Skybox f5 transponder fault

[kyle2211]

Hi guys,
Today i installed a skybox f5 into a friends house, she already had sly hd so had the two f plug connections, my initial thoughts were one cable skybox f5 and the other to the sly hd box so she could run both boxes as she wanted to keep both..... However the skybox f5 was unstable on alot of transponders this way and only when i unplugged the sly hd feed it sorted itself???? I thought this wouldve been fine any ideas anyone?
Im thinking of installing a couple of other f5's in my house but thinking i may get the same problem?
For those wondering i ended up using the f5's loop to keep both boxes on so one co ax remains unused.
All help appreciated as always :)

[scottj130208]

Some of the f5 have problems with certain types of lnb s mine done the same I had to purchase a no signal fix from e bay to sort it out now I receive all channels properly its something to do with the h/v switching voltage the f5 are known for this problem you can replace your lnb to a zinwell which will fix this I found getting the lead was much easier all round hope this helps