Suitable Antenna Designs

Post Reply
sfutcher
Posts: 4
Joined: Sun May 01, 2022 4:28 pm

Suitable Antenna Designs

Post by sfutcher »

Can anyone point me to a suitable antenna design for receiving the signal from the Meteor Beacon, which is inexpensive and easy to construct?
I would plan to install it in my loft.
tony_ccd
Posts: 8
Joined: Mon May 02, 2022 4:32 pm

Re: Suitable Antenna Designs

Post by tony_ccd »

There's a link to the BRAMS receivers and antenna here:
https://brams.aeronomie.be/receiving_station
sfutcher
Posts: 4
Joined: Sun May 01, 2022 4:28 pm

Re: Suitable Antenna Designs

Post by sfutcher »

Many thanks - Ill take a look
AndrewLutley
Posts: 1
Joined: Thu May 19, 2022 11:40 am

Re: Suitable Antenna Designs

Post by AndrewLutley »

The UK Radio Astronomy Association (UKRAA) have the 50MHz Moxon Aerial in stock - https://www.ukraa.com/store/categories/ ... view/16/51. This is a fairly compact design.

Andrew
tony_ccd
Posts: 8
Joined: Mon May 02, 2022 4:32 pm

Re: Suitable Antenna Designs

Post by tony_ccd »

I have just got a vertically beamed Moxon up and running. It is made of insulated wire in 15mm plastic conduit. I had to add a catenary string to keep the driven element horizontal as in the attached photo. An N-type connector with a bit of tape around it fits snugly in the 3-way conduit box. The insulation and PVC pipes mean I had to trim about 3cm off the wires even though I had already modeled it for 0.95 velocity factor. It still resonates at around 49.9MHz, but I got bored with snipping bits off the wires and taping up the insulated spacers. The SWR at 50.4MHz is around 1.2.
I can swap between my 4 ele yagi which is around 8 feet up presently and the Moxon. The Moxon shows a much higher noise level, presumably because of the large area of sky noise. However, some aircraft trails are stronger on the Moxon than the beam. I have tried to align the Moxon to cancel as much signal as possible, being only 50km from the beacon, but there is still far too much direct carrier. I have also attached a plot from Spectrum lab covering the last 5 minutes.
The starting point for the design was this blog from G1YBB:
https://g1ybb.uk/easy-building-of-a-mox ... ith-4nec2/
I did some further modelling in MMANA-GAL.

Tony
Attachments
20220521_164330.jpg
20220521_164330.jpg (1.49 MiB) Viewed 19500 times
20220520_170511.jpg
20220520_170511.jpg (1.93 MiB) Viewed 19500 times
capt2479.jpg
capt2479.jpg (118.98 KiB) Viewed 19500 times
tony_ccd
Posts: 8
Joined: Mon May 02, 2022 4:32 pm

Re: Suitable Antenna Designs

Post by tony_ccd »

Here is a plot where I switch the antenna every 30 secs or so from a 4 ele yagi to the vertical pointing Moxon - now slightly tipped towards the beacon. As I stated earlier,the b/g noise is quieter on the Yagi, but the aircraft trails are usually brighter on the Moxon, and the direct carrier is definitely weaker on the Moxon.The jury's still out at the G3OVH QTH.
capt2205211721.jpg
capt2205211721.jpg (114.59 KiB) Viewed 19498 times
Post Reply