GMRS info request

[Prerunner1982]

At one point, I did look to see if there were any available callsigns that contained "WTF", but apparently that trigram is popular/desired among many. Can't imagine why.

When I was looking at a vanity callsign one of the ones I came across was WX5WTF and I thought it fit perfect for Oklahoma weather but there was already a pending request for it and I didn't want it bad enough to take it away from someone else.

 

[OverlandOzzy1]

Just obtained my GMRS license. Now am on the hunt for a used 275 if anyone has one available

 

[socal66]

Mount options: I haven't looked a Jeep cowl recently, but I recall that there are many options for Jeep-specific mounts - I'll let the Jeep Guys comment on those. A good generic option for the hood is a Diamond K400 lip mount with either a UHF mount or NMO mount to match your antenna.

Mounting on the hood or tailgate can cost a little antenna efficiency, but not enough to tie yourself in knots over. Try to space the antennas apart from each other and from the metal window pillars. When I ran hood mounts on my 4runner, the configuration that seemed to work best was to put one antenna on each side (the rule of thumb I use is half a wavelength - about 40inches for 2m ham), and locate them at least a foot from the A-Pillars (far enough for radio separation from the metal pillars and far enough that when I open the hood, the antennas don't hit the windshield). The fiberglass will be less of a screening obstruction than metal. A hood mount might look something like this:

View attachment 165041

This is good to hear. I'll probably go with the rear mount when I have both radios. For now I will use the cowl mount that I fabricated for my GMRS radio and see how that works.

Another question...

What is the best practice with regards to grounding mobile antennas? I read things like they should be grounded to a flat metal surface of a certain size, etc. If I ensure that there is simply good conductivity from the antenna to the vehicle frame would that be sufficient enough?

 

[LostInThought]

This is good to hear. I'll probably go with the rear mount when I have both radios. For now I will use the cowl mount that I fabricated for my GMRS radio and see how that works.

Another question...

What is the best practice with regards to grounding mobile antennas? I read things like they should be grounded to a flat metal surface of a certain size, etc. If I ensure that there is simply good conductivity from the antenna to the vehicle frame would that be sufficient enough?

GOOD QUESTION! Though we're strarting to get down into details that most people with a radio never learn. First let me knock off a little terminology:

UHF - ultra high frequency. This includes 70cm ham (420-450MHz) and GMRS (462-467MHz).
VHF - very high frequency. This includes 2m ham (144-148MHz)
HF - high frequency. Most of the other ham bands from around 50MHz and lower. CB radios are down here.
RF - radio frequency signals/waves

There are two issues here. Both confusingly referring to a "ground" of some sort. The VHF/UHF antenna specs *SHOULD* state if either or both are required. (but getting it exactly right is more important for HF than for the typical mobile VHF/UHF which are pretty forgiving.) Here's a rundown:

• An electrical "ground" in which the mount itself is in electrical contact with the vehicle body. Some antennas are more sensitive to a lack of this than others. Other antennas don't care so much. If a grounded mount is required, it should be mentioned in the antenna specs. If the mount is bolted onto the body (or includes set-screws to make that contact like the lip mount I mentioned earlier) then this is taken care of. Electrical ground can be notoriously bad for luggage rack mounts and while I've played with adding a grounding wire here from the mount to one of the rack's mounting bolts, I'm not sure that it was a net improvement. For other antennas, the shielding of the coax cable connects the antenna mount to electrical ground via the radio chassis's electrical ground. The presence/absence of grounding can sometimes cause efficiency problems with an antenna, or introduce more noise (static etc) on the radio. For HF you sometimes have to add grounding straps to connect doors, trunk lids, body panels to the chassis to reduce noise/static. YMMV.
• An RF "ground" plane(aka counterpoise) is essentially a mass of metal under the antenna. Again, this matters more for some antenna designs and not so much for others. The antenna specs should tell you "ground plane required" or "no ground plane required". For VHF/UHF antennas that do need an RF ground plane, the center of a metal roof works best, the edge or corner of a metal roof/trunk-lid/hood is second best, and after that any mass of metal under the antenna (except, I *think* HF likes this best). In cases where the RF ground is present, but the specific antenna doesn't require it, I haven't seen any performance issue. Only when they are needed and not present.
  • How big should the RF ground plane be? Technical answer is at least 1/4 wavelength radius, This means about 7" radius or 14" diameter for UHF and about 20" radius or 40" diameter for VHF. BUT again these frequencies/wavelengths are pretty forgiving. Bigger doesn't hurt at all and smaller doesn't hurt much.
  • What about magnetic mount antennas? Unless the antenna specs say "not suitable for mag mount" the magnetic coupling between the mount and the metal roof should provide enough RF ground plane.
  • Why do some antennas need an RF ground plane? That's a sneaky little bit of magic. The ground plane acts like a mirror for the RF waves, effectively making the antenna appear and behave as if it were twice as long, helping to "pull" the RF power away from the sky straight above and "push" it more toward the horizon (or more specifically, along the ground plane). If that sounds weird, unclear, and non-intuitive, you've just joined millions of ham radio operators world-wide.

