How many opted to get the GPS option for their 6500 or 6700?

Duane N9DG

Over on QRZ.com there was a thread started about creating a network of coordinated DF stations to identify and locate bad actors in the ham bands. I immediately thought of the 6500/6700 with GPS option and time stamped VITA-49 packets. And that also made me wonder how many of the 6500/6700's out there already have the GPS option installed?

And I believe that I read somewhere that the 6Ks with the GPS option can timestamp data packets from a collection of GPS option equipped 6K stations that can then be sent to a processing server for further analysis. At least it is my understanding that the 6K's HW is designed to support that kind of system. Don't know if the SW in the radio is in place to do that yet or not...

As could be predicted, many of the comments in that thread are thinking too small, or too old school.. It just seems to me that the 6K's could be quite useful for such an effort as part of a pretty highly automated system, and be the RF listening piece of such an effort..

The thread:
https://forums.qrz.com/index.php?threads/coordinated-rdf-to-locate-jammers-and-other-rotten-folks.50...

Neal_K3NC

Pretty interesting idea, seems a bit focusing on a negative side of the hobby but different strokes for different folks!

Bill-W9OL

everyone knows tht all Flex ownerusers are the best mannered and skilled operators.
anyone here going to dispute that?

WA6FXT Mike

Neal, if we don't focus on bad operations, then who should? My 6700 has the GPSDO and is ready for the software. Mike

Andrew VK5CV

Duane, This is one reason I got the GPS option. However the software to use the data is not there yet. A distributed network could discover and locate lots of natural and unnatural signals and not just those of earthly origin. Andrew de VK5CV

Jim KJ3P

Interesting concept.  If there were enough stations reporting coordinates and received dBm, I'll bet a clever algorithm could provide a general location.  Then the folks with the DF loops could take over.  As always, spearheading and coordinating such an effort is the large obstacle.  How about a letter to the ARRL and its OO department?

   --jim

kr4k

Are the I/Q samples in the VITA-49 packets now time stamped when you install the GPS option? If so, what is the recorded time precision and format?

First step in the case of intentional jamming is to alert the FCC, which has a US-based HFDF system, operated out of Columbia, MD.

Bill-W9OL

Way back when I was considering the Flex, Someone told me that we could use it to keep our computers in super correct sync.
So I bought it.
But now there are software programs that do that automagically for us.
So I'd be willing to take part in a system to analyze bad signals and attempt to locate them no matter whether they were Ham signals or darn sweeping signal buzz I hear here in Chicago area a lot.

Walt - KZ1F

I believe Steve was referring to timestamp packets as a future for geographic diversity reception. Not the yagi and dipole in your backyard but your antenna and one hundreds of miles away. Not there yet. I did order the option when I ordered the 6500. I probably would not do it again.

Ken - NM9P

I chose not to get the $500+ gps option yet, figuring that I can always add it later when capabilities arrive that will make good use of it. But the idea of a network of gps linked receivers would have more applications than merely DFing interference and bad behavior....primarily utility in locating ships in danger, lost hikers, and assisting In other emergencies. Ken - NM9P

EA4GLI

I opted for it. Just a piece of advice.... it comes with an indoor antenna, not outdoor! The GPS antenna didn't like a recent heavy rain. 

John K4SQC

My only reservation is the definition of a "bad actor" is very much in the eyes of the observer.  I think we could all agree that someone operating outside of their band privileges, playing music, basically violating the rules as laid down in FCC regs is a problem.  Beyond that, it is an open field.  I guess it is being proposed that Flex owners who are so motivated join the ARRL Official Observer ranks.  There is 85 years of experience in that program and very well-known rules and reporting mechanisms.

I bought the GPS options because I see the digital modes as the way of the future.  With them tight frequency control and accurate time keeping are crucial. I have the frequency well in hand.  What I am waiting for is an applet that will let me use my Flex as the time source to keep my computer in sync.  I have the software on the computer, I just need SSDR to externalize the GPS time string, maybe through the accessory port.  Nothing is more frustrating than to see the words "wrong clock" appear on the N0UK EME screen  or via a text message from a local friend.  As many of you know with CW or SSB being off by seconds or even minutes is not really a problem except maybe with QSLing.  With the more robust digital modes a 1 sec error can be the difference between a decode and no decode.

