zap

You can. There's nothing that says you can't in the current revision of the rules, most today are primarily focusing on internet linking though. In this case, it sounds like a good old fashioned (still see it occasionally today) RF link would be the best option. To sum up the Repeater Builder site on RF linking, there are 3 basic types of links. Point to point (simplex), half-duplex (shotgunning), and full duplex (link repeaters). In a point to point link, repeaters are linked through a link radio on each repeater. The radios run simplex (often with split PL/DPLs). When on repeater is keyed, it keys the link radio which sends a PL/DPL that only the other link radio receives, keying that repeater transmitter. The downfall to a point to point system, it can't be expanded to any more than two repeaters and it's questionable for use on GMRS the way the rules are currently laid out. Next is shotgunning where a link radio simply transmits on the input/output of the next repeater. You start out with a "hub" which is just a basic repeater. The next repeater's link radio transmits on the hub's input and listens to it's output. You continue like this down the line (wouldn't recommend it for more than about 2 or 3 hops). The finial link setup is a full duplex system. Basically it's another repeater…just for linking. Every site consists of a local repeater and a link repeater. The link repeaters run at 100% duty. They use PL detect to keep from keying the local repeaters. The benefit to the first and last setups, they are band independent. You could use a common link band (say 900 MHz, 420 MHz, 220 MHz, etc) for all of the link radios where the shotgunned link radios have to be on whatever band the next repeater down the line towards the hub is. However, shotgunned is the most applicable method in terms of staying within the confines of the rules in Part 95A. So, you generally need a controller that will handle links such as the NHRC 3.1, NHRC 4 and up, Electra 2000, RC2103, etc. so you can turn the link on and off, a link radio (1-5W with a yagi antenna is generally plenty), and a repeater. It is important to take into consideration power consumption (may want to make the off-grid repeater the hub), and the fact you will need separation between the repeater's antenna and the link radio's antenna. The Repeater Builder site has a good page about off-grid repeaters. It's a good read if you haven't read it yet. http://www.repeater-builder.com/tech-info/solar-power-thoughts.html

What antenna did you get for your repeater? I'm still working through a pile of surplused dB antennas so I haven't had to purchase one yet. Sent from my iPhone using Tapatalk

You don't. You either sacrifice the widebanded-ness for something like a Larsen nmo2/70 or go to something like a Larsen NMO150WB (wideband vhf 5/8 wave) and a wideband uhf antenna. I live in an extremely flat area. Storm chasing, never needed an antenna with gain. Our skyward guys have a decent uhf link system. Covers something like 10 counties. Sent from my iPhone using Tapatalk

MLPV430 About a few inches smaller than a 1/4 wave 450-470MHz antenna. http://tapatalk.imageshack.com/v2/15/01/20/88f265ff22f14183171c7ff060ecf318.jpg Sent from my iPhone using Tapatalkhttp://tapatalk.imageshack.com/v2/15/01/20/377bf22c55c00fc06f5cd17c3133d971.jpg

I actually have two (if you want to really get into the reasoning of why that particular antenna is installed where it is)…the other was on my Trailblazer, on the roof. One night I was coming down a dimly lit city street and hit the antenna a little more than half way up on a low hanging tree branch traveling roughly 15 MPH, which is frankly slow to me. By then, the damage was done. The antenna had actually pulled the NMO mount out of the roof of the vehicle. Notice now, Comet sells a spring for that antenna. I guarantee you I'm not the first one who has pointed out to them (out of first hand experience) that the antenna they market as a Search and Rescue antenna, is way too stiff to be useful in a real Search and Rescue environment. They may have also been looking like they were facing several lawsuits. Back to the antenna being on my Trailblazer. While it was on the roof, I actually took the time to hook the antenna up to an analyzer and the results I got, are what I quoted in my previous post. Now back to where that antenna happens to be on my Jeep. I'm not sure if you've ever spent a lot of time in heavily wooded areas, especially driving vehicles through them, but you're always gonna hit antennas on something. After witnessing what happened to the roof of my daily driver, I carefully picked a mounting location that would both be sturdy enough for that antenna (until I found a different antenna solution that would suit my bandwidth needs). So I chose to sacrifice some signal to mount the antenna on something much more sturdy than the roof. I might also add, the only current use for that VHF 1/4 wave antenna on the roof of that Jeep, is for an APRS tracker I have in that Jeep. Here is another interesting little tit bit to look at. A quarter wave antenna (VHF or UHF) cost roughly $5-12 (or I can even get a Larsen NMO150WB for $30). My wideband UHF knobs, $30. The last CA2x4SR I bought cost roughly $75. However, if roof mounted, the CA2x4SR can cost you several hundred dollars at a body shop if one was to hit the antenna on something in the right spot. For the other options, you'd be worrying about dragging the roof before you ever even considered the antennas doing damage to the roof from snagging on something. That is the primary difference between commercial antennas and amateur antennas. Commercial antennas are designed to take a beating through a parking garage, in the woods, over rough terrain, even survive a roll over. You break a base, you can usually buy a base without buying a new antenna. You snap a whip, you can generally get another for less than $10. You just don't get that kind of quality out of an amateur antenna, and you definitely don't get that out of the 2x4SR.

