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-   -   Expedient SATCOM Antenna (http://www.professionalsoldiers.com/forums/showthread.php?t=18907)

Electron 07-15-2008 05:21

Expedient SATCOM Antenna
 
I've created an antenna that is growing in popularity very quickly. It is a field-expedient SATCOM antenna that weighs less than a pound and could fold up small enough to fit into a sandwich baggie. Since it is a high-angle satellite in that area, the antenna could plug directly into the PSC-5. It only takes about 10-15 minutes to make and will work when hand-held, tossed on the ground, mounted on a vehicle or a rooftop. It is flexible and durable and could replace the bulky "X" wing in a pinch. The Team Sergeant has posted the plans in the SF Only forum. Tests recently done have determined the actual gain to be somewhere around 2.6 dB.

glebo 07-15-2008 06:10

field exp SACTOM ant
 
I'm gonna PM you and give you my soc email. I'm the 18E training developer up here in SWC. If ya don't mind, showing/instructing the new E's on how to build that would be great for them. We teach them now how to build an expedient sat ant (three element yagi) with tinker toy sticks or pieces of wood, but if yours is different, hey another tool for the bag.

thanks

Electron 07-15-2008 06:24

HI-Gain SAT Ant Instructions
 
If anyone is interested, here's how: 1005 divided by the frequency in MHz will give you the length in feet. Multiply by 12 to get the length in inches. For example: a TX freq of 265 MHZ would require a 45 1/2 inch long wire. An RX freq of 250 MHz would require a wire 48 1/4 inches long. The RX freq is almost always lower than the TX freq, so the RX antenna would be slightly longer. (the closer you get to the exact length, the better your gain will be) Use the solid core 12-3 electrician wire that is normally used to wire household electrical sockets and stuff.

Use a BNC plug-to-two BNC jack Tee connector and two BNC plug-to-red and black binding post connectors. Connect the binding post connectors to the tee connector, ensuring that as you look at it, the same color posts are diagonal from each other. ADD 1 inch to the length of each of your wires to compensate for a stripped 1/2 inch, 90 degree bend at each end of the wire that will be inserted into the binding posts. Form each wire into a loop, insert the stripped end into the binding post and cinch down tightly. The RX loop must be on the bottom and the TX loop on top.

Connect to your radio and it's game-on.

Swamp 07-15-2008 11:46

Electron, sent you a e-mail....Regards

Electron 07-16-2008 12:24

Photo of the Antenna
 
1 Attachment(s)
Your antenna should look similar to this...

Dealer 07-17-2008 06:32

PM Sent, E.

Electron 07-17-2008 14:35

NSN for Connector
 
The NSN for the BNC to Binding Post connector is
5935-01-371-4140

The NSN for the BNC Plug to two BNC Jack is
5935-01-496-4794

The NSN for the 3-Piece BNC crimp connector is
5935-00-071-7477

Another useful NSN is for a connector adapter set:
5935-01-373-6505

HeavyDrop 08-09-2008 21:55

Thanks!!
 
1 Attachment(s)
I successfully made comms with higher during an air assault. I noted higher gain than the AV-2055 and it fit in my cargo pocket. Electron also adapted this idea for vehicle use. We rolled with it successfully for more than 2 months on GMV and RG31! Credit where credit is due!

KillerCommo 08-25-2008 09:32

...interested
 
Sound alot better than what I'm working w/ now. I'd like some more info Electron. Thanks.

Akinci 08-25-2008 10:00

PM sent

Team Sergeant 08-25-2008 10:00

Quote:

Originally Posted by HeavyDrop (Post 220261)
I successfully made comms with higher during an air assault. I noted higher gain than the AV-2055 and it fit in my cargo pocket. Electron also adapted this idea for vehicle use. We rolled with it successfully for more than 2 months on GMV and RG31! Credit where credit is due!

If and when you get the time get rid of the connectors. By looking at your set up you are losing quite a bit of gain with all those connectors.

What do you think Electron?

TS

Chris Cram 08-25-2008 17:47

Quote:

Originally Posted by HeavyDrop (Post 220261)
I successfully made comms with higher during an air assault. I noted higher gain than the AV-2055 and it fit in my cargo pocket. Electron also adapted this idea for vehicle use. We rolled with it successfully for more than 2 months on GMV and RG31! Credit where credit is due!

It looks like a plug-and-play from the parts box, circumventing the shorts issues. (clever)

As per TS's comment...
Quote:

By looking at your set up you are losing quite a bit of gain with all those connectors.
Could you prefab a PVC version using a single BNC mount, 4 Binding Posts and enough hot glue to keep clean, dry and intact?
Or are you trying to have a unit that you can put together and maintain with field parts?

Simplicity is a very good thing. :munchin

HeavyDrop 08-26-2008 12:34

Simple!
 
1 Attachment(s)
Getting rid of the connectors would help for sure. But the gain was adequate and using the connectors made it more durable and replaceable for use in the field. The versions that we constructed with the soldering iron were not as durable and needed to be encased in foam and wrapped in 100mph tape for use on the vehicles.

charlietwo 08-26-2008 12:51

An Echo adding equipment to the team that doesn't weigh anything -- quite the concept! :p
Kudos, Electron! Can't beat ingenuity!

C2

Electron 08-27-2008 09:58

Getting Rid of the Connectors
 
I would recommend getting rid of the connectors if you can. Make all your measurements, add them up and try to make it from one continuous piece of wire. The one I have pictured above is made from one continuous piece with only one solder joint to connect the ends together. The other solder joint is to connect the RG-58 shield-to-ground. The connectors might affect the gain, but with the connectors, you can have a variety of wire lengths for a better frequency range, so there would be a trade-off from performance. Even the antenna using the connectors gets average gain.


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