Posted: 9/28/2015 3:18:58 PM EDT
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The wife and I have talked numerous times about having some alternate emergency communications, since I don't expect she will go ham, plus my daughter and brother and their families won't either, GMRS was my next logical step. THis is our SHTF for communications.
I took the plunge and ordered a 1 - Vertex VXR-7000 50 watt repeater and duplexer 2 - Motorola Astro Saber Walkie's for the wife and I (I need to find the post on batteries for the Sagers, would love to find a convertacom) 3 - Motorola CMD1225 20 watt 20 ch units, one will be a base unit, the others will go in the SUV's I am not loaded so that investment alone was a bit, I plan to mount the repeater on the eve of the house on a 20-30 foot mast, the effect hight will be about 40' above ground level, but I sit on one of the tallest parts of my county overlooking the metro area which is 3-4 miles away, where I work is 4 miles away, all flat, wife will be about 6 miles at her place of work. Remembering how my old repeater worked on a 60 foot tower with a 12db omni Sinclair, I got 12miles solid radius handheld. I am going to use a Comet 9db antenna so my coax run will be 40 foot into the attic, my question is what type of coax can I get by with, or should use, I figure the 40 foot is pretty much a no biggy on line-loss for the most part, but know I need to squeeze everything I can due to my height limits. I am going to mount a small 5db omni for the control station, mainly to access the other 6 repeaters in my area to help extend my coverage when in bad zones or on the edge. Also simplex for around the property. I do plan to get a 60-80 foot tower up when funds allow or I can find a location to mount it higher, but just excited to get started, if I can garner 10 miles solid walkie and 15 mobile I will be thrilled. Any tips appreciated. |
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...my question is what type of coax can I get by with, or should use... emphasis mine. Buy the Best you Can Afford! LMR400 @ 50' Cable Run Attenuation: 1.4 dB RG8 @ 50' 2.3 Fo Time, all about Coax Coax Loss Calculator link |
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emphasis mine. Buy the Best you Can Afford! LMR400 @ 50' Cable Run Attenuation: 1.4 dB RG8 @ 50' 2.3 Fo Time, all about Coax Coax Loss Calculator link Quoted:
...my question is what type of coax can I get by with, or should use... emphasis mine. Buy the Best you Can Afford! LMR400 @ 50' Cable Run Attenuation: 1.4 dB RG8 @ 50' 2.3 Fo Time, all about Coax Coax Loss Calculator link Thanks, agreed, I don't want to skimp, will look over and get some ordered, forgot to ask connector type on repeater, I know the antenna's. |
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LMR-400 bare minimum. Hard line if you can get it for the right price. Bigger is always better with repeaters. And make sure the duplexers can handle the power that your putting into them (the cellwave and other mobile duplexers tend to only be rated around 25 watts). Get pass/notch cans if you can find them for a good price.
Have the duplexers tuned by someone with a service monitor/tracking generator. Make sure the antenna covers the GMRS band. ETA- If your base antenna is going to be near the repeater antenna I would put a circulator in as well. A quality preamp can't hurt either... |
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2 - Motorola Astro Saber Walkie's for the wife and I (I need to find the post on batteries for the Sagers, would love to find a convertacom) Any tips appreciated. AWESOME way to jump in For the life of me I can't find the thread where we discussed saber batteries - I thought it was this thread at first: http://www.ar15.com/forums/t_10_22/682158_Commercial_non_ham_radios___post_up_your_collection.html But now I'm pretty sure it was another.... |
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LMR-400 bare minimum. Hard line if you can get it for the right price. Bigger is always better with repeaters. And make sure the duplexers can handle the power that your putting into them (the cellwave and other mobile duplexers tend to only be rated around 25 watts). Get pass/notch cans if you can find them for a good price. Have the duplexers tuned by someone with a service monitor/tracking generator. Make sure the antenna covers the GMRS band. ETA- If your base antenna is going to be near the repeater antenna I would put a circulator in as well. The repeater will have a duplexer, not sure of the brand, but the people I am purchasing from seem reputable, used-radios.com out of Aurora Colorado, they said it was rated for the repeater, yes they will tune it, I am looking and your right, lot of stuff that is dual band, more 2m70cm stuff. I checked the Comet Comet GP-9NC is a dual band 11 DB covering 460-470 with a 1.5 SWR for around $219 The other I am leaning towards is the Comet CA-712EFC single band 460-470 with a 1.5 SWR for around $129 What is a circulator? I will have about 20-30 feet of separation from the antenna. Would some type of metal shielding work for RF bleedover? I will look into the LMR-400, I know once I go "big time" with a tower I will go the hardline route, I don't remember what I had on my old setup in the 80's, but a 25 watt Uniden, on a 60 foot tower and a 12 bd Sinclair was one kicking system, sadly it was lost in a fire. I am stoked though, this has been a long time in the planning. This will probably spur me on to getting my ham ticket, much to my wife's dismay I bet, just one more hobby... |
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AWESOME way to jump in For the life of me I can't find the thread where we discussed saber batteries - I thought it was this thread at first: http://www.ar15.com/forums/t_10_22/682158_Commercial_non_ham_radios___post_up_your_collection.html But now I'm pretty sure it was another.... Quoted:
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2 - Motorola Astro Saber Walkie's for the wife and I (I need to find the post on batteries for the Sagers, would love to find a convertacom) Any tips appreciated. AWESOME way to jump in For the life of me I can't find the thread where we discussed saber batteries - I thought it was this thread at first: http://www.ar15.com/forums/t_10_22/682158_Commercial_non_ham_radios___post_up_your_collection.html But now I'm pretty sure it was another.... It was that thread, I have't visited it in a while, I am total jelly now, there is some decent looking gear! Battery Post |
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Re-think using LMR-anything for repeater use.
