WRKC935

Oh, I certainly agree that lightning can be VERY destructive and not directly hit the equipment that it damages. 
Part of the R56 installation manual is the grounding and bonding section.  Now the standard that this manual is detailed to the point of the minimum distance between a rack and the cable tray above it and the distance from the cable tray to the interior lights.  Nothing is missed that you would find inside of a communications site.
I have seen where voltages were induced on metallic but non-electrified objects like file cabinets.  And yes, they are required to be grounded as well for that reason.  One of my favorite lightning stories was a personal experience from back when I was working in the computer field and one of our contract customers was the Ohio department of corrections.  One of their facilities had a control room that sort of stuck out off the rest of the building in an atrium sort of area, AKA "The Yard".  Of course this structure had 1 inch bars over the windows and it was the most physically secure part of the whole campus.  The lightning hit the outside of the building and traveled down the outside of the structure via the bars on it and then arced to the ground, which was evident by looking at the outside of the building.    The current was so high in the bar's that it created enough of a magnetic field to put colored bar's in all the computer monitors.  I had to go home and get a degaussing coil I had from working on television sets (old school CRT stuff) and take it there to get the screens fixed up.  You could tell it was the bars on the windows because the color bars were spaced perfectly with the same spacing as the window bars.  
But even that HUGE magnetic field that was less than 2 feet from a half dozen computers did no damage to and of the computers in the room that were up and running at the time of the strike.  Which further's my personal stance on the protection of electronic gear in a box of some sort to protect it from an EMP.   And with that situation, the bars weren't acting as a faraday cage, they actually increased the "EMP" energy getting into the building via the huge magnetic pulse they created. 

Here's the issue with this.
We don't know what we don't know when it comes to an EMP.  And much of what we do know about it, or think we know comes from Hollywood where all the battery powered everything from automobiles to wrist watches are going to throw sparks all over the place and fry in a very dramatic manner.
Yet it's said that old tube gear will be fine.  Which honestly makes little sense. 
So here's what I know about it.  And this comes from being an R56 certified installer and digging deeper into the bonding and grounding aspect of it.
First thing is you can't 'prevent' lightning, you can only attempt to prepare for it and hope you have done all that is needed.  We all know some CB operator that disconnects his antenna cables in puts them in a glass jar.  News flash on that.  Lightning jumps up to 9 miles during a strike.  That little bit of glass, the 6 to 8 inches of rubber on a car tire or whatever is NOT going to stop the strike.  And in truth, disconnecting the antenna cable if the cable and antenna isn't grounded at all past the shield being connected to the chassis ground of the equipment actually increases the chance of a strike. Glass jar be damned.  The antenna has no where to bleed off the charge that builds up on it and it actually becomes a better path to ground because it's charged and other stuff isn't.  Less of a voltage difference.  Yeah, you may see some arcing on the connector in the jar, but that is an indication of the very thing I am talking about. 
You ground and bond everything to a common point to bleed off that charge.  But you also bond it all together for when it does get hit.  If you have a  couple radios, a computer, power supply and such all connected together as a station, and your your tower gets hit.  If EVERYTHING is bonded, then all that gear jumps to several thousand volts and then back to zero,,, but it all does it at once since it's bonded together.    If you remove that bonding.  Lets say on the computer you are using for HF packet and the power supply.  Now all of a sudden, there is several thousand volts of potential difference between the power supply the computer and the radio.  Guess what happens.  
So back to the EMP business.
An EMP is nothing more than a light lightning strike.  And if you think about that statement, think about lightning and the voltages and currents present you will realize that 10 million amps across a number 2 or even a 4/0 wire is going to be THOUSANDS of volts in the wire.  Yet, towers get hit all the time.  R56 is a standard used for 911 centers where they CAN'T unhook their antenna's and stop working during a storm.  And if there is a tower at the center with radios connected to it and the dispatch console, then there is a direct DC path (considering the voltage potential of lightning) from the top of that mast to the headset of the dispatcher. 
So what do we really know about an EMP?  Do we need to stick radios in Faraday cages to expect them to survive the pulse?  What happened to all the electronic equipment (yes it was tube back in the day) when the US and Russia would test nukes in Nevada and the island chains they were known for?  And when did the testing actually stop?  Well the US's last test was in 1992.  And the North Korean's was in 2017.  Yet there is no information available about peoples cars stopping, radios dying, or any of that.  So at what point would you need to store a radio in a Faraday Cage in order to protect it?  And the answer is striking.  If the EMP is that strong, the radio would need to be stored 30 to 50 feet below ground in a Faraday Cage to survive because you are close enough that the blast wave will destroy it at ground level.  Now of course connected to the grid, and an antenna that distance increases, but not if you have proper bonding and grounding and correct surge suppression on the equipment in question. 
Antenna size and type will also play a role in this.  A big HF antenna like a 40 meter dipole will take a bigger induced voltage than a UHF DC grounded folded dipole Like a DB-404 or other DB series base station antenna.  This is due to the design of the antenna.  Folded dipoles are closed loops with one end being grounded.  HF type dipoles are open ended and typically are NOT grounded.  In fact the standard half wave dipole is suppose to be a balanced design.  So in theory a balun of proper design can be used with an HF dipole to protect the antenna to some degree when coupled with a proper surge suppressor. 
A good reference for this stuff is the Military grounding and bonding manual that goes into not only lightning suppression but EMP mitigation.
 