 

[Prerunner1982]

Wow, enjoyed all the conversation today fellas.

 

[Boppa's Travels]

Obsessive Compulsive Disorder is correct. Minor really, mostly things on my desk have to be parallel or dress right dress if you were prior military. And when my antennas started multiplying I placed them evenly on the vehicle.
CB on the drivers fender, opposite the AM/FM stereo antenna.
2m APRS antenna on passenger rear corner.
HF on driver rear corner.
2m voice antenna in the middle of the roof.
Almost like the 5 side of a dice.. 2 in front, 2 in rear and 1 in the middle.
I then added the GMRS antenna between the two on the back to make it 3 antennas across the back of the vehicle.

There was a lady I worked with for several years that was OCD. She had a glass container with beads that she would stick pens with flowers on the end. I would always walk in take my pen from my shirt and swap them out. I guess that was mean but it became a running joke with us.

 

[Boppa's Travels]

At one point, I did look to see if there were any available callsigns that contained "WTF", but apparently that trigram is popular/desired among many. Can't imagine why.

hmm I wonder why?

 

[Boppa's Travels]

hmm I wonder why?

Oh dang that just reminded me to check the FCC to see if I have a call sign yet.

 

[Boppa's Travels]

Yep I have a call sign. Just added to my profile.

 

[Boppa's Travels]

GOOD QUESTION! Though we're strarting to get down into details that most people with a radio never learn. First let me knock off a little terminology:

UHF - ultra high frequency. This includes 70cm ham (420-450MHz) and GMRS (462-467MHz).
VHF - very high frequency. This includes 2m ham (144-148MHz)
HF - high frequency. Most of the other ham bands from around 50MHz and lower. CB radios are down here.
RF - radio frequency signals/waves

There are two issues here. Both confusingly referring to a "ground" of some sort. The VHF/UHF antenna specs *SHOULD* state if either or both are required. (but getting it exactly right is more important for HF than for the typical mobile VHF/UHF which are pretty forgiving.) Here's a rundown:

• An electrical "ground" in which the mount itself is in electrical contact with the vehicle body. Some antennas are more sensitive to a lack of this than others. Other antennas don't care so much. If a grounded mount is required, it should be mentioned in the antenna specs. If the mount is bolted onto the body (or includes set-screws to make that contact like the lip mount I mentioned earlier) then this is taken care of. Electrical ground can be notoriously bad for luggage rack mounts and while I've played with adding a grounding wire here from the mount to one of the rack's mounting bolts, I'm not sure that it was a net improvement. For other antennas, the shielding of the coax cable connects the antenna mount to electrical ground via the radio chassis's electrical ground. The presence/absence of grounding can sometimes cause efficiency problems with an antenna, or introduce more noise (static etc) on the radio. For HF you sometimes have to add grounding straps to connect doors, trunk lids, body panels to the chassis to reduce noise/static. YMMV.
• An RF "ground" plane(aka counterpoise) is essentially a mass of metal under the antenna. Again, this matters more for some antenna designs and not so much for others. The antenna specs should tell you "ground plane required" or "no ground plane required". For VHF/UHF antennas that do need an RF ground plane, the center of a metal roof works best, the edge or corner of a metal roof/trunk-lid/hood is second best, and after that any mass of metal under the antenna (except, I *think* HF likes this best). In cases where the RF ground is present, but the specific antenna doesn't require it, I haven't seen any performance issue. Only when they are needed and not present.
  • How big should the RF ground plane be? Technical answer is at least 1/4 wavelength radius, This means about 7" radius or 14" diameter for UHF and about 20" radius or 40" diameter for VHF. BUT again these frequencies/wavelengths are pretty forgiving. Bigger doesn't hurt at all and smaller doesn't hurt much.
  • What about magnetic mount antennas? Unless the antenna specs say "not suitable for mag mount" the magnetic coupling between the mount and the metal roof should provide enough RF ground plane.
  • Why do some antennas need an RF ground plane? That's a sneaky little bit of magic. The ground plane acts like a mirror for the RF waves, effectively making the antenna appear and behave as if it were twice as long, helping to "pull" the RF power away from the sky straight above and "push" it more toward the horizon (or more specifically, along the ground plane). If that sounds weird, unclear, and non-intuitive, you've just joined millions of ham radio operators world-wide.

Thanks for that info.

 

[socal66]

GOOD QUESTION! Though we're strarting to get down into details that most people with a radio never learn. First let me knock off a little terminology:

UHF - ultra high frequency. This includes 70cm ham (420-450MHz) and GMRS (462-467MHz).
VHF - very high frequency. This includes 2m ham (144-148MHz)
HF - high frequency. Most of the other ham bands from around 50MHz and lower. CB radios are down here.
RF - radio frequency signals/waves

There are two issues here. Both confusingly referring to a "ground" of some sort. The VHF/UHF antenna specs *SHOULD* state if either or both are required. (but getting it exactly right is more important for HF than for the typical mobile VHF/UHF which are pretty forgiving.) Here's a rundown:

• An electrical "ground" in which the mount itself is in electrical contact with the vehicle body. Some antennas are more sensitive to a lack of this than others. Other antennas don't care so much. If a grounded mount is required, it should be mentioned in the antenna specs. If the mount is bolted onto the body (or includes set-screws to make that contact like the lip mount I mentioned earlier) then this is taken care of. Electrical ground can be notoriously bad for luggage rack mounts and while I've played with adding a grounding wire here from the mount to one of the rack's mounting bolts, I'm not sure that it was a net improvement. For other antennas, the shielding of the coax cable connects the antenna mount to electrical ground via the radio chassis's electrical ground. The presence/absence of grounding can sometimes cause efficiency problems with an antenna, or introduce more noise (static etc) on the radio. For HF you sometimes have to add grounding straps to connect doors, trunk lids, body panels to the chassis to reduce noise/static. YMMV.
• An RF "ground" plane(aka counterpoise) is essentially a mass of metal under the antenna. Again, this matters more for some antenna designs and not so much for others. The antenna specs should tell you "ground plane required" or "no ground plane required". For VHF/UHF antennas that do need an RF ground plane, the center of a metal roof works best, the edge or corner of a metal roof/trunk-lid/hood is second best, and after that any mass of metal under the antenna (except, I *think* HF likes this best). In cases where the RF ground is present, but the specific antenna doesn't require it, I haven't seen any performance issue. Only when they are needed and not present.
  • How big should the RF ground plane be? Technical answer is at least 1/4 wavelength radius, This means about 7" radius or 14" diameter for UHF and about 20" radius or 40" diameter for VHF. BUT again these frequencies/wavelengths are pretty forgiving. Bigger doesn't hurt at all and smaller doesn't hurt much.
  • What about magnetic mount antennas? Unless the antenna specs say "not suitable for mag mount" the magnetic coupling between the mount and the metal roof should provide enough RF ground plane.
  • Why do some antennas need an RF ground plane? That's a sneaky little bit of magic. The ground plane acts like a mirror for the RF waves, effectively making the antenna appear and behave as if it were twice as long, helping to "pull" the RF power away from the sky straight above and "push" it more toward the horizon (or more specifically, along the ground plane). If that sounds weird, unclear, and non-intuitive, you've just joined millions of ham radio operators world-wide.

