#gps #gps


Rickw9rea@...
 

Looking for some input.  My shack is located in my metal pole building ( metal sides / roof ) I have the GPS with the patch antenna that I have used outside of the building while calibrating my QCX and QCX+....however I am looking to run WSPR as well as the clock and keep the GPS connected.  Can I enclose my current GPS put it outside and run into the shack with a cable ( I guess my question would be how long of a cable run can I get by with ) Or should I purchase another GPS and run an external antenna?  Thanks 73
--
Rick w9rea


N3MNT
 

If you have a window, try placing GPS near window.  If you need to run any length of wire, try shielded 4 conductor wire.


Rickw9rea@...
 

Thanks for the reply.  I don't have a window however  i think I will try your suggestion first,  I have a pvc feed through that I bring coax through I would only need about 8 feet of cable.  Maybe I could get by with that. tnx\
--
Rick w9rea


Curt wb8yyy
 

Rick

I think 8 feet of cable should work.

Now the big trade-off:  put the entire GPS outside, but keep it from getting wet or moist (possible, folk do it with ATU's) or coax to an external GPS antenna.  I don't have a strong input either way, but I would be tempted myself to put the GPS in a sealed container and go for it.  Inspect it regularly. 

73 Curt


N3MNT
 

I am thinking entire GPS outside ( in waterproof container ( even tupperware) and run 4 conductor shielded signal cable into shack.


 

I have exactly that with mine for four years. Small Tupperware, a couple of drainage/air holes in the bottom, and it survives the bitter cold Maine winter with no problem.

Frank  W1FRA


Shane Justice <justshane@...>
 

Rick,

If you are not too cost driven, I can recommend placing an external, amplified GPS antenna outside the building and running the cable into the building. If you are using the QLG-1, remove the patch antenna, place the resistor, inductor, and SMA  connector on the QLG-1, and connect the external antenna to the SMA connector and you are set. 

The external gps antenna I used has a magnetic base, so if the siding material on your building is ferromagnetic, you can just place it on the siding.

No muss, no fuss, not maintenance.

I can supply part numbers/Amazon order info if you want to go this route.

73,
Shane 
KE7TR


On Oct 9, 2020 at 08:14, Rickw9rea <rickw9rea@...> wrote:

Thanks for the reply.  I don't have a window however  i think I will try your suggestion first,  I have a pvc feed through that I bring coax through I would only need about 8 feet of cable.  Maybe I could get by with that. tnx\
--
Rick w9rea


Arv Evans <arvid.evans@...>
 

GPS signal levels are quite low, but has anybody considered a "passive repeater" in the form of inside and outside tuned antennas connected by a low-loss coupler?
_._


On Fri, Oct 9, 2020 at 11:34 AM N3MNT <bob@...> wrote:
I am thinking entire GPS outside ( in waterproof container ( even tupperware) and run 4 conductor shielded signal cable into shack.


Shane Justice <justshane@...>
 

Arv,

These modern receivers have such a low noise floor that an amplified antenna is not required in an open sky situation. The amplified antenna is just extra insurance for situations where the are sky obstructions, and/or limited sky views available (think urban canyons, tunnels, and the like).

All the good, current receivers take all this into account in their signal processing chains, and you get this for the cost of the unit. The external antennas all come with weatherproof cables with connectors installed, ready to be threaded onto the socket on the board. 

In contrast, putting the whole GPS in a tupperware box, to be mounted outside in the weather, and bring in TTL level signals in the "shack" through a cable, is putting a lot more effort into accomplishing the goal of getting GPS data into the U3S/QCX/etc. You'll have to deal with a thicker cable, additional connections, RF noise injection on the TTL lines, and the poor signal levels of TTL over 5 or more feet, for starters. Unless you just like fiddling with stuff, getting a pre-made external GPS antenna and cable is the fastest, least trouble-prone, most efficient way to get the GPS data into the receiver.

