K4KPN-6 6 Meter APRS Digi / I-Gate Full Availability

August 10, 2018

Observing a need for a 6 meter APRS I-Gate in this region, KYPN realized the K4KPN-4 BPQ32 node could probably meet this need without any additional hardware investment. Recent versions of the BPQ32 node software have considerable built-in APRS digi/gate capabilities that only need to be configured and enabled.

The past few months showed that the past trend of most activity on the node being on the UHF 9.6k, 220 1.2k, and 10m RP ports was still holding true today. Thus we pondered could the APRS features on the 6m port be enabled and would they coexist with the existing Node and its BBS, Chat, and RMS functions? If both could coexist then it was frankly a no-brainer to do it.  The 6m port puts out a stout signal that penetrates well into the valleys and hilly terrain common to the area.

The 6 meter APRS scene has seen bursts of activity over the years, but good 24x7x365 digi/gate infrastructure is very rare outside of a few pockets of activity. The rest has been more of  what I’d call seasonal activity of folks firing up on frequency to listen for packet/APRS DX during the late Spring and Summer e-skip seasons. Others use it as a less congested alternative to the mess that 2m APRS can be in some areas.

At one time there was a push to build up packet infrastructure on 50.620 across the country for the PropNet network. The WSPR mode and network came on the scene and its many advantages stagnated PropNET growth. What remains of PropNet seems mostly focused on PSK31 operations on HF. No PropNET packet operations have been noted on 50.620 for over a decade now. This means 50.6200 MHz is an underutilized frequency begging to be put to good uses.

Testing showed both APRS and conventional packet should coexist fine on the Jonesville BPQ32 node’s 6m port. Thus on the afternoon of July 9, 2018 KYPN spun up K4KPN-6 on 50.6200 MHz 1200 baud AFSK packet mode. K4KPN-6 offers both full WIDEn-n compliant digipeating and basic R-I-R (2-way) I-Gate messaging functions.

The current plans are to run K4KPN-6 24×7. The 6m port beacons an APRS compatible beacon every 5 minutes to help detect DX openings. Beaconing faster would provide a better chance of catching meteor burns, but 5 minutes was felt to be a good compromise value for a mixed use port.

The advanced APRS digipeater functions available in BPQ32 are downright slick and one can tell John gave them some thought. The I-Gate side has some cosmetic issues, but it is plenty usable from a functionality standpoint. I’ll try to run some changes/improvements past John (G8BPQ) this winter. He is busy sailing/traveling during the Summer months. Thus I avoid bugging him with non-critical feature requests and minor bug reports that can wait. John should be deemed a Saint for his patience with his user base and his willingness to continually improve BPQ32/LinBPQ.

So far K4KPN-6 looks like a valuable asset both locally and for the 6m APRS DX folks. Best of all with our existing 6m port on the Jonesville BPQ32 system there was no need to buy anything else. Just enable and configure the functions you want in the bpq32 config file and restart the node. Obviously you’ll need an APRS-IS login and password if you want to use the I-Gate functionality.

Node and application stack (BBS, Chat, RMS) remain available on the 6m port. The APRS functions are just another application running on the node.

 

6m APRS Path Recommendations?

Making use of the K4KPN-6 6m APRS digi/I-gate functions is no different than operating on 2m APRS. Paths of WIDE1-1 or WIDE1-1,WIDE2-1 are good choices for 1-hop and 2-hop paths.

 

6m APRS Beacon Rate Recommendations?

The 6 meter APRS frequency is not overloaded like the 2m APRS is in so many areas of the country. There is plenty of spare airtime on the channel. Thus the use of aggressive beacon rates is unlikely to be an issue. 5 or 10 minute rates for infrastructure sites should be fine in most areas.

Temporary use of even faster rates for testing or during meteor shower peak times should not be an issue and would increase the odds of snagging a burn. Mobiles can probably dial things down to 1 or 2 minute rates.

 

6m APRS Biggest Range Challenge? Noise Floor

The 50 MHz band propagates locally just like the 30-50 MHz VHF-Low band that you may be familiar with. Not so great in a pure urban environment. So so in a suburban environment, but ultimately best suited to rural environments where its range and terrain penetration qualities can shine.

