Lscott

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

Thanks for the info. I was fairly sure there wasn't a problem. I was interested in tweiss's opinion since he seems to think it's an issue based on a rather broad comment in his post. I used myself as an example where I was sure it wasn't doing exactly what he said likely was. Maybe there is something that he's seen, read or whatever where it could be. The FCC's rules are not always that clear cut about what's permitted and prohibited. No harm in trying to find out.

Were would the problem be for example in my case out of curiosity since I’m doing exactly the above? I’m licensed for both services and use a Kenwood TK-370G-1 which is Part 95 certified, unmodified and has a full front panel keypad. The radio is not enabled, through hardware and software, for front panel programming. However it is programed for both GMRS simplex channels, a couple of GMRS repeaters and various local UHF Ham repeaters.

I have the D878UV HT. The radio itself seems to be mostly OK and not a bad value for an analog - DMR HT. The main issue I have is with the darn programming software. One version they fix a number of outright bugs. It's good for a version or so then they bugger it up again. It's really frustrating. It's like there is no quality control and no version control. You would figure once they fix a bug it would stay that way, nope. I reamed their tech support out over this issue several times by email. Of course it's all in China so how much do you think they are going to care. I haven't even bothered to load the latest firmware release. I did try the radio programming software. Some stuff they fixed the other things that I noticed they didn't bother with fixing. 8-/ Normally when they do an update they issue both a new firmware file for the radio and a new version of the programming software. They likely need to do this because the memory layout changes from one version to the next for the code plug. The notes say to save the code plug using the old version then reload it using the new one. The last update was so bad they had to issue an update just for the radio programming software. Right now the radio sits around and I'm not actively using it. I'm waiting to see if they finally get their act together. I'm just about done with the bugfest. Now about the 220 band. The activity seems to be hit or miss depending on the area. Where I'm at, Detroit metro location, I haven't noticed much use. Other places I hear it's popular. If you can get a radio that includes it without a significant cost premium I would say go for it. The reason why it's not more common is the band is not a world wide armature allocation like 2 meters or 70cm bands. Most manufactures don't want to include it because it is pretty specific to ITU region 2 which is where the US is located. That leaves out about 2/3'rd of the world wide market. One other thing. You can find amplifiers easy enough for 2 meters and 70cm. Good 220 amps are hard to find. I've looked for used ones at Hamfests and haven't had much luck. The ones I have seen are beat to crap and or the seller thinks it made of gold with a price to match. The only cheap FM one I have seen is from Btech. I've read some mixed reviews on them. Basically it's just to boost the power from an HT. I've thought about getting one for my Kenwood tri-bander, TH-D74A, the price is cheap enough considering. https://baofengtech.com/amp-v25 Dual band antennas for 2 meters and 70cm are also easy to find. The two bands are harmonically related, 70cm frequencies are approximately 3 times 2 meter frequencies. That makes designing dual band antennas reasonably easy to do. However 220 is not. So finding a tri-band antenna for 2 meters - 220 and 70cm are not that common. One example is the SBB-224/SBB-224NMO. http://www.cometantenna.com/amateur-radio/mobile-antennas/ma-tri-band/ Most likely you will get a good dual band 2 meter and 70cm antenna and a separate one for 220. Then you use triplexers and patch cables to split out the 220, or just use a coax switch to flip between the antennas. https://mfjenterprises.com/products/mfj-4936s?_pos=2&_sid=060a07025&_ss=r

If you want something smaller and likely cheaper look at this one. This one is a bit over 6 inches tall. https://www.pctel.com/wp-content/uploads/2018/11/Product-Datasheet-25.pdf Check out the model PCTCN4347. This is pre-cut, tuned, so you don't need to do anything. A generic one where you have to cut the whip to tune it is here. https://www.theantennafarm.com/catalog/pctel-maxrad-pctcnmft-5913

I'm not sure about the exact model radio you installed. Many of the Kenwood's will program down into the Ham Band even if the software pops up a warning about the frequency being out of range. Most of the simplex and repeater operations on the 70cm Ham band are between 440 MHz and 450 MHz. I have a collection of HT's, 4 watt radios TK-370G-1's, that work down to a bit above 440 MHz I use for both Ham and GMRS. With a 1/4 wave antenna the bandwidth can be rather large. I built a small one out of some stiff bus wire and a BNC connector. The SWR was below 2:1 from 430 MHz to 470 MHz covering the usable section of the Ham 70cm band and all of the GMRS frequencies. If you can do that with the antenna you installed, and the radio will program down low enough, you can have access to both services on UHF with just one antenna and radio. Most radios work fine as long as the SWR is 2:1 or less. Not a bad deal if it tunes right. You can do a frequency sweep and see where you're at. If the low SWR point is a bit too high you can get a replacement whip and cut it a bit longer to try to cover the GMRS frequencies and as much of the Ham 70cm band as practical. Good luck on trying to get your Ham Tech Class license. The test is pretty easy. I went to a Ham swap once many years ago with my brother, who was already a Ham, just to look at some test gear, and he offered to pay the fee if I sat for the Tech Class test. I had no idea he was going to ask me try try it. I said OK it's your money. Surprised, I passed with no studying!

That does look like a neat install. How easy is it to get up on top to remove the antenna when necessary? I assume you have a cap to screw on the mounting base when the antenna is removed to keep out the elements.

The problem with a virtual machine is only the Pro versions of Windows 7 has the necessary features. Same with Windows 10. If you have the Home versions then you need to install a 3’rd party virtual machine manager. There is an excellent open source, free, you can down load called VirtualBox. I’ve run Windows 3.11 on DOS, Win98SE, Win NT4, Win2000, WinXP, Win7 Pro and Win10 Pro in it. I’ve also ran several versions of Linux too and one of the last releases of IBM’s Warp4 OS. All worked. https://www.virtualbox.org/