Can somebody help me understand Antennas?

[Alpine Warthog]

Can somebody help me understand this graphic I found on Midland's site?

I live in NorthWest PA in the Allegheny "Mountains" Lots of tall hills and the National Forest is my backyard. I've been running the Midland ghost antenna mounted to the top of my windshield lightbar. Got decent reception but for some reason nobody around here will respond to a radio check ?

anywhoooo, I just removed the lightbar and I'm not likely to put it back on so I'm hunting for better placement or a better antenna. I was a radio troop a long time ago and even with all the radio/antenna theory I had thrown at me, I'd never seen a graphic like the one below. Is there any validity to it? I worked the whole band from HF to UHF and Sat so I know about skipping and the changing of the ionosphere and NVIS antennas but for the life of me, I can't get a dang GMRS or CB antenna to run reliably.

Sponsored

 

[jav_eee]

Ignore that graphic. Midland caters to people who don’t know any better and just want something with a a simple setup. They like to razzle dazzle with graphics like that that reallly don’t show you the whole story, only a false promise of what their expensive “gain” antennas can do.

so you have an NMO mount? Where exactly is it placed on the vehicle?

jeeps are notoriously horrible hosts for radio antennas. For your terrain you’d want a 1/4 wave whip BUT you’d want it located centrally on the (metal, which jeeps don’t have) roof.

depending on where your mount is you might try one anyway.

https://theantennafarm.com/index.ph...iew=productdetails&virtuemart_product_id=9288

https://theantennafarm.com/index.ph...view=productdetails&virtuemart_product_id=767

 

[Hootbro]

Looks like a wave propagation chart for an omni directional antenna. Makes sense that the lower dB gains would be more global hemispherical and as gain is adjusted higher the propagation front/aft goes more elliptical.

Their graphic is really a dumbed down view and does not show both axis.

You really need a data sheet with the antenna chart from the antenna manufacturer to know what the expected wave propagation is at a given frequency and gain.

 

[Alpine Warthog]

This was how I had it mounted. Just a simple bent sheet metal tab I modded to attach to the light bar. I received well, and I once used one of the kiddos back at the house to talk to me on an FRS little handheld as I drove around town ( brick and steel buildings maxing at 8-10 stories but mostly 4 stories) and I got about a mile away from home before her signal faded but she kept saying she could hear me pretty good with only a little static. But that's the one and only time I've ever actually spoken to another station ? I seem to get ignored otherwise.

I ordered a tab to mount to the side of the cowl and am considering a new whip antenna to replace the ghost.

I was also considering getting a molle rack across the front (and under the freedom tops) and mount the ghost there but that runs into the interference from being under the roof

 

[Radio Guy]

This was how I had it mounted. Just a simple bent sheet metal tab I modded to attach to the light bar. I received well, and I once used one of the kiddos back at the house to talk to me on an FRS little handheld as I drove around town and I got about a mile away from home before her signal faded but she kept saying she could hear me pretty good with only a little static. But that's the one and only time, I've ever actually spoken to another station ? I seem to get ignored otherwise.

I ordered a tab to mount to the side of the cowl and am considering a new whip antenna to replace the ghost.

I was also considering getting a molle rack across the front (and under the freedom tops) and mount the ghost there but that runs into the interference from being under the roof

A mile range to an FRS radio is actually very good. For someone to hear you on FRS or GMRS you must not only be on the same channel but also have the same CTCSS or DCS tone to open up their speaker. Most GMRS comms are via a high site repeater. So are you calling people using the correct tone or are you hearing distant people on a repeater but calling them on simplex?

 

[Alpine Warthog]

I guess I don't understand "tone". I am definitely on simplex, but also don't you have to be on a specific channel to run repeater?