Note:  There’s a reason why a surprising number of users remain active in the VHF-Low Band spectrum even though it doesn’t get much press. Current marketing/sales efforts are geared towards selling more expensive and complex systems on the higher bands. The range and simplicity of VHF-Low systems are still a good fit for some users.

Don’t laugh at Low band. VHF….  I know of a 46 MHz system installed in the early 1980’s that is still in use. Now that’s serious ROI. Also note that the VHF/UHF Part 90 narrowbanding mandate did NOT apply to VHF-Low systems.

Back on topic….

All things being equal 6 meters has more range potential than 2m. Problem is in the real world of RF all things are rarely equal. On 6m you are probably using a lower gain base antenna and most likely a less efficient mobile antenna system compared to say 2 meters. In most real world installs some of this will be offset by higher standard transmit powers, less free space losses, lower feedline losses, and better terrain penetration. All that aside, the main range limiter for 6m operators today is the higher local noise floor (NF) compared to the higher bands.

The old enemy of power line noise remains, but it is now joined by a wide variety of noise spewing consumer electronics clobbering both HF and the lower VHF spectrum. Sadly this is a problem that will only get worse unless the FCC cracks down on a lot of the cheap poorly designed/filtered junk behind so much of the problem. Even then it would take ages for device attrition to clean up the spectrum much. Plus we’ve become a society that expects everything to be super cheap versus paying for higher quality equipment.

Where you live and operate can make a huge difference and must be factored in unless you like surprises. I was stunned at the NF differences between the old KY QTH and our temp place here. Living out in farm country most of my life definitely spoiled me. I wouldn’t call this “urban” by any means, but having several neighbors nearby = a lot more noise on the bands. I was initially worried about the big power distribution lines a few hundred yards away out back. Turns out they are actually the least of the NF problems here LOL.

Every amateur radio band has it’s pros, cons, and unique propagation characteristics. Six meters is no exception to that rule. It remains a local workhorse of a band that also offers some fun DXing at times. It is called the Magic Band for a good reason.

WA4ZKO /7


K4KPN-10 Storm Damage

July 3, 2018

Update July 4th . K4KPN-10 is back in service.

So far the damage sounds like a power supply (likely repairable), a few fuses/tripped breakers, and unfortunately the tragic sacrifice of a kind gentle soul of a Rev 1 SCS Tracker TNC to the thunder gods. Thankfully there were spares nearby and we were able to get things back online last night.

There may be some brief outages later in the week due to electrical work/repairs at the site.

73 de WA4ZKO

Apparently around noon eastern time the Dry Ridge site took a major lightning hit. Mike ran by and his quick assessment is the site is dark and the transfer switch got smoked pretty good. Judging by telemetry things ran till the UPS systems told things to shut down.He did a cold start and it looks like at least a PSU and the Tracker modem on K4KPN-10 is dead…radio came on but may well be damaged.

He’s heading back out there this evening to get the tower lights back on and start checking and bringing the commercial gear online. Once the commercial gear is back up he’s going to call me and we’ll start doing further damage assessment on the ham gear. I have some spares on hand, but depending on how bad things are K4KPN-10 may be down for the count.

WA4ZKO /7


6 Meter APRS Lives

June 21, 2018

Update:  Dale N0KQX has joined in from SW Kansas as of June 24th. N0KQX-6 has already been heard several times at K4KPN-4 in KY.  The K7BC-6 Virginia I-gate appears offline since the 21st. A few more I-gates on frequency would be nice. I believe I can enable gating on K4KPN-4’s 6m port (ah the flexibility of BPQ32) without impacting general packet operations on that port. I plan to test that option on my next trip back thru 4-land.

It’s not every day you hear and “digi” off the 50 MHz APRS digipeater at the Pentagon.

K4AF-6_20180619_6m_APRS_map_pent

Map showing location of the K4AF-6 six meter digipeater at the Pentagon. I believe this is part of the MARS radio station located there. Frequency is 50.620 MHz using 1200 baud AFSK packet.

 

June 19th 2018 a nice strong opening into NE Virginia revealed that the 50.6200 MHz 1200 baud 6 meter APRS and long time 6m packet “calling” frequency still has some action on it.

