G2/G3/G4/G5 antenna clarification

[bitmorechoke]

I'm trying to figure out the exact antenna configurations for these models - in other words, which bands are served by the internal antenna, the external antenna, and the charger base connection.

I've found a few forum posts on the subject, but they contain a lot of noise and speculation and it also isn't always clear which model the poster owns.

For the sake of getting something down on paper my best guess at this stage is that the dock connector antenna pin (and therefore the charger base antenna) connects to the internal antenna on dual frequency models, otherwise it connects to the external antenna. This seems consistent with comments I've seen, and it probably makes sense if we assume that the internal antenna is inferior to the external antenna, and that Unication aren't making any design decisions about which band is more important to the user.

If you know better (or can link to a definitive source) please correct me!



Some clues drawn from the charger base manual:



Also relevant:

 

[RaleighGuy]

You did not include the G5 UHF B 380-430 MHz version

 

[w2lie]

Dealer here. From what I have been told and experienced, the amp charger antenna is a pass through and feeds both the external And internal antenna band.

on the g5 models, the external anteman is always the 700/800
On single band models, the external antenna is always the single band.
On g3 models, the external antenna is the uhf band.

sorry if this reply has bad formatting or I missed something. I’m replying via a mobile browser.

 

[900mhz]

my G4 antenna has a blue band and states 763-870 MHz. My G3 UHF antenna is green and states 450-512 MHz. If that helps. My G3 is a UHF D-band model

 

[bitmorechoke]

You did not include the G5 UHF B 380-430 MHz version

Added, thank you. I also added the UHF A model (discontinued?)

the amp charger antenna is a pass through and feeds both the external And internal antenna band.

Thanks. That's interesting, and it conflicts with several comments I've read on this forum. How confident are you that this is true? And given that it uses a single pin, any idea how it would avoid compromising the selectivity of the inbuilt antennas? Or can they just share a common connection without harm?

on the g5 models, the external anteman is always the 700/800
On single band models, the external antenna is always the single band.
On g3 models, the external antenna is the uhf band.

Awesome, thank you, that fits nicely with what I suspected.

my G4 antenna has a blue band and states 763-870 MHz. My G3 UHF antenna is green and states 450-512 MHz. If that helps. My G3 is a UHF D-band model

It does help, thanks. And it suggests that there must be two versions of 'green' antenna - if yours specifically states 450-512 MHz then there must be another one for the 400-470 MHz band. Unless I've missed an extra colour somewhere? I've lost the sticker AND o-ring from mine but it's the 400-470 MHz version and I'm sure it was green?

I've tweaked the table, assuming w2lie is correct and the charger antenna serves both bands on dual band receivers:

 

[kruser]

From my testing of the amplified charging base with a VHF/7-800 MHz G5, the antenna port pin contact for the charging base does supply signal to both radios in the G5.
Without charging base power, the marked pin on the pinout will still supply external RF to the secondary (VHF) band only. When the amplified charging base is powered, the external antenna pin or contact does supply external RF to both the secondary and primary radios.
I'm not certain how they do this as following the PC board traces in the G5 and charging base was not easy. But it looked like the primary bands external antenna port contact goes through some additional circuitry. Probably some type of active splitter/filter to isolate both radios from the single antenna port which is why the amplified charging base only supplies RF to the secondary radio when not powered. The charging base needs power for whatever part of the circuit is active and requires power to supply RF to the primary band. Also, in an unpowered state, the G5's top antenna SMA jack still supplies RF to the primary band or radio.
I've found the contacts to not be reliable and must be wiped down with an alcohol pad or cleaned with a pencil eraser at times when the pager does not seem to be getting a signal from the external antenna port or the user experiences audio issues when the pager is placed into the amplified charging base.
I've also read that the G5 can automatically switch the primary band only from using an external antenna or the G5's SMA jack depending on the signal quality or strength. I've never verified this to be true or false.

So... you can use an unpowered amplified charging base to get external RF into the secondary radio but you won't have any benefit to the primary band or radio and no audio options of course. I tested this in a mobile environment where the VHF signal was too weak to be received inside the vehicle but worked well with an external antenna.

I wish I'd have had the time to follow the circuit traces and make a crude schematic but that looked to be a tedious job so I gave up on that idea.
I also cannot get a VHF signal at all inside my apartment. The exterior walls are made of a wire mesh making indoors more like being in a Faraday cage. I must use the amplified charging base and an external antenna for my G5's secondary band or radio to get a signal.
The difference is zero signal indoors on the VHF band to full signal on the VHF band with an external antenna hooked to the charging base or manually tied to the ground and antenna pins shown on the pinout.

The internal antenna in the G5 is a simple wire loop just like what's inside a typical Motorola Elite or Gold Flex or Pocsag pager if you have ever seen that antenna arrangement. At least that's how the antenna is constructed for the secondary radio in a VHF (136 to 174) G5 model. I suspect other secondary bands in G5'sand probably all dual band models use the same exact wire loop for the secondary band internal antenna. There's really no room for much else.

 

[bitmorechoke]

Wow, thanks kruser, that's remarkably thorough!

In my own case I got the G3 as VHF is useful on the fireground and interstate, but there's nothing on it at home. I occasionally miss the (very) rare UHF call in the house, but I always believed the charger antenna was dedicated to VHF so I never bothered connecting anything. Reckon I might try running a dedicated UHF roof antenna now

Interesting - and potentially quite useful - to know that the charger antenna connection behaves differently when powered and unpowered. I'm curious now how it behaves for single band models. On the one hand, you'd imagine it would simply connect to the primary radio. On the other hand, it's possible that the switching/filtering behaviour is common across models, and without power the primary receiver is still isolated from the bottom pin?

I've tweaked the table again, and added the UHF-B variants of G2 and G3, which I'd missed before.

I assume this means Unication actually have 3 flavors of 'green' antenna available?! W2lie are you in a position to confirm this?

 

[tvengr]

my G4 antenna has a blue band and states 763-870 MHz.

My G5's have a purple band for the same frequency range.

 

[bitmorechoke]

My G5's have a purple band for the same frequency range.

The purple marker is on the old version of the antenna. Unication recently improved the antenna design and gave it a blue marker.

 

[kruser]

The purple marker is on the old version of the antenna. Unication recently improved the antenna design and gave it a blue marker.

My G5 also has the original purple banded antenna marked 763-870 MHz.

 

[w2lie]

Added, thank you. I also added the UHF A model (discontinued?)

Not carried by Unication USA. AFAIK, It can be special ordered but would take some time to arrive.

It does help, thanks. And it suggests that there must be two versions of 'green' antenna - if yours specifically states 450-512 MHz then there must be another one for the 400-470 MHz band. Unless I've missed an extra colour somewhere? I've lost the sticker AND o-ring from mine but it's the 400-470 MHz version and I'm sure it was green?

yes, there are two flavors of the green antenna. I wish they used another color to show the difference, but both are green. 400-470 and 450-512 are both green. The only way to tell them apart is by the sticker on the top of the antenna.


Additionally, since it was commented here, the purple antenna was phased out and replaced by the blue antenna for 700/800. The Blue antenna has a little more gain to it than the original purple. If you have a purple antenna now and wanted to upgrade or replace the antenna, you would look for the blue band. All new G4 and G5 pagers today ship with the blue band antenna, unless you are @N1GAW

 

[blackbelter]

My G5 (UHF D) came with the blue band antenna. I use an RS 800 antenna on my amp charger with awesome results. Almost 100 percent of my monitoring are on P25P2 with one UHF DMR station and never felt the need to change or replace the supplied stubby antenna.