The I have one on my Jeep and had one on my Trailblazer. They work as advertised as far as bandwidth goes but that's really the only good thing I have to say about them. I've never noticed one outperforming a 1/4 wave antenna and they aren't built to what I would call commercial standards. In fact for a while I actually switched to a Austin 500C (highly recommend that antenna but UHF is only about 10 MHz wide...after consulting with Richard he didn't think he could build one with enough UHF bandwidth to cover both 70 cm and GMRS) an noticed no change, especially on the VHF bandwidth. I don't see much of a point in DX'ing UHF FM. 10 miles simplex is more than adequate for me, especially for any simplex family road trip GMRS activities one might be doing. The only difference I've noticed between a common 5/8 over 5/8 and my little PCTEL knob is about 1/2 mile less repeater usage over flat terrain. I just run a regular Larsen NMOQ for VHF on my DD. For UHF I run this. http://www.hol4g.com/ac/product.aspx?number=MAX-BMLPV430&p=164550&sc=3566 My XJ currently has a CA2X4SR...it's okay. Working on moving over to the PCTEL and a NMO150WB where the Comet is. I may move the APRS tracker over to the 150 and then just run the Sti-Co quarter wave being used for ARPS for my VX-4000. Most current pics I have of the Jeep (has a Larsen NMO-Q with spring instead of the Sti-Co). http://i1245.photobucket.com/albums/gg586/zap_uh_lack/536357ED-81D3-4249-BA0A-D791BABD1506_zpszce0jkwz.jpg http://i1245.photobucket.com/albums/gg586/zap_uh_lack/3eb1317a-26f5-4207-befd-ae5ed1640f7f_zps0c093522.jpg

That's a nice looking antenna pastor. I have a friend who may want a handful of those for his tractors since some of them don't have the OEM business band option.

And there's a whole nother level of fun. New Mexico has some of the best wide area coverage 2m repeaters in the country. One up there on Sandia (the non-ML one, think it has a 100 hz pl) easily covers 100+ miles towards the west.

Not entirely accurate. You don't have attach an antenna on a fiberglass body to the metal chassis, especially with above 136 MHz communications. There are options such as no ground plane antennas (half-wave, matched antenna) which offer Unity gain without a ground plane as well as ground plane kits for running ground plane dependent antenna. Antenna placement on the roof of a vehicle isn't as important as most people think, as long as there is a quarter wave of ground plane (sheet metal) in all directions and you can get it as high as practically possible, you're golden.

Technically a full wave isn't naturally resonant (needs a matching coil). I've found very little difference between 1/4, 5/8 wave, and 5/8 over 5/8. Very little difference between 25 and 45 Watts too. I run a PCTEL wideband knob (it's almost a 1/4 wave long) as I use my radio on 3 different services.

Somewhere, one of my friends has a 40W, 90/95A Midland radio from the 90's. It was miles ahead of the GM300 (for the same price point as what I remember) as far as the display goes…but I can't find the software nor programming cable anywhere.

Will do.

Nope. Haven't heard anything on the outputs that isn't traffic through the repeaters.

Hello David, I'm not too terribly far from you in Lubbock. I actually am supposed to be in Albuquerque in the next few weeks for work (working weekend that ends in a day or two on the slopes). I cover West Texas and parts of New Mexico (really whatever I can fit in).

If you're just using a chinese radio for UHF...I'd highly recommend the a UHF antenna for the Motorola Jedi series of radios. It's a 3-4 dB improvement off the bat.