Little bit of expansion on the discussion of DIY cages.
I have worked with commercial Faraday cages in the past doing RF work.  Reasoning was you can't truly evaluate the performance of a radio receiver when it has multiple RF signals near it. 
The commercially sold cages we used were a sheet metal room (technically sheet aluminum and not metal) with an aluminum frame that the outer shield was screwed to. It was also glued with a conductive construction adhesive.  The door on the unit was staggered and 6 inches thick with the inner face reaching into connect to the inner shield and had finger stock that surrounded the inner part and a separate ring of finger stock on the outer ring.  There was enough room in the cage for a workbench and the required test equipment, a chair for the desk and a bit of space to move around.  It was probably 6 by 6 or 8 by 8, but no bigger.  Special electrical filters were connected to the power feed for the interior and while there was a 'window' it was inset into the door and has copper screening on the interior and the exterior hole was also screened.  So it's technically possible to have a window, it still needs to maintain the 100% shielding inside and out.  Air ducts were connected to the HVAC but there were special screens that needed weekly attention to keep them clean as the screen material was a very fine mesh and collected a TON of dust and crap.
 
Again, there is no really secret sauce for building a cage.  The info is on the web. 
 
 

Ham testing will NOT go away until the rest of the world agrees to it.  The ITU (International Telecommunications Union) set the rules for all countries to follow with regards to radio communications. 
One of the biggest things that allow's GMRS to exist with no real verification of knowledge is the fact it's UHF and low power.
Other than Canada and Mexico, no other countries are going to be in the communications range of any US station (other than MAYBE Russia and users in Alaska, but even that's a big IF. 
Lower frequencies especially HF stuff will carry for extremely long distances when the conditions are right and that happens much more often than band openings in the UHF region. 
So it's really not as easy as the FCC just handing out ham licenses.  The ITU was the reason that the Morse Code requirement hung in so long.  And it was the maritime industry and regulations for ship to shore communications that was the driving force.  A bit of history.  Just prior to the ITU lifting the International code requirement, ships over a certain size were required to have a licensed radio operator on board that knew Morse Code for emergency communications.  That requirement was lifted a year or two before the ITU met and recended the Morse Code requirement for ham licenses.  The whole idea was that a ham operator would be able to receive and handle emergency traffic from a ship at sea that was having problems.  With the full implementation of the EPURB satellite system and a new requirement that all ships were required to have on board emergency radios that would automatically give location information via GPS to the monitoring stations for the system, there was no longer a need or requirement for Morse Code. 
So ham radio requirements were lifted for the first level of ham license (No Code Technician) and the flood gates opened.  The higher class licenses still at that time had a code requirement, mostly due to the older hams raising hell claiming that it would be the end of ham radio,,,, of course that didn't happen and the requirements for code were lifted for all ham license classes. 
I actually started as a No Code Tech, and held that license for over 10 years.  I did finally upgrade to general, but I am yet to get my Extra class license.  I may do it at some point, but I really don't know that I care enough to bother.  Regardless, I will maintain my current call sign as I have had it now for almost 30 years (originally licensed in 1994). 
Point is there is a reason that hams have to test.  And those are the reasons.  With GMRS on UHF we don't really have much ability to interfere with other services in other countries.  With Ham radio on HF or even 50 Mhz (6 meters) there is that possibility and operators need to know where they can operate and where they can't. 
And remember, GMRS radios are NOT suppose to have VFO's, or be programmable one any frequency outside the bounds of the 30 frequencies we are allocated.  Ham radios are not that way.  Granted, they do have transmit blocks in the newer radios.  But the old tube gear was smile and dial so to speak.
 

