Satalitte Issue

775 means the receiver is not getting signal from the dish.
Verify that the cable from the dish goes directly to the receiver dish input.

775 means that your receiver and satellite antenna are not communicating with each other. Double check all of your coax cabling to make sure that there is no stray coax shielding wires that are shorting out the signal in the center connector.

Make sure the satellite dish or carry out, cable is run straight to receiver box. No splitters or filters in the line from those 2 pts.then do your setup .

It is not uncommon for people to hook those portable cubes or dishes into the cable outlet on the RV. It will not work as that cabling usually has splitters. Unless you have an outlet that is marked satellite you will need to run the coax in through an opening and perhaps eventually install a direct outlet in the side of the motorhome. You will need another cox from the satellite dish to run it directly to another tv unless you have a SWM system and I doubt that works in the portables.

You want to begin with a coax cable running directly from the antenna to the receiver (through a window if necessary) and check to see if you can find the signal. You also need to know what kind of antenna you are using as it could be different than the home antenna. If you have SWM at home but not in this antenna (or vice versa) you will need to go into the receiver setup, select Multiswitch (most likely for a tripod) or SWM if you have a special SWM LNB and set the antenna type you are using. You will then be able to go to Signal Strength followed by Signal Meter. You can use this to get the 101 signal and then peak from there if you are using an antenna that can pick up 99 and 103 as well (necessary for the HD programming).

Take Bill.Satellites advice to the bank.
Anytime I attempt to help anyone with their satellite problem, the first thing I do is run the cable directly from the dish to the receiver. No splitter, no control boxes, no kinks. One cable, direct connection. Then proceed.
9 times out of 10 the problem is in the routing between a connection outside the RV and the connection to the receiver.

One other thing to check is the coax cable to ensure that it isn't the problem. I had a cable with a broken center conductor that I had not noticed while trying to setup at night that kept me from receiving a signal.

YOu said you hooked it up.. Ok, how....

What kind of antenna
What cable did you use

Some generic comments/advice:

Many people use the park-cable line and simply run a cable from the outlet in the RV to the receiver, this will NOT WORK for two reasons.

1: The wall plate with the switch, LED, 12 volt outlet and antenna port is not compatable with the receiver, it is an enectronic device that blocks communications with the antenna.

2: The cable is very likely lowest bidder RG-59 and very high loss (Though that should not get you the error you are getting).

Suggestion: For the moment run RG-6 cable in via a window direct from the antenna to the receiver, NOTHING between them save that cable (That is if you are not using a roof mounted dome)

If that works get back with us for more information on how to do it.