Tutorial: (Internal SDR) Adding External Threaded Antenna Port
#1
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Howto: Create Threaded Antenna Port For Internal SDR (Pinetab)

My video with tips/instructions for safely opening your Pinetab + This Tutorial:  https://odysee.com/@RTP:9/howto-open-pinetab-cover-safely-adding:4

This can be done for any device with internal SDR. In this case, the Pinetab. Pinebooks and any other device can add this in same fashion. Just be careful where you choose to drill your holes (so finished product does not to put too much pressure against fragile piece internally, and so antennas/cords do not get in the way of leaning your device). Here we installed it to fit small antennas inside the keyboard case itself (when leaning upright). Also measuring antenna wire is important so as not to stretch/damage it internally. Leave a slight extra bit of slack.

Adds a way to change out different antennas without having to opening your Pinetab (greatly enhances the usability/options for SDR).

The Pinetab optionally carries internal SDR (Software Defined Radio). You can also be added later. This is what I have. I love using the Pinetab for SDR controls after this small mod. Works as well as my external and makes for a very thin/compact total SDR kit (might try adding transmitter later) Big Grin

Backstory:

Tried a few internal options but signal was very weak with internal (tried a couple, didn't expect much). I wasn't able to use it for what I needed (multiple antenna types). Still might explore more there but like this options.

Decided it was time to try a modification using parts I had laying around. I not only wanted to be able to change out factory antenna, I wanted an easy way to do this without opening the Pinetab case each time, via a threaded exit port end coming out of the case (for screwing on different types of antennas/cables).

I checked my tools/parts inventory. I noted an antenna I had laying around with a pigtail clip for a LoRa mcu. A matching pigtail was fastening the factory included antenna. The LoRa antenna end itself was unscrewable (see it laying at top right), allowing easy changing out of different antennas. This would be it.

[Image: 2c8990e073884f3d8831912bbdf18e59.jpg]

In the picture below we see the sdr on the small black board, attached by blue/white ribbon cable:

[Image: 5c2816830e5a37d789615f6ef40b81dd.jpg]


Getting Started:


Open your Pinetab case (see link to my video on doing this safely at top of this tutorial) also here: https://odysee.com/@RTP:9/howto-open-pinetab-cover-safely-adding:4

Measure the length of antenna wire to create an idea where to place the hole. Use a marker to plan it.

Carefully drill the hole in back cover (be safe- take off the cover first).

Unclip the factory antenna wire (see above picture: originally antenna still inside the case, lightly tucked under a ribbon cable; new antenna wire shown attached.

I grabbed plyers to bend the thin (maybe 1/2 inch long) small/straight metal piece on the opposite side of the threaded end to make it fit inside the case as neatly as possible (with case completely closed) without too much trouble. I didn't want to risk damaging screen from the inside.

Get a 90 degree bend antenna wire -> SMA (shown in video at top- this was changed as seen in video for better results/less stress to wire).

Grind off a few mm with a dremel or other grinding tool, being careful to ensure it will fit with case closed.

I then used electrical tape to add an extra layer of padding to the hard metal tube opposite the threaded end (the side inside the case).

Would the other end fit inside when I attempt to close the case?

I then set the threaded end straight up, pulling this threaded end through the top of the Pinetab cover, exiting out the back/outside the Pinetab (see picture above/below). 

I fastened the small thin bolt + washers over the threaded piece to hold it snug without wear & tear.

As the picture shows, the threaded end exits the back of the tablet allowing you to change/screw on all different types of antennas.

Some antennas for LoRa. Other antenna setups perfect for receiving live satellite images of the earth.

See below:
[Image: e9ab931a6d26492d1909e015da0c2f7d.jpg]
Take the newly modified back cover and place over the Pinetab. Then carefully snap each edge shut, leaving the side closest to the threaded end for last (to be sure it fits without adding pressure).
I was sure not to put too much pressure on that side, as I didn't want to chance breaking either my screen. This is a big reason I wrapped the harder metal parts (opposite the threading, inside the case) in electrical tape- to cushion any possible pressure put on inside of my screen.
Another antenna shown as an example (LoRa fits inside the keyboard stand discreetly while in use):
[Image: cace1cd0ee4627f8b812f0944405668b.jpg]
One nice thing is small antennas like LoRa, along with antenna cord hooked to larger ones, fit nicely inside the keyboard case without any pressure:
[Image: a6aa9e5fd857a16053828bbbb2447ae0.jpg]

I ran a couple tests to be sure the bending with plyers didn't harm anything. Before doing the mod, I took pictures of the signal strengths/waterfall, attempted to pick up various bands for comparison. This way I could see if there were issues with the bend made in antenna wire metal piece (opposite the threading directly inside the case). The modification made a huge difference- being able to use external antennas increased clarity and distance by probably 40+ x. Worth it.
One of my before/after mod tests was simple FM radio. Only read a weak signal with internal/built in antennas.

[Image: 73e510c23af2b16490d8db45eb46c53f.jpg]
My other main test was another stable radio goto: keyless entry car keys. I used this and took photos before, and after the modification. See for yourself:
[Image: d3a0f92011af76c5beaadc9fd4720a27.png]
Everything is working beautifully. Each antenna showing their unique strengths (as they should).
This was fun. Big Grin
Hope someone finds useful. Really makes for a totally awesome/ideal small SDR kit you can carry (with small antennas discreetly inside keyboard stand). 

Cheers!

See this video (as linked above) that corrects a part in the pictures:  https://odysee.com/@RTP:9/howto-open-pinetab-cover-safely-adding:4
- RTP

"In the beginner's mind there are many possibilities, in the expert's mind there are few." -Shunryu Suzuki

My Blog: https://politictech.wordpress.com
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#2
Pretty nice! I like it!
  Reply
#3
(02-20-2021, 03:09 PM)guenther Wrote: Pretty nice! I like it!

It works great for all different types of things now, the thin bolt keeps it nice and snug as a very compact sdr kit.

Thank you for your feedback! Smile
- RTP

"In the beginner's mind there are many possibilities, in the expert's mind there are few." -Shunryu Suzuki

My Blog: https://politictech.wordpress.com
  Reply


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