The below excerpt was taken from Repeater-Builder.com ..."In duplex service you want to avoid any coax that has dissimilar metals rubbing against each other (such as Belden 9913) or any LMR-(any 3-digit or 4-digit number) cable since both use an aluminum foil shield rubbing against a copper braid (and they are not the only ones with that type of construction). In a coax cable any dissimilar metals in contact with each other are bad news. Aluminum oxide is formed when raw aluminum is in contact with oxygen, and the chemical reaction that converts the top few molecules of the exposed surface of aluminum into aluminum oxide is almost instantaneous. Aluminum oxide makes a dandy diode. All those millions of contact points between the copper braid and the aluminum oxide layer on the aluminum foil become millions of little tiny diodes. In the presence of high RF power levels all those little diodes cause RF noise. The amount of noise energy on any one frequency (such as on your repeater input frequency) is a low level, but when you have the noise source inside the same feedline that feeds a sensitive receiver it doesn't take much level to be audible."... |
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Go with a Hardline coax if you want to get the best out of the system. Also make sure to use N type connectors to minimize losses at this UHF frequency range. I can't give you any advise on the rest of the system because I don't have enough experience with GMRS.
Please post some details and take pictures as you build your repeater system. |
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I had to look up what hardline was, that was what I used back in the 80's, wantr to say mine was 1/2" Heliax.
I think all the connectors are N-type. GMRS can be 50 watts, the repeater is 50, mobiles I went the 20 watt route since I will be pretty close to the repeater, 10 miles usually or less. Thanks for the insights, now to locate some 1/2" hardline for the repeater, from Repeater-Builder, sounds like I can run with the LMF since that will be simplex and is only a 30 foot run for the base unit. |
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It was that thread, I have't visited it in a while, I am total jelly now, there is some decent looking gear! Battery Post Quoted:
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2 - Motorola Astro Saber Walkie's for the wife and I (I need to find the post on batteries for the Sagers, would love to find a convertacom) Any tips appreciated. AWESOME way to jump in For the life of me I can't find the thread where we discussed saber batteries - I thought it was this thread at first: http://www.ar15.com/forums/t_10_22/682158_Commercial_non_ham_radios___post_up_your_collection.html But now I'm pretty sure it was another.... It was that thread, I have't visited it in a while, I am total jelly now, there is some decent looking gear! Battery Post yep there was another post with pictures of the exact ones to get also |
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Re-think using LMR-anything for repeater use. The below excerpt was taken from Repeater-Builder.com ..."In duplex service you want to avoid any coax that has dissimilar metals rubbing against each other (such as Belden 9913) or any LMR-(any 3-digit or 4-digit number) cable since both use an aluminum foil shield rubbing against a copper braid (and they are not the only ones with that type of construction). In a coax cable any dissimilar metals in contact with each other are bad news. Aluminum oxide is formed when raw aluminum is in contact with oxygen, and the chemical reaction that converts the top few molecules of the exposed surface of aluminum into aluminum oxide is almost instantaneous. Aluminum oxide makes a dandy diode. All those millions of contact points between the copper braid and the aluminum oxide layer on the aluminum foil become millions of little tiny diodes. In the presence of high RF power levels all those little diodes cause RF noise. The amount of noise energy on any one frequency (such as on your repeater input frequency) is a low level, but when you have the noise source inside the same feedline that feeds a sensitive receiver it doesn't take much level to be audible."... That is something I didn't know. Good info! Learn something every day! 1/2" hardline or bigger would be ideal. Just setup a new site both commercial and ham on some 7/8".... N connectors are a must. With hardline you would need DIN to N. DIN connectors are what are common for hardline. PL259/SO239 are only acceptable for lower frequency applications as they are NOT 50 ohms. I will not use SO239 for anything above HF. GMRS falls under part 95 certs... So yes, most moto gear does not meet it's requirements. Now.... would anyone know that something that is part 90 is not part 95 without looking at the equipment? Nope... Now, setting up a system without a service monitor and letting it splatter all over the place due to not being tuned correctly......................................................................................................................................... |
