coryb27

Antenna “Gain” might reduce your S/N ratio, especially in the case of a directional antenna, because you will be receiving less noise and competing signals. But, it will not impact the signal strength of the desired signal. In the case of an omni directional antenna, the impact is really minor since you really don’t hear much fromdirectly overhead or below the antennna.

I guess everything I have ever learned is wrong, guess I should sell my Areoflex and Sitemaster.

Check with member "Corey" - He may have some info on systems networked in several states, including some in parts of Indiana.

For what reason? The 420 is already a great antenna, I can't electrically see any benefit to phasing two of them together.
 
Corey

For the price of that you can get a way better repeater. I purchase Motorola MTR2000's in the 100W full duty cycle version for 600 all day on ebay and run them at 50W. We use 7 of them on our GMRS network, and I have 4 more in the garage looking for sites. You can not go wrong since these devices have been used on public safety and commercial trunking systems for years and are still in use today. Great equipment for the money.

For the price of that you can get a way better repeater. I purchase Motorola MTR2000's in the 100W full duty cycle version for 600 all day on ebay and run them at 50W. We use 7 of them on our GMRS network, and I have 4 more in the garage looking for sites. You can not go wrong since these devices have been used on public safety and commercial trunking systems for years and are still in use today. Great equipment for the money.

For the price of that you can get a way better repeater. I purchase Motorola MTR2000's in the 100W full duty cycle version for 600 all day on ebay and run them at 50W. We use 7 of them on our GMRS network, and I have 4 more in the garage looking for sites. You can not go wrong since these devices have been used on public safety and commercial trunking systems for years and are still in use today. Great equipment for the money.

scan on the low side(462.xxxx) w/no pl tone.

Neither. the concept of fixed is really orthogonal to the temporary/permanent axis. Of course, philosophically speaking, everything is temporary. However, there is a clear difference between in motion and not-in-motion. Clearly a repeater cannot be used while in motion. In this case I'd take fixed to mean it will remain stable at its location while it is supporting whatever activity it is designed to support. When that ceases, it will move on.  
Probably the edge case would be a mobile repeater that was only turned on when the vehicle in which it was mounted was parked. I.e. not in gear and the parking brake set. Such might be the case for some kind of shopping trip, treasure hunt, etc. I'd ague that was also fixed, since it did not move while operating.
 
In any case. I suspect on the FCC's enforcement priorites list, tracking down borderline "fixed" repeaters ranks slightly below use of Part-90 equipment on GMRS.

I've said it before and I'll say it again, you can't do a vehicle-installed repeater. Repeaters must not be capable of operating while moving, and cannot have a mobile operation mode. It's written in the Part 95 definition of a repeater station. They must operate at a fixed position. The specifics of what defines a fixed station is a question I'm trying to raise to the FCC's attention.
 
There's no spectrum entering or leaving GMRS. Consider frequency availability in the cities. Public safety is still building out on T-band here around Los Angeles because there is no spectrum available on 700 MHz, 800 MHz, or 450-470 MHz. Frequency reuse on those three segments is intense. Likewise, there's a lot of frequency reuse and congestion on GMRS, and coordination is necessary to protect against interference. In the suburbs out of the coverage areas of the cities, GMRS appears unused. Likewise, T-band and 800 MHz also appear unused. That doesn't mean there aren't any users. You just can't hear them, especially from ground-level. FRS users can exit receive range after a few thousand feet; low-level repeaters typical of private use can exit range in a few miles. Same goes for simplex or building-mounted repeaters in Part 90. The FCC won't deallocate 452.600 because they didn't hear anyone at their Denver field office in the last 25 minutes. For that same reason, they won't deallocate 462.600.
 
Since there's already a lot of Part 95 462/467 MHz equipment out there in a poorly regulated (relative to Part 90) fashion, getting FRS and GMRS users to stay off those bands would be impossible. Removing FRS or GMRS would also kill an industry of unlicensed two-way radio manufacturing (which is a bigger industry than you think), threaten emergency preparedness for what is easily hundreds of thousands of people, and provide very, very little benefit to the FCC. Trying to change the service to illegalize the operating modes of the existing radios is too monumental a task, and is one of the reasons why FRS gained the 8 repeater output channels. The pressures of the license-by-rule system on FRS and fixed channel set of GMRS would actually favor expansion of the band over contraction.
 