Little bit of expansion on the discussion of DIY cages.
I have worked with commercial Faraday cages in the past doing RF work.  Reasoning was you can't truly evaluate the performance of a radio receiver when it has multiple RF signals near it. 
The commercially sold cages we used were a sheet metal room (technically sheet aluminum and not metal) with an aluminum frame that the outer shield was screwed to. It was also glued with a conductive construction adhesive.  The door on the unit was staggered and 6 inches thick with the inner face reaching into connect to the inner shield and had finger stock that surrounded the inner part and a separate ring of finger stock on the outer ring.  There was enough room in the cage for a workbench and the required test equipment, a chair for the desk and a bit of space to move around.  It was probably 6 by 6 or 8 by 8, but no bigger.  Special electrical filters were connected to the power feed for the interior and while there was a 'window' it was inset into the door and has copper screening on the interior and the exterior hole was also screened.  So it's technically possible to have a window, it still needs to maintain the 100% shielding inside and out.  Air ducts were connected to the HVAC but there were special screens that needed weekly attention to keep them clean as the screen material was a very fine mesh and collected a TON of dust and crap.
 
Again, there is no really secret sauce for building a cage.  The info is on the web. 
 
 

Here's the issue with this.
We don't know what we don't know when it comes to an EMP.  And much of what we do know about it, or think we know comes from Hollywood where all the battery powered everything from automobiles to wrist watches are going to throw sparks all over the place and fry in a very dramatic manner.
Yet it's said that old tube gear will be fine.  Which honestly makes little sense. 
So here's what I know about it.  And this comes from being an R56 certified installer and digging deeper into the bonding and grounding aspect of it.
First thing is you can't 'prevent' lightning, you can only attempt to prepare for it and hope you have done all that is needed.  We all know some CB operator that disconnects his antenna cables in puts them in a glass jar.  News flash on that.  Lightning jumps up to 9 miles during a strike.  That little bit of glass, the 6 to 8 inches of rubber on a car tire or whatever is NOT going to stop the strike.  And in truth, disconnecting the antenna cable if the cable and antenna isn't grounded at all past the shield being connected to the chassis ground of the equipment actually increases the chance of a strike. Glass jar be damned.  The antenna has no where to bleed off the charge that builds up on it and it actually becomes a better path to ground because it's charged and other stuff isn't.  Less of a voltage difference.  Yeah, you may see some arcing on the connector in the jar, but that is an indication of the very thing I am talking about. 
You ground and bond everything to a common point to bleed off that charge.  But you also bond it all together for when it does get hit.  If you have a  couple radios, a computer, power supply and such all connected together as a station, and your your tower gets hit.  If EVERYTHING is bonded, then all that gear jumps to several thousand volts and then back to zero,,, but it all does it at once since it's bonded together.    If you remove that bonding.  Lets say on the computer you are using for HF packet and the power supply.  Now all of a sudden, there is several thousand volts of potential difference between the power supply the computer and the radio.  Guess what happens.  
So back to the EMP business.
An EMP is nothing more than a light lightning strike.  And if you think about that statement, think about lightning and the voltages and currents present you will realize that 10 million amps across a number 2 or even a 4/0 wire is going to be THOUSANDS of volts in the wire.  Yet, towers get hit all the time.  R56 is a standard used for 911 centers where they CAN'T unhook their antenna's and stop working during a storm.  And if there is a tower at the center with radios connected to it and the dispatch console, then there is a direct DC path (considering the voltage potential of lightning) from the top of that mast to the headset of the dispatcher. 
So what do we really know about an EMP?  Do we need to stick radios in Faraday cages to expect them to survive the pulse?  What happened to all the electronic equipment (yes it was tube back in the day) when the US and Russia would test nukes in Nevada and the island chains they were known for?  And when did the testing actually stop?  Well the US's last test was in 1992.  And the North Korean's was in 2017.  Yet there is no information available about peoples cars stopping, radios dying, or any of that.  So at what point would you need to store a radio in a Faraday Cage in order to protect it?  And the answer is striking.  If the EMP is that strong, the radio would need to be stored 30 to 50 feet below ground in a Faraday Cage to survive because you are close enough that the blast wave will destroy it at ground level.  Now of course connected to the grid, and an antenna that distance increases, but not if you have proper bonding and grounding and correct surge suppression on the equipment in question. 
Antenna size and type will also play a role in this.  A big HF antenna like a 40 meter dipole will take a bigger induced voltage than a UHF DC grounded folded dipole Like a DB-404 or other DB series base station antenna.  This is due to the design of the antenna.  Folded dipoles are closed loops with one end being grounded.  HF type dipoles are open ended and typically are NOT grounded.  In fact the standard half wave dipole is suppose to be a balanced design.  So in theory a balun of proper design can be used with an HF dipole to protect the antenna to some degree when coupled with a proper surge suppressor. 
A good reference for this stuff is the Military grounding and bonding manual that goes into not only lightning suppression but EMP mitigation.
 

