Larsen's NMOHFGPS Mount w/GPS?

[KE4WMF]

Hello,

I just spotted Larsen's (new?) NMOHFGPS antenna mount which includes a GPS antenna. It does not appear to have been discussed here already. More info at http://www.larsen-antennas.com/docfiles/ASB10/SalesSheets/NMOHFGPS.pdf. It looks like my Byonics GPS2 just died. I'm trying to determine if the NMOHFGPS can replace it? Or is this GPS antenna just an antenna which requires plugging into a real navigator or GPS unit?

I'm told external GPS antennas make all the difference in the world as far as performance goes. And it looks like the FTM-350AR will now work with external GPS. Hmmmm... my little wheels are turning!

Anyway, does anyone know what this antenna (the GPS part) is used for? Just to plug into a GPS unit?

Thanks!

Scott

 

[office888]

It's just an antenna.

You still need a device to plug in to.

I need to just spend the $149 and get the 20ch internal GPS transceiver to throw into my Toughbook...

 

[KE4WMF]

Thanks for the reply. I think I'm going to buy one. Then I'll see if it can be opened up to drop in the replacement GPS2. Otherwise, I'll invest in a GPS unit with external antenna input and use this slick mount.

 

[KE4WMF]

Hello,

I received an NMOHFGPS mount yesterday. I wasted no time getting into it to see if my idea will work. I'll share some photos in case this mount is researched by others in the future:

Overview...

The bottom...

I'm not sure how fond I am about the need to drill another little hole to accept this mount. The pin is to prevent the mount from rotating in the standard 3/4" hole. I don't suppose a second hole matters if it stays covered forever.

Peeling back the foam gasket reveals the bolts/screws which hold it together...

The gasket, bolts, and screws removed...

Oddly enough, it took a lot of work to get this open. Larsen seals it with black RTV before screwing it shut.

The GPS antenna appears to be about the same size as Byonics' GPS2. My goal is to replace this antenna with the GPS2 and then run the serial cable in lieu of the included coax. I also want to see if I can snake a different NMO mount with shorter coax and attached mini-UHF connector.

The left piece is made from aluminum, the center piece is plastic married to a metal hold-down bolt, and the radome is plastic...

A closer look at the plastic/metal marriage...

I'm not sure how strong the bottom is. I imagine the anti-rotation pin is required since the clamp force cannot be too tight without risking broken plastic. That would also explain why Larsen recommends the use of any of their NMO mount antennas. Translation: LIGHTWEIGHT antennas. It would be nice, albeit more expensive, if the bottom piece was also made from aluminum. That would ensure the NMO mount is bonded with the mounting surface and allow more clamping force. Or is this stronger than I think? I'm considering running a braided strap from within the little metal box. I just don't know if there's room. :blush: I know a half-wave will work fine without a groundplane. Some of Larsen's NMO antennas require one. So perhaps this mount is working better than I'm giving credit?

Thoughts?

Scott

 

[KE4WMF]

Hello,

I finally received my pieces and got the NMOHFGPS installed:

GPS-2 disassembled and installed in place of the NMOHFGPS antenna...

Mounted...

Underside...

With trim piece installed...

I still need to solder my RF connections and attach another bonding strap. But this didn't turn out bad for an after-work project.

73,

Scott