New Repeater Planned for Grand Junction, CO

[WQWG565]

Hi,

 

I have programed a Motorola Radius GR500 (40 Watt), and am getting ready to run some back yard tests before I put it up on the hill. I'll be using a hand built ground plane antenna on top of a pretty high point (not the highest) in town, should give good coverage, just wondering if there are any tips that anyone has before I go live with this thing.  

 

RX 467.550, and TX 462.550, a PL code will be set, and given out when I figure out what exact one I want to use. This will be a club/emergency repeater.

 

 

[PastorGary]

From previous experience, don't publish the CTCSS or DCS codes here at MyGMRS or locally in your area.  It may be wise to split the input and output tones or codes to help keep unauthorized users from getting in.  I always ued to use a DCS to activate my systems and a CTCSS on the output side. This isn't foolproof because some scanners as well as some radios have the capability to determine DCS or CTCSS - however, unless they are physically near a base station or mobile while that is transmitting into your repeater, they will not be able to catch the repeater input code.

 

Good luck with the system.

[WQWG565]

Thank you!

 

I wasn't planning on posting the codes as I'd like it to be for club use only at this time, and the area is small enough that I don't think there'll be any trouble with the tone in and out being the same--but I think that we may wind up using separate tones in order to buffer out the riff-raff.

 

With any luck, I'll have this up and running within a couple weeks

[PastorGary]

Please keep in mind that as a "club" repeater, each user or user-family must be licensed individually.

 

You can refer to 47CFR95.3 >

§95.3   License required.

Before any station transmits on any channel authorized in the GMRS from any point (a geographical location) within or over the territorial limits of any area where radio services are regulated by the FCC, the responsible party must obtain a license (a written authorization from the FCC for a GMRS system).

[WQWG565]

Thank you I've got a Facebook page that I'm editing, and I'll post that information. Also looking at a website as well All the folks that I know that will be using this system are licensed properly.

 

I appreciate the page you guys run!

 

TTFN

 

WQWG565

[PastorGary]

[zap]

CCR's aren't capable of some of the more prevailing signaling methods…

 

 

Sent from my iPhone using Tapatalk

[ASRM]

This is why I decided to not list tones, instead a person can contact us via myGMRS or part of the local GMRS community that have repeaters up in the area.

 

I am seriously toying with doing MDC1200 as the way to access the repeater if it ever becomes a problem, or just go Part 90, I have a Non-profit I own/run that would qualify if need be.

[WQWG565]

CCR's aren't capable of some of the more prevailing signaling methods…

 

 

Sent from my iPhone using Tapatalk

 

Apologies for my limited knowledge on this, What is a CCR?

[zap]

This is why I decided to not list tones, instead a person can contact us via myGMRS or part of the local GMRS community that have repeaters up in the area.

 

I am seriously toying with doing MDC1200 as the way to access the repeater if it ever becomes a problem, or just go Part 90, I have a Non-profit I own/run that would qualify if need be.

I have a for profit that qualifies me. (Zapped Communications)

 

CCRs are cheap Chinese radios.

 

 

Sent from my iPhone using Tapatalk

[WQWG565]

I have a for profit that qualifies me. (Zapped Communications)

 

CCRs are cheap Chinese radios.

 

 

Sent from my iPhone using Tapatalk

[WQWG565]

LOL! CCR... That makes sense, and pretty funny. I have a yaesu rig in my truck, and the hand helds are the Baofeng uv-5r.

 

I will be setting a RX tone for the repeated, and probably a different pl for the TX of the repeater as mentioned above. I've also toyed with the repeater TXing in the clear with a pl for RX... Probably do that with the next repeater install that I have planned... I've just have to secure another site on top of the mountains to the east now.

 

My future plans for the area include remote areas for hunters, hikers, and other recreational stuff. Just need funding to get things set up.

 

There's no GMRS radio provider in the area at all, so for me, starting a for-profit club is not an issue.