Well, if we are gonna get into 'real' Faraday Cages, then lets actually talk about their construction.
First off, they are layered.  There is an outer and inner layer and they are NOT connected together. 
Hole size in the shielding material is what sets the minimum / maximum frequency that is blocked.  In other words.  A fine mesh will block a higher frequency than chicken wire will with 1 inch holes in it.  Consider the holes with regard to frequency wavelength.  If the hole is larger than the wavelength of the frequency in question, it will pass right through like it wasn't even there.
A strong understanding of the signal level and the attenuation level of the Faraday Cage needs to be taken into account.  A cage is not a perfect attenuator.  It has very high attenuation levels, but a signal that is strong enough will get through at a much reduced level. 
 
Proper construction.
A 2X4 or 2X6 frame is sufficient spacing to get a very high attenuation level with modest materials.  Those being standard wood framing and aluminum screen. For an added sense of security, thin sheet metal can be used in place of the screen.  You have an inner layer and an outer layer.  of the conductive screen material.  And remember they can't in any way be connected or you will loose attenuation properties.  The other thing you need is a GOOD earth ground.  This is not the 1 or 2 ground rods that are grounding your electrical service entrance, you will need to do better and it's advisable that the grounds be kept short as possible.  So if you are planning on building a cage, do it on the first floor or in the basement near an outside wall so you can get the ground wires out the wall and to the ground field withthe shortest wire possible.   Longer wires equal bigger antenna's and you don't want that. 
To put a door on the cage, you will need to ensure that the entire perimeter of the door be connected to the screens, both inside and outside.  Couple ways of dealing with this is either finger stock, copper or other metallic door trim / weather stripping, or construction methods that taper the inner and outer screens in a way that when the door / cover is in place that a 100% seal exists in all locations around the door inside and out.  
Again, can't say this enough, the INNER shielding material is NOT connected to ANYTHING including the outer shielding material.
 
For those that are looking to play around and build something similar to the professional level cages, this should be a good starting point.  Sure you can locate copper screen and use that.  It will work the best but it's also very expensive.  Not worth the money to protect your Baofeng radios. 
 
If you are REALLY wanting to go for broke and build a large cage, and be able to occupy the space, there are methods of bringing power and RF into the cage, but special filters and methods are required and are put in place outside the cage and are bonded to the same ground as the outer layer of the cage.  Remember that you need both layers of screening on all sides, including the roof and floor.  There is no reason that you can't set the floor screen and then sheet over it with layers of plywood or other subflooring material as long as the screening isn't molested (floating floor material.And of course you can also drywall the walls and ceiling but it's advisable to use construction cement and not screws to fasten the drywall to the framing.  Screws can be used sparingly to assist in placing the drywall until the adhesive is dry but will need to be removed after that happens to ensure the best isolation.  If you bring electricity into the cage, do NOT bring a ground with it and you HAVE to use an isolation transformer with proper filtering right at the entry point on the OUTSIDE of the cage,  DO NOT use conductive conduit to route wiring through within the inner shield. 
Detailed construction instructions are available on the web for building a Faraday Cage.  Study those plans carefully and scale your project to your needs.
 
 

And that was my whole point.  Thing is that the South Korea and China saw no damage either.  And I was at a loss to find any information on damage done in the US from tests when they were conducted, which was the point of what I said. 
EMP is a real thing, and I am not trying to minimize the effects of it when it comes to things like the electrical grid. 
But to hear some people talk about an EMP is that anyone with ear rings in will be electrocuted by the voltage induced between them across your head.  We had cars with computers in the 90's.  No one seemed to be effected by the EMP from any of the testing in that era.  Sure those detonations were below ground.  But if the EMP is that powerful to effect every car in the midwest from a high altitude air burst then how is it that no one was effected at all during any of the testing.  Or were those effects just not documented?  I don't know. 
 

