Ideal setup for portable setup?

I’d like to be able to set up a satnogs station at various locations. It needs to be portable. I have decided on a non-penetrating roof mount, with a piece of top-rail pipe for the mast, Then a Wimo turnstile antenna for the Antenna. Now, I’d like to have a raspberry pi with an SDR and Preamp in a weather proof box on the mast, powered by Power Over Ethernet, for simplicity and portability. A lot of folks mention the PoE may cause lots of hash and noise… I will have to see…

My question for the group: Which Raspberry Pi is the best for an outdoor SatNogs install? Is the 4 too “hot” and overkill for the project? Is the 3b a better solution? The price between the two is negligible.

Please share your ideas and your setup (with photos) if you can.

Thanks
-Kevin (KK4YEL)

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Kevin,

There was some discussion in the past regarding the location settings of the station and the issue it raises with scheduling. It’s in this forum, but I didn’t search for it (and I’m not sure how up-to-date it is).

Having said that, both of my stations are 3B’s, and both are in my garage. Temperature in there ranges from just above freezing to 90’s - with no issues thus far. I think Florida humidity may be your biggest problem, though.

–Roy
K3RLD

I really don’t mind having to swap out the Pis once a year or so.
that being said, for my home setup, I could move the setup to a more permanent setup, but that wasn’t my intent. I’d like to bring this to clubs to show them (with demo) and then perhaps encourage more Satnog stations in the area.

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@kk4yel I’m kind of in the same boat. I’ve got an aspiration for doing demos with a portable unit, in addition to a more “permanent” home unit.

To that end, the road-show model uses a 5-gal bucket half-filled with quickcrete (got the idea off a guy showing it on YouTube) and a PVC “sleeve” for some painter-pole “masts” that collapse down to fit in my Wrangler (i.e. small vehicle, limited space, everything MUST collapse down and not present a poking hazard while driving), guy wires for the excessively windy days, and assorted clippings of copper and Aluminum to demo the variability of what it means to make an “antenna”…
few in the general public appreciate the efficacy of the humble V-dipole, rotated to horizontal, until they see a properly sized “coat hanger” pull down signals from space :wink:

Coax is RG-6, connectors are all adapted to F.

My demo style is geared towards excitement (and amazement) that “it actually works” rather than efficiency… excitement spawns interest and curiosity, and efficiency comes later when exploring that interest. That’s where you truly learn.
It’s kind of a “Barnum & Bailey’s” circus approach to Space RF. :crazy_face:

All with the express purpose of showing that literally anyone can fab up their own system, and with the hidden ulterior motive of teaching (& learning) a bunch of things through building one

I found the 3B Pi’s to be less “noisy” than the 4, but I still recommend metal cases for both heat dissipation as well as RFI abatement.
Ferrite beads on EVERYTHING because when you go “on the road” you never know what RF conditions you’re going to find. Spend extra time on making sure you have a clean power source while on the road.

I still prefer the simplicity of PoE for the road-show demo unit, even if it might introduce additional noise into the system, but there too it opens up a welcome line of Q&A at each demo to talk about concepts like noise floor, etc…

Keep in mind that the audience I’m targeting for the demo stuff is NOT ham radio enthusiasts or folks with deep knowledge of RF {anything}. I want to get school kids, and Teachers, Librarians and Parents, excited about reaching out and up… and through this effort, they’ll pick up an appreciation for many things RF related, which I think is kind of taken for granted these days.

Anyways, I hope to publish a more extensive write up on my own portable station ideas (and failures) as things progress.

Cheers,

-Lucky

I’ll add that I’m a HUGE fan of tape-measure-based antennas when it comes to doing demos.

It’s not that they’re necessarily the most efficient, or easy to work with… anyone who’s had one snap back on their face will agree… :hot_face:

It’s that they stand out!

A proper looking (& performing) antenna, built with commercial-grade materials and attention to detail will do a great job, but might not attract as much attention from a crowd of passer-by’s.
In fact, we’re so used to seeing these out in public that we kind of dismiss them from view. Kind of an aesthetic visual filter for our daily lives.

A bright yellow band of spring metal contorted into strange shapes draws attention to itself, and curiosity from those who eventually figure out what it is.

It invites the first question, often out of incredulity that it works, but mostly out of basic genuine curiosity.

The fact that here in the US, there’s a store (rhymes with “arbor wait”) that often gives away 25’ tape measures (with a purchase) as a loss-leader to get folks into the store just means that I have a ready, reasonable-priced, source of material with which to concoct all manner of antenna examples, with the express purpose of drawing attention.

Obviously don’t use them is you’re trying to do this at home and they have “aesthetic restrictions” to what you do in your neighborhood…

Put simply, it’s an attention getter, a conversation starter, a source of humor, and a subtle way of getting folks to rethink their assumptions about RF in general.

Oh, and they’re cheap to replace, ‘cause… reasons. :wink:

I’m still working on the QFH version for various bands. I don’t expect stellar results, but like I just explained, that’s not the point.

As always, check out the fantastic videos on YouTube of others building dual-band J-Poles, classic Yagi’s, and maybe an eggbeater or two.

Cheers,

-Lucky

From my experiments, the 4 uses far more power than 3. In my area, heat is not a problem, but I would use a Pi 3 if I was going to use battery power.

The only upside for the Pi 4 for a Satnogs station (in my experience) is the bigger ram, which helps when saving raw IQ files to the ramdisk and compressing them before upload.