I suppose it all boils down to your personal tradeoffs between using your time, spending your money, and your perceptions of what provides you with the greatest sense of accomplishment.

I prefer conquering a problem and having it stayed conquered for many, many years. I care about establishing a capability and being able to build upon that capability toward some goal, then moving on to the next challenge, the next capability, the next function, not continuously fighting with problems created by missteps with earlier, suboptimal implementations that require recurring maintenance/repairs.

It all depends upon what you want from your projects.

73,
Shane
KE7TR




On Oct 9, 2020 at 11:44, Arv Evans <arvid.evans@...> wrote:

GPS signal levels are quite low, but has anybody considered a "passive repeater" in the form of inside and outside tuned antennas connected by a low-loss coupler?
_._


On Fri, Oct 9, 2020 at 11:34 AM N3MNT <bob@...> wrote:
I am thinking entire GPS outside ( in waterproof container ( even tupperware) and run 4 conductor shielded signal cable into shack.


 

There are always more proper ways to do something. My inexpensive, ie cheap, Tupper ware from the recycling at the dump, and 40ft of twisted pair of the telephone service truck works fine. Is it perfect Darned if I know, its always worked and I'm on to other projects !


Alan G4ZFQ
 

GPS signal levels are quite low, but has anybody considered a "passive repeater" in the form of inside and outside tuned antennas connected by a low-loss coupler?
The problem is that the coax is not low loss. An active antenna is required.
So you may as well just use an active antenna.

73 Alan G4ZFQ


Arv Evans <arvid.evans@...>
 

Apparently you missed the point of my suggestion.
_._


On Fri, Oct 9, 2020 at 1:57 PM Shane Justice <justshane@...> wrote:
Arv,

These modern receivers have such a low noise floor that an amplified antenna is not required in an open sky situation. The amplified antenna is just extra insurance for situations where the are sky obstructions, and/or limited sky views available (think urban canyons, tunnels, and the like).

All the good, current receivers take all this into account in their signal processing chains, and you get this for the cost of the unit. The external antennas all come with weatherproof cables with connectors installed, ready to be threaded onto the socket on the board. 

In contrast, putting the whole GPS in a tupperware box, to be mounted outside in the weather, and bring in TTL level signals in the "shack" through a cable, is putting a lot more effort into accomplishing the goal of getting GPS data into the U3S/QCX/etc. You'll have to deal with a thicker cable, additional connections, RF noise injection on the TTL lines, and the poor signal levels of TTL over 5 or more feet, for starters. Unless you just like fiddling with stuff, getting a pre-made external GPS antenna and cable is the fastest, least trouble-prone, most efficient way to get the GPS data into the receiver.

I suppose it all boils down to your personal tradeoffs between using your time, spending your money, and your perceptions of what provides you with the greatest sense of accomplishment.

I prefer conquering a problem and having it stayed conquered for many, many years. I care about establishing a capability and being able to build upon that capability toward some goal, then moving on to the next challenge, the next capability, the next function, not continuously fighting with problems created by missteps with earlier, suboptimal implementations that require recurring maintenance/repairs.

It all depends upon what you want from your projects.

73,
Shane
KE7TR




On Oct 9, 2020 at 11:44, Arv Evans <arvid.evans@...> wrote:

GPS signal levels are quite low, but has anybody considered a "passive repeater" in the form of inside and outside tuned antennas connected by a low-loss coupler?
_._


On Fri, Oct 9, 2020 at 11:34 AM N3MNT <bob@...> wrote:
I am thinking entire GPS outside ( in waterproof container ( even tupperware) and run 4 conductor shielded signal cable into shack.


Arv Evans <arvid.evans@...>
 

I think that you also missed the point of my suggestion.  
Using just inside and outside antellas with just a low-los
bulkhead connector through the wall might be worth testing.

Arv
_._


On Fri, Oct 9, 2020 at 2:43 PM Alan G4ZFQ <alan4alan@...> wrote:
> GPS signal levels are quite low, but has anybody considered a "passive
> repeater" in the form of inside and outside tuned antennas connected by
> a low-loss coupler?