Here's the issue with this.
We don't know what we don't know when it comes to an EMP.  And much of what we do know about it, or think we know comes from Hollywood where all the battery powered everything from automobiles to wrist watches are going to throw sparks all over the place and fry in a very dramatic manner.
Yet it's said that old tube gear will be fine.  Which honestly makes little sense. 
So here's what I know about it.  And this comes from being an R56 certified installer and digging deeper into the bonding and grounding aspect of it.
First thing is you can't 'prevent' lightning, you can only attempt to prepare for it and hope you have done all that is needed.  We all know some CB operator that disconnects his antenna cables in puts them in a glass jar.  News flash on that.  Lightning jumps up to 9 miles during a strike.  That little bit of glass, the 6 to 8 inches of rubber on a car tire or whatever is NOT going to stop the strike.  And in truth, disconnecting the antenna cable if the cable and antenna isn't grounded at all past the shield being connected to the chassis ground of the equipment actually increases the chance of a strike. Glass jar be damned.  The antenna has no where to bleed off the charge that builds up on it and it actually becomes a better path to ground because it's charged and other stuff isn't.  Less of a voltage difference.  Yeah, you may see some arcing on the connector in the jar, but that is an indication of the very thing I am talking about. 
You ground and bond everything to a common point to bleed off that charge.  But you also bond it all together for when it does get hit.  If you have a  couple radios, a computer, power supply and such all connected together as a station, and your your tower gets hit.  If EVERYTHING is bonded, then all that gear jumps to several thousand volts and then back to zero,,, but it all does it at once since it's bonded together.    If you remove that bonding.  Lets say on the computer you are using for HF packet and the power supply.  Now all of a sudden, there is several thousand volts of potential difference between the power supply the computer and the radio.  Guess what happens.  
So back to the EMP business.
An EMP is nothing more than a light lightning strike.  And if you think about that statement, think about lightning and the voltages and currents present you will realize that 10 million amps across a number 2 or even a 4/0 wire is going to be THOUSANDS of volts in the wire.  Yet, towers get hit all the time.  R56 is a standard used for 911 centers where they CAN'T unhook their antenna's and stop working during a storm.  And if there is a tower at the center with radios connected to it and the dispatch console, then there is a direct DC path (considering the voltage potential of lightning) from the top of that mast to the headset of the dispatcher. 
So what do we really know about an EMP?  Do we need to stick radios in Faraday cages to expect them to survive the pulse?  What happened to all the electronic equipment (yes it was tube back in the day) when the US and Russia would test nukes in Nevada and the island chains they were known for?  And when did the testing actually stop?  Well the US's last test was in 1992.  And the North Korean's was in 2017.  Yet there is no information available about peoples cars stopping, radios dying, or any of that.  So at what point would you need to store a radio in a Faraday Cage in order to protect it?  And the answer is striking.  If the EMP is that strong, the radio would need to be stored 30 to 50 feet below ground in a Faraday Cage to survive because you are close enough that the blast wave will destroy it at ground level.  Now of course connected to the grid, and an antenna that distance increases, but not if you have proper bonding and grounding and correct surge suppression on the equipment in question. 
Antenna size and type will also play a role in this.  A big HF antenna like a 40 meter dipole will take a bigger induced voltage than a UHF DC grounded folded dipole Like a DB-404 or other DB series base station antenna.  This is due to the design of the antenna.  Folded dipoles are closed loops with one end being grounded.  HF type dipoles are open ended and typically are NOT grounded.  In fact the standard half wave dipole is suppose to be a balanced design.  So in theory a balun of proper design can be used with an HF dipole to protect the antenna to some degree when coupled with a proper surge suppressor. 
A good reference for this stuff is the Military grounding and bonding manual that goes into not only lightning suppression but EMP mitigation.
 

