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Posted: 10/4/2014 7:23:16 PM EST
[Last Edit: 10/4/2014 8:34:15 PM EST by Mr_Harry]
I need to put up an external antenna at my house. I have a spool of RG-6 Quad Shield that is rated at 8.5 db Loss per 100 Feet

The antenna I will be using will have at least 25 db of gain so I see no problem in line loss.

The cable run will probably be close to 100 foot since I want to have it away from all my transmitting antennas.


Personally I do not think it will be an issue but wanted to know f anyone has tried it.


Thank you

Link Posted: 10/4/2014 7:48:07 PM EST
Should be fine, what equipment are you connecting?

I have a Lucent high-end antenna with an N connector to LMR-400 type cable running down my little tower to a surge suppressor in a box. I have an adapter on the other side of the suppressor and run RG-6 to my Trimble Thunderbolt. Works fine, lasts long time!
Link Posted: 10/4/2014 7:51:53 PM EST
Dumb question: I use GPS to know where I am and where I am going when traveling. What do you use it for at a fixed location where you already know where you are? Tracking continental drift, or what?
Link Posted: 10/4/2014 7:59:07 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By ClingingBitterly:
Dumb question: I use GPS to know where I am and where I am going when traveling. What do you use it for at a fixed location where you already know where you are? Tracking continental drift, or what?
View Quote


Time, which gives you frequency precision and stability if your rig can reference it. When my rig says I'm on 146,000,000.000 Hz, that's exactly where I'm at. It's really only needed by the guys trying to make contacts on the really high microwave bands, or using certain test equipment, or just people with a little OCD like myself. You wouldn't believe all of the repeaters around here that are a little or a lot off of frequency.
Link Posted: 10/4/2014 7:59:53 PM EST
I doubt that's the rating at GPS frequencies.

Am I missing something?
Link Posted: 10/4/2014 8:13:21 PM EST
[Last Edit: 10/4/2014 8:27:30 PM EST by KwaiChangCaine]
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Originally Posted By Him:
I doubt that's the rating at GPS frequencies.

Am I missing something?
View Quote



The coax attenuation? Regular RG6 runs 6 to 7 dB loss per 100 ft at GPS frequencies. I didn't look up the exact freqs but I think it's a little over 1 GHz.

ETA: Looks like it's a litter higher in freq than I thought, so around 8 dB, which is closer to what Mr_Harry said, would be more accurate.
Link Posted: 10/4/2014 8:35:39 PM EST
[Last Edit: 10/4/2014 8:45:13 PM EST by Mr_Harry]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By KwaiChangCaine:
Should be fine, what equipment are you connecting?

I have a Lucent high-end antenna with an N connector to LMR-400 type cable running down my little tower to a surge suppressor in a box. I have an adapter on the other side of the suppressor and run RG-6 to my Trimble Thunderbolt. Works fine, lasts long time!
View Quote



Thank you


I will be using the G3RUH GPS unit

I'm still still looking at antennas, the "Reference Antenna" route (like the Lucent)
The cost a little more, but I'm not sure what the difference will be in it.


Link Posted: 10/4/2014 8:39:01 PM EST
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Originally Posted By KwaiChangCaine:


Time, which gives you frequency precision and stability if your rig can reference it. When my rig says I'm on 146,000,000.000 Hz, that's exactly where I'm at. It's really only needed by the guys trying to make contacts on the really high microwave bands, or using certain test equipment, or just people with a little OCD like myself. You wouldn't believe all of the repeaters around here that are a little or a lot off of frequency.
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Originally Posted By KwaiChangCaine:
Originally Posted By ClingingBitterly:
Dumb question: I use GPS to know where I am and where I am going when traveling. What do you use it for at a fixed location where you already know where you are? Tracking continental drift, or what?


Time, which gives you frequency precision and stability if your rig can reference it. When my rig says I'm on 146,000,000.000 Hz, that's exactly where I'm at. It's really only needed by the guys trying to make contacts on the really high microwave bands, or using certain test equipment, or just people with a little OCD like myself. You wouldn't believe all of the repeaters around here that are a little or a lot off of frequency.



