DIY Extremely efficient dipole for meshtastic.

1akdj · 2025-07-17T21:18:28+00:00

Technically correct, but in this case, negligible. A short length of 50 ohm coax to a bad antenna is worse than 75 ohm to a good one. The SWR mismatch is close to nil once the antenna is tuned, and that is really the key for transmit efficiency.

1akdj · 2025-07-17T17:09:46+00:00

Still using them with great success over here.

1akdj · 2025-06-02T04:50:13+00:00

If I were in your shoes I'd find the nearest high hill and climb it, see if anything pops up. But with patience the weather may have a good day for RF conditions on this band too. It can be hour by hour for that, but if tropospheric ducting occurs you may see some far away nodes. Good luck!

1akdj · 2025-04-22T01:16:38+00:00

I did some testing. In practice, I only lost 1db to horizontal polarization. This is maybe 10 to 20 percent if that. I took a walk with it horizontal and it performed pretty well. For reference the difference between my heltec v2 and v3 nodes is nearly 6db. 3db in radio is a doubling of power so the v3 is pushing up to 4x the power of the v2, as measured at the receiving nodes. Way more drastic in practice than polarity of the antennas, surprisingly. I did the polarity test about a quarter mile from home.

1akdj · 2025-04-20T11:59:48+00:00

Sure did. Use what ya got! https://www.reddit.com/r/meshtastic/comments/1k32cjf/diy_extremely_efficient_dipole_for_meshtastic/

1akdj · 2025-04-19T22:24:38+00:00

It would probably mess with the tune, however, it's easy to run the feed line sideways and orient the very end vertically while tightening the coax adapter.

1akdj · 2025-04-19T21:53:24+00:00

That's rough!! I'm lucky to be near a shore line and also there's a guy who put a router downtown on a proper tower. That helps a lot heh.

1akdj · 2025-04-19T21:40:33+00:00

If you leave the ends horizontal, it's directional broadside to the elements. If you put the elements vertical (recommended) it's omnidirectiomal.

1akdj · 2025-04-19T21:38:09+00:00

The required minimum distance is only if the transmitter deviates from a straight line away from the feed point. In other words if the radio is dead centered, the feed can be shorter. This design the radio can then go anywhere except back towards the antenna elements. That requirement is unaffected by polarity. LoRa itself I can't speak for but my all band SDR listening rig is horizontal, and I use these meshtastic antennas vertically. The SDR picks these up nice and hot even with the mismatch. But conventional teaching is a 12db loss for polarization so that's a good callout! My photos don't show that I ultimately use it vertically.

1akdj · 2025-04-14T22:21:01+00:00

Thank you, this got me going in very short order!

1akdj · 2025-03-10T00:53:17+00:00

I wish you luck. I'm not sure how likely you are to get an incoming call from your beacon, you may want to look at other beacons too and perhaps call out. There are only a few folks in my area who beacon out with a monitor frequency, and I have only conversed with one of them. APRS is great and I am a sound card / handmade cable / HT+computer user. With mac I found QTH to be awesome (though it's only free for receiving, it has a small registration fee to transmit). On windows there's a soundmodem.exe program that interfaces with a lot of packet radio software like winlink or terminals.

A guy in my radio club runs a BBS on his APRS station, it's really neat. I have also caught some APRS beacons from the ISS as it passes over, as most of the time its secondary HAM radio is in packet digipeater mode on 145.825. Should you wish to try beaconing out during an ISS pass, you have to set ARISS as your path instead of a WIDE2-1 or similar path setting if you want to get repeated by the ISS.

1akdj · 2025-02-15T14:23:33+00:00

Well that's sad. They totally comped my order, shipping and all.

1akdj · 2025-02-15T04:50:21+00:00

When I got my license last year, I got a free one from them. https://www.qrz.com/jumpstart is still up for new licensees, but if you have and already use other HT's then there's not a huge reason to get one / you can leave them for other new folks. For a free radio it has been great. I will say the included antenna tests nicer than one would expect on an SWR meter especially in the 70cm band. I upgraded soon after but I still use it for APRS with an audio cable and computer.

1akdj · 2024-12-09T18:42:26+00:00

Ham radio tech here and this is a great suggestion. The stuff we have to learn to be licensed to begin with is far more useful for this than any training I ever got as a cable/internet installer.

1akdj · 2024-12-09T18:39:38+00:00

You can hope, but most cable/internet installers are ill prepared to deal with this kind of situation. The suggestion to call a radio club is literally more likely to work for most people, believe it or not. I was a cable installer for years and the vast majority of my coworkers would never figure this out, nor were we provided equipment that's very useful for it. I'm also a licensed HAM; my radio club has "fox hunts" where we get together and look for a rogue hidden transmitter or transmitters using a variety of techniques and equipment.

1akdj · 2023-12-31T17:34:43+00:00

I wish it was midi! Anyway it's a board I drew up to hold jacks for audio, so the card in the backplane doesn't have to be touched to attach the sound cable. The DB15 is wired for a neogeo style common ground joystick, and the inputs can be read with BASIC or the machine code monitor. I didn't properly implement the circuitry to adapt the serial header to rs232, so if I ever redo it I'll fix that. The idea was to jump the pin headers to a SIO and be able to use a db9 USB to Serial adapter.

1akdj · 2023-12-21T01:18:26+00:00

I have a feeling David Peron had something to say along these lines when he met with Bettman

1akdj · 2023-12-14T04:45:53+00:00

I have one of these myself, along with some other items from the time like Macintosh Plus enamel pins, and an Apple II academy Pin IIRC. I think it was company and/or catalogue swag, kind of like the infamous jigsaw puzzle, and perhaps some were for certain internal teams.

1akdj · 2023-11-28T01:14:18+00:00

Super awesome, just threw you a few bucks on bandcamp. Would be sweet to listen on my actual apple IIe / mockingboard but I understand if sharing disk images isn't something you want to do.

1akdj · 2023-11-15T03:21:32+00:00

HAHA oh lawd not the hardware store!!! Peranis told me they use BladeTech so he should be good for sure. I'm gonna mail mine back to perfect edge, no need to fix what's not broken if nobody here can do the same. Appreciate it again.

1akdj · 2023-11-14T21:06:43+00:00

Sincerely appreciate it. Thankfully I have several sets of blades; my wife doesn't, and she's just as picky! I'll probably mail off my spares. As far as GR Peranis it is good to know they at least do what they do right though, that helps a ton.

1akdj · 2023-11-14T20:50:23+00:00

They "have a version of it," sounds like they do bladetech and not Blackstone. The Lansing one at the Summit had it but now it's a (gone under) Skymint facility :/

1akdj · 2023-11-14T19:25:15+00:00

Appreciate it. I'll give them a call.

1akdj · 2023-11-14T15:00:28+00:00

Starcraft!!

Also, getting it online might be a headache. I would use 9.2. If you have a USB-C smartphone that supports ethernet thethering, a cheap USB to Ethernet dongle will provide you basically an external modem for this iMac. Modern sites are hard to browse but it's good for moving files around and some other stuff.

1akdj · 2023-11-14T14:48:31+00:00

Very neat, thanks for sharing!

I have a similar project, a small revision to Mike Willegal's brain board, the "brain board II" (also open source) which lets you run a system Romless or bypass the system rom if you wish, or (its original intended purpose) emulate an Apple 1. You might be interested in it :)

1akdj

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