You cleared-up confusion on my part regarding the "USB to TTL" converter device. From your description I realized that modern USB protocol was being converted to older UART protocol (which the NEO 7M required) and the mystery was solved. Many thanks.

Thanks Ken for your very helpful video. I have constructed a similar Neo-7m frequency reference and like you had issues with gps reception indoors. My solution was to build the combination of antenna and Neo 7m module into a weatherproof box mounted on my roof. I used cheap 6 core security cable to connect the box down into my lab. The 6 core cable allowed me to connect the Neo 7m module's power, serial TX and RX and PPS output downstairs into a USB UART module interfaced with the U-center software. I can now get rock solid gps reception with the ability to select any desired PPS frequency.

@myHB_KC

2 жыл бұрын

Good stuff Grant. I used an antenna taped to a nearby window and that solved the problem.

Excellent. Just discovered yesterday that this is possible, and wanted a quick start guide. Works perfectly.

@myHB_KC

2 жыл бұрын

Since I made this, there are a ton of GPS standards out there.

You have the GPS antenna up-side down! The metal side is ground, the ceramic structure is the antenna and needs to face up.

@myHB_KC

3 жыл бұрын

and 25 feet from the nearest window. I have an antenna taped to the window and has worked ever since.

Very Informative, thanks for sharing. I too need something to calibrate HP frequency counter that I am adding a OCTX option.

@myHB_KC

8 жыл бұрын

+John Jewel yes it has become a very inexpensive piece of test equipment an very easy to use. Many people I know have built this. Have fun building it.

Did you ever try substituting directly the GPS signal for the counter's timebase; that way you counter is GPS disciplined?

All frequencies exept 1PPS are not garantied by manufacturer (ublox) to be precise. Because only in case 1 pulse per second internal sofware of module make additional correction of the exact moment of rising edge of this pulse. (Align Pulse to TOW=0)

Very nice. I'm surprised you are getting a fix with the antenna on the bench though! If you are at a fixed position then it might be worth changing the fix mode, as once you have surveyed your position there is no need to solve for location, just time. According to a skim read of the specification the output is quantised... maybe that is why your display is changing?

@myHB_KC

8 жыл бұрын

+NivagSwerdna I was losing lock because of the antenna. I was just experimenting at the time but I have since switched to an antenna outside. Actually an antenna the same as shown but mounted outside. Locking is not a problem now.

@dalevanderzee4086

6 жыл бұрын

try placing a large metal plate under the antenna, it will help

is that the pps pin? when set that high is it multiplying a pulse from the sat? ill look it up at some point if i dont hear back but im in the middle of something. have you tried comunicating with it over i2c? i know the 6 and 8 have it but I havent read data sheet on 7. going to need that for current project. I think I found the register info but many are "reserved for future use" on the 6 I have a 6m that i broke it out on because they wanted 5 bucks more for the model with a trace lol(used copper tape and a fine hand at the time.now i can etch my own).

@myHB_KC

7 жыл бұрын

Hi.That point is not pps. Using the software you can control what frequency comes out at that pin. I think it's good up to 10 MHZ. I haven't tried I2C, but a friend has. He's actually controlling the NEO-7M with an arduino.

@jwuethrich8385

7 жыл бұрын

yeah i want it contolled by pi but in a polling rather tahn flood my uart mannor. the gps sync/time signal some how plays/governs the frequency phase though...i know they use gps to make sure cell towers are all in phase and at same time on their clocks

@myHB_KC

7 жыл бұрын

I'm not much into GPS. I use it to calibrate frequency counter, SDR, etc and it fits the bill.

Can you please give details about the different modules shown with perhaps links to where they can be obtained, including the software?

@myHB_KC

9 жыл бұрын

Hi gbennett58 I will set you up with all the info this evening. Can you send me your email address?

@geoffreybennett1895

9 жыл бұрын

Ken Chase My email is geochaben *at* charter *dot* net. I hope that will defeat the bots. Thanks!

This video was my salvation

@myHB_KC

4 жыл бұрын

Glad it was a help Roland

Do you find that there is a lot of jitter/phase noise? Apparently, unless the desired frequency perfectly divides into 48mhz, the output is made of some percentage of the clock cycles using one whole number divisor and the remaining clock ticks using a different whole number divisor.

@SQ5DBF

7 ай бұрын

Output frequency must be devided by an integer of 48 MHz (intenal GPS module clock). Otherwise, you will have jitter.

@philipgiacalone5605

2 ай бұрын

Jitter can occur, even if the frequency divides perfectly into 48 MHz. This is because once a GPS fix happens, the more precise GPS timebase will not perfectly match the oscillator's timebase. The video at the following link further demonstrates and explains the problem: kzread.info/dash/bejne/d4R915uqZbjFYbA.html

Hi Ken great video , but I am having trouble getting 10000 hz signal , followed you video using a Winners URT i get a locking of the PPS Light but no apparent change in frequency of the PPS I have tapped the resistor prior to the PPS led , Bryan vk7kwb

@myHB_KC

3 жыл бұрын

Hi Bryan Can you provide a link to your module?

ken.. suppose i buy 2 such neo 6 m gps module.. and configure both to produce 10 khz.. my question is.. will both the 10khz output will be synchronised with each other.. ?

@myHB_KC

3 жыл бұрын

They should be. Syncing is done by the satellite signals. If both are receiving the same signal, then my guess is they would be sync together. I'm no expert on this subject.

Good! Win XP !

your frequency counter looks like DIY made, is it true? may i have the schematic, firmware or link for your diy frequency counter? thank you, sory for my english

@myHB_KC

2 жыл бұрын

Hi Rakhmat. The frequency counter is a module I bought long ago and I don't remember where I ordered it from. All I had to do is put it in a case. There are lots of similar counters from ebay and aliexpress.

@rakhmatvaris

2 жыл бұрын

@@myHB_KC thank you for fast answer.

Hi any chance you can provide details of the UART and software download please? Thanks in advance

@myHB_KC

2 жыл бұрын

Hi Andrew. That was 6 years ago and I don't have my documentation anymore. What you can do is seach on NEO-7M GPS in youtube or google. There are a ton of videos. Make sure not to use a NEO-6, stick to NEO-7. Sorry.

@myHB_KC

2 жыл бұрын

Hi Andrew. Try this website. This is how I go started working with the NEO-7M sites.google.com/site/g4zfqradio/u-blox_neo-6-7

@andrewverran3498

2 жыл бұрын

@@myHB_KC thanks Ken.