The problem is that the coax is not low loss. An active antenna is required.
So you may as well just use an active antenna.

73 Alan G4ZFQ







Michael.2E0IHW
 

On 09/10/2020 21:42, Alan G4ZFQ wrote:
GPS signal levels are quite low, but has anybody considered a "passive repeater" in the form of inside and outside tuned antennas connected by a low-loss coupler?
The problem is that the coax is not low loss. An active antenna is required.
So you may as well just use an active antenna.

73 Alan G4ZFQ
The passive idea can work for mobile phones.
Yagi outside on a pole, low-loss coax to  inside dipole.
Hold mobile phone close for indoor use.

Michael 2E0IHW


Shane Justice <justshane@...>
 

Very good! I was going to comment that buying a piece of Tupperware alone would cost more than the amplified GPS antenna and the parts to integrate into the QLG-1...

Good job there!

Shane


On Oct 9, 2020 at 12:50, Frank W1FRA <allenfr@...> wrote:

There are always more proper ways to do something. My inexpensive, ie cheap, Tupper ware from the recycling at the dump, and 40ft of twisted pair of the telephone service truck works fine. Is it perfect Darned if I know, its always worked and I'm on to other projects !


Shane Justice <justshane@...>
 

Alan,
While I was waiting for the inductor to supply power to the active antenna, I hooked that antenna up to the QLG-1, and much to my amazement, the gps got a full 3D solution and this was inside my house with a 15 foot deep overhang over the full length patio.

Hense my assertion that the modern receivers are so sensitive that they may not need an amplified antenna in some situations.


On Oct 9, 2020 at 13:43, Alan G4ZFQ <alan4alan@...> wrote:

> GPS signal levels are quite low, but has anybody considered a "passive

> repeater" in the form of inside and outside tuned antennas connected by
> a low-loss coupler?

The problem is that the coax is not low loss. An active antenna is required.
So you may as well just use an active antenna.

73 Alan G4ZFQ







Shane Justice <justshane@...>
 

Apparently.


On Oct 9, 2020 at 14:16, Arv Evans <arvid.evans@...> wrote:

Apparently you missed the point of my suggestion.
_._


On Fri, Oct 9, 2020 at 1:57 PM Shane Justice <justshane@...> wrote:
Arv,

These modern receivers have such a low noise floor that an amplified antenna is not required in an open sky situation. The amplified antenna is just extra insurance for situations where the are sky obstructions, and/or limited sky views available (think urban canyons, tunnels, and the like).

All the good, current receivers take all this into account in their signal processing chains, and you get this for the cost of the unit. The external antennas all come with weatherproof cables with connectors installed, ready to be threaded onto the socket on the board. 

In contrast, putting the whole GPS in a tupperware box, to be mounted outside in the weather, and bring in TTL level signals in the "shack" through a cable, is putting a lot more effort into accomplishing the goal of getting GPS data into the U3S/QCX/etc. You'll have to deal with a thicker cable, additional connections, RF noise injection on the TTL lines, and the poor signal levels of TTL over 5 or more feet, for starters. Unless you just like fiddling with stuff, getting a pre-made external GPS antenna and cable is the fastest, least trouble-prone, most efficient way to get the GPS data into the receiver.

I suppose it all boils down to your personal tradeoffs between using your time, spending your money, and your perceptions of what provides you with the greatest sense of accomplishment.

I prefer conquering a problem and having it stayed conquered for many, many years. I care about establishing a capability and being able to build upon that capability toward some goal, then moving on to the next challenge, the next capability, the next function, not continuously fighting with problems created by missteps with earlier, suboptimal implementations that require recurring maintenance/repairs.

It all depends upon what you want from your projects.

