Lscott

The repeater I was trying to locate turns out it’s on the top of a building that’s listed as the roof top at 206 feet above ground level. So per your points it wouldn’t have been required to be registered with the FCC. There is also a Ham repeater on the top of what is now GM’s headquarters. That’s only 14 to 15 miles line of sight from my house. http://www.gmarc.org/wp/wp-content/uploads/2020/05/RenCen-repeater-qsl-compressed.jpg There is also another Ham repeater just a mile or so from the GMRS one on top of another building at 300+ feet. Both of which are just under 5 miles to the west of my location. Both Ham repeaters do self ID. Since the above are not on a tower, and the antennas are mounted close to the roof top there is no legal requirement they be registered with the FCC? I was not aware of any FCC requirement to register if you’re on a tower however. That’s new one for me. Thanks for educating me on that. I also monitor the security frequencies from two local malls. It was rather interesting when the police protesters showed up by the one in Sterling Heights a few weeks back. Both use repeaters. Nether one self ID’s that I can tell from several years of monitoring them. Both are listed in a well known on line scanner database. https://www.radioreference.com In that one of the two shows the call sign for the repeater. There is nothing listed for the other one. Again doing an FCC GEO search on either the input or output frequencies yielded nothing that makes sense. A search of just the frequencies used for the city, where I’m guessing the repeater is located at the mall, didn’t yield anything useful either. How would one use freely available sources to track down the owner, and the call sign, of the non ID’ing repeater? So for the two malls how can they operate with out either the repeater nor the hand held radios used ID? Is there a specific FCC rule that allows this or are they in violation?

What you said is true I’m sure for commercial systems, public safety etc. I don’t recall seeing anything in the FCC rules requiring a GMRS repeater to be registered with the FCC. Neither are Ham repeaters, but you do work through a local frequency coordination body which is not part of the FCC. The only requirement is each station must ID, so as long as only qualifying family members use the machine it doesn’t need to self ID. Each qualifying family member when they ID satisfies the requirements. However if non qualifying family members use it then it’s impossible to determine who is the owner unless it self ID’s. This was EXACTLY the problem I had trying to identify the local repeater I’m currently using. No self ID, nothing shows up of any use when doing an FCC GEO search on the exact frequency over a limited range of 50 miles. I finally tried contacting the owner because it was listed on this site’s repeater database, by shear luck and I still wasn’t really sure. But even then the info was wrong because the owner died and the listing wasn’t updated for a few years. Months went by and no response to my emails, unknown at the time they were going to a dead guy’s account. Then when it was updated everything got worked out really quick. If it had ID’ed with the current owners call sign a simple lookup of that in the FCC license database would have given me the contact info I needed and saved me a lot of screwing around.

That doesn’t make any sense to me. The point of ID’ing is so the owner of the repeater can be contacted in case of a problem. I don’t own the repeater I mentioned and I’m sure the FCC won’t be knocking on my door, nor anyone else using it with their own call sign, if there are issues. Without a proper ID how would they know who really is in control of it? It’s a lot less work to get the call sign of the owner from the on-air self ID, look them up in the FCC database then contact them directly. The other choice is having the FCC pull the plug then wait around to see who shows up to check the system out wondering why their repeater quit. If nobody shows up, the repeater is off the air problem solved anyway. Might even pack it up and take it with them on the way out the door. If their nice they could leave a nasty note taped to the empty rack.

I’ve looked at those cheap repeater controllers. Those are the ones you connect two radios together using the mic/speaker jacks and key the other radio using VOX. The main complaint I have with using one for a quick throw together repeater is the lack of an ID function. I have looked at the “ID- O-Matic” which has it but you need a COR it seems to make the thing work, which of course an modified radio doesn’t provide. So that brought me back to the first option about hacking the hardware to add an ID function. The cheap controllers without the ID could be used in two cases. The first is a half-duplexer repeater, which has the limitations you pointed out previously, and used exclusively by the licensed user. The second is with GMRS, but only if qualified family members use it exclusively since everybody ID’s using the same call sign. All other cases the repeater needs to self ID. The strange thing is the one GMRS repeater by me, which I have the owners permission to use, along with a few friends, I have NEVER heard it ID yet. How the owner is getting away with it beats me other than the FCC doesn’t want to bother with it. It doesn’t get much use so unless you know it’s there you wouldn’t notice.

