SaVVy 2 element 20-2m portable yagi
Obliczymy ostateczną cenę na podstawie wybranego pliku. Sprawdzisz ją i zaakceptujesz przed płatnością.
Zapisane na tym urządzeniu.
This is a 2 element portable yagi antenna based on commonly available 17' whips as the elements. Covers 20-2m bands.
- Ocena
- 5 / 5
- Polubienia
- 32
- Pobrania
- 314
- Wydruki
- 1
- Wyświetlenia
- 1928
- Oceny
- 1
Aktualizacja u źródła:
Informacje o modelu
- Źródło
- Printables
- Kategoria
- Electronics
- Licencja
- Creative Commons — Attribution
The SaVVy is a lightweight 2 element portable yagi antenna based on commonly available 17' whips as the elements. Covers 20-2m bands. I designed this for 3/8-24 whip mounts, but it can be easily modified for M10. The whole assembly including whips and choke is just under 5 lbs.
Construction
Print 2x of the hubs in PETG or similar, 100% infill.
Once printed, press in the heat-set inserts (see below). I used a large soldering iron to heat up and press them in. They're tapered so they generally self-align.
When inserted, use a file or sandpaper to smooth out the surface. Look at the pic of the hub with the inserts installed for reference.
Print 2x of the end caps in PETG or similar, 100% infill.
The boom is made out of 1" x 0.063" aluminum square tubing. This is commonly available at home improvement stores like Home Depot or Lowes. A 4ft boom would be sufficient if you like, although you may see better performance (especially on 15-20m) with a longer boom. 6' is likely a good compromise.
Use the hubs as a drill guide - the center bolt hole on the hub is designed for a 3/8" bolt.
Place the hubs on the ends of the boom and drill for the bolt.
Insert the end caps and bolt the hubs to the boom.
Drill the middle of the boom for the u-bolt mount (see below)
The director and driven ties are laser cut and bent sheet metal - I designed them for 0.063" 304 stainless. These are really optional - you can accomplish the same thing by using ring terminals and wire.
For the director, you just want to electrically connect both whips and the hub bolt together.
For the driven, connect the ground of a SO239 connector to one whip and the hub bolt. Connect the center conductor to the other whip
The mount backing plate is designed for 0.060" 304 stainless. You can choose to use washers instead.
You can purchase all the sheet metal parts in the link in the parts section
Step by step build video
Items to purchase to complete the antenna
U-bolt antenna clamp mount:
SO-239 bulkhead connector:
17' whip antennas (you'll need 4x total)
3/8-24 to M10 adapters (if you go with the 3/8-24 version)
3/8-24 heat set inserts
M10 heat set inserts (optional - these will also fit in the hub). Either of these works fine.
1" x 0.063 square aluminum tubing. I built this with a 4' length, but 6 or 8' would probably work even better, especially for the lower bands. Experiment!
Common mode choke of some kind. I used this one from LDG Electronics
You could use whatever you have handy, or make an 'ugly choke' out of coiled coax
Hardware Kit containing the director tie, drive tie, and the mount backer plate are available for purchase here:
Operation
Set the driven whips to roughly 1/4 wave length each on the driven elements
Set the director whips to 4% shorter than 1/4 wave length on each director element
Adjust the whip length to fine tune the SWR
You can try, instead a reflector-driven arrangement for a different pattern. In that case, tune to the driven elements as usual and instead make the reflector elements 4% longer than the driven.
I used a 25' push up mast to mount the antenna. Use anything that works. The higher the better, however performance is still pretty good lower to the ground.
Experiment
Enjoy
Field Test
W6IWN gave the antenna a solid shake down. This was the earlier version with aluminum machined hubs. This version uses 3d printed hubs - performance is identical. The printed hubs just make it more cost effective for everyone:
Feel free to modify, remix, etc