF into the air. Obviously there are no guarantees – it’s a hobby, we provide it for free – but currently KYPN has no plans to change K4KPN-10 for the foreseeable future.

Not sure how much of the local packet gear will be back online before we head back west in a few weeks. Dad’s health and my day job project list will have at least myself coming back to 4-land fairly often this summer. Plenty of opportunities to finish whatever is not completed this time around.

Last but not least, no I’m not back to stay. We will be very “bi-coastal” for a few more years for work/play and helping care for an elderly parent. That said our retirement is coming sooner or later. I like southern Idaho just as much (same quality of life and a heck of a lot cheaper) but the XYL fell in love with NW Wyoming. She recently switched the car registration, moved her business, and made herself an official Wyomingite. You can guess how our WY vs ID homestead planning conversations go….Wyoming it is LOL.

I will do another post soon detailing what is coming back permanently, some background, what is coming back conditionally, and what will be turned off in a few years.

Stay tuned!

Jeff
WA4ZKO


K4KPN-10 Antenna Upgrades Completed

October 8, 2017

After a few tower climbs to repair some lightning damage to the feedpoint the K4KPN-10 30m Robust Packet I-Gate/Digipeater is back on its primary antenna.

Thanks to a client that gave me some old LDF after we did a tower upgrade, the 9913F coax has been replaced with LDF that is much better suited to that environment. I also replaced the radio whose PA had failed so the gate is back in full TX/RX mode with much improved transmit and receive performance.  Seems to be getting out as expected and some HF noise floor reduction work at the site has yielded some serious receive SNR performance improvements.

Jeff
WA4ZKO


K4KPN-10 I-Gate Now Receive Only

June 21, 2017

As of June 20, 2017 the KYPN sponsored K4KPN-10 30 meter Robust Packet APRS I-Gate is now a RX only I-Gate.

During recent maintenance at the site, the PA in the Yaesu FT-100D radio there was found to have failed. This is the 2nd Yaesu FT-100 of mine that has suffered PA failure and I gather this is very common failure for that radio. You would think it was a post-2001 era ICOM radio LOL. In fairness this radio was purchased used and with unknown TX hours/treatment in the past. I did do the fan modification to it and it was in a cool climate controlled environment, but again I have no idea of how it was treated in the past.

I obtained this radio cheap off the used market due to a damaged display so I’m not shedding any tears over it. Since it is remote operated via CAT control the display was a non-issue. It was well suited to a “tower site” 24x7x365 radio versus putting a more expensive HF radio at a tower site that takes a few lightning hits each year.

Even if replacement parts can be found I don’t plan to fix it for several reasons. We can’t run much more than single digit power at that site and it has always suffered from “big ears, tiny mouth” syndrome (RX range far exceeded its TX range).  I’m gone from the area most of the time and a friend has been helping me keep an eye on it since transmitters operating under the “automatic” rules need to be closely monitored. There has been some past concerns with digi/beacon rate abuse on the 30m channel from 2-land and we had recently discussed just running it as a receive only I-gate. Guess you could say this event has sealed the deal on that particular discussion.

I’m not a huge fan of RX only I-Gates, but given the increasingly sparse 24×7 gate coverage here in North America the pros outweigh the cons. Maybe some dedicated soul will put up a 24×7 30m RP I-Gate in the southeast sometime. If that happens I’ll probably pull the plug on this gate or run it on another band for tinkering. We have had it on 80/40/17/6m briefly a few times for tests, but I feel the HF RP APRS network is best served by NOT “fragmenting” all over the HF bands.

 

73
Jeff
WA4ZKO