K4AF-6_20180619_6m_APRS_KYRDG_Terminal

The monitor for the 6m (50.620 1.2k) and 10m packet/robust packet ports at the K4KPN-4 N. Kentucky node. K4AF-6 is at the Pentagon. K7BC-6 is a few miles to the SW. Both are just over 400 miles away. Opening was very brief. June 20th would produce a stronger opening. Times are UTC.

 

On June 20th things would liven up even more with the Conway AR node “CON50” W5AUU-6 (likely bleed-over from 50.615 MHz) coming in. There was also an extended and strong e-skip opening to Wash DC with APRS packets bouncing around and being digipeated like it was 2m APRS at times. Several K4KPN-4’s beacons were getting digipeated and I-gated into APRS-IS via K7BC-6 in Springfield VA.

 

6m_aprs_raw_pkts_20180620

The June 20th 6 meter APRS opening into the Wash DC area lasted for over an hour. K4AF-6 was even audible at times on a HT (Yaesu VX-8DR) setting on my desk. Gotta love the Magic Band of 50 MHz!

Distances involved where about 410 miles from Kentucky to DC. So I wouldn’t call it really short skip, but definitely shorter than normal. General rule of thumb is when 6 meter e-skip shortens up to 250-300 miles then it’s time to start checking 144 MHz for possible e-skip on that band.

Good to see there is still some life on 6m APRS. Band openings can make things interesting, even on VHF packet. Also nice to see there is some packet radio gear at the Pentagon MARS / AR station(s).

K4KPN-4’s 10m port beacons every 10 minutes and the 6m port beacons every 5 minutes with APRS compatible beacons to help detect band openings. The 50.620 MHz 1200 baud port on K4KPN-4 also supports WIDE1-1 digipeating in addition to normal packet radio connects.

 

WA4ZKO

 


SCS Tracker DSP TNC Firmware v1.7F Available

June 19, 2018

SCS Tracker DSP packet radio TNC firmware version 1.7F is now available for download from the Files section of the Robust Packet Yahoo Group or via the the beta firmware option in the SCSupdate program.

An easily overlooked source code formatting error snuck into a subroutine portion of the code in a way that didn’t throw any errors when compiled. This impacted the HDLC state machine’s ability to properly track multiple incoming frames. This is the bug detailed in some of my recent RP Group postings.

While this should be considered “beta” firmware for now, it appears to have solved the above problem. My initial testing is showing the problem resolved. If you use your Tracker DSP TNC for VHF/UHF packet then you should strongly consider installing this free firmware update.

NOTE: I have SCS looking into another packet mode bug that is on the transmission side of things. The TNC will never send more than 2 frames regardless of MAXFRAME settings. This may be a Winlink Express bug and more testing is needed. This would generally only impact 9600 baud users with degraded upload speeds.

Do note that RPR is hard coded to limit maxframe to 2 by design. This issue does not impact RP mode.

My thanks to John KX4O of VAPN for his help and testing.

Thanks to SCS for their excellent ongoing support and desire to further improve the Tracker DSP TNC for both ARPS and non-APRS uses.

WA4ZKO


K4KPN BBS & RMS Gateway are Available

June 9, 2018

KYPN would like to announce the full availability of the KYPN Dry Ridge BPQ32 based packet radio site as of June 9, 2018.

The following packet radio applications are available:

K4KPN-1    BBS
K4KPN-4    Node
K4KPN-13  Chat/Conference Server
K4KPN-14  RMS Gateway

The above packet radio applications are normally available 24x7x365 to appropriately licensed amateur radio operators on the following frequencies/modes:

SYSTEM PORTS:
441.0500 MHz 9600 baud *
145.6900 MHz 1200 baud
223.6600 MHz 1200 baud *
28.1480 MHz USB dial, 28.1495 CF, Robust Packet “NET10R” *
50.6200 MHz 1200 baud **
* High availability, primary port.
** Dual-use port, both general use & 6m APRS WIDE1-1 Digi

All 5 bands and 3 modes are published to the Winlink channel listing.

Recommended user software:

KYPN recommends Outpost Packet Message Manager version 3.0.0.333 for BBS access. Full installer is available for download here.

KYPN recommends Winlink Express v1.5.12.0 or newer for RMS access. Available for download from here.

More details can be found on the K4KPN-1 packet BBS under messages #1 thru 8.

More details in future blog posts and the work in progress draft KYPN System FAQ.