Here's the issue with this.
We don't know what we don't know when it comes to an EMP.  And much of what we do know about it, or think we know comes from Hollywood where all the battery powered everything from automobiles to wrist watches are going to throw sparks all over the place and fry in a very dramatic manner.
Yet it's said that old tube gear will be fine.  Which honestly makes little sense. 
So here's what I know about it.  And this comes from being an R56 certified installer and digging deeper into the bonding and grounding aspect of it.
First thing is you can't 'prevent' lightning, you can only attempt to prepare for it and hope you have done all that is needed.  We all know some CB operator that disconnects his antenna cables in puts them in a glass jar.  News flash on that.  Lightning jumps up to 9 miles during a strike.  That little bit of glass, the 6 to 8 inches of rubber on a car tire or whatever is NOT going to stop the strike.  And in truth, disconnecting the antenna cable if the cable and antenna isn't grounded at all past the shield being connected to the chassis ground of the equipment actually increases the chance of a strike. Glass jar be damned.  The antenna has no where to bleed off the charge that builds up on it and it actually becomes a better path to ground because it's charged and other stuff isn't.  Less of a voltage difference.  Yeah, you may see some arcing on the connector in the jar, but that is an indication of the very thing I am talking about. 
You ground and bond everything to a common point to bleed off that charge.  But you also bond it all together for when it does get hit.  If you have a  couple radios, a computer, power supply and such all connected together as a station, and your your tower gets hit.  If EVERYTHING is bonded, then all that gear jumps to several thousand volts and then back to zero,,, but it all does it at once since it's bonded together.    If you remove that bonding.  Lets say on the computer you are using for HF packet and the power supply.  Now all of a sudden, there is several thousand volts of potential difference between the power supply the computer and the radio.  Guess what happens.  
So back to the EMP business.
An EMP is nothing more than a light lightning strike.  And if you think about that statement, think about lightning and the voltages and currents present you will realize that 10 million amps across a number 2 or even a 4/0 wire is going to be THOUSANDS of volts in the wire.  Yet, towers get hit all the time.  R56 is a standard used for 911 centers where they CAN'T unhook their antenna's and stop working during a storm.  And if there is a tower at the center with radios connected to it and the dispatch console, then there is a direct DC path (considering the voltage potential of lightning) from the top of that mast to the headset of the dispatcher. 
So what do we really know about an EMP?  Do we need to stick radios in Faraday cages to expect them to survive the pulse?  What happened to all the electronic equipment (yes it was tube back in the day) when the US and Russia would test nukes in Nevada and the island chains they were known for?  And when did the testing actually stop?  Well the US's last test was in 1992.  And the North Korean's was in 2017.  Yet there is no information available about peoples cars stopping, radios dying, or any of that.  So at what point would you need to store a radio in a Faraday Cage in order to protect it?  And the answer is striking.  If the EMP is that strong, the radio would need to be stored 30 to 50 feet below ground in a Faraday Cage to survive because you are close enough that the blast wave will destroy it at ground level.  Now of course connected to the grid, and an antenna that distance increases, but not if you have proper bonding and grounding and correct surge suppression on the equipment in question. 
Antenna size and type will also play a role in this.  A big HF antenna like a 40 meter dipole will take a bigger induced voltage than a UHF DC grounded folded dipole Like a DB-404 or other DB series base station antenna.  This is due to the design of the antenna.  Folded dipoles are closed loops with one end being grounded.  HF type dipoles are open ended and typically are NOT grounded.  In fact the standard half wave dipole is suppose to be a balanced design.  So in theory a balun of proper design can be used with an HF dipole to protect the antenna to some degree when coupled with a proper surge suppressor. 
A good reference for this stuff is the Military grounding and bonding manual that goes into not only lightning suppression but EMP mitigation.
 

First off what is a 'channel block'  forgive my ignorance.  I have been a commercial radio tech for going on 15 years and a ham for 30.  Never heard that term.  I see things in zones and channels.
If you are scanning the simplex channels with NO tone, and scanning the repeaters with tone the radio can stop on either one if a repeater is transmitting.  If it's not looking for any tone, then any tone will work as well as no tone at all.  Because it's not looking for it.
No clue what radio you are using, so I can't even comment on the idea of priority scan.  If it's a commercial radio, and it has priority scan running it will look at a channel, then the priority list, then the next channel in the scan list then the priority list again, then the next scan list member.  This can slow scanning down a good bit, and commercial radios are NOT good scanners.  They are not fast with standard scanning, and when you turn on priority scanning they get really slow. 
 
My advice, if you are gonna be scanning, buy a scanner.  In fact as long as the stuff you are scanning is analog and not P25 trunking, buy several scanners.  If you do have trunking stuff you are wanting to monitor, get a scanner for that too.  Analog scanners are dirt cheap because they don't listen to the police any more in many places.  But if you are wanting to monitor GMRS, ham or other analog stuff they work great.
 And trying to figure out what a radio in scan mode is doing by looking at percentages of when it stops and opens up isn't really gonna work out for you.
 
 

Oh I can't afford free towers.  Especially big broadcast towers.  What you end up finding out is the towers typically will not pass a structural analysis and can't be used unless extensive reinforcement is done to them, if it's possible at all.  When the power that be (local building inspectors) ask for the results, you don't be a permit to stand the thing back up.
 
