coryb27

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?

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

How high is the antenna? Is the antenna resonant on the freq? What type of cable, how long is the cable run to the antenna, did you hook the duplexer up backwards?
 
I am guessing TX and RX on duplexer us backwards, try swapping your cables.
 
Corey

How high is the antenna? Is the antenna resonant on the freq? What type of cable, how long is the cable run to the antenna, did you hook the duplexer up backwards?
 
I am guessing TX and RX on duplexer us backwards, try swapping your cables.
 
Corey

Here is our reply in the Docket, posted today:
 
https://ecfsapi.fcc.gov/file/1061939433150/FCC%20Comment-MSI.pdf

Here's my letter acknowledging the meeting with the FCC, per their request, to keep a record of the communication:
 
https://ecfsapi.fcc.gov/file/1060628686973/FCC-Letter-2018-06-06.pdf
 
We'll be drafting a reply to the petition shortly.

The FCC made it clear that they wanted quality comments, not a large quantity. So I don't necessarily want to flood them with comments. I think it would be a good idea for people to only submit a filing to the FCC if they strongly disagree with the position I put forward. No need for everyone to file just to say the same things or to go off the reservation with other issues.
 
Regarding the duration of the data burst -- it really depends what modulation and baudrate they want to go with. If it's low speed, 5 seconds might be reasonable. If it's high speed, 5 seconds may be completely unnecessary. But I also don't want to sit here and argue over numbers. As long as there's some sane limit to the number of these bursts, and most importantly, busy channel lockout, I'm fairly happy.
 
If you do want to file now, the docket is here. Click "+ New Filing" or "+ Express" to get started:
 
https://www.fcc.gov/ecfs/search/filings?sort=date_disseminated,DESC&proceedings_name=10-119
 
Topics the FCC wanted feedback on specifically:
Would automatic data transmissions cause interference with other GMRS operators? How so? (Strong arguments needed)
  Should these be restricted to certain channels? Why? Motorola seemed okay with avoiding repeater inputs for now, to avoid interference.
  What should the duty cycle limits be? Proposal so far was no more than every 2 minutes with less than a 5 second burst.
  What other restrictions might be needed to avoid disruption of other GMRS operators?

Using a properly mounted NMO places the antenna over a ground plane surface at a proper resonant distance and has a DC ground.  If a mag mount is used, the bottom of the antenna itself is above the ground plane surface by at least an inch and the resonant length of the antenna may be off.   It also has no DC ground connected to the vehicle body at that point because of paint layers, etc.

From personal experience - If an NMO body mounted antenna is cut to a resonant length for lowest possible SWR, and that same cut antenna is then placed on a mag mount, the SWR will be a bit higher.  If the antenna on a mag mount is then re-cut to compensate for the additional height of the mag mount above the vehicle body, the antenna will then be non resonant if placed back on a body mount NMO.

I have also found that most (but not all) NMO mag mounts have factory supplied coaxial cable and PL259 that are somewhat inferior to what might be used with an NMO body mount from a frequency sensitive and loss per foot aspect.  

I have no issues with any of the inexpensive Chinese radios as long as you keep them off my GMRS repeaters.  After trying to diagnose some audio issues for weeks it came down to a few operators on Baofeng's. Second hand part 90 equipment is easy to find and is inexpensive, some of it is even part 95 approved. Every radio has its place and Baofeng's place is not in GMRS service.
 
Just my $.02
 
Corey

Final update to this post.

Finally the repeater is working. After a coworker Kevin (WQWU443) recommended I take the duplexer to A.R. Communications in Monmouth County NJ. I have to say the owner of the company was really cool and showed me around the shop while they looked into what was wrong. After re-tuning the duplexer, they hooked the repeater up to the duplexer and found a ton of de-sence and the SWR sky high [same issue I was having at home.] They kept the system for the weekend and on Tuesday it was ready.

Here are the problems they found:
1) A minor issue inside one of the "cans" of the duplexer. I am not sure how the insides of the flat packs look, but I was told there was a small dent or something causing some of the issue. They "swapped" sides putting the low frequency on the high side and high frequency on the low and were able to by-pass whatever the dent was doing.
2) The stock jumper's between the radio and the duplexer were causing some issues with loss. They replaced the jumpers free of charge.
3) They recommended I check my power supply as on their equipment was letting the TX side run 25-40 watts on low/hi power. At home, I checked and was only getting 17 watts only. Turns out that even though I have a 15A continuous power supply at 12.5V, the system requires 13.5 at 20A to work properly. For safety I ordered a 30A 13V power supply recommended by a few hams as a replacement. This should let me get full power output when it arrives.
 
I also found a problem, and that is that the GR1225 seems to drop its TX power from 40 watts to less than one watt. It does transmit and I can hear it on a portable if I am within a few hundred yards, but the meter doesn't even kick on when I transmit. For the time being a back up repeater is in use and is showing results.
 
The SWR is very low, 1.04 and a .0071 reflection which is MUCH better than the 19 I was getting. With the test unity antenna about 15 feet up at 17 watts and a very rf unfriendly area [a lot of trees and buildings] I was able to talk clear across town (about 4 miles.) Now before anyone says 'thats not that far' keep in mind that this is low power, no gain, low height and a congested area [buildings and trees] so I would think its reasonable.

I want to thank everyone again, Especially Corey and Kevin and the guys at A.R. Communications. I've learned quite a bit from this whole experience and hope to learn a bit more while improving the system overall!

Using a Laird 460-470   5.0 db  omni  base  antenna and 1/2 inch Andrew Hardline for nearly a decade. No issues ever.
 
 
https://www.theantennafarm.com/catalog/laird-technologies-fg4605-8029

I was only speaking from experience, in no way am I trying to bash anybody's setup. The original poster asked for an opinion and I offered mine. I have 3 Tram/Browning omni sticks in the garage, all 3 are junk. If you connect them to a spectrum analyzer with a VSWR bridge to measure return loss and resonance in the GMRS spectrum you would see what I am talking about. Your analogy of how far you can talk with an HT connected to one is no true measure of its performance. Just for fun I connected my XPR HT to my DB-404 @ 30 feet and was able to work repeaters 35 to 45 miles away on just 2 watts of power, with coax and connector loss I figured less then 1W at the antenna. As an owner of several GMRS repeaters and a commercial UHF system I am speaking by real world experience. My best advice to anybody getting into this hobby is don't be cheap with the antenna or feed line as it is the number one factor excluding height that will effect your overall performance.
 
Corey
 
https://mwgmrs.com

I have no issues with any of the inexpensive Chinese radios as long as you keep them off my GMRS repeaters.  After trying to diagnose some audio issues for weeks it came down to a few operators on Baofeng's. Second hand part 90 equipment is easy to find and is inexpensive, some of it is even part 95 approved. Every radio has its place and Baofeng's place is not in GMRS service.
 
Just my $.02
 
Corey

Is the duplexer possibly tuned backwards?

I guess I like stuff to much, gosh, I wish there was a "dislike" button now...................lol jk.. Works for me now

I logged on today and attempted to "Like" someones post on a thread and it popped up with an error saying
 
"You have reached your quota of positive votes for the day"
 
This is my first time logging in today, any ideas?

Speaking of "tower work", this is the new antenna going up at WLOX-TV in Biloxi, Mississippi, this week. They had to change frequencies due to the spectrum auction involving the T-Moble cell carrier.
575,000 to 715,000 watt ERP from a 1201 foot tower.  Base of the new antenna is 21 inches in diameter.