I have wanted a 10 MHz reference for a long time.


And it is also Nice to know where you are.
Link Posted: 10/4/2014 9:08:00 PM EST
[Last Edit: 10/4/2014 9:26:18 PM EST by KwaiChangCaine]
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Originally Posted By Mr_Harry:
And it is also Nice to know where you are.
View Quote


My dad had his Garmin GPS and was comparing it to my Trimble Thunderbolt, and we could not figure out why the altitude readings wouldn't match until we did a little research. To oversimplify, the Trimble Thunderbolt uses raw GPS data and treats the Earth as a perfect sphere, where the consumer GPS units take into account that the Earth is actually an ellipsoid. Had I not found that bit of info I would have believed that my GPS was defective, but now I know how to calculate my exact altitude, which is already built into GPS units made for navigation.

ETA: Where is ar-jedi? I think he's the expert on this stuff. The antenna I'm using is the regular one, but they also make these for use in high RF environments. I bought one but haven't tried it.

http://www.ebay.com/itm/NIB-Lucent-PCTEL-GPS-TMG-HR-26NCM-26dB-Timing-Antenna-N-f-w-Collar-Mount-MaxRad-/361061319907?pt=LH_DefaultDomain_0&hash=item5410ee84e3
Link Posted: 10/4/2014 10:48:16 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By KwaiChangCaine:


My dad had his Garmin GPS and was comparing it to my Trimble Thunderbolt, and we could not figure out why the altitude readings wouldn't match until we did a little research. To oversimplify, the Trimble Thunderbolt uses raw GPS data and treats the Earth as a perfect sphere, where the consumer GPS units take into account that the Earth is actually an ellipsoid. Had I not found that bit of info I would have believed that my GPS was defective, but now I know how to calculate my exact altitude, which is already built into GPS units made for navigation.

ETA: Where is ar-jedi? I think he's the expert on this stuff. The antenna I'm using is the regular one, but they also make these for use in high RF environments. I bought one but haven't tried it.

http://www.ebay.com/itm/NIB-Lucent-PCTEL-GPS-TMG-HR-26NCM-26dB-Timing-Antenna-N-f-w-Collar-Mount-MaxRad-/361061319907?pt=LH_DefaultDomain_0&hash=item5410ee84e3
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Originally Posted By KwaiChangCaine:
Originally Posted By Mr_Harry:
And it is also Nice to know where you are.


My dad had his Garmin GPS and was comparing it to my Trimble Thunderbolt, and we could not figure out why the altitude readings wouldn't match until we did a little research. To oversimplify, the Trimble Thunderbolt uses raw GPS data and treats the Earth as a perfect sphere, where the consumer GPS units take into account that the Earth is actually an ellipsoid. Had I not found that bit of info I would have believed that my GPS was defective, but now I know how to calculate my exact altitude, which is already built into GPS units made for navigation.

ETA: Where is ar-jedi? I think he's the expert on this stuff. The antenna I'm using is the regular one, but they also make these for use in high RF environments. I bought one but haven't tried it.

http://www.ebay.com/itm/NIB-Lucent-PCTEL-GPS-TMG-HR-26NCM-26dB-Timing-Antenna-N-f-w-Collar-Mount-MaxRad-/361061319907?pt=LH_DefaultDomain_0&hash=item5410ee84e3


that's the exact GPS antenna i use. buy with confidence, it works. that said, modern GPS receivers are really good and even most cheap patch antennas will work. just be sure you have enough signal at the actual receiver, given coax loss.

ar-jedi
Link Posted: 10/4/2014 10:50:41 PM EST

ps don't forget that if your antenna is up on your mast or tower, it's coax downlead also needs lightning protection.

ar-jedi



Link Posted: 10/4/2014 11:00:40 PM EST
[Last Edit: 10/4/2014 11:01:34 PM EST by ar-jedi]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By ClingingBitterly:
Dumb question: I use GPS to know where I am and where I am going when traveling. What do you use it for at a fixed location where you already know where you are? Tracking continental drift, or what?
View Quote

a GPS receiver provides a once per second "tick", referred to as 1PPS (one pulse per second).
this 1PPS signal is the result of the atomic clock ensemble aboard each GPS satellite.

