7-800 mhz question/obervation

[KN4HTC]

I've noticed that a lot of areas (NC for example) have systems that have a mix of 700 and 800 mhz frequencies. I've wondered how having such a wide frequency range would actually work.

Based on looking up the FCC licenses for the sites, am I correct to conclude that most of the portables/mobiles on those systems (regardless of whether it's a 700 or 800mhz system) actually transmit somewhere in the 800-810 mhz range and receive either in the 770/850 mhz range?

 

[mmckenna]

Like many amateur radio repeaters, there are standardized frequency splits between the repeater input and output.
On 800MHz, it's 45MHz. Subscriber radios will transmit in the 810MHz range and the repeaters transmit in the 855MHz range.
On 700MHz, it's 30MHz. Subscriber radios will transmit in the 769MHz range and the repeaters transmit in the 799MHz range.

The radios will support this. Most modern 700/800MHz radios will easily handle the 769-860 range no problem. Some trunked systems have a mix of 700MHz and 800MHz channels, again, each repeater will handle itself just fine.

For the antennas, most are broad banded enough to handle it, too.

Some of the newer Kenwood non-public safety oriented radios will do 800 and 900MHz in the same radio.

 

[KN4HTC]

Interesting to know. I figured the band split was too wide for the radio to be happy with a single antenna. Ha ha.

I'm curious about the newer Kenwood's that will do 800 and 900 mhz. What models are those?

 

[slicerwizard]

On 700MHz, it's 30MHz. Subscriber radios will transmit in the 769MHz range and the repeaters transmit in the 799MHz range.

You have that backwards.

 

[mmckenna]

You have that backwards.

That's about typical for me.

 

[mmckenna]

I'm curious about the newer Kenwood's that will do 800 and 900 mhz. What models are those?

NX-3400 portable.
RX: 851-870MHz, 935-941MHz
TX: 806-825MHz, 851-870MHz, 896-902MHz, 935-941MHz.

It'll do analog and NXDN -OR- DMR

 

[KN4HTC]

NX-3400 portable.
RX: 851-870MHz, 935-941MHz
TX: 806-825MHz, 851-870MHz, 896-902MHz, 935-941MHz.

It'll do analog and NXDN -OR- DMR

Does anyone still produce 900 mobiles? I haven't saw any from Kenwood.

 

[mmckenna]

Does anyone still produce 900 mobiles? I haven't saw any from Kenwood.

NX-3921G is the 900MHz mobile. Unfortunately they do not have an 800/900MHz mobile like they do on the portable side, just separate 800MHz (NX-3920) and 900MHz (NX-3921).