BATC Forum

Hi
I have been using a standard 2.4GHz video sender for a while for a 'roving camera' but I'm now finding it getting less reliable due to the plethera of 2.4GHz devices that are now around.
One of my applications I tend to have a maximum required distance of around 10 metres, has any one tried a simple aerial (dipole?) on the output of the DTX1, or should I use a tiny PA?

10m ; you should only need a 1/4 wave stuck in the back of the receiver & likewise DTX1. Output is approx -5dBm & a half decent receiver should work down to -90dBm, so this would give a range somewhere about 500m @ 500mHz in line of sight conditions with no aerial gain (not sure what frequency you're using - path loss at 500m @ 500mhz is about 80dB). No amp. needed at 10m !

Thanks for this info, it confirms my thoughts (I was guessing 200m) but casual chats with others reckoned it would not work.
I have not thought too much about frequency yet but it may be 50/50 amateur/jfmg, which is why I'm looking at the DTX.

Many thanks

Ray

This may seem a strange question but does the use of one's call sign as the channel name on a digital transmission alone satisfy the licence conditions for identification every 15 minutes and at the start of a transmission?

Thats a good point.

I kinda think the ident should be in the same format as the rest of the transmission... or morse.

But I don't know!

Hi Ray, thought occurred to me actually. The receiver sensitivity / threshold is quite dependent on the bandwidth being used. i.e. although 2MS/s & 1/2 FEC signal might work down to nearly -100 dBm , at wider bandwidths (higher bitrates which I rather suspect you will be using for high quality / good motion MPEG performance) and higher FEC this will drop by up to 20dB (depending on parameters) I guess suck it & see

BTW Good Q on callsign laurence... ?

regards Mark.

As far as i'm aware you only need to identify your callsign by the mode you are using.

but...

On D-Star voice in theory you dont need to give your callsigns as the rig is already showing it... even via a repeater.
On TV you could identify in Voice,Video and Digital channel name etc but via a repeater the channel name does not work.

Grey area as usual

Rob
M0DTS

Rob is correct - as long as we run standard DVB modes putting the call sign in the SI is more than adequate - when going via repeater, as far as Ofcom is concerned, it's the repeater that then needs to be identified in the SI.

73

Noel - G8GTz