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Not be a dick, but is it legal to use astro sabers on GMRS? Is there a type acceptance thing with GMRS? Technically, it isn't part 95 certified. https://fccid.io/AZ489FT4782 Is anyone going to give you problems? Probably not, but there's always the possibility. |
Yeah, I did some digging, posters are right 
Will still run it since my opinion is it is probably tighter than the Chinese gear, when I worked for a radio shop we ran part 90 on GMRS since carrying 2 portables or having 2 UHF mobiles didn't make sense. Ordering the hardline today, I want to say the antenna and the repeater out are type-n female connectors. The base unit I may just use RG214 |
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[snip] With hardline you would need DIN to N. DIN connectors are what are common for hardline. [snip] Andrew, and others I'm sure, make N connectors for 1/2" LDF4-50 (Heliax). I've only seen DIN on the larger stuff, like the 1-5/8" we use on cell sites. |
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Andrew, and others I'm sure, make N connectors for 1/2" LDF4-50 (Heliax). I've only seen DIN on the larger stuff, like the 1-5/8" we use on cell sites. Quoted:
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[snip] With hardline you would need DIN to N. DIN connectors are what are common for hardline. [snip] Andrew, and others I'm sure, make N connectors for 1/2" LDF4-50 (Heliax). I've only seen DIN on the larger stuff, like the 1-5/8" we use on cell sites. I've got a few for 1/2" some where. DIN is the new N…that is all. |
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Yeah, I did some digging, posters are right
Will still run it since my opinion is it is probably tighter than the Chinese gear, when I worked for a radio shop we ran part 90 on GMRS since carrying 2 portables or having 2 UHF mobiles didn't make sense. Ordering the hardline today, I want to say the antenna and the repeater out are type-n female connectors. The base unit I may just use RG214 The Saber III and Systems Saber's were 90/95A accepted. Back in the late 80's pretty much every manufacturer's UHF radios had 90/95A acceptance. Of course, the 1225 line also has that acceptance. I love my Astro Sabers but personally I wouldn't bother tracking some down for GMRS. Reason being, currently no digital is allowed on GMRS (not saying that it isn't being done) but I think DMR would be the format winner of that if it was allowed (since it allows for rapid, exponential expansion of the service). Just me though. On another, AVA and battery, note. The Lithium Ion batteries mentioned in the thread will not charge in a AVA. You need the next size smaller battery to work with an Astro Saber (1100 mA I believe). |
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The Saber III and Systems Saber's were 90/95A accepted. Back in the late 80's pretty much every manufacturer's UHF radios had 90/95A acceptance. Of course, the 1225 line also has that acceptance. I love my Astro Sabers but personally I wouldn't bother tracking some down for GMRS. Reason being, currently no digital is allowed on GMRS (not saying that it isn't being done) but I think DMR would be the format winner of that if it was allowed (since it allows for rapid, exponential expansion of the service). Just me though. On another, AVA and battery, note. The Lithium Ion batteries mentioned in the thread will not charge in a AVA nor will the AVA lock with an Astro Saber (Saber yes, Astro Saber no). You need the next size smaller battery to work with an Astro Saber (1100 mA I believe). Quoted:
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Yeah, I did some digging, posters are right
Will still run it since my opinion is it is probably tighter than the Chinese gear, when I worked for a radio shop we ran part 90 on GMRS since carrying 2 portables or having 2 UHF mobiles didn't make sense. Ordering the hardline today, I want to say the antenna and the repeater out are type-n female connectors. The base unit I may just use RG214 The Saber III and Systems Saber's were 90/95A accepted. Back in the late 80's pretty much every manufacturer's UHF radios had 90/95A acceptance. Of course, the 1225 line also has that acceptance. I love my Astro Sabers but personally I wouldn't bother tracking some down for GMRS. Reason being, currently no digital is allowed on GMRS (not saying that it isn't being done) but I think DMR would be the format winner of that if it was allowed (since it allows for rapid, exponential expansion of the service). Just me though. On another, AVA and battery, note. The Lithium Ion batteries mentioned in the thread will not charge in a AVA nor will the AVA lock with an Astro Saber (Saber yes, Astro Saber no). You need the next size smaller battery to work with an Astro Saber (1100 mA I believe). Thanks on the Saber lesson, I do like the style of them, I figured it would be my first weapon before I pulled my CCW  More truth in that from a conversation I had once with a cop at the radio shop.
Thanks on the battery tip 
I found out the old radio shop I worked for in the 80's was bought out by some younger guys, going to take a trip down tomorrow and see if he has any 5/8 hardline he can sell me, he was going to see if he had any used antenna's they have taken out of service, I know the PD went to 800 so they had old UHF antennas all over town. |