Setting up a bunch of repeaters blindly across all 8 channels just creates a bunch of interference for the other licensed users of the bands. Just because a repeater is open doesn't mean it isn't interference. This applies moreso during emergencies. Packing a bunch of users into GMRS in an attempt to lead the FCC to believe an already alive service is still alive doesn't make any sense. Setting up a bunch of repeaters in that close of proximity both in frequency and in physical space would also create intermodulation problems, further polluting spectrum.
 
If you want to use wide splits and/or tiny mobile repeaters with appreciable output power, use Amateur spectrum in either a wide split on 70cm or crossbanded to 2m/900. That spectrum has already been made available for hobbyist use. GMRS isn't supposed to be a tinkering band, type certification tries to ensure equipment already works when it reaches GMRS spectrum. Amateur is also free from frequency coordination concerns on temporary setups, restriction on mobile duplex operation, and linking concerns.
 
Cavity filtering only costs about $100, and considering there's a transmitter and receiver sharing an antenna, skimping on filtering isn't a good idea. Trying to implement a miniaturized filter would cause greater harm with receiver desense than benefit from running high transmit power, and with the filter order you need to get acceptable isolation even at 10 MHz, you're gonna spend more in component cost and tuning labor than you will buying a sixpack cavity filter. Single-channel repeaters don't cost much more than $400 to build ($100 cavity filtering, $75 transmit radio, $75 receive radio, $100 repeater controller and interface; power supply and antenna fill the balance). Performance isn't great, but it's certainly acceptable. Getting the cavities tuned is about knowing the right people or knowing enough theory to make cheap tools work (such as SDR + noise generator). Knowing a friend with the right tools is the right path to take, since they'll know more about the nuances of making a repeater work well. Building your first repeater alone isn't something I'd recommend, they aren't plug-and-play solutions and there's a reason this stuff costs money.

Or, it may not. I can't find any mention about what technology is used for the duplexer. I couldn't even find a picture or a video of the repeater with the case open.  Also, the specifications do not mention Rx/Tx isolation.  But, at a $400 price point, whatever duplexer they are using, it can't cost much -- though, it is probably the most expensive thing in the box.

I had posted this as a response in another forum topic and wanted to see what others thought. How do you run your system and have you had any issues running it the way you do?
 
I decided long ago to list my repeaters as open with no CW ID running and stating "It is your responsibility to ID as required by FCC rules and regulations". I figure what good is a repeater if it sits idle most of the time, I built my last machine to cover a huge recreational area and I want people to use it. Unless I get complaints I wont change a thing. I have listened to people tell me about repeaters that sat Idle 95% of the time until they failed, what a waste of money. I rather see it burn up knowing it served people well then die a slow painful death idle in a shack.

Linking via the internet is legal, the FCC is fully aware of the MyGMRS linking network. (https://link.mygmrs.com/map) Rich has been invited to attend FCC meetings and has pend opinions that the FCC takes into account while making decisions. I as others run smaller local networks that can be linked into the national network at the push of a button. After reading this from start to finish the OP is asking for a beginners repeater but takes the tech talk to advanced levels and far outside the realm of UHF.GMRS. From what I can gather he wants to use handhelds to talk to a mobile repeater that intern repeats it to a repeater, again not legal. This group has a lot of combined knowledge if one is willing to listen, take advice and learn. I think I will just watch from the sidelines on this one, good luck on your project.

Ian. You titled this topic “A Beginners Repeater.” But, then you describe a very complex system that nobody here seems to fully comprehend. Then, when people suggest you simplify things, you respond that each suggestion offered won’t meet your beginner needs. Finally, you seem to misunderstand or misinterpret parts of Part-95 and in so doing, you seem to go in unsupportable directions and avoid other, much simpler, potential solutions.
 
At this point, I too will join the growing crowd watching from the bleachers, at least until you can provide a simple use case example that does not involve any discussion of how it should be done. Something like: “4 people are hunting in the woods and a 5th person is coordinating their a actions from a fixed location and they need to share their ideas for lunch.” Really, something that basic would be a good way to start getting the help you have requested.

