Hello,

There should be a reciprocal relationship between the modules
regardless of height, antennas etc. as long as TX power and RX
sensitivity of the modules are the same (which they appear to be).

The modules are unlikely to have very good input filters at 868MHz, so
any adjacent channel interference (GSM etc.) is likely to cause the
out of balance behaviour.

Try heading in a different direction outside, or go somewhere else
with your experiment.

For your real world application, are you likely to have any site close
to adjacent channel transmitters (cell or broadcast) ? If so, think
about a decant front end filters. This could be costly, but might save
you...

Regards,

Mark



On Oct 25, 9:25*am, wrote:
On Oct 24, 2:26*pm, "Anthony Fremont" wrote:





Mark wrote:
On Oct 24, 2:00 pm, "Paul Hovnanian P.E." wrote:
wow so many of these replies are wrong..

This is normal when antenna "theory" comes up.

in almost all cases, *RF path losses are RECIPROCAL.

I agree, including the antenna gains (meaning that the antennas at each end
don't have to match).

(even a 1/2 silvered mirror is reciprocal to light)

Well that guy is usually on a differet page.

As some have said, the cause of your issue is probably interference to
the outside receiver.

That's what I think is the most likely cause. *The guy outside probably has
his Nextel phone with him. *;-)

Or maybe something about the indoor setup is causing the indoor Tx to
operate at lower power.

I suppose that's possible too. *The OP should make sure the power supplies
are equivalent (meaning that the output power would suffer more than the
receiver gain with a drooping supply). *So check the indoor supply.

It is very unusual for RF path loss to be non-reciprocal.- Hide quoted text -

- Show quoted text -

It is assumed that the path to and from the office should be inferior
to the line of sight path out on the street. This may or may not be
true. The building may actually be offering gain in certain
directions. I would start by seeing if the same condition existed at
many more locations. If it does then other ideas need to be examined,
I would start by examining the RF environment outside the building.

Jimmie- Hide quoted text -

- Show quoted text -