Ignore my post about the GE Mastr II and GE Custom MVP...those are rock bound rigs. I may also point out, some of the PC programmable radios mentioned on this website (nearly any radio made prior to 1999) will require a DOS computer and a real serial port to program. Also, be careful with some radios as there are a few that had computer software that initially programmed in DOS and the later revisions programmed in Windows (the RSS for the Motorola M1225 for example, Versions 1 and 2 are DOS based where 3/3.2 and 4 were Windows based). Some of the Kenwoods (TK-x80 for example) have multiple Versions (firmwares). Version 1 requires a DOS based software and Version 2 a Windows based software.

Have you tried the radio through a different antenna? I've seen a few of the UV5R radios with just bad antennas...

I have a post some where on here with a graph of how duty cycle (stated from the service manuals) relates to power output. I used both Motorola Radius (M1225, SM50/120 have the exact same stated specs in their service manuals) and GE Custom MVP. I figured is add in using active cooling later when I felt like calculating the general thermodynamics. Might be worth merging the two threads. Shows the three common power splits for the motos, 1-10, 10-25, 25-40/45. Note, the 1-10W radios can actually handle a 100% duty below 4W. They are the most inefficient of the three but my math was actually backed up by the service manual.

Know what radios you're planning on using? Know if you will be using a single antenna or dual antennas? Do you know where the planned location for your repeater will be? One thing to take into consideration, what kind of use are you expecting? Heavy, light, occasional check-in's, etc. If your going with a mobile base that can often dictate the power output you can run.

I've got one somewhere…never have hooked it up or tested it. I'm not a fan of how it mounts though (see antennas mounted in a flimsy collar at the base of the antenna fold over all the time). Not a huge fan of Comet mobile antennas but I have a few and they do work as advertised. You may want to do a little reading up on dB, path loss, and most importantly, dBi versus dBd. Radio Mobile is a good program to test repeater performance based on location and what not.

A couple of things. Hold off on that antenna. If the $97 buy now should give you an idea of the reserve. For that you can nearly look at new antennas. (I'll post some links below). The RG-8X is not the best feed line to use, but it'll work. Attenuation at 450 MHz is about 4 dB per 100 ft. (Similar to RG-213). 1/2" hard line would be better but it's pricey. Attenuation at 450 MHz is 1.45 dB per 100 ft ( $2.69 /foot ) but the connectors are a little more expensive. When you're dealing with repeaters…site and antenna are the most important things. Then comes loss in feed line and connectors. Try and get as much stuff with N connectors as possible (less loss than UHF connectors). Not all antennas are built equally. Some focus radiated energy above the horizon line of the antenna but that is only good if your antenna is sitting at the bottom of a valley and you're on the slopes. Antennas which radiate downwards work best for high places (look for antennas with counterpoises sloped downwards or none at all). Here's a small gain antenna for nearly the "buy now" price of that other. http://www.hol4g.com/ac/product.aspx?number=CTC-BS450SN-C&p=190651&sc=3563 This one is another $50 more (if you have a Tessco account it's $157.85). I actually have one of these…not a bad little antenna. https://www.tessco.com/products/displayProductInfo.do?sku=89263&eventGroup=4&eventPage=1 Here's another place to look. Personally I'd avoid antennas under $100. http://www.theantennafarm.com/catalog/antennas-191/base-antennas-193/commercial-base-antennas-258/omni-directional-antennas-976/380-525-mhz-uhf-antennas-250/uhf-omni-directional-ant-1096/

Sounds like an old com-spec pl board I found in a junk like (that works) that I'm probably going to interface to a Micor I'm putting up at a friends farm so him and his family can have a business like radio system. Sent from my iPhone using Tapatalk

I've noticed some differences in power outputs on some of the Chinese stuff but haven't gotten my hands on the TYT mobiles. Which wattmeter are you using?

I'm pretty much in the same boat as far as age and family situations go (except my daughter is due in February). I started off as a ham…then got into GMRS (I probably use GMRS more than I do anything else FM). Repeaters are fairly simple. Receiver, transmitter, controller (optional depending on setup), cables to interconnect everything, a duplexer and antenna (or two antennas to remove the duplexer from the equation). A lot of people here tend to start out with mobile based repeaters. A couple of UHF surplus radios and some stuff to interconnect them. If you have some extra UHF commercial gear, you may want to consider keeping those at first.

Unfortunately for GMRS…you can't rely on the honesty system like you can with amateur radio. Just a sad truth of GMRS.