I think his was a full cross band, duplex, design. The two radios are cross connected. He did his initial testing with the antenna on his tower. He is also the main radio tech for a local city’s transportation department. He done some tower climbing and repeater installs. Many of his comments are similar to yours. The one I remember most is a story where another tech went out to check the repeater equipment in the shack at the tower base. Opened the door only to discover a huge hornets nest inside. By the time help arrived he was passed out on the ground from all the stings. Luckily he survived.

That all depends. I have a Ham buddy who built a special event repeater, for local marathons and bike runs, really cheap with some used radios and a good power amp. The way it was done is using cross-band repeating so the expensive cavity filters get ditched. Most Ham HT’s can be programmed to do split band operation. You RX on one frequency on one band, say VHF, and TX on another, UHF, when you press the PTT button. For Ham radio this usually ends up being the 2 meter and 70 cm bands. On the repeater side a simple diplexer is enough to work the VHF and UHF radios into and can be had for $50 to $75 new. Then he takes advantage of the local high rise buildings. Through his contacts he has access to the roof tops. No need for an expensive tower and feed line. When you’re on top of a 10 to 15+ story building you get some decent coverage. Since the repeater can be located close to the temporary antenna you don’t need expensive feed line. And what you do use is fairly short thus keeping the losses down and thus the TX’er power required. Granted his conditions are not the general case but if one looks around and takes advantage of the local resources you can save a huge amount of money and effort. However if one wants to build an in-band repeater, then yes it gets more complicated and likely expensive as you pointed out.

The usual non compliant consumer marketed Chinese wireless crap being sold in the US. Some years ago there was a problem with “high power telephone wireless handsets” that claimed 1 mile plus range. Turned out they were operating on the Ham 2 meter band. After a series of complaints to the FCC the issue was addressed.

Unfortunately data transmissions are allowed on any MURS channel. While the FCC requires monitoring for activity before transmitting I seriously doubt for automaticity operating stations they employ “busy channel lock out” and just key up regardless. Even with a max power output of 2 watts and a simple antenna a data transmitting station can ruin a given channel for a 1 to 2 mile radius with frequent use. With only 5 channels it doesn’t take many stations keying up automatically to ruin things for MURS in an area. I remember driving through a particular area near me frequently and could always count on picking up a data burst every few minutes on one of the channels. That went on for months. Eventually I locked it out of the scan list in my mobile Ham rig. Like you I found it very annoying. Lately about the only thing I do hear is the local Walmarts, Sams Clubs etc. and seldom at that.

