Author Topic: How to power a remote receiver on a hilltop  (Read 166 times)

kopcicle

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How to power a remote receiver on a hilltop
« on: September 26, 2021, 10:26:41 PM »
or ...
 How to enjoy amateur radio while buried in radio frequency interference desiderata

TLDR version at the bottom :-)

Introduction.
You can look up AF7XT on QRZ but all you are going to get is a condensed history of my motorcycle experience.
You can look up "kopcicle" and most any random nonsense on the web and get even more nonsense.

Purpose.

I live in radio frequency interference hell. The only way I'm going to be able to operate HF amateur radio is with a remote receiver.

Implements of destruction .

A simple but robust general coverage HF antenna
An SDR receiver as simple as a RTLSDR dongle or eventually an SdrPlay something.
A simple single board computer with a USB port for the dongle and CAT5 for the POE/WAP
POE , power over ethernet to a 2.4g wireless access point
An antenna (or two) . A vertical gain antenna composed of stacked half waves at approximately 18-24Db gain.
-A parabolic antenna with approximately 24Db gain.
-or both using the common "dual diversity antenna connectors"

The above is simply a proof of design/concept, bucket of readily available parts just to see if this is feasible.
There is always the possibility that the very concept is flawed or, I'm totally full of ****.

The reason I'm here is , well, you can blame that on TJ. Actually I have the RF and computer side of things well in hand if not actually working. When last I checked I still had some buffering/lag to deal with still and may need to use a real time operating system and or more ram, and or I missed something somewhere.
What I don't have is a way to power this collection of parts at a remote location . The total current drain is minimal but as we all know there isn't always sunshine or wind to charge a battery bank.
Climate is what you expect and weather is what you get. That covers the wind generation.
It's daylight or it's nighttime or there are clouds. It is what it is.
I need a sensible method of getting DC from a panel or 6 to a battery and a way of getting single or three phase AC to a rectifier for conversion to DC to battery, and , have both inputs play nice.

TLDR version: I want a remote HF radio receiver on a hilltop that I can push downhill via commodity 2.4GHz as well as control the receiver. I need help with the charge/discharge control.

Okay I've rattled on long enough. Time for someone else's input.   

~kop

« Last Edit: September 26, 2021, 10:28:59 PM by kopcicle »

boB

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Re: How to power a remote receiver on a hilltop
« Reply #1 on: September 26, 2021, 10:37:49 PM »
Kop, you and I both have the SAME idea, want and desire...    And I have thought about it some.

In Everett, WA where I have lived for the last 20+ years, it used to be semi-quiet on HF.  The last 10 years or so have been EMI hell in my neighborhood.  WAY too high.  And it's not coming from my house.  The power went out in the neighborhood 2 years ago and I hooked my rig up to batteries.  Dead quiet and  plenty of HF stations heard.  S-Zero level.   Power came back on a couple hours later and so did the RFI.  Wideband noise.

As long as I had to reset all of my clocks, I turned the power off to my house.  NO change in noise level.  So it's not me.

Anyway, I have wanted to do the same thing you are talking about.  If not in Everett, in Phoenix, AZ near to where my winter retirement will be.
It is much better there but not perfect.  Not what you or I would like to have.

What is needed is a piece of land that is affordable but that is basically line of sight to my house so that the remote receiver can communicate.

As far as the solar power, I would definitely choose a regular PWM charge controller to get the least amount of noise and birdies.

MPPT noise can be reduced but probably not quite enough for our liking.  Another way to fix that on a remote receiver would be to have a separate shack for the power that is a lengthy piece of wire away from the radio receiver.  Solar panels are radiators in my opinion.

At least a remote receiver would not require a large system.

boB


P.S.   You have a  BSA 441 Victor  ?!?!?!   I   LOVE that bike !   A friend in high school had one of those thumpers.   Makes a great vibrator but there is just something about that bike that I loved !   Simple old style !

« Last Edit: September 26, 2021, 10:40:35 PM by boB »
K7IQ  He/She/It

kopcicle

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Re: How to power a remote receiver on a hilltop
« Reply #2 on: September 26, 2021, 11:18:39 PM »
addendum:

The typical Beagle Bone is only about 500ma @ 5v
The usual radio is about 1A at 12V
The receiver isn't quite 100ma (USB)

Bob, if you email your Lat/Lon I'll see if I can access any number of hilltops from your location.
I have access to some odd places so it's possible.
Or you can register and play with radio mobile online https://www.ve2dbe.com . Many thanks to Roger Cloude.
I do have estimated path loss figures for a local hill to TJ and myself I can send to you.
Maybe overly cautious but they are accurate to 2 meters so not to give away the location of my mailbox ....