 

The KYPN team.


K4KPN System FAQ

June 1, 2018

This is a work-in-progress….

FAQ #1 – Any other HF bands than 10 meters?

Answer:  Not at this time. We may add 80/40 or 30/17 meters in the future, but that is a big maybe at this time.

 

FAQ #2 – Why only 10 meters, why not a lower band?

Answer:  The 10 meter port’s primary purpose is to provide an additional coverage option for local fringe locations that even the 6 meter 1200 baud packet port struggles with due to noise/distance etc.

Remember 28 MHz behaves very much like 30 MHz VHF-Low with propagation characteristics well suited to the hills and valleys common to our coverage area. 10 meter Robust Packet fills the need.

We are not offering lower bands at this time due to the main HF antenna the site is dedicated to remote HF/VHF station use and that takes priority for now. A future site may allow for a 30/17m port, but no scheduled date of availability or guarantee on that.

 

FAQ #3 – Why Robust Packet, why not one of the soundcard modes?

Answer:  We have not found soundcard modems to be reliable enough for 24x7x365 use at a remote site. It is one thing if the system is down in your basement or over in the corner of your hamshack, but modem evaluation criteria changes when the system is miles away at a tower site. We also wanted a mode/modem that was suitable for BOTH interactive use with packet applications (BBS, Chat server, etc) and message transfers. Lot of the other modes are okay for message transfers as that was what they were designed/optimized for, but often poor choices for interactive connections.

Robust Packet is hardware modem based and gives us an excellent mode for interactive access and plenty of message transfer speed for our particular needs. It also works well with weak noisy signals, has considerable immunity to multi-path, and often works in fringe locations where the 6 meter AFSK packet port will not.

 

FAQ #4 – Is DX use of the  6 or 10 meter ports allowed?

Answer:  Yes, but please yield to any local users on QRG.  The 10 meter port beacons every 10 minutes to help detect band openings.

The 6 meter port beacons an APRS compatible beacon every 5 minutes to help detect band openings. The 6m port also functions as a WIDE1-1 APRS digipeater.

 

FAQ #5 – What is WYJAC, BBSJAC, etc?

Answer:  WYJAC (WA4ZKO-4) / BBSJAC (WA4ZKO-1) is a test/dev node and BBS at our 7-land QTH. The Dry Ridge site is linked to it over a private network, thus you will see those nodes/applications showing at times. It will also allow migration/expansion of the KYPN packet network and applications later on down the road.

Please do not leave messages on the WA4ZKO-1 BBS as it is just a test BBS for now.  Please leave all messages on the K4KPN-1 BBS unless instructed to do otherwise.

 

FAQ #6 – Is telnet access available?

Answer:  Yes, but it will be considered on a case by case basis. For now it is restricted to those with access to the inter-tower KY<>WY VPN LAN/WAN network. Those within VHF/UHF range will be required to have a functional and actively used “RF” packet station before telnet access will be considered. The goal of the packet BBS is to provide a RF only messaging system, not breed laziness and apathy towards having effective RF access.

Yes having a Winlink RMS gateway on the system kind of conflicts with the above LOL. It is secondary to the conventional packet systems. Trust me, it took some convincing for me to even offer it, especially on VHF/UHF.

The K4KPN-14 Winlink gateway is on “probation” as far as I’m concerned. If it’s not used then it will eventually be turned off. If it becomes a PITA in terms of admin or abuse then it will be turned off. Many said they wanted it, now we’ll see if that was just talk and how it will be used 😉
 

FAQ #7 – Does the KYPN systems have backup power?

Answer:  The K4KPN-10 HF RP APRS I-Gate/Digi is at a secure tower site with backup power options.

The K4KPN-1 (BBS), K4KPN-4 (Node), K4KPN-6 (6m digi/I-gate), K4KPN-13 (chat svr), and K4KPN-14 (RMS) systems are located on a private tower site near Jonesville. This site has short term battery bank backup in place to allow it to stay online till manual transfer to an on-site generator.

The K4KPN-15 2m APRS I-Gate/Digi is located in Williamstown. The station has very limited battery backup. Normally it will be shut down during an extended power outage. It should NOT be counted upon for emergency uses. Also note current plans are to decommission it in January 2020.

 

To be continued….

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