So that is why I am very glad I bought the option.

Frank WA3NHK

This would be an interesting technical challenge for the community to develop. In my world we use "Multilateration Time Difference of Arrival (TDOA)" techniques. Definitely not traditional cross-DF measurements. Precise GPS time makes this possible. TDOA is a bit like LORAN-C, but spelled differently. Google for "wide area Multilateration" as applied to ATC surveillance systems and you'll see what I mean. 73. Frank

Walt - KZ1F

@John - Would you explain something to me? You mention wanting to use the GPS as an accurate time source. You already have that? Windows either out of the box or easily configured utilizes a NTPD to sync the computer's internal clock. Over time the computer drift is minimized such that your clock is incredibly accurate. My vague recollection is accuracy is something on the order of 1/10 ms. So long as any IP transmission your computer software makes has to span a single hop you've lost any absolute accuracy anyway....Right?

rfoust

NTP makes small adjustments over time rather than "jolting" a clock back to the correct time.  I have to run a 3rd party program (Dimension 4) to keep my clock in sync for JT65.  If I don't, the allowed drift by ntp is too great.

Walt - KZ1F

Hi Robbie, yes, that's why I said 'over time'. RFC 1305 has an accuracy of 200ps. The 1/10ms was my re collection of the Heathkit most accurate clock which stipulated, in hi spec mode it was accurate to .1ms. That suffered no ttl latency as it picked up NIST broadcasts so the was just atmospheric radio latency.

Walt - KZ1F

Dimension 4, that's an oldie. How are they different than using time.nist.gov? I run Linux and use an ntp client pointing to nist. Rather than using TCP port 37 (rfc 1305) you were using the daytime protacol on port 13? You want to use 37. I didn't know Windows consumer uses daytime proto. It look like the server class use the more accurate ntp.

KY6LA_Howard

During the K1N expedition they had a system for accepting reports of jammers and pirates. The reports were fed into a program to ID the location of the Jammers. Not sure what the final results were but perhaps those Jammers were one of the feW legitimate targets for finding out who they were. I have GPSDO that I bought on the yet unfulfilled promise of wide area diversity reception On The Other Hand. I DOUBT that I would participate in such an experiment because of the "Who is going to determine who is a Bad Actor" issue. The last thing we need is more self styled "nay Nay, I am going to Tell on You" frequency police

Duane N9DG

I have been able to hold Windows clocks to within 1 second with just a registry setting tweak alone, no 3rd party NTP client needed.

What I have done is change the value of this key to something fairly frequent, few tens of minutes or maybe once an hour  vs. the only once a week that Windows NTP defaults to (All the standard Windows registry hacking disclaimers apply....):

HKEY_LOCAL_MACHINESYSTEMCurrentControlSetservicesW32TimeTimeProvidersNtpClientSpecialPollInterval

The registry value is in seconds, basically the key describes how often Windows pings the NTP server for a new time update.

After changing the value you do need to restart the W32Time service, or reboot, for the new setting to take effect.

And I don't know if this is still workable on Win 8.x or 10. Have not had a need to try to do that with those OSes. It certainly works fine on Win XP and Vista and 7.

Also this will not work if your computer is part of a Windows active directory domain. Which should not be the case for most in home shack PCs.

k3Tim

This is really cool - thanks for pointing this out Frank.  I assume it would  be ideal if ALL aircraft had ADS-B. 

_.--
 k3Tim

Bill-W9OL

Ken, the heck with those lost hikers, if they are so **** to get lost when even the cheapo watches have gps direction capability, they deserve to 'sleep with the cohotes".

LOL and I carry my Eagle Scout Card in my wallet to this day. LOL
Me and my trained S&R German Shepherd retired from S&R 2 years ago...when I reached 68 and my xyl said that 2 MI's were enough.

Martin AA6E

GPS time tagging would open up some interesting radio science, including DFing of unknown transmitters.  If you could phase lock the oscillators of multiple separated receivers, you would be able to do "Very Long Baseline Interferometry" (VLBI) as practised in radio astronomy for many years.  But typical GPS units are not going to get you phase locking.  (You may need GPS plus Rubidium frequency standards or better.)