That's very strange. I just tried it again and it works for me. Maybe you have some security limitations on your computer. Anyway here is a snippet of what is there. It is a radio propagation modeling program using publicly available geodata. I this this would along the lines of the for pay service you use but for amateur radio, or other radio service, uses. **************************************************************************************************************************************************** Calculations The hart of every RF simulation tool is the prediction model. There are many models that predict RF propagation but the most known is the 'Hata-Okumura' model. This model is 'the mother of all models'. Over the years new models have been developed where the growth of commercial cellular networks like GSM UMTS, and now WiMAX are the main drive. These networks operate in th UHF and SHF bands (450 to 2400 MHZ). Other frequency's are used for broadcast of Radio and TV (VHF and UHF, 50-800 MHz) and a small portion for PAMR and PMR networks. Their focus is in the VHF and low UHF frequency's (50-500 MHz). The prediction models used for these networks are devided by coverage distance. For GSM, DCS and UMTS (900-2400 MHz) these models are limited to predictions over a short range. Due to the nature of broadcast the distance over wich predictions are made is extensively bigger than for cellular networks. The difference in range for the model is devided in to two main categories: 2-way communication or 1-way communication.This choice is influenced strongly by the en-user terminal. A if a uplink is required, a hand held terminal will limit the coverage because these devices have limited transmit power and poor antenna performance. In the case of broadcast A Radio receiver does not need to talk back to the broadcaster so bigger powers do no harm to the link budget. When prediction over small distances are required to be accurate it is important that the influence of local buildings (clutter) is taken in account. when predictions are performed over bigger distances the dominance of clutter decreases and eventually can be left out of the calculations. This simplifies the formula for calculating RF propagation. Accurate RF predictions require detailed clutter and height data bu this data is generally expensive and only affordable when income out of the exploitation of a radio network is high. For amateurradio, emergency services, and students for example it is not realistic to have this accurate data available. Therefore low budget and easy accessable data must be accessed. Radio Mobile uses geodata that is available on the internet for free. Based on the Hata model many other models have been derived. Also models have been improved for their specific purpose. But some general models have been almost the same and available for free. On very well known model is the Longley-Rice model. This model is accurate over a wide range of frequencys and over various distances. Based on this model the US Institute for Telecommunications Science (ITS) created a propagation prediction model know as the Irregular Terrain Model or ITM. Radio Mobile uses the ITM model. To understand the operation and limitations of the model I have collected information about the Longly-Rise and ITM model on this website. ******************************************************************************************************************************************************** The link below is for the "on-line" version. Maybe you'll have better luck with this link. http://radiomobileonline.pe1mew.nl/ This is the snippet from the link above. ****************************************************************************************************************************************************** Welcome To the website dedicated to Radio Mobile Online. Radio Mobile Online is the online version of the popular RF propagation tool Radio Mobile by Roger Coudé. Radio Mobile Online can be found at: http://www.ve2dbe.com/rmonline.html Radio Mobile Online is a radio wave propagation prediction tool dedicated to amateur radio. It uses digital terrain information and a mathematical model to simulate radio transmissions between two fixed sites (radio link) or between a fixed site and a mobile (Radio coverage). The digital terrain information comprises two databases: Elevation and land cover. Those databases are located on the server and represent a total of 198 GigaBytes. Radio Mobile is a popular tool for RF studies. Between 2012 and 2015 663304 studies have been performed and 26198 accounts have been made. More information? Follow this link: RMW Online popularity. ***************************************************************************************************************************************

You might want to try it again. The website is in the Netherlands. I tried earlier today, no luck. Tried again just a few minutes ago and now it seems to be working. All I did was click on the link in the post using Firefox on my laptop. http://radiomobile.pe1mew.nl/?Welcome...

That's very true. I have a couple of friends with GMRS licenses, also looking to get their Ham license when the local clubs open up again for testing, that are using non Part 95 certified equipment on GMRS. I had to advise them the use of those radios is not per the FCC rules. They had asked for some advise about equipment and operating. I felt I needed to do that as being a responsible Ham and GMRS operator and not miss lead them. They are adults and can make their own decisions. I just wanted them to be fully aware of what they are doing. Some have pointed out that a number of non Part 95 certified radios are being used for GMRS that most likely meet or exceed the frequency stability, bandwidth and can be adjusted to comply with the power output requirements for GMRS. The opinion that some people just don't care if that's the case as long as the major technical requirements are met is understandable. I think sooner or later the FCC will just throw in the towel on using Part 90 radios on GMRS and make it legal. It likely will be just like the FRS/GMRS combo radio mess. They knew people were not getting the licenses but used the radios on the then GMRS only channels. Rather than waste resources busting people using the radios illegally, or ignoring those people and making excuses for not doing anything, they took the easy way out and just made the already wide spread practice legal by changing the rules. Problem solved, and they don't have to make excuses anymore for not enforcing the rules. Same thing with CB radios years ago. So many people quit getting licenses, or failed to ID per the rules, and the FCC had a hard time keeping up with the volume of license applications they did get, the FCC finally dumped the requirement and made it "license by rule". Again they simply made legal what people were already doing and got rid of a administration headache at the same time, again they took the easy way out.

Have you use this software before? http://radiomobile.pe1mew.nl/?Welcome...

Yeah, I can see your point. Many of the older Hams hangout on HF. They might have a VHF/UHF radio but likely don’t use it much except on the morning or evening commute. The other times the portable radio gets used at the Ham Radio flea markets then goes home to sit around until the next one. Alas there are those few Hams that just have an elitist attitude and won’t talk to people with a Tech Class license. Sometimes you can tell by the call sign format the license class. Certain formats are reserved for higher license classes. I’ve kept my original Tech call sign just to surprise those that look me up on the FCC database or on QRZ.

