Matronics Email Lists :: View topic - simple antenna for 704 mHz

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

simple antenna for 704 mHz

Matronics Email Lists Forum Index -> AeroElectric-List

View previous topic :: View next topic

Author Message

rd2(at)dejazzd.com
Guest

Posted: Tue May 24, 2022 5:28 am Post subject: simple antenna for 704 mHz

Hi all-

I have a SwitcheOn box in a metal hangar to turn on/off the engine heater remotely with my cell phone. The box uses the IoT cell network at 704 Mhz (~42 cm full wave) and the signal strength is dismal, so the box often goes offline and I have to drive up to the hangar and restart it, which defeats its purpose. With hangar door open, the signal improves.



I'd like to build a simple antenna, but my antenna knowledge is limited. Would the following work (see attached screenshot): 

-strip jacket and outer conductor to expose 42 cm of inner conductor with insulation – this becomes the full wave antenna; 

-let that 42 cm antenna hang from top of hangar down along the wall (so as not to anger the FBO); 

-ground the outer conductor at the antenna end to the metal hangar. 



Any suggestions, thoughts?



Thanks

Rumen

Screenshot_2022-05-24_at_08-58-59_Amazon_com_Goupchn_25ft_Low_Loss_Coaxial_RG58_Extension_Cable_N-Type_Male_to_SMA_Male_Coa[...].png

Description:

Filesize:

135.86 KB

Viewed:

6221 Time(s)

Screenshot_2022-05-24_at_08-58-59_Amazon_com_Goupchn_25ft_Low_Loss_Coaxial_RG58_Extension_Cable_N-Type_Male_to_SMA_Male_Coa[...].png

user9253

Joined: 28 Mar 2008
Posts: 1925
Location: Riley TWP Michigan

Posted: Tue May 24, 2022 6:41 am Post subject: Re: simple antenna for 704 mHz

According to this website

https://service.shure.com/s/article/quarter-wave-antenna-dimensions?language=en_US

a 704Mhz 1/4 wavelength antenna is 4 inches long.

Strip about 6 inches of outer insulation from the coax.

Push the outer braid so that it expands and slides back over the coax cable.

Trim the outer braid so that it is 4 inches long.  This acts as a ground plane.

Cut the center conductor so that 4 inches is exposed.

Do not connect to metal hangar.

_________________
Joe Gores

david(at)carter.net
Guest

Posted: Tue May 24, 2022 7:10 am Post subject: simple antenna for 704 mHz

I bought an inexpensive magnetic mount external antenna for my GSM / 4G switch (different brand from yours, but works the same.)



https://smile.amazon.com/SUPERBAT-Magnetic-External-Antenna-T-Mobile/dp/B09GFCZ35B



There are lots of similar antennas available on Amazon. 

Here's one with a non-magnetic mount: 

https://smile.amazon.com/Bingfu-Waterproof-T-Mobile-Cellular-Amplifier/dp/B07R9JGLV5

---

David Carter

david(at)carter.net (david(at)carter.net)



On Tue, May 24, 2022 at 10:43 AM user9253 <fransew(at)gmail.com (fransew(at)gmail.com)> wrote:



 	  Quote: 	
		  --> AeroElectric-List message posted by: "user9253" <fransew(at)gmail.com (fransew(at)gmail.com)>

 

 According to this website

 https://service.shure.com/s/article/quarter-wave-antenna-dimensions?language=en_US

 a 704Mhz 1/4 wavelength antenna is 4 inches long.

 Strip about 6 inches of outer insulation from the coax.

 Push the outer braid so that it expands and slides back over the coax cable.

 Trim the outer braid so that it is 4 inches long.  This acts as a ground plane.

 Cut the center conductor so that 4 inches is exposed.

 Do not connect to metal hangar.

 

 --------

 Joe Gores

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=507041#507041

 

 

 

 

 

 

 ===========

  -

 Electric-List" rel="noreferrer" target="_blank">http://www.matronics.com/Navigator?AeroElectric-List

 ===========

  FORUMS -

 eferrer" target="_blank">http://forums.matronics.com

 ===========

 WIKI -

 errer" target="_blank">http://wiki.matronics.com

 ===========

 b Site -

           -Matt Dralle, List Admin.

 ="noreferrer" target="_blank">https://matronics.com/contribution

 ===========

rd2(at)dejazzd.com
Guest

Posted: Tue May 24, 2022 9:05 am Post subject: simple antenna for 704 mHz

Thanks David, however an antenna that looks like an antenna is what I want to avoid due to FBO restrictions. 



---

david(at)carter.net
Guest

Posted: Tue May 24, 2022 9:22 am Post subject: simple antenna for 704 mHz

On Tue, May 24, 2022 at 1:06 PM rd2 <rd2(at)dejazzd.com (rd2(at)dejazzd.com)> wrote:



 	  Quote: 	
		  Thanks David, however an antenna that looks like an antenna is what I want to avoid due to FBO restrictions.





	


100% understand. I found that all I needed to do with mine was to raise it a few feet on the interior wall of the metal t-hangar to get adequate reception. The fire-resistant dividing walls in the hangar are sheetrock attached with screws. The magnetic base of the antenna grips one of the screw heads about 10' up & very close to the sliding metal door. It's inside, so no one is the wiser. 

