kipandlee

Ah no. When you see gain spec of 9dbi that’s a gain over an isotropic antenna that doesn’t exist. It’s for reference only. What you really want is a gain spec over a dipole,  or a simple quarter wave, which is the smallest antenna that can be physically built. The difference in gain between the two is 2.15db. So the real practical gain is now 6.15db.
 
But wait, we’er not done yet! Now you have to figure in your coax loss. For a typical run of 75 feet of LMR400 at 450MHz, close enough to the GMRS band at 462 to 467, the loss is another 2.03db. So your real gain is around 4.82db, which is a factor of 3.03 increase. For 5 watts in it looks like you have an effective radiated power of 15.17 watts.

I would differ on this view. It depends on what the goal is. If you want to know the maximum possible useful GMRS range in an area, then yes, equipment will matter a lot. However, if you want to know your maximum useful range, then you, by all means, need to test with the same equipment you are going to use.
 
An old developers saying goes something like: Test what you will use. Use what you tested.

Just a caution to be civil here. This thread has the potential to get political fast, and that's not okay here. For casual listening to the protesters, I have no issue with sharing that information. I do have a problem with using that information for nefarious purposes, however. Just like how it's okay to share information for monitoring police and the military within the confines of the law, but once you try to use it for nefarious purposes that goes out the window and becomes a problem here.

I think this group coined the term "CCR" to mean what it does here.
 
For 50 years before this forum, I, and many others used the term "CCR" to refer to a quartet of musicians:
Stu Cook, Doug "Cosmo" Clifford, and the Fogerty brothers, Tom and John.

I was going to tackle this project, and compile such a list. ...however, after researching radio and electronics related acronyms, shortcuts, and abbreviations for about 20 minutes, I realized that it was overwhelming, so the only one left for me to consider was OMG!. ...and I quit.  Will be happy to answer one-at-a-time as needed, just not publish 14,000 at once.

If you transmit on a repeater channel you will receive (listen) on the channel displayed (462.550 in your example) and transmit on another frequency exactly 5.0mHz higher. (467.550 in the case of your example.) 
If you are on a simplex (non-repeater channel) you will transmit and receive on the same frequency. (462.550 in your example.)
 
There is a problem with the radio nomenclature where the word channel is used with two different meanings. First, the FCC has designated 30 UHF frequencies use. For convenience sake, each of these frequencies is assigned a channel number: 1 to 22. The 8 frequencies reserved for repeater inputs are grouped with the corresponding receive frequency so there end up being only 22 channels numbers. As noted above, whether you transmit on your receive frequency or the repeater's receive frequency depends on how you configure your radio.
 
Now, radios also have arrows, dials or some other means of selecting the frequency, and these selections are also called channels. How channels are assigned in the radio differs from manufacturer to manufacturer even model to model. Some vendors of FRS radios call each combination of a frequency and a PL tone a channel.
 
Hope this helps.

For me, it was a collection of conditions.
 
My family spends a significant amount of time in rural and undeveloped areas with no cellular infrastructure. Being able to have some form of communication while on foot or mobile, without everyone getting an amateur radio license, was a must. Especially when we tend to move about in separate groups.
 
Also, somewhat in the same category, I do things like 4-wheeling and other outdoor activities. Many of my friends use FRS and GMRS to communicate while spending time outside. It seems to be going more mainstream.
 
Then, of course, there is always a risk of infrastructure failure. I needed a way for my wife to reach me while I am out of the house, if an emergency occurs. She had her amateur radio license, but it long expired and she is not interested in getting it again. There are several public GMRS repeaters around me that run on emergency power, if needed.
 
So, it was just an obvious and affordable option for our needs.

To summarize WPXM352’s excellent response to your question… One of your club members is an expert the other is not.

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.
 
***************************************************************************************************************************************

Receiver pre-amps are NOT magic. In many cases, they'll actually make a system worse.
 
Signal needs to be greater than noise. The benefit of a pre-amp is in raising the strength of the desired signal above the noise floor. If you raise the noise floor at the same time that you're raising the signal, you've done nothing to improve the Signal to Noise ratio.
 
You need to have proper front end filtering in place before you even consider a pre-amp. If you're using a 'flat pack' compact mobile duplexer, you're not doing yourself any good to add a pre-amp. If you've already spent the money to hang a quality antenna that's up above the tree line, and you're running a high quality bandpass/band reject duplexer, you might see some improvement by adding a pre-amp. Might. We have no idea what your system is currently, or how it's performing.
 
Do you have the tools and knowledge to measure receive sensitivity of your repeater? Do you have the tools and knowledge to measure de-sense?

100%agreed on this, with both you and Cleveland. I haven't found a better resource for gmrs (and general radio) info, hands down. There IS a sub on Reddit (r/gmrs), but it doesn't even come close to this site (though I think there are a few users on both, myself included).

If you have no PL tone programmed for receive on a channel, you will hear everything on that channel. Well, everything that is strong enough to break the audio squelch.

968's advice is valid but the higher amperage supply I recommended will be less stressed and not prone to overheating and stressing its components. I run a 30 amp supply on my radios which pull 13 A at transmit.

One mag-mount solution that I have had good luck with (for not very much money) is the Tram 1235 NMO mag-mount with the Tram 1126-B 1/4 wave antenna.
 
You should be able to pick up a set for $25-35 on eBay or Amazon.  I'd look on Amazon, since if you don't like it, you can return it.

Nevermind, it was a mechanical issue. One of the wires in the remote cable came out of the connector and didn't make contact with the pin. Inserted it into the connector and I'm in business.

Also check for splitters in the house. Way back when i worked for Spectrum we would get calls with similar complaints. Alot of times we found splitters with 2 cables and 1 or  empty ports with no terminations on them. As others said check the COAX. Anything less than RG6 shielded can cause the issue. My motor home would block on on multiple channels when my GMRS repeater (in the MH) would transmit. Found alot of connections (rg58) with crimps looking like they used a pair of pliers. I replaced all cable in the MH with RG6 quadshield and all my issues went away. 

If his Fox News is on Cable channel 64, then you can't do anything about it.  CATV Hyperband channel 64, no matter whether it's NTSC analog or ATSC QAM Digital, covers a 6MHz wide bandwidth between 462 and 468MHz.  If you transmit anywhere in there, (GMRS) it will overload the TV or converter box.
 
Likewise, if you are transmitting in the 70cm ham band, depending on what frequency you are using, you will wipe out Cable channel 59, 60, or 61. the 2-Meter ham band rides on the same band as Cable channel 18, and MURS will wipe out channel 19.
 
NOTE: Cable channels above 14 are NOT the same frequencies as over-the-air TV channels above 14.  Also note that with digital TV, the station can display whatever "virtual channel" they want you to see.  Perhaps your local CBS affiliate still advertises themselves as "News-4", even though they switched to RF channel 27 over 19 years ago.  Cable systems like to call digital channels much higher numbers such as "Hyper-tier 653" because it makes them sound bigger than they actually are - makes you think they have more channels out there that you just don't pay enough to get.
 
Here is a list of actual frequencies vs. channel numbers for Standard, IRC, and HRC type cable systems, along with standard over-the-air broadcast.
 
https://www.jneuhaus.com/fccindex/cablech.html
 
The visual carrier frequency is shown in this chart. TV is transmitted in Vestigial Sideband mode, meaning a full carrier and upper sideband, but the lower sideband is rolled off 1MHz below the carrier. The lower edge of the channel is 1.25 MHz below the visual carrier and the upper edge is 4.75 MHz above the visual carrier.

There are a ton of encoders and decoders out there, but if another operator is free-handing it and is not transmitting in a consistent speed, they fail to copy correctly.
 
Yes old-timers and people who took the time to learn will give you grief. But many of those same people will brag about all of their unattended, automatic FT8 contacts to Japan when they were sleeping. So I wouldn't sweat it.
 
There really is no way of gauging how many people use automatic tools, but I'm willing to say it's a lot. Especially since many HF radios made in the last 20 years have memory slots for pre-programmed words and phrases that are used often.

I hope to have a valid answer to this very soon.  I have sent an inquiry email to the offices of Fletcher Heald & Hildreth, who are THE experts in the field of communication law.
 
I hope they will respond.

now that's just ridiculous who needs that much cushion on a seat 

It's slim pickins for new, Part 95 hardware.  There is a bunch of grandfathered hardware out there, though.

A few errors here.
GMRS regulations were updated in 2017 and are now Part 95 Subpart E The full text of Part95E is available here. To be legal on GMRS, radios must have been type accepted or certified for: Part-95, Part-95A or Part-95E The icom IC-F6021 is Part-90 certified, but not certified for GMRS. However, it will operate on GMRS frequencies. There have been several discussions about using Part-90 radios, and other "ham" or Part-15 certified radios on GMRS. Many people do this, many don't  Search through the threads and you can read the various opinions.

There are 1659 repeaters listed at myGMRS.com and assuming that 20% are inactive and or otherwise not on line, that still leaves 1328 repeaters. How many of those are WB versus NB?
 
I would submit that most of them are surplus WB "legacy" repeaters. Many owners have a ton of money invested in them, so if GMRS were required to go NB only, I'd bet that many of them would simply pull the plug, thus impoverishing the utility of the service.

have repaired a few antennas using heat shrink tubing worked great and cheap

That is a huge step in the wrong direction, IMHO. We need FRS & GMRS to stop sharing frequencies. Let FRS be low power narrow band and give GMRS operators more wideband frequencies. I'm tired of sharing the channels with 4 and 5 year old kids screaming at their cousin who is only 30 feet away, about how much they love play dough.