Chaining wireless equipment

[joel at tristesse.org]

Hi gang,
I've been playing with different kinds of wireless equipment and have 
come up against something that may be a wireless problem or a general 
routing one, but hopefully someone has seen something similar!

When I've established a link between two 802.11 devices, I usually 
manage to transfer files between the two ends at around 300KB/s. 
However, when I start chaining them together, the speeds drops off to 
about 125KB for two and 50KB for three. If I test the speed between 
two points, it's still 300KB, and spanning two of the three links is 
still about 125KB.

The equipment I've used has included:
 - Apple Airport to a Linux router
 - RG1000s with Karlbridge firmware in Turbocell mode
 - Apple Airport to Lucent Ethernet Converter (which is a slower link, 
but the same dropoff in speed occurs)

At one of the nodes the devices are connected with a crossover cable 
and at the other by a switch. I've tried replacing the switch with a 
Linux router and this does not seem to have affected the performance 
at all.

Presumably a few of the people on this list who have set up community 
networks will have chained repeater nodes in such a way - has anyone 
noticed the same thing? Anyone not had any problems at all doing this?
Thanks!
Joel