In TJ's case the received signal  is 13.50 μV or so and 28dB to spare off of just 200mw on both ends with 18dB gain antennas. Due to my being a cheapskate and not having donated to Roger in a while my estimates were made @ 3.3GHz.(2,4g is behind a pay wall)  Not as good as I usually do but perfect.

My path is a little tougher because I have to either elevate above, burn through, or cut down some trees.
The next issue is lag/buffering. To be useful this has to be near real time less light speed delay.

I'll set up the test cell shortly and report back.


ralph day

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Re: How to power a remote receiver on a hilltop
« Reply #3 on: September 27, 2021, 08:11:19 AM »
"where my winter retirement will be."

Akkkk!  Where will the next generation of top notch, reliable r/e stuff come from?  Unless you're one of those who can't stop doing what they love boB.

After the acoustics, Trace, Xantrex, Outback and Midnite (did I miss any?) in your and Robin's past, what could be next?

boB

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Re: How to power a remote receiver on a hilltop
« Reply #4 on: September 27, 2021, 09:32:26 PM »
"where my winter retirement will be."

Akkkk!  Where will the next generation of top notch, reliable r/e stuff come from?  Unless you're one of those who can't stop doing what they love boB.

After the acoustics, Trace, Xantrex, Outback and Midnite (did I miss any?) in your and Robin's past, what could be next?


This will have to be it I think.  I am running out of years left !   BUT at the same time,  I can't doing things so we will see

 ;D
K7IQ  He/She/It

kopcicle

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Re: How to power a remote receiver on a hilltop
« Reply #5 on: September 28, 2021, 05:30:10 PM »
https://web.archive.org/web/20050424080056/http://www.guerrilla.net/reference/antennas/2ghz_collinear_omni/
http://www.radiomanual.info/schemi/ACC_antenna/Aerialix_ARLX-OM2400_kit_user.pdf
The first link I'll call Mod 0 . I used it with some success but it didn't scale well.
The latter link probably doesn't scale well past 12Db but I tried a theoretical 18Db several times.

TJ has the information on a path between his QTH and the most obvious elevation he can see.
I'd post it here but placing a bullseye on someone isn't my idea of fair play :-)
My elevation data is accurate to a meter.

Ive used the Seano 2511CD PLUS PC-card, prism 2.5 chipset (also sold by Netgate / Engenius) but they are EOL so I'm SOL except for the used market. These are 200nw PCMCIA cards.

My experiments included taking an old 3m dish up to the peak and using an LPDA (Log Periodic Dipole Array for you non RF types) a feed horn. I made contacts up to 52 miles away and had usable bandwidth for web use out to 24 miles. Several stations turned Yagi antennas  toward the hill and the results were predictable, exceptional links.
One caution that should have been obvious. Do not point the 3m dish at the sun.

As a start , make use of Roger Cloude's site http://www.ve2dbe.com/english1.html to establish a coverage map of your near field and identify the nearest available elevations for the HF receiver and 2.4GHz downlink.
Once you find the ins and outs of the tool see what your possible links are at reduced power and gain levels. I suggest no more than 100mw and 12Db gain to begin with. Better to reduce expectations initially and be pleasantly  surprised later. Adding more antenna and power is easy but only if the initial link actually exists.
The tool on the site is "radio mobile online" . Register and have a go .

Several caveats arise.
For any measure of predictable communications there can be nothing in the way. Line of sight is essential.
This would probably work best with a vertical gain array on the mountain and the dish below.
For diversity antenna operation just why not put a dish and a vertical on the hill ?
Climate is what you expect and weather is what you get. Water vapor soaks up 2.4g energy like a sponge.
There is no substitute for gain. Not only in the amplifier chain but in the antenna system. More is better.
Find a happy medium between amplifier gain and antenna gain. This allows you place the radio at or near the feed point of the dish but right at the base of a vertical array.
Last but not least is the critters. Not only would you not believe what wild rodents will eat but what people will steal.
Camouflage and security by obscurity is an art form , practice it  .

Bob, I know you have pressures on your time so PM Lat/Lon (accurately as possible)  for your QTH and I'll get some possibilities.

On a further note is https://www.hfsignals.com/index.php/ubitx-v6/ . Several in the community are working on a remote control resembling CAT . The project has continued without me for a couple years now so it could be anything at this point.

So I didn't buy the deluxe kit so I don't even have the batteries yet.
That's why I'm here

My initial current budget is a bit less than 3A/H . This includes the single board computer, the receiver, and the TX/RX at 2.4g at approximately 100mw . Even with increased computing power and TX/RX the current draw should not exceed 5.5A/H.

The only power sources available are a bit of wind and solar. The installation would be remote and largely inaccessible for months of the year. It's the price you pay for having a quiet receiver.

Enough for now. Someone else's turn 

~kop