Thanks again for all the helpful info...

Ok so it seems that there is no "rule of thumb" that applies specifically GRMS or HAM with regard to antenna grounding and that it will always be based on the requirements for a specific antenna. This means that I need to do my research on the specific antenna in question and if I want to mount it on my rear tailgate I need to ensure that it is appropriate for that situation and that I'm not purchasing one that expects to be grounded on a flat metal surface as an example. Antennas that ground through the coax to the radio also provides another situation that I need to be aware of because if I mount the radio in a manner that doesn't ground the chassis I may need to run a wire or strap from the chassis to a suitable grounding point. As a matter of practice would you say that any radio should be grounded regardless of the antenna grounding requirements anyway?

 

[LostInThought]

Yep I have a call sign. Just added to my profile.

Congrats!!

 

[Boppa's Travels]

Congrats!!

thanks

 

[KN6DXV]

Yep I have a call sign. Just added to my profile.

welcome fellow Ham, now that its official you need a rig radio and bog_O antenna
LOL.

 

[LostInThought]

Thanks again for all the helpful info...

Ok so it seems that there is no "rule of thumb" that applies specifically GRMS or HAM with regard to antenna grounding and that it will always be based on the requirements for a specific antenna. This means that I need to do my research on the specific antenna in question and if I want to mount it on my rear tailgate I need to ensure that it is appropriate for that situation and that I'm not purchasing one that expects to be grounded on a flat metal surface as an example. Antennas that ground through the coax to the radio also provides another situation that I need to be aware of because if I mount the radio in a manner that doesn't ground the chassis I may need to run a wire or strap from the chassis to a suitable grounding point. As a matter of practice would you say that any radio should be grounded regardless of the antenna grounding requirements anyway?

Yes, standard practice is to run BOTH power and ground from the vehicle's battery directly to the radio. This minimizes RF noise from the alternator and accessories.

What I'd suggest is to look at a few YouTube videos. There are lots on ham installs for a Jeep. I don't know if Brad is a hot-button right now, but his friend does a decent job of installing his radio:

 

[KN6DXV]

welcome fellow Ham, now that its official you need a rig radio and bog_O antenna
LOL.

 

[KN6DXV]

these are my current rig radios. Up top is a Yaesu FT 891 HF rig, and center console is Yaesu FTM 100 70cm and 2m.

 

[Boppa's Travels]

welcome fellow Ham, now that its official you need a rig radio and bog_O antenna
LOL.

Already started on my General. Maybe by the end of the month. Will hope to be out till the first of September. I guess if I have good internet I could take while I out

 

[KN6DXV]

Already started on my General. Maybe by the end of the month. Will hope to be out till the first of September. I guess if I have good internet I could take while I out

So I studied my butt off, I got my tech and general at the same time. The extra was too hard, so I took about 2 and a half weeks to study for the test. thank God I passed them all on the first try. I really didn't want to rack my brain and then wait a couple of weeks to take it again. Keep plugging away, I found since your already in study mode just get them all out of the way. Its going to be learn as you go anyway and don't worry what anyone has to say about being a gen or extra. its your business not theirs. If people are not being ambassadors they rant worth listing to. just my 2c. lol

 

[Boppa's Travels]

Yes, standard practice is to run BOTH power and ground from the vehicle's battery directly to the radio. This minimizes RF noise from the alternator and accessories.

What I'd suggest is to look at a few YouTube videos. There are lots on ham installs for a Jeep. I don't know if Brad is a hot-button right now, but his friend does a decent job of installing his radio:

Yeah I watched his video when it was posted and then back to find out the radio. Discontinued.