Batboard

Hey guys. Does anyone know the length of time an LTR idle burst is supposed to be transmitting for? There's an LTR system up here that seems to be transmitting one way longer than it's supposed to (something like half a second or so). Thanks

First of all, is the whole duration of the burst data, or is there a long period of unmodulated carrier? If so, they may have their key up/key down timings set stupidly.

Second of all, are you sure it isn't a Passport system? They both use the same physical layer signaling but the protocol is slightly different, and IIRC the Passport idle burst is long than an LTR burst.

Passport would be my guess. Isn't the purpose of the longer burst on the passport system for RSSI?

mikegilbert wrote:Passport would be my guess. Isn't the purpose of the longer burst on the passport system for RSSI?

I'm not sure what you mean, but the longer burst is simply because the Passport idle burst has more bits in it, and thus takes longer to send, than does the LTR burst.

Not that I've measured, but I don't notice any significant difference in the length of the data bursts between LTR & Passport. In Passport the bursts are every 3 seconds, as opposed to the 10 seconds in LTR, but the burst length seems to be in the 100-200ms range for either one.

Todd

I was under the impression the reasoning behind the frequent (passport) data bursts was to assist in RSSI.

??

The system in question is a UHF LTR system that I've confirmed isn't running Passport (the radios are regular HT1250LS (not LS+).

The reason I'm asking about the idle burst length is that I'd like the ability to scan the 5 voice channels conventionally but not have to hear the idle bursts. I figured I can use the RX unmute delay to accomplish this, but wasn't sure what setting would be optimal.