coryb27

Googles Best translation! Greetings 73 there is a Repeater 462,625 Virginia close to me and for one week as i monitored it has nothing is WQSD892 in Chesapeake will this inactive or this off here can help me and chequiarlo

What does “duty cycle” mean? I bring up duty cycle every time I hear somebody talking about making a repeater out of cheap Chinese mobiles and worse any type of handhelds. Duty cycle is the maximum time an amplifier may transmit within a five minute interval, expressed as a percentage, to avoid overheating. Suppose a mobile amplifier is rated at 30% duty cycle. This means that it may transmit for no longer than 1.5 minutes and must remain off for not less than 3.5 minutes. Some people forget that a repeater is transmitting for 2 or more people, duty cycle will be reached quickly if you get into conversation. More people in the conversation just amplifies the issue. Once a radio reaches it's thermal design limits it will no longer be able to adequately cool the output transistors. Even if a radio is not hot to the touch the transistors are, in part because of the inefficient transfer of heat to the units housing or internal heat sink. The longer you exceed the duty cycle the more heat builds on the transistors, surrounding electronics and heat sink effecting it's ability to remain on frequency without spurious emissions. Exceed duty cycle long enough and you will need a new transmitter or radio. I have tested a few Baofang and TYT radios on my service monitor without great results. All of the radios started deviating outside of the allotted channel bandwidth after simulated conversation at 50% duty cycle, the longer I allowed this the worse if got. Testing was done using an Aeroflex 2975 IFR recently back from the calibration lab. GMRS is a tiny sliver of spectrum surrounded by the commercial land mobile part 90 service. It is important that any repeaters that are built or re-purposed are held to the highest standards and operated as to not cause any interference inside or outside of our allocated spectrum. I wont get into the part 90/95 debate but i do stand firm that non certified import equipment has no place on GMRS.

1. This is a HAM radio not for use on GMRS, 2. Cross band is just what it says VHF to UHF it will not have an option for single band repeat. 3. The duty cycle on this unit is around 50%, one long winded conversation would cause it to melt down.

Test equipment can be costly depending how much your using it.

Welcome to the group, I hope we have any answers you may seek!

We are using Asterisk as the server (running on a raspberry pi 3) and the RTCM made by micro-node. Cheaper hardware solutions vs the RTCM are available but require other configuration. I have not used any of the other hardware so I wont touch on that. I chose the RTCM for its single unit design and application specific properties. The interfacing with the RTCM is rather simple, I went with the MTR2000 repeater for reliability, full duty cycle and used market availability. Our group hosts its own local node server (Asterisk running on a raspberry pi 3) with 6 repeaters connected to it. This local node also allows us access to the MyGMRS national linking network hosted by the owner of this site. By entering commands in Asterisk or using DTMF, links to other systems can be connected or disconnected on the fly. Things like usage counters and the visual map show links with red lines as well as what site is transmitting by changing its marker from green to red, all of this in real time. Its not as hard as it sounds, Rich from MyGMRS was a huge help, you can also find a linking thread in the private section here. Along the way I found a company that was able to build a custom cable for interfacing the MTR2000 with the RTCM, it provides a reliable solution that's repeatable and works flawless. The MTR2000 repeater can be configured to work with the RTCM rather simply using the repeaters wire-line card to handle the audio and the 96 pin J5 connector to pull ctcss, core, ptt and power. We are using the RTCM and MTR at 6 sites with a stand alone MTR at a 7th and could not be happier. These machines are worth every penny, its not 2 mobiles in a box its a true full duty cycle, commercial grade repeater. Due to the simplicity I have several more RTCM / MRT2000 combos ready to go I just need to fined a few more tower sites with internet. Hope this answers a few questions.

We are already doing it http://link.mygmrs.com Corey

I use a Telewave 44A Broadband 20-1000 MHz as it requires no collection of slugs and measures power up to 500W. HRO has them for $860 but you can find a lightly used one on ebay for a few 100 bucks, some may have current calibration and if your lucky the case. I went down the Bird rout and realized the cost of slugs adds up quick and decided on the Telewave 44 was a better investment.

OMG the Woodpecker, I remember this famous numbers station from the 80's

I would not even concider this a mid tier radio, mostly sold on Amazon and eBay its nothing more then a kids toy. For starters it has no ability to do repeater offsets, or programmable tones. A closer look at the company's website and its an Alibaba store front with the typical rebranded TYT, HYT and Baofang offerings as well as some new Chinese junk I have not seen before. I lookup the website registration and it was recently re-hosted and the ownership records updated in January of this year. I would not waste a single cent on this junk, I will stick to my Motorola gear.

