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Clock kit antenna question #antenna
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I have a clock kit finished and I am starting the build for an QLG1 GPS module I bought from a fellow ham. Question 1. Can I build the kit using the supplied antenna which mounts to the board and also use an external antenna later? 2. Do the little GPS antennas work well?
Thanks for thoughts or your experiences. 73, David W2DAB |
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Dave Edwards
I have Garmin units that cannot get a GPS link, unless I step
outside. My clock syncs to GPS quickly, inside, and downstairs in
the basement. And the clock and antenna are inside an enclosure.
Very phenomenal!!!! ....Dave KD2E On 3/31/23 11:06 AM, David Bamford via
groups.io wrote:
I have a clock kit finished and I am starting the build for an QLG1 GPS module I bought from a fellow ham. Question 1. Can I build the kit using the supplied antenna which mounts to the board and also use an external antenna later? 2. Do the little GPS antennas work well? |
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Bojan Naglic
Hi David,
As to question 1: You can use either one or another but you have to decide which. This is from the QLG-1 Assembly Manual: Remote active antenna installation73 Bojan S53DZ |
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Civil GPS receivers use the C/A, unclassified codes. https://ocw.mit.edu/courses/12-540-principles-of-the-global-positioning-system-spring-2012/1957f01c355428f594932ef718e4c3ab_MIT12_540S12_lec7.pdf gives a good high level description of the GPS signal structure. These are the slides from a 1-hour lecture, MIT Class. See slide 25 for a description of various types of startups and times.
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Most simply there is a 1.023 MHz spread-spectrum "chip" code that provides sub microsecond, approaching 10's of nanosecond time resolution that can be acquired in relatively low SNR conditions. On top of that there is a 50 bps data channel with lots of data needed for position and timing. Receiving those data in a low SNR signal environment can be challenging. Best practice is to let the GPS receiver do a full acquisition and reception of all messages in a clear sky environment for 15-30 minutes to receive and store all data. After that, inside, the receiver only needs to do the much less challenging "Hot" start for timing acquisition. FYI, the reason cell phone GPS's work reasonably well inside is that the cell signaling provides the GPS data needed and a significant headstart in timing search. Butch N0BLW On Fri, Mar 31, 2023 at 10:56 AM, Dave Edwards wrote:
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I'll take a shot at question #2.
I have both a QLG1 with the pcb patch antenna and a QLG2 with a remote antenna situated in the shack. Both units are located in the ground floor shack at a lat of 49N. Both units work extremely well. As you'd expect the remote antenna on the QLG2 has a better SNR and picks up more satellites a little faster. However, both of my clocks work well and in my opinion, the difference between the 2 units is minimal. 73, Rick VE7TK Website: https://www.ve7tk.epizy.com/ |
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Thanks, So my enclosure is the QRP-Labs metal enclosure and I'm thinking that will block the signal. I want everything inside the box so I will be routing an sma jack to the back and attaching a GPS antenna from there.
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thanks Rick, is your clock kit in the metal enclosure?
73 Dave |
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No. The 1st QLG1 is in a plastic food dish. My 2nd QLG1 is in a 3D printed plastic case.
If you're using a metal case the patch antenna inside will not work and the remote external antenna will be your only option. -- 73, Rick VE7TK Website: https://www.ve7tk.epizy.com/ |
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Randall Phelps
I built two clock kits using the QLG1 GPS modules and both work EXTREMELY well! Both were able to “find” the satellites quickly and keep perfect time! I don’t know about using an external antenna later. I suppose maybe depending on your location, is the external antenna really necessary? For me, the QLG1 works great!! 🤓
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David Moorman <dmoorman4@...>
Probably depends on your building. Mine is made of reinforced concrete slabs resting on a steel framework, and believe me, very little RF energy makes its way into or out of the building. Antennas must be outside. The QLG2 would not link up until it was put on the balcony.
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Dave K9SW On Mar 31, 2023, at 2:13 PM, Randall Phelps <Kd8jn@...> wrote: |
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Bruce K1FFX
I have my QLG-1 in a corner of the kitchen next to a window on the first floor of
a 1916 house just outside of Boston (to give you the latitude). The patch antenna works really well. I initially tried it in the basement in my radio room but that was unreliable. - Bruce K1FFX |
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I have several systems and radios inside my metal building shack that require GPS signals. I had no joy with any of them until I found this item:
https://www.ebay.com/itm/313206552340?chn=ps&_trkparms=ispr%3D1&amdata=enc%3A1wJJWBH0IRGCBBH1QoyLlvg76&norover=1&mkevt=1&mkrid=711-213727-13078-0&mkcid=2&itemid=313206552340&targetid=4580840331958309&device=c&mktype=&googleloc=&poi=&campaignid=437225721&mkgroupid=1235851340419610&rlsatarget=pla-4580840331958309&abcId=9300906&merchantid=51291 Long link I know, but I ran the antenna outside placed the relay antenna on the ceiling in the shack and Bingo! excellent GPS reception throughout the shack. 73 Ray |
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Alan G4ZFQ
On 01/04/2023 16:20, Ray D Congdon via groups.io wrote:
until I found this item:Yours is a lot better than the one I got a year or more ago. I had to set the antennas very close before it worked. 73 Alan G4ZFQ |
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William Smith
My GPS units automatically switch to the external GPS puckk when they detect that it's drawing current, but that may be a feature of the chipset in use (Adafruit Ultimate GPS HAT).
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Even though I'm just using it for timing I find it works much better with a proper antenna mounted outdoors with a clear view of the sky. The one unit with https://www.amazon.com/gp/product/B082R86DCL is rock solid all day every day, while the one in the condo window drops out from zero to five times a day. Still _more_ than enough accuracy for the digital modes, but interesting to watch the location drift. 8*) 73, Willie N1JBJ On Mar 31, 2023, at 11:06 AM, David Bamford via groups.io <flashicon@...> wrote: |
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