[zap]

Makes sense. I though about "talking" my way onto the tower Custer County SO uses for a QRP repeater. Site has LOS to Monarch pass, Pikes Peak, most of the Wet Mountain valley, Pueblo, the Springs, and possibly Walsenburg. Think I had a design for it at one point that only required a 7W setup on a DB413.

[WQWG565]

Repeater is going to its final home this weekend! I'm building a more robust antenna tomorrow, tuning it, and then enclosing it in PVC. The rig will go on a 15' poll that will be on a 20' tower ~550' above the city on the south side ov the Valley. Just have to get the output PL tone set fully, and the install will be complete.

[WQWG565]

The repeater didn't make it fully up, went online for a bit, then had some issues with the power in the shack. I'll update when it's online again

[WQWG565]

One of the Grand Junction Area Repeaters is online It's only 38' off of the ground, but will serve the area it's in really well. 

 

I have two or three more repeaters planned for the area, Just need to gain interest in the area for more users.

[WQWG565]

Update: I'm moving the repeater to Black Ridge tomorrow. This should provide a lot more coverage for the area as the radio will be 2,847 feet above the average terrain.

 

I'll keep this thread updated.

[WQWG565]

After having the repeater on Black Ridge for a couple days, we realized that we needed a Notch Filter in order to communicate further than 5 miles from the repeater location. All the Broadcast equipment on the site was numbing the receiver really bad. So today I was able to get the repeater 100' above the average terrain, and it is now online and running.

[n4gix]

So the repeater was moved off the mountain? The antenna is at 100' AGL now? That will give about 15 miles LOS average.

[WQWG565]

It's up higher, I put the wrong calculation in.... It's more like 250 AAT. Still testing distance, but it's shooting way over 15 miles. I'm able to hit Mile Marker 64 on I-70 from its location on the map. The repeater is WCG1.

 

Will follow up with real world test results in the coming weeks.

[coryb27]

So the repeater was moved off the mountain? The antenna is at 100' AGL now? That will give about 15 miles LOS average.

 

My repeater is only a 150 AGL and I get a solid 45 miles in all directions, not sure why 100' would only give 15 miles LOS? I am getting almost 15 miles of HT coverage. From experience, if you have a decent repeater, good cable, quality antenna 100' of the ground and only see 15 miles something is wrong. I would have to estimate 25+ depending on terrain and type of equipment your using to work the repeater.

 

Just my $.02

 

Corey 

[WQWG565]

For this area the repeater serves the down town area great. The valley isn't too long, so even a 15 mile range would be just fine.

 

The feedback is greatly appreciated

[n4gix]

Corey, line of sight (LOS) calculation is nothing but the math of physics. It is a geometrical formula that determines the distance at which the tips of the antennas have a clear, unobstructed path between them, assuming no other man-made or natural obstructions.

 

The actual LOS could be much less, but never more! The earth is round after all. It would be so much simpler had the earth been flat... <snicker>

 

Rather than bore folks with the complex math, here is a screen clip of an LOS calculator. I was a bit low because I was relying on my faulty memory. The actual LOS is more like 17 miles. Note that this assumes that the receiving HT or mobile has an average height of 6'.

http://puu.sh/nNq9k.png

Screen clip courtesy of http://www.hamuniverse.com/lineofsightcalculator.html

 

Now LOS is not an absolute predictor of actual propagation distance, as your observations illustrate. LOS assumes nothing is in the way of the radio signal between the antenna and the horizon at a chosen height above ground. It does not take into consideration any attenuation caused by weather, band conditions, antenna gain, path loss, or other factors such as dB loss in coaxial cable.

 

Likewise it doesn't consider any favorable circumstances such as signal refraction, reflection, or tropospheric scattering. Nonetheless, the physics and geometry do provide a solid basis for best case performance.

 

By the way, the actual LOS calculated for your 150' AGL is 20 miles. So your "guesstimate" of 25 miles is reasonable. Keep in mind that the higher the repeater's antenna, the more it is likely to "shoot over obstructions".

