Mobile phone signal booster wiring

[GILow]

Hi all,

We have a CelFiGo on board. Bought it a few months ago after reading lots of positive reports, plus a friend has one and loves it. Because we were planning to unstep the mast we’ve only used it with the external antenna on the aft rail, and it was pretty good.

Now we’ve got the mast down I’d like to wire it in properly. But I’m not sure about where to put the antenna and what coax to run.

I’m thinking maybe the antenna on the upper spreaders? We will have synthetic rigging but an aluminium mast, so not sure how badly that combo would affect the signal?

I feel like it should stay clear of the masthead vhf antenna and it’s also quite a bulky antenna so I’d be worried about it blocking the tricolour and anchor light.

Should I use LMR400 cable or something else?

Mast is about 16 meters tall (50 feet).

The amplifier itself uses those tiny little screw in antenna connectors (FME?) which feels like it might limit our choices.

Here’s the device itself..

https://nextivityinc.com/products/roam-r41/

Thoughts?

Matt

[aboon]

Sounds like a good way to go. The ideal solution would be to put the CelFiGo next to the antenna on your top spreader. This would give the greatest range as it eliminates the loss of the cable to the top antenna. However, you need to feed 12 V up the mast (as well as the coax down to the bottom antenna) and future repairs and maintenance could be a challenge.
LMR400 is a good solution. You will cop about 4 dB of loss (cable + connectors) but generally the advantage of antenna height overcomes the extra cable loss. LMR240 is lighter and more flexible than LMR400 but has twice the loss.
The CelFiGo has SMA connectors so you will need an SMA male on the bottom end. Look for an antenna with a type-N female connector and fit a type-N male on the top end of the cable. Type-N connectors are more rugged and have some weatherproofing, but cover the joint with a single layer of plastic tape then a good seal of butyl rubber tape. Having a single run of coaxial cable is ideal, but you could put a connector near the mast base and run a shorter length of more flexible cable to the CelFiGo. Slightly more loss but might be the practical way to go.
With an antenna on your spreader, the mast will upset the omni-directional pattern of the antenna. The effect will vary with the frequency band being used but put it as far from the mast as possible. Synthetic rigging shouldn't affect it unless it is carbon fibre.
I used to have an antenna on my arch but gave it up as there were no devices with antenna sockets. I haul a 4GX hotspot up the mast in a dry bag these days and use WiFi calling (unless the Starlink is on!).

Andrew

[GILow]

Originally Posted by aboon

… The ideal solution would be to put the CelFiGo next to the antenna on your top spreader.
…

Hi Andrew,

Thank you for the excellent write up. Lots of super helpful stuff there.

Yes, I was tempted by the idea of putting the amplifier up on the mast but it was my concerns about heat in direct sunshine that had me most worried. Otherwise I’d happily sort out the cable issues.

Thank you also for decoding the connector type. I’m thinking of using an online supplier to make up at least the top end of the cables for me (so that I can easily feed the unterminated ends down the mast) and I was not totally sure which connector to ask for.

Matt

[aboon]

I got cable a couple of years ago from here, good service:
https://www.eyou.com.au/category/rf-...le-assemblies/

[El Rubio]

Matt, I'm an Engineer with a wireless company in the USA. I m VERY familiar with these type devices. They are prone to oscillation or feeding back upon themselves. the analogy I often use is when a singer on stage get's in front of a speaker with their microphone and it squeals. Proximity of the donor and server antennas will cause the same issue at RF frequencies. Placing the amplifier close to one of the antennas can cause the same issue.



CelFi makes excellent booster amps and has excellent tech support ( at least in the US). The donor antenna looks like it may be a magnetic mount designed for cars. You might want to try to get something with a traditional mount that could be installed on your mast or spreader. Make sure you get an omni directional donor antenna. The server antenna that comes with it should be fine for inside your cabin. Position it in different areas to find best overall coverage before you mount it. Feedback should not be a problem if the donor is high on the mast. You could also add a splitter to the server line and a second or maybe a 3rd antenna if you like. Chances are the one antenna will suffice and cover your boat well, but it's an option if you need it. Don't place the server antenna(s) near the amplifier either.



If you go with coax cable like LMR400 or other not very flexible cabling, get a short run of something thinner like the LMR240 instead of a N type to SMA. Stiff heavy cable can put a strain on the SMA. LMR400 isn't that stiff or heavy, but the tradeoff is not going to affect performance. Weather seal every connector exposed to the weather.



Get the CelFi Wave app which will help you configure and monitor performance. Some will let you adjust gain, but not sure about this one. Gain brings up another issue - maybe. All that gain is at a cost of DC amps. At maximum, it will draw 1.5A at 12VDC. I don't know what kind of load it has when "idle", but there is a fair amount of activity between your phone and the network even when not in a call or data session. It will also amplify anything that falls within the frequency range. Is it something your batteries can afford to leave on all of the time.


Hope this helps.

[Jammer]

LMR400 being of aluminum construction may have a short life aboard. I would suggest RG213.


El Rubio is absolutely correct that you will want a short whip between the RG213 and the antenna on one end and the RG213 and the device on the other. I would use a 6" piece of RG178 or an up to 36" piece of RG400. Pasternack will provide what you need and it will be perfect and on time, bring money.

[GILow]

Thanks guys, more great info and advice.