Just joined the group so this is my first post.
I've just installed the HF multicoupler to use 3 receivers from a Wellbrook ALA100 antenna:
Upon switching on everything is ok but I noticed signals were coming in stronger (about 10db) than normal.
For instance tuning in Radio 5 on 909kHz midday on my Winradio G313i I get the following S meter readings:
without multicoupler S9+20db (-44db). With multicouper S9+30db (-33db).
Is this normal as I thought it as no or very little gain ?
The HF Multicoupler is designed to have 1 or 2 dB overall gain with all ports terminated in 50 ohms. If you are running it with two ports open circuit then there will be additional gain as you have noticed. If you terminate the unused ports with 50 ohm loads the the gain will be correct.
We usually set it to give a small overall gain to compensate for the losses in the the extra co-ax jumpers between the Multicoupler and the receivers.