due to the satellites relative motion, and a bit of atmospheric hocus-pocus (technical term), there is a bit of jitter (time variation) from one pulse to the next.

but, if you average thousands of these pulses (i.e., over thousands of seconds), you end up up with an astonishingly accurate 1PPS metronome.

this metronome can be used to steer a traditional crystal oscillator into perfect timekeeping, and thus provide a near-atomic reference 10MHz signal.

this process is called "disciplining", where an accurate reference signal is used to constantly correct a less inherently accurate slave signal.

and, hence, the GPSDO -- GPS disciplined oscillator.

a GPSDO marries the excellent phase noise (short term) characteristics of an oven stablized AT cut quartz crystal with the unerring (long term) stability of the atomic clocks orbiting in the GPS satellite constellation. low noise, and no drift -- that's the way i like my reference frequency sources!

ar-jedi

Link Posted: 10/4/2014 11:40:40 PM EST
[Last Edit: 10/4/2014 11:56:33 PM EST by Mr_Harry]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By KwaiChangCaine:


My dad had his Garmin GPS and was comparing it to my Trimble Thunderbolt, and we could not figure out why the altitude readings wouldn't match until we did a little research. To oversimplify, the Trimble Thunderbolt uses raw GPS data and treats the Earth as a perfect sphere, where the consumer GPS units take into account that the Earth is actually an ellipsoid. Had I not found that bit of info I would have believed that my GPS was defective, but now I know how to calculate my exact altitude, which is already built into GPS units made for navigation.

ETA: Where is ar-jedi? I think he's the expert on this stuff. The antenna I'm using is the regular one, but they also make these for use in high RF environments. I bought one but haven't tried it.

http://www.ebay.com/itm/NIB-Lucent-PCTEL-GPS-TMG-HR-26NCM-26dB-Timing-Antenna-N-f-w-Collar-Mount-MaxRad-/361061319907?pt=LH_DefaultDomain_0&hash=item5410ee84e3
View Quote View All Quotes
View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By KwaiChangCaine:
Originally Posted By Mr_Harry:
And it is also Nice to know where you are.


My dad had his Garmin GPS and was comparing it to my Trimble Thunderbolt, and we could not figure out why the altitude readings wouldn't match until we did a little research. To oversimplify, the Trimble Thunderbolt uses raw GPS data and treats the Earth as a perfect sphere, where the consumer GPS units take into account that the Earth is actually an ellipsoid. Had I not found that bit of info I would have believed that my GPS was defective, but now I know how to calculate my exact altitude, which is already built into GPS units made for navigation.

ETA: Where is ar-jedi? I think he's the expert on this stuff. The antenna I'm using is the regular one, but they also make these for use in high RF environments. I bought one but haven't tried it.

http://www.ebay.com/itm/NIB-Lucent-PCTEL-GPS-TMG-HR-26NCM-26dB-Timing-Antenna-N-f-w-Collar-Mount-MaxRad-/361061319907?pt=LH_DefaultDomain_0&hash=item5410ee84e3



Thank you

That is the type I was wanting





Link Posted: 10/4/2014 11:41:42 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By ar-jedi:

a GPS receiver provides a once per second "tick", referred to as 1PPS (one pulse per second).
this 1PPS signal is the result of the atomic clock ensemble aboard each GPS satellite.

due to the satellites relative motion, and a bit of atmospheric hocus-pocus (technical term), there is a bit of jitter (time variation) from one pulse to the next.

but, if you average thousands of these pulses (i.e., over thousands of seconds), you end up up with an astonishingly accurate 1PPS metronome.

this metronome can be used to steer a traditional crystal oscillator into perfect timekeeping, and thus provide a near-atomic reference 10MHz signal.

this process is called "disciplining", where an accurate reference signal is used to constantly correct a less inherently accurate slave signal.

and, hence, the GPSDO -- GPS disciplined oscillator.

