At 05:06 AM 7/6/2009, kd8bxp@aol.com wrote:

On the FM birds how come the split is V/U or U/V? Are there any V/V birds?

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I know there is a reason, so I am curious that is all!

Yes, there is a reason. V/V would make the satellite work much like a terrestrial repeater. Terrestrial repeaters on 2m require bulky, heavy cavities, which are impractical to launch on a satellite. There's also the issue of possible detuning, due to the vibration of launch and thermal cycling while in space.

One way a V/V satellite _could_ be made to work is to have separate receiver and transmitter satellites joined by a tether. A very low powered link on another band could pass the signal between the 2 sats, just as is done for some terrestrial repeaters.

However, this configuration is also more expensive to launch, and any in band birds take away one of the big advantages of working crossband - being able to hear your own downlink, and monitor the channel while transmitting.

73 de VK3JED / VK3IRL http://vkradio.com