If you're dealing with variable propagation channels (especially HF), phase coherence is probably not useful anyway.  Instead, you can look at differential time delays of modulated signals, which is a millisecond game (down to 100 usec maybe). A group of us did some preliminary work on HF Time of Arrival a few years back, using data tagged with the GPS seconds pulse. Conclusion: radio location of jammers (our interest) should be doable but not easy.

Flex 6000's with GPS and time tagged data would certainly help.

rfoust

Thanks Duane, good to know.  I stumbled across Dimension 4 years ago, and never really bothered to figure out how to get w32tm to be more accurate.

k3Tim

How accurate does Dim4 really set the clock? If I use a "local" server and sync multiple times, the PC time will jump about 300 msec or so.
To perform the DF work mentioned in this thread using multiple stations and time stamped VITA 49 packets, I'd expect the clock accuracy will determine the final resolution of the DF.  Speed of electromagnetic propogation of 9.836e+8 feet / second that works out to about 1000 feet resolution with 1 microsecond accuracy. Not bad but not great.  BTW a CDMA cell phone has clock accuracy to a microsecond.


 Tim 

Duane N9DG

There are indeed a fair number of GPS option 6K's out there I see. I did not get that option as I did not see a near term use for it. And figured that I could add it if a reason did present itself later.

Also I actually have not previously pondered the DF possibilities of the 6K's beyond thinking that time based DF approaches should be possible with it. Then that thread started on QRZ and that got me thinking about it in some more detail from a purely a technical perspective, and the state of readiness of the SmartSDR/API such that someone could maybe pursue it. I also weighed in on that QRZ thread mainly as a "hey guys there are some new state of the art ways to possibly pursue this idea" alert. Make those reading that thread aware that there are new approaches to consider instead of just the very old school ways that the thread was initially focused on. There is a very big lack of awareness out in general ham radio land of just what the 6K hardware is actually capable of, especially when using them in ways other than working with just one signal at a time like traditional radios are limited to.

And also as I ponder this concept some more, I could also see some of these same ideas being applied by HF contest sponsors as a means to near real-time "referee" a contest. Wouldn't that be a  new concept? Prior to wide-band sampling SDRs such an idea would have been extremely difficult to implement. Now it seems to be entirely within the realm of being possible.  

rfoust

Hi Tim - No idea really.  Looks like Dim4 is really just another NTP client.  Since Duane provided info above on how to tweak the built in windows time sync to sync more frequently, there probably really isn't any difference between the two.  But I'm not a NTP expert.

I suspect the vita 49 packets could have a MUCH more accurate timestamp since it isn't relying on the internal PC clock, or whatever Windows is doing to keep track of time.

Frank WA3NHK

In 2020 practically all aircraft in the US will be required to carry ADS-B. (Other countries have their own deployment schedules.). Yes, full ADS-B equipage would be the ideal. But the WAM systems that I've looked into for work can also use plain old SSR replies and squitters on 1090 for a WAM solution. 73. Frank

Duane N9DG

Yepp, there's no linkage whatsoever between Windows NTP time setting accuracy and VITA-49 packet time stamping...

Norm - W7CK

I'd be surprised if the ARRL OOs would do anything at all with the information.  Shoot, here in Phoenix, we have had the same jammer on 2 meters for over 5 years.  Nothing has ever been done and they show no interest in addressing the issue.  Most people have just given up and moved on.  Like someone said on one of the other threads, just spin the dial to a different location if you don't like what's going on.  I guess that's one approach.  Hopefully the nice folks will continue to outnumber the feeble minded ones.

I didn't order the GPS with my 6700.  I didn't see any use for it and after more than 2 years, I still don't see any.  Shoot, by the time the software catches up, I'll most likely be upgrading the rig!

Andrew VK5CV

I got an outside active antenna from the 'net very cheaply.
There are even marine use intended ones.
Andrew

Jim KJ3P

Norm,

Here in EPA, OO's are very active, and something like your situation would be addressed immediately.  Has the repeater owner/trustee contacted the OO coordinator in your section?  Check with the ARRL Section Manager to get contact info.

   --jim KJ3P