I just want to know where all these people willing to pay a 100 per year to use the repeaters are! Lets face it, my network covers 3 states and several 1000 sq miles and we have 51 users. Anytime I have needed help with climbers or manpower its always my same core group standing in the driveway. What you are talking about is basically a part 90 community repeater service not GMRS. Again as i stated selling tones is not legal...nor welcome. I would like to hear Pastor Gary's thoughts?

All I am trying to say is you cant sell access nor do you have to start a non profit or get a CPA involved. Capital and operating expenses is in reference to supporting the equipment, paying tower rent or even leasing a repeater. Now if you start selling private access tones that is not allowed at all. I manage a system of GMRS repeaters linked from Highland Indiana to Rhinerander Wisconsin and have never had the need to send a letter or pull the plug. We have had jammers over the years but we out last them, best to just ignore them. I promise the second you start sending letters or trying to boot people off your repeater you will have jammers as well. I have even heard of instances of repeater sites being vandalized, and it all started with "you are not allowed to use this machine" Its hard to send a letter to somebody that wont ID while driving around in a mobile. Engaging them on the air just makes it worse and PD/DPL tones can be captured rather quickly with a scanner so in reality changing them works for about a day. If you start changing tones and pulling the plug you will end up with a quiet repeater that nobody uses. Just me $.02 Corey

You can't technically charge for use of a repeater, only for the upkeep and operation costs. You can not in any way profit from a GMRS repeater. I do not charge anybody and the reason is simple. The moment people start contributing they want a say in how its run. I do this as a hobby and have substantial investment, its a labor of love. My payback is hearing people use and enjoy it. Below is the FCC part 95 sub part that outlines this better. Corey (1) The station to be shared must be individually owned by the licensee, jointly owned by the participants and the licensee, leased individually by the licensee, or leased jointly by the participants and the licensee. (2) The licensee must maintain access to and control over all stations authorized under its license. (3) A station may be shared only: (i) Without charge; (ii) On a non-profit basis, with contributions to capital and operating expenses including the cost of mobile stations and paging receivers prorated equitably among all participants; or (iii) On a reciprocal basis, i.e., use of one licensee’s stations for the use of another licensee’s stations without charge for either capital or operating expenses. (4) All sharing arrangements must be conducted in accordance with a written agreement to be kept as part of the station records

Antenna gain is selected based on the site and required coverage area. It is a total misconception that more gain is better. Depending on the antenna height and terrain you can do more damage then good with higher gain. Site engineering is an important part of any system, science and methodology will always provide the best results over what one may think. Unless you are stacking UHF Yagis you will gain nothing by phasing omni's together, you would be better off setting them up diversity using power dividers but this involves its own engineering and the proper test equipment. Co phasing omni's was and still is popular for 10 and 11 meter but that is HF AM not UHF. I currently have several DB-420, DB-411, DB-408, DB-404 and a single Sinclair SC329-HF2LDF in use at different sites both part 90 Commercial and GMRS. Each one selected for the installation and desired coverage. The antenna is the biggest factor in any radio system with the coax the second, trust the science. I have and still do see allot of people wasting money and being unhappy with system performance over bad antenna selection. Just my $.02 Corey

Trouble is most people dont understand what S/N ratio, insertion loss, return loss, impedance, noise floor, velocity factor etc even are. The Yagi example has noting to go with gain at all. I have shown countless people using calibrated industry standard equipment RX gain is nothing more then S/N. If you take a 3dB Yagi and a 18dB yagi, mount them in a fixed position at a fixed signal the uV level received by the test equipment is going to be the same. This is why filtering, pre-amps and attenuator's have a place. Simple really, a filter to reduce the S/N ratio and provide adjacent channel rejection, pre-amp to boost the signal and proper attenuation to lower the noise floor.

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

Also, Gain has nothing to do with RX..... If you need better sensitivity try using a filter tuned to the frequency, into a pre amp and then you need to pad out any gain from the preamp that is above the noise floor.

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.

I dont understand why you are so dead set on solid state filters? If it was possible people would have been doing it long ago, that 10W toy repeater you linked to is no better then a couple HT's in a box. Yes it may use some type of solid state filter but i am guessing the loss and electrical efficiency are what limits it to 10W. I would bet it is just a notch filter, this would be like using a "mobile notch duplexer" vs "4 cavity pass reject duplexer" The mobile duplexer is smaller and cheaper but the performance loss of using such a duplexer reduces the repeaters overall effectiveness. The single largest factor with notch type duplexers is the inability to exceed 70dB isolation between the RX and TX. BTW I license part 90 frequency in the 452 range, it took months to get a repeater pair because of the waiting list, no such thing as underused or open spectrum. You want a good preforming repeater, purchase a quality pass / reject duplexer. Just my $.02

UHF and VHF are both Motorola XPR5550 with handheld control heads.

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.

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.

I user the Motorola MTR2000 at every one of my sites, a 40W can be picked up on ebay for 600 or less. These machines are bullet proof.