 

One neat site for generating a predictive propagation map is found here: http://www.ve2dbe.com/rmonline.html

As indicated on the Radio Mobile Online website, it uses digital terrain information and a mathematical model to simulate radio transmissions between two fixed sites or between a fixed site and a mobile. The digital terrain information comprises three databases: ground elevation, land cover, and population density, which combined total 200 GB of information.

 

Since the site is in French, a good English set of instructions may be found here: http://ham.stackexchange.com/questions/1921/how-do-i-make-a-rf-propagation-map-for-a-repeater

 

Here is a screen clip from there for my repeater. I've been using this map as I drive around the area making tests. I've been very conservative in my estimates, figuring it's better to be surprised than disappointed...

 

One thing is immediately clear from this. I really should have a more directional antenna with the azimuth aimed southwest. I'm "wasting" a lot of my system towards the northeast and the bloody lake!

http://puu.sh/nNs9N.jpg

[coryb27]

Corey, line of sight (LOS) calculation is nothing but the math of physics. It is a geometrical formula that determines the distance at which the tips of the antennas have a clear, unobstructed path between them, assuming no other man-made or natural obstructions.

 

The actual LOS could be much less, but never more! The earth is round after all. It would be so much simpler had the earth been flat... <snicker>

 

Rather than bore folks with the complex math, here is a screen clip of an LOS calculator. I was a bit low because I was relying on my faulty memory. The actual LOS is more like 17 miles. Note that this assumes that the receiving HT or mobile has an average height of 6'.

http://puu.sh/nNq9k.png

Screen clip courtesy of http://www.hamuniverse.com/lineofsightcalculator.html

 

Now LOS is not an absolute predictor of actual propagation distance, as your observations illustrate. LOS assumes nothing is in the way of the radio signal between the antenna and the horizon at a chosen height above ground. It does not take into consideration any attenuation caused by weather, band conditions, antenna gain, path loss, or other factors such as dB loss in coaxial cable.

 

Likewise it doesn't consider any favorable circumstances such as signal refraction, reflection, or tropospheric scattering. Nonetheless, the physics and geometry do provide a solid basis for best case performance.

 

By the way, the actual LOS calculated for your 150' AGL is 20 miles. So your "guesstimate" of 25 miles is reasonable. Keep in mind that the higher the repeater's antenna, the more it is likely to "shoot over obstructions".

 

One neat site for generating a predictive propagation map is found here: http://www.ve2dbe.com/rmonline.html

As indicated on the Radio Mobile Online website, it uses digital terrain information and a mathematical model to simulate radio transmissions between two fixed sites or between a fixed site and a mobile. The digital terrain information comprises three databases: ground elevation, land cover, and population density, which combined total 200 GB of information.

 

Since the site is in French, a good English set of instructions may be found here: http://ham.stackexchange.com/questions/1921/how-do-i-make-a-rf-propagation-map-for-a-repeater

 

Here is a screen clip from there for my repeater. I've been using this map as I drive around the area making tests. I've been very conservative in my estimates, figuring it's better to be surprised than disappointed...

 

One thing is immediately clear from this. I really should have a more directional antenna with the azimuth aimed southwest. I'm "wasting" a lot of my system towards the northeast and the bloody lake!

http://puu.sh/nNs9N.jpg

 

 

Here is a link to mine http://chainolakesgmrs.org/chain/ I have the interactive map hosted on the repeaters web site. I have found this to be vary close to real world experience as i have tested extensively. I totally understand how LOS works but it does not take into account HAAT this is why you will always see diffrent performance in the real world. Not only has this been true for my GMRS repeater but my multi site UHF business system as well. My 150' AGL tower has an HAAT 332', this is why i can work it just fine 40 plus miles away without any issues.

[WQWG565]

I'm going to be using these links for sure! Thank you for all the valuable information!