Outdoor antenna for Max HD4

I have a Max HD4 that is in the bay of tour bus. I need to put external antenna(s) for LTE on the roof of the bus.

What model antennas should I get? I was a little confused by the antenna product page.

Also, it looks like the cables for the external antennas are only 3m (about 10 feet). I need them to be about 12 or 13 feet. Any recommendations on the best way to achieve this?


Hello @RoverRadio,
Where are you based, you are going to need a few antennas and depends on the area that the tour buses are operating in.
Here are two previous posts that may help,

Happy to Help,
Marcus :slight_smile:


I’m in United States, using AT&T and Verizon SIMs.

Was hoping to pick one (or more, since I have Max HD4) of the Peplink antennas here: https://www.peplink.com/products/accessories/#antenna


Hello @RoverRadio
If you wish to use the Peplink range of antennas as is, then these are the options for the four (4) modems.
2 x ANT-100-LTE4-G
4 x ACW-854

If you are planning to use the Wi-Fi WAN, then use the four (4) combination of two (2) each
2 x ACW-853

2 x ACW-854

If the existing fly leads on the antennas are not long enough for you, consider these options:

  • Moving the router closer or where the antennas are going
  • Have (no more than 5 meters) extension SMA cables made up using LCU-195
  • Have the fly leads on the antennas shortened to 0.15m with new connectors and then have cables made using LCU-400 to extend these (no more than 10 meters)

Why LCU-195 or LCU-400 cable? This cable is more flexible and better for locations where there is vibration or movement, or cables have to bend around a lot during the installation than the ridged LMR-195 or LMR-400 equivalent.

You can get these antennas through a Certified Peplink Partner, find one who is an RF specialist; they will have the resources and skills to customise the cabling for you.
Happy to Help,
Marcus :slight_smile:

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Great info, thanks so much! I think I’ll opt for the 3x 853 and 2x 854 option.

Would there be an optimal distance apart to mount these on the roof of the bus?

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Hello @RoverRadio,
Recommended distance apart needs to be based on frequency intermodulation and harmonics (complex maths), though if you were to keep them half a meter (or about 2 feet) apart, that would be adequate, any more than this is not necessary for most situations. Some people have successfully operated these at a quarter of a meter apart (about 1 foot). I’ve run them at 1 meter apart (more due to particularities of the installations).
Happy to Help,
Marcus :slight_smile:


Hi Rover,

as Marcus wrote, it depends on the frequency. If the frequency is lower (like 800 MHz), then the distance has to be bigger than a higher Band (like 2400MHz).
The distance should be in my opinion at least lambda/2 (λ/2) (nearly 50cm at 800MHz - perfect for LTE)