I’m not sure. The few minutes I poked around on the USGS site all I found were the small 7.5x7.5 topo maps that looked like a postage stamps scattered across the Detroit Metro area. I need to spent a bit more time looking around there to see if there is something that covers several counties that can be downloaded.

Thanks. I’ll have to look at that. I’ve got a friend who is looking for a cheap tower to put up. Something like an old TV type with a multi-band stick antenna. It would good to know what his likely range will look like based on the surrounding terrain.

That’s a wee bit outside of my threshold of financial pain. I guess I’ll have to do some more poking around on the USGS site and see if there is anything remotely like the service you have.

What source are you using for the topo maps to get the elevation data?

There is an open source project for solving transmission line problems using Smith charts. I was alerted by a fellow Ham and EE who uses it. https://www.w0qe.com/SimSmith.html

You might want to check with a local Ham Radio club. Many members have various types of antenna measuring equipment and one of them likely would he happy to help check it for you. You may be in for some luck. The last weekend of June is Field Day for Amateur Radio. Many groups, even single operators, setup in local parks, parking lots etc. and operate off of portable/emergency power power. It's a good place to meet other radio minded people and somebody I'm sure has the equipment on site to check your antenna system out. Oh, don't be surprised if somebody suggests getting your Ham License. http://www.arrl.org/field-day

Run 4 watts.

That's a nice chart you did. Anyway what you pointed out you'll see elsewhere with the FCC rules where the language isn't clear. There is another area on the forums for FCC rule discussions. If you have further questions that area that would be the place to get answers and a lot of opinions.

I believe that is correct. The FCC has them reserved exclusively for repeater inputs. This link is a nice summary. https://en.wikipedia.org/wiki/General_Mobile_Radio_Service The link below is the most current version of the Part 95 sections. For GMRS you want subpart E. https://www.ecfr.gov/cgi-bin/text-idx?SID=85a15d2032f9f51fa68cef9b9657e610&mc=true&node=pt47.5.95&rgn=div5 I have stuff like this printed out as PDF files, stored on the computer and smart phone along with all my radio operating manuals for easy reference.

This is what the FCC has to say about it when the rules were last changed: § 95.1767 GMRS transmitting power limits. This section contains transmitting power limits for GMRS stations. The maximum transmitting power depends on which channels are being used and the type of station. (a) 462/467 MHz main channels. The limits in this paragraph apply to stations transmitting on any of the 462 MHz main channels or any of the 467 MHz main channels. Each GMRS transmitter type must be capable of operating within the allowable power range. GMRS licensees are responsible for ensuring that their GMRS stations operate in compliance with these limits. (1) The transmitter output power of mobile, repeater and base stations must not exceed 50 Watts. (2) The transmitter output power of fixed stations must not exceed 15 Watts. ( 462 MHz interstitial channels. The effective radiated power (ERP) of mobile, hand-held portable and base stations transmitting on the 462 MHz interstitial channels must not exceed 5 Watts. © 467 MHz interstitial channels. The effective radiated power (ERP) of handheld portable units transmitting on the 467 MHz interstitial channels must not exceed 0.5 Watt. Each GMRS transmitter type capable of transmitting on these channels must be designed such that the ERP does not exceed 0.5 Watt.

Sort of a silly question but did you check to see if the repeater requires a PL tone to access? If it does and you don't have one set, or the correct one, the repeater won't do anything.

I have 4 of the TK-370G-1’s and 2 of the TK-370-1’s. The later are just 32 channel regular FM only. Both are Part 95 certified I believe. The TK-3170-1 are nice, Part 95 certified, if you can find any at a reasonable price. The antennas are either the ones they came with, eBay or local Ham swap, the rest are from a cheap 5 pack I purchased from an eBay seller. I did do an SWR scan of the cheap 5 pack ones and was surprised the SWR was comfortably below 2:1. I was hoping I didn’t get a “50 ohm resister in a rubber stick”. Yea there are a few like that around. When mobile I use a high gain dual band antenna. It has low enough SWR across the Ham bands and the GMRS frequencies. The antenna is almost 60 inches tall. Comet no longer makes this model. I wish they did. I’ve had two for nearly 20 years. One is on the Jeep’s roof rack the other is used inside when I lived in an apartment. That one has never been out doors. Still looks new. CA-2x4MB, 4.5 dBi on VHF, and 7.4 dBi on UHF