a GPSDO marries the excellent phase noise (short term) characteristics of an oven stablized AT cut quartz crystal with the unerring (long term) stability of the atomic clocks orbiting in the GPS satellite constellation. low noise, and no drift -- that's the way i like my reference frequency sources!

ar-jedi

View Quote View All Quotes
View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By ar-jedi:
Originally Posted By ClingingBitterly:
Dumb question: I use GPS to know where I am and where I am going when traveling. What do you use it for at a fixed location where you already know where you are? Tracking continental drift, or what?

a GPS receiver provides a once per second "tick", referred to as 1PPS (one pulse per second).
this 1PPS signal is the result of the atomic clock ensemble aboard each GPS satellite.

due to the satellites relative motion, and a bit of atmospheric hocus-pocus (technical term), there is a bit of jitter (time variation) from one pulse to the next.

but, if you average thousands of these pulses (i.e., over thousands of seconds), you end up up with an astonishingly accurate 1PPS metronome.

this metronome can be used to steer a traditional crystal oscillator into perfect timekeeping, and thus provide a near-atomic reference 10MHz signal.

this process is called "disciplining", where an accurate reference signal is used to constantly correct a less inherently accurate slave signal.

and, hence, the GPSDO -- GPS disciplined oscillator.

a GPSDO marries the excellent phase noise (short term) characteristics of an oven stablized AT cut quartz crystal with the unerring (long term) stability of the atomic clocks orbiting in the GPS satellite constellation. low noise, and no drift -- that's the way i like my reference frequency sources!

ar-jedi




I appreciate all the explanations

I have been doing a lot of reading of the data sheets etc

Link Posted: 10/4/2014 11:56:21 PM EST
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Originally Posted By Mr_Harry:
i have been doing a lot of reading of the data sheets etc
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the canonical source of "why it all works":

http://tf.nist.gov/general/pdf/2297.pdf

ar-jedi
Link Posted: 10/4/2014 11:58:41 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By ar-jedi:

the canonical source of "why it all works":

http://tf.nist.gov/general/pdf/2297.pdf

ar-jedi
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Originally Posted By ar-jedi:
Originally Posted By Mr_Harry:
i have been doing a lot of reading of the data sheets etc

the canonical source of "why it all works":

http://tf.nist.gov/general/pdf/2297.pdf

ar-jedi



Thank you

Link Posted: 10/5/2014 11:03:22 AM EST
[Last Edit: 10/5/2014 11:04:55 AM EST by stimpsonjcat]
I have some 75ohm hardline spec sheet says 4.3db loss per 100ft at 1MHz.

Want 100ft?

Posted Via AR15.Com Mobile
Link Posted: 10/5/2014 11:34:03 AM EST
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Originally Posted By stimpsonjcat:
I have some 75ohm hardline spec sheet says 4.3db loss per 100ft at 1MHz.

Want 100ft?

Posted Via AR15.Com Mobile
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Thank you but I'll pass.

Part of the reason of using the RG-6 is ease of running it.
Link Posted: 10/5/2014 5:30:10 PM EST
You should be fine. We have multiple sites with 30 meter rg59 runs to the gps antennas. They all work well. Except for the fact that some person ordered white coax for a few of the sites and as it fails we replace it with uv stabilized black cable.
Link Posted: 10/5/2014 5:34:44 PM EST
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Originally Posted By Jazzemt:
You should be fine. We have multiple sites with 30 meter rg59 runs to the gps antennas. They all work well. Except for the fact that some person ordered white coax for a few of the sites and as it fails we replace it with uv stabilized black cable.
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Thank you
Link Posted: 10/5/2014 5:35:25 PM EST
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Originally Posted By ar-jedi:

a GPS receiver provides a once per second "tick", ...
...ar-jedi

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Ah Ha. Good concise explanation!

For my purposes I don't see a need for such precision, so I have opted to go with measuring the patterns in melting cheese.

But Chive on!
Link Posted: 10/5/2014 5:38:13 PM EST
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Originally Posted By Mr_Harry:
That is the type I was wanting
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