Linking via the internet is legal, the FCC is fully aware of the MyGMRS linking network. (https://link.mygmrs.com/map) Rich has been invited to attend FCC meetings and has pend opinions that the FCC takes into account while making decisions. I as others run smaller local networks that can be linked into the national network at the push of a button. After reading this from start to finish the OP is asking for a beginners repeater but takes the tech talk to advanced levels and far outside the realm of UHF.GMRS. From what I can gather he wants to use handhelds to talk to a mobile repeater that intern repeats it to a repeater, again not legal. This group has a lot of combined knowledge if one is willing to listen, take advice and learn. I think I will just watch from the sidelines on this one, good luck on your project.

Agree with the previous posters - CommScope DB404, DB408.    Normally you can only find the B version, which are rated for 450-470 MHz, but they play just fine down to 438 MHz for amateur service.  Sinclair and Telewave (ANT450D) make similar models, with even greater bandwidth and quality. 
 
The common feature among these antennas are that they are corporate-fed types, with large diameter elements.   Try and stay with this type of antenna if possible (just from experience).  The other benefit of these is that they are wideband (2:1 bandwidths of 20 to 100 MHz) and DC grounded; direct DC grounding helps reduce noise, and also better protects against lightning induced voltages. 
 
I have not had the same performance experience with the series fed fiberglass antennas.  Also, these fiberglass covered antennas do not have direct DC grounding, have more limited bandwidth, and are prone to noise problems as they age when wind blown.  While the DB4XX and other dipole antennas look like they would have more mechanical and electrical issues due to exposed cabling, I have seen many last 20-30 years, even at coastal sites.   

DB404 is my go to antenna for repeaters in the UHF band. If I can squeeze out a few more dollars its the DB408. I have some that are over 25 years old and still going strong. They seem to hold up well with snow, ice and rain of CNY.  I plan to order 2 DB408 for my new tower in VA as soon as i get the base set.

Big fan of the Andrew DB line of folded dipoles, I own and operate DB-404, DB-408, DB-420 and DB-411 all are excelent options and will out preform and out last any fiberglass stick on the market today. Just my opinion but one based on experience.
 
The under $400 ones Include the DB-404, and DB-411, you can find DB-408 and DB-420 for under 400 used if you hunt hard enough.

I operate a linked GMRS repeater network that's part of MyGMRS. It uses 5 MTR2000 part 90 machines linked with Voip and covers 1/4 of the state of Wisconsin. Just like NavyBOFH said you will at some point need to make a compromise on your requirements for a total part 95 certified solution. From the title of your post "a beginners repeater" you sure had a strange list of demands, I am still hung up on the Solid-state ladder filters as I have never seen these in use in GMRS or LMR of witch I own repeaters in both services and user either duplexers or vertical separation with separate antennas.
 

Rich messaged me last night and everything is fixed. Not sure what the problem was but it seems to work now. Thanks again for you help everyone.

Looking to do my part in helping the best GMRS site continue to thrive. Anybody know where to purchase the subscription? I'm sure its on here somewhere just havent found it...
 
Thanks Ryan-wqvy669
 

The repeater antenna I recommended, the DB404-B has a gain of 5.9dBi, with no beam tilt.  That is a great antenna to use if you have it high in the air, and height always out-performs antenna gain.
 
A 10dBi gain antenna at 30 feet will do well in a situation like this, but won't have the range of a 5dBi antenna at twice the height.
 
One must also keep in mind that antenna gain comes as a compromise.  To make gain, the antenna must have a narrow beam-width... as in the antenna system is designed to pull the energy up off the ground, and down out of the sky, focusing it into the horizon.  If you have a high-gain antenna on a tall tower, it will have great distance range, but will also provide very poor results up close to the tower site.  The signal will simply over-shoot the target radio.
 
Real world case:  I take care of a UHF Ham repeater in Campbell Nebraska on 444.475/449.475.  It is using a DB420, which has 11.3dBi gain, and it is mounted at about 290 feet on a commercial tower.  Other repeaters link into this site from well over 40 miles away.  I live 7 miles away from this site, and can use a 2-Watt handheld from my back yard just fine.  If I travel closer to the machine, I drop in and out, and can no longer hold the machine when I'm 1-3 miles away, due to no ground coverage, and signal overshoot.  I'm inside the shadow ring of the antenna system.
 
Summary: Use a higher elevation, and a not-quite-so-high gain antenna for a project like this ranch.  The lower gain antenna will have much better ground coverage near the tower site, without shadow rings around the site, and the height will make up the distance covered.

How can you just leave us all hanging, what was the outcome?

How can you just leave us all hanging, what was the outcome?

How can you just leave us all hanging, what was the outcome?