Srpawski, I think you have the idea behind the cossband principle. I don't want to conflict with what the others have said, nor get too involved in technicalities. So I offer--
.
"Coyote's Crossband Repeater-Redux'd" --
.
A cross band repeater, by its very name, implies it repeats one band of frequencies to another- several examples:
#1. Handheld A transmits on 440.0 Mhz to a cross band repeater receiving on 440.0 Mhz. The repeater rebroadcasts out this signal on 146.0 Mhz. The Remote receives on 146.0 and re-transmits back to Handheld A on 440.0. Only two frequencies, in two seperate bands, are used.
.
#2. Handheld B transmits to the crossband repeater on 440.0 Mhz. The remote repeater rebroadcasts this time on 146.16 Mhz, but listens on 146.76 Mhz and transmits back to Handheld B on 440.0. This would be the case in using the remote to access a distant 2 metre repeater. If this 2 metre repeater being access'd required a PL tone, the crossband remote would have to transmit it...ie: 146.16 Mhz, PL 67 Hz.
.
#3. Handheld C transmits to the crossband repeater on 440.0. The remote rebroadcasts out on 146.16. The crossband repeater listens on 146.76 but transmits back to Handheld C on 445.0 Mhz. Handheld C is set to receive on 445.0. PL tones can be added.
As you can see, there are a lot of variations as to how this crossband system can be configured. PL tones are not necessarily required. You can design the system as simple as #1 above or go for it, making it a lot more complex.
.
_____________________________________________________________
.
A side note..... I have ponder'd at the legality of a ham crossband repeater. It should have it's own form of ID, though I guess the user announcing something like
.
"this is KZ6XX transmitting thru the KX7XX remote..."
.
....... should do it...but how often is that done** ??
The other thing that is murky-- to me anyway-- is using a 2 metre signal as the control frequency. Controls are supposed to be 220 and above.... seems to me years ago this was a controversy when a manufacturer came out with the first 2/440 crossband repeat-enabled radio. As I recall, it was determined to be legal.... doesn't matter, I operate one, scoff law or no....
.
.
.
......................................CF
______________________________________________________________________
.
**Virtually never in my case. I have a crossband remote myself- back home in the mountains-- it sits on a mountainside, listening/transmits(15 Watts) on 146.52 Mhz and transmits back on simplex on 423.xxx. Mhz. I turn it on in the summer to talk to friends summiting the peaks for SOTA, and the rare motorist hams that finds their way into our remote valley... it extends a UHF handheld out +100 miles to certain mountain peaks....
.
(I have even had an FCC engineer visit my home- quite a few times over the years (he is a friend.... for family hikes and dinners)... never a word's been said about it... I let "sleeping dogs lie......"
)