And that says nothing of the cost of dismantling a standing tower, transporting it and erecting in at a new location.
I personally went through this with a Rohn 80 that was only 10 years old at the time.   While it would still pass analysis, the concrete alone to put it back up was going to cost me 15K.  With a total cost of about 50K to get the thing standing.  I didn't have enough land to do it either, which of course is a concern. 
Point is if a tower that costs tens or even hundred of thousands to erect is FREE, free is TOO expensive for most.
 

I see how if you want to split hairs here that it applies. 
What I am saying is that if I go down to the local TV station that has two UHF MSF5000's repeaters sitting on a deck at 750 feet. Yes, they are there I have worked on them.  If I get permission from them to go up  there and reprogram one for a GMRS frequency, lower the power to 50 watts (100 watt stations) then I am completely legal as far as the FCC is concerned.  Now that's not going to happen since they use those repeaters.  But, the FCC regulations regarding GMRS don't have any restriction on me doing it.  That's the point I was trying to make. 

So me in the part 95 regulations where it says you can't place an antenna above X height.  It's NOT there... anywhere.  What you can build for a tower is going to be limited by your location with regard to airports, flight paths and other factors.  And yes, getting the proper permitting for a 1000 foot tower may not may not be possible in a specific location.  You may be limited to 20 feet and be required to have obstruction lighting on it even at that height if you are right off the end of a runway.  But that is still not a GMRS SPECIFIC height restriction.  It's a general restriction that would apply to any tower including one for a TV antenna.  

Yes, this is correct.  But if you either have the structure already, permission to install on a tower owned by others, or have deep enough pockets to stand up a tower there is no limit to the height of a GMRS antenna.  On LMR, the coordination body / FCC limits ERP, power out and height to maintain coverage only extends to your licensed operating area.  Yes, we are limited to 50 watts out on power.  But we have no ERP restriction outside the 467Mhz channels that are limited to .5 watt ERP.
And while the FCC has the requirements in place for obstruction marking (tower lights) in their regulations, it's the FAA that sets these standards.

And this thread ladies and gentlemen is why some of us that actually work or have worked in the communications industry and might know a bit more about these topics than the casual user tend to steer clear of posts like this and giving technical answers to questions.  There is always somebody that thinks that someone told them something else that they have ZERO first hand knowledge of will argue with guys that do this crap for a living.  It gets old.  And is one of the reasons that guys like me no longer bother with these forums like we did. 
But here's the sad part of all of this.  There are some on here that DO know.  And when they get driven off of here due to the BS, you loose that knowledge base. 
 

Your spelling is Wong / Wrong.... sorry, couldn't resist
 

Yeah,
add repeaters are EXPENSIVE, hard to support, and will either bring you constant complaints that the coverage doesn't go someplace specific they want it to or that no one will ever use the thing.  But it's usually both issues that arise.
Obviously need to cover radio operations, passing a conversation.  Waiting on others to break in.  Not trying to talk over the reset tone.  Roger beeps are for CB and not GMRS. 

Yeah,
add repeaters are EXPENSIVE, hard to support, and will either bring you constant complaints that the coverage doesn't go someplace specific they want it to or that no one will ever use the thing.  But it's usually both issues that arise.
Obviously need to cover radio operations, passing a conversation.  Waiting on others to break in.  Not trying to talk over the reset tone.  Roger beeps are for CB and not GMRS. 

Yeah, I got involved with a forum that started as outdoor warning siren techs and manufactures.  We would exchange info on different things we had seen, odd issues that we couldn't figure out and crap like that. 
Then the 13 year olds took it over.  And they wanted to discuss leaning poles and what specific frequencies the sirens operated at and all sort of nonsense that had no bearing on keeping them running.   Then of course they started disagreeing with people.  Once case the guy that dude was arguing with was the guy that designed the equipment in question.  He was the designer for that manufacture.  And this clown is arguing with him about what he's saying about the equipment is incorrect. 
That was the beginning of the end. All of use that were in the industry left.  And it was a shame, because at one point it was a very helpful took to reference.  Now, not so much.
But I actually am tired of stirring the pot. And any more, there is no need to stir it.  It just happens on its own.  And again, it just gets boring to see a horse beat to pink slime.
 