Well, for the FRS event I was on my Midland MXT275 and she had a little X-Talker. I was actually impressed with the little X-talker and talking on Ch 19. I hadn't messed with any privacy codes and didn't set up any repeaters (I'm not up to that kind of speed)

I can run around town on ch4 and hear the local school and also kids playing (with little FRS presumably) I'll even hear work crews randomly.
I've gone on 1 jeep run with the local club and I got one response to a radio check but the rest of the run, I got ignored ( or what I said wasn't important enough to warrant a response)

 

[stampedingTurtles]

I can run around town on ch4 and hear the local school and also kids playing (with little FRS presumably) I'll even hear work crews randomly.
I've gone on 1 jeep run with the local club and I got one response to a radio check but the rest of the run, I got ignored ( or what I said wasn't important enough to warrant a response)

When you were on the jeep run with the local club, were you hearing other people on the radio (and they just weren't responding to anything you said)?

 

[mumbo]

We finally bit the bullet and got our amateur licenses. Not that hard and the best option IMHO.

That being said, I believe GMRS is your next best option. The higher power Midland radios support repeaters. Get a long antenna from Ham Radio Outlet in the right frequency range for GMRS.

 

[jav_eee]

Get a long antenna from Ham Radio Outlet in the right frequency range for GMRS.

Long?

 

[Alpine Warthog]

When you were on the jeep run with the local club, were you hearing other people on the radio (and they just weren't responding to anything you said)?

Exactly, yes, but they really weren't that important, it was nothing that REQUIRED a response.

We finally bit the bullet and got our amateur licenses. Not that hard and the best option IMHO.

That being said, I believe GMRS is your next best option. The higher power Midland radios support repeaters. Get a long antenna from Ham Radio Outlet in the right frequency range for GMRS.

Yup, got my GMRS license (HAMiture is something I'll play with after GMRS and CB are settled). I'm attracted to the size of the ghost antenna since GMRS will likely be for trail runs, in the woods. I'm not sure its popular enough to be useful for natural disasters but the fact that it talks with little FRS radios is a huge advantage since LOTS of people have those little guys.

I also used to run a steel whip antenna on my XJ (and I want to again, just trying to sort the GMRS first) but that had problems with grounding since it was mounted to a roof rack, and I could never seem to get a solid ground.

Most frustrating thing is used to run one of these in my sleep. And now I can't even get a little antenna to work reliably.

 

[Minty JL]

Looks like a wave propagation chart for an omni directional antenna. Makes sense that the lower dB gains would be more global hemispherical and as gain is adjusted higher the propagation front/aft goes more elliptical.

Their graphic is really a dumbed down view and does not show both axis.

You really need a data sheet with the antenna chart from the antenna manufacturer to know what the expected wave propagation is at a given frequency and gain.

I agree with all of this.

If changing the antenna type is still not gaining the desired results, the only other option you really have is to compensate with more power.

I started with the ghost antenna and I found it to be a bust. I bumped up to the "6db" gain antenna the that yielded better results. I put that in quotes because that was what it was rated at.

I have a rack on the back of my JTM, so taking simple RF theory in to account with LoS I mounted up on top of my rack.

Lastly, if there is not a strong repeater network in your area, it won't really matter what you buy or throw at it. Plus its all a matter of how many GMRS users there are in your area as well.

I'm near Annapolis, MD and I catch some repeater users around me with some of that traffic coming out of central PA.

Hope this helps some if not, at least some factors or things to consider

 

[Minty JL]

Long?

Yes, the taller the antenna, the better LoS you have

 

[jav_eee]

I'm attracted to the size of the ghost antenna since GMRS will likely be for trail runs, in the woods

it should work just fine in that instance. midland lists their ghost antenna as 5/8 wave so the beam pattern (with a proper ground plane) will stay closer to the ground which might not work well with high repeaters or valley to hilltop situations.

im starting to think you have a tone issue. If the group is using a tone you’ll still hear them they just won’t hear you. You might break through if they’re close but add a little distance and that PL tone starts to work well to block out unwanted transmissions

 

[jav_eee]

Yes, the taller the antenna, the better LoS you have

that’s great and all for flat plains. He said he operates in hilly terrain. A shorter 1/4 wave antenna would be better for hilltop repeaters than a longer 5/8 wave.

 

[Alpine Warthog]

I have a rack on the back of my JTM, so taking simple RF theory in to account with LoS I mounted up on top of my rack.

I've got a fiberglass camper shell, I considered mounting it to with a counterpoise disk under the antenna. that would get it to the highest point.

Would I have to ground the ghost antenna up there?

Sponsored