73,
Shane
KE7TR




On Oct 9, 2020 at 11:44, Arv Evans <arvid.evans@...> wrote:

GPS signal levels are quite low, but has anybody considered a "passive repeater" in the form of inside and outside tuned antennas connected by a low-loss coupler?
_._


On Fri, Oct 9, 2020 at 11:34 AM N3MNT <bob@...> wrote:
I am thinking entire GPS outside ( in waterproof container ( even tupperware) and run 4 conductor shielded signal cable into shack.


Alan G4ZFQ
 

Hense my assertion that the modern receivers are so sensitive that they may not need an amplified antenna in some situations.
Shane,

Yes, I've seen lots of reports here of reception in seemingly impossible places.

But I've tried repeater antennas and they have only worked when nearly on top of the RX antenna. Maybe I've not done it correctly and that's not typical?

73 Alan G4ZFQ


Ian VA7ITM
 

On Fri, Oct 9, 2020 at 10:34 AM, N3MNT wrote:
I am thinking entire GPS outside ( in waterproof container ( even tupperware) and run 4 conductor shielded signal cable into shack.
At the very bottom of https://www.qrp-labs.com/qlg1.html is an example waterproof case.

73 Ian VA7ITM


Hans Summers
 

Hi Shane

Yes the modern GPS chips are very sensitive. However there's also magic in the QLG1 GPS kit antenna... the reason the QLG1 GPS PCB is so "big" compared to other GPS modules is intentional, the large groundplane under the patch antenna greatly improves the antenna performance and therefore overall sensitivity. The patch antenna is also custom-manufactured for QRP Labs and is sized and tuned to match the requirements of the PCB groundplane; I sent the factory assembled QLG1 PCBs and they figured out the exact size and tuning for the antenna to be perfectly resonant on 1575MHz. So the high sensitivity of the QLG1 GPS is due both to the sensitive GPS receiver chip and also the PCB design and antenna matching. 

Generally people should try the QLG1 with its own patch antenna. In my applications it will work well. I don't find any need to operate it with a clear sky view etc., it works fine indoors. 

I've never used an active external antenna with it but the PCB is designed to take an SMA socket for people who want to do that, and they also need to fit an inductor and resistor; note that the quoted 27nH inductance should be viewed as a minimum, not an exact requirement. So almost anything goes. Wind some wire around a high value resistor and you've done it in 30 seconds. No need to fuss over finding exact 27nH inductors. 

In Tokyo I used to have the GPS outside the window on the railings outside the window, and I ran about 10 meters of 4-conductor cable (shielded/screened cable) to the shack. It always worked fine. Even though since I was on the 3rd floor of 7, and with lots of tall buildings all around, there wasn't much sky view. I haven't tried more than 10 meters distance between QLG1 and U3S/QCX/etc. 

Note that when using common plastic food containers as an enclosure, be careful: the sun is a pretty harsh foe... several times I left things for 6 months, a year... then went back to check and as soon as I touched the plastic tub, it fractured instantly into hundreds of tiny fragments. Strong UV decomposes some plastics quite fast. Depends on where you live too... Tokyo has a lot of sunshine 80-90% of days and strong. Turkey too where I live now. The food containers would last longer in England :-)

73 Hans G0UPL 


On Sat, Oct 10, 2020, 06:00 Shane Justice <justshane@...> wrote:
Alan,
While I was waiting for the inductor to supply power to the active antenna, I hooked that antenna up to the QLG-1, and much to my amazement, the gps got a full 3D solution and this was inside my house with a 15 foot deep overhang over the full length patio.

Hense my assertion that the modern receivers are so sensitive that they may not need an amplified antenna in some situations.


On Oct 9, 2020 at 13:43, Alan G4ZFQ <alan4alan@...> wrote:

> GPS signal levels are quite low, but has anybody considered a "passive

> repeater" in the form of inside and outside tuned antennas connected by
> a low-loss coupler?

The problem is that the coax is not low loss. An active antenna is required.
So you may as well just use an active antenna.

73 Alan G4ZFQ