Yeah, but at least in that case, you can go in the archives and grab the original design documents and put them in from of the guy and ask him how he's more familiar with the equipment than you are?
Outside of one guy at work, we don't have that problem.  We work together.  The one boob.. I taught to tune a specific duplexer, and did it wrong.  I went to him, applogized for the mistake and tried to retrain him.  He was having none of that.  The method that I taught him, mind you I am standing there telling this clown I had told him incorrectly, was fine and that was the way he was gonna do it. 
But that's the way this guy is.  And he's scared of me.  Like a LOT. Never really gave him a specific reason, he just is.  And the other employee's can't figure it out.  This clown will fart, burp, make noises, laugh in a loud and obnoxious way around anyone, except ME.  Our boss included.  I walk in the tech room and he pulls himself up to his desk, shuts his mouth and works.  Minute I leave, he's right back at it. 
He did one day after I got on him for screwing off and not doing his job and butting into mine finally decided to muster the courage to tell me th 'go to hell' and called me an asshole.
I IMMEDIATELY replied that my reservations for Hell were confirmed the prior week and as far as being an asshole, I appreciated the recognition of my continuing efforts.
And it wasn't that he said it that was so funny.... It was the way he said it.  Like he knew I was gonna pound him for it.  So his voice was cracking and he was almost timid about it.  When I fired back, the whole room got up and left.  But of course as soon as they cleared the door they all busted out laughing. 
Gotta love co-workers

Yeah, I got involved with a forum that started as outdoor warning siren techs and manufactures.  We would exchange info on different things we had seen, odd issues that we couldn't figure out and crap like that. 
Then the 13 year olds took it over.  And they wanted to discuss leaning poles and what specific frequencies the sirens operated at and all sort of nonsense that had no bearing on keeping them running.   Then of course they started disagreeing with people.  Once case the guy that dude was arguing with was the guy that designed the equipment in question.  He was the designer for that manufacture.  And this clown is arguing with him about what he's saying about the equipment is incorrect. 
That was the beginning of the end. All of use that were in the industry left.  And it was a shame, because at one point it was a very helpful took to reference.  Now, not so much.
But I actually am tired of stirring the pot. And any more, there is no need to stir it.  It just happens on its own.  And again, it just gets boring to see a horse beat to pink slime.
 

Yeah, I got involved with a forum that started as outdoor warning siren techs and manufactures.  We would exchange info on different things we had seen, odd issues that we couldn't figure out and crap like that. 
Then the 13 year olds took it over.  And they wanted to discuss leaning poles and what specific frequencies the sirens operated at and all sort of nonsense that had no bearing on keeping them running.   Then of course they started disagreeing with people.  Once case the guy that dude was arguing with was the guy that designed the equipment in question.  He was the designer for that manufacture.  And this clown is arguing with him about what he's saying about the equipment is incorrect. 
That was the beginning of the end. All of use that were in the industry left.  And it was a shame, because at one point it was a very helpful took to reference.  Now, not so much.
But I actually am tired of stirring the pot. And any more, there is no need to stir it.  It just happens on its own.  And again, it just gets boring to see a horse beat to pink slime.
 

First off, I never said that keeping unauthorized users off a radio system was the only reason for trunking.  But it WAS a sales point. 
Never heard of people using 'illegal radios to access a trunked system'  Maybe not in your state... Ohio has had several instances of people being busted for selling radios that were programmed for the state wide system. 
Never heard of it prior to trunking?  I have worked with the FCC and in one case the FCC and FBI tracking someone that was interfering with repeater systems that were County EMA equipment.  All EMA's fall under Homeland Security.  And due to that screwing with them can be considered a terrorist activity.  And that's not some guess or interpretation, that was directly from the agents I was working with. 
We also figured out that the radio that was being used was indeed a cheap import.  The 'roger beeps' on those radios are distinctive and the logging recorder that we had running did hear that specific set of tones multiple times in the case where the FBI was involved.  The other times were fire and police repeaters that the FCC came out and tried to hunt the person or persons down but had no luck, other than whoever it was stopped doing it.  But it was made public in the radio communities that the FCC was in town and that is what seemed to make it stop. 
Back to the trunking thing.. Yes, the primary reasons for trunking systems is frequency management and sharing.  But interoperability, access control and radio resource management are also big parts of it too.  And wide area coverage beyond the county level is a big piece of it was well.  You simply couldn't use a single frequency across three or more counties that contained any significant population. 

And this thread ladies and gentlemen is why some of us that actually work or have worked in the communications industry and might know a bit more about these topics than the casual user tend to steer clear of posts like this and giving technical answers to questions.  There is always somebody that thinks that someone told them something else that they have ZERO first hand knowledge of will argue with guys that do this crap for a living.  It gets old.  And is one of the reasons that guys like me no longer bother with these forums like we did. 
But here's the sad part of all of this.  There are some on here that DO know.  And when they get driven off of here due to the BS, you loose that knowledge base.