---

David Carter

david(at)carter.net (david(at)carter.net)



 	  Quote:

rd2(at)dejazzd.com
Guest

Posted: Tue May 24, 2022 11:36 am Post subject: simple antenna for 704 mHz

Yeah, I tried this method, but it did not work... had a similar 8 dB antenna (supposedly) specifically tuned to my frequency from amazon. Magnetic base on a T-shaped bracket high (close to ceiling) electrically connected to hangar wall. (all my T-hangar walls are sheet metal); have a way to measure signal strength - no difference...seems the only way is to bring a camouflaged antenna to the outside. 



---

Ceengland

Joined: 11 Oct 2020
Posts: 391
Location: MS

Posted: Wed May 25, 2022 5:31 am Post subject: simple antenna for 704 mHz

What's the roofline of the hangar look like? Most metal buildings have gaps where the ridge cap covers the roofing (easy to run an antenna cable through). A 4" black spike on a magnetic base attached  far from the edges of the roof would be out of sight from the ground, and virtually invisible from the air. Biggest trick would be getting it up there without being seen.

On Wed, May 25, 2022 at 12:19 AM rd2 <rd2(at)dejazzd.com (rd2(at)dejazzd.com)> wrote:



[quote]Yeah, I tried this method, but it did not work... had a similar 8 dB antenna (supposedly) specifically tuned to my frequency from amazon. Magnetic base on a T-shaped bracket high (close to ceiling) electrically connected to hangar wall. (all my T-hangar walls are sheet metal); have a way to measure signal strength - no difference...seems the only way is to bring a camouflaged antenna to the outside. 



---

_________________
Charlie

rd2(at)dejazzd.com
Guest

Posted: Wed May 25, 2022 4:03 pm Post subject: simple antenna for 704 mHz

Not doable either... and can't get up without being seen. Roof of a row of T-hangars is pretty flat and in proximity for observation. 



---

rnjcurtis(at)charter.net
Guest

Posted: Wed May 25, 2022 4:53 pm Post subject: simple antenna for 704 mHz

Sent from Mail for Windows

From: rd2 (rd2(at)dejazzd.com)

Sent: Wednesday, May 25, 2022 8:05 PM

To: aeroelectric-list(at)matronics.com (aeroelectric-list(at)matronics.com)

Subject: Re: Re: simple antenna for 704 mHz

Not doable either... and can't get up without being seen. Roof of a row of T-hangars is pretty flat and in proximity for observation. 

�

Can you get to the roof from inside, punch a small hole, in an inconspicuous spot, and feed the cable as Joe Gores described, out the hole.  By the way, if I were to make up this antenna I would finish it off with a piece of shrink tubing long enough to cover the braid exposed on the surface.

Roger

 	  Quote: 	

 	  Quote:

rd2(at)dejazzd.com
Guest

Posted: Wed May 25, 2022 6:38 pm Post subject: simple antenna for 704 mHz

Good ideas (to work from inside). The question is would such antenna lying flat on the roof (horizontal) or one hanging down sticking to the wall work better. (?)



---

nuckollsr

Joined: 24 Mar 2009
Posts: 95
Location: Medicine Lodge, KS

Posted: Mon Jun 06, 2022 4:58 am Post subject: Re: simple antenna for 704 mHz

Rumen, did you resolve your antenna issue? If not, I may have a potential solution. I've got a 'thru the roof' antenna I built for a local EMS member that's too long (465 Mhz) that can be cut down to accommodate your target frequency. It was originally intended to poke thru a metal roof via 5/8" hole and bond to the inside surface for weather sealing. It would also work nicely thru a side wall of the building.



It's only a 4" 'spike' protruding off the surface . . . unobtrusive. Easily removed and patched in future.



I can dig it out and trim to your requirements.

0606220753[1].jpg

Description:

Filesize:

551.03 KB

Viewed:

6132 Time(s)

rd2(at)dejazzd.com
Guest

Posted: Mon Jun 06, 2022 6:47 am Post subject: simple antenna for 704 mHz

Bob, thanks, not necessary at this point -

 - I ended up experimenting and building a coax 1/2 wave dipole antenna inspired by a ham operator. I purchased some 15' of coax with SMA on one end, removed the insulation at 1/4 Y, exposed 1/4 Y of the center conductor, folded back 1/4 Y of the braid over the coax and finished over w/heat shrink tubing, thus making, as an extension of the coax, a quick and simple 1/2Y antenna not requiring a ground plane. Inside my "faraday cage" the signal now is 6 dB better than with the original antenna. Not enough, but more stable. If the box doesn't go offline in future weeks/months, this temp solution becomes permanent, otherwise will poke it out through a 1/4" hole on the side wall.

Rumen



---

JasperWheeler
Guest

Posted: Mon May 13, 2024 11:38 am Post subject: Re: simple antenna for 704 mHz

Roofing services encompass a wide range of offerings aimed at maintaining, repairing, or replacing the protective covering of a building, and one increasingly popular option is the installation of a metal roof. Known for its durability, longevity, and energy efficiency, a metal roof offers numerous benefits to homeowners. Whether it's standing seam, corrugated, or metal shingles, metal roofs provide superior resistance to weather elements, including wind, rain, and snow, ensuring long-term protection for the home. Additionally, metal roofs require minimal maintenance and are often made from recycled materials, making them an environmentally friendly choice. With their sleek appearance and exceptional performance, metal roofs are a top choice for homeowners looking to enhance the durability and curb appeal of their properties through professional roofing services.

Display posts from previous:

	Matronics Email Lists Forum Index -> AeroElectric-List	All times are GMT - 8 Hours
Page 1 of 1

Jump to:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum