Advice Needed UHF antenna coupling

[zorrin]

Hello,
I found 2 UHF antennas and I would like to couple them.



What type of coupler should I use ?




To fix them together on a horizontal tube, I decided to move the fixing from the back to the center of the antennas.
The weight would be better distributed between the front and the rear.



In this photo the vertical tube passes through the center of the antenna.

Do you think this is blocking reception?

 

[ozumo]

Have a look at this link, signal was measured with a pole mounted at several locations along the antenna:

Aerial positioning tests : polarity of obstructions – A.T.V. Poles, Brackets, Clamps & Aerials

www.aerialsandtv.com

 

[zorrin]

Have a look at this link, signal was measured with a pole mounted at several locations along the antenna:

Aerial positioning tests : polarity of obstructions – A.T.V. Poles, Brackets, Clamps & Aerials

www.aerialsandtv.com

Thanks @ozumo
I think I'm going to put the fasteners on the back of the antennas...

 

[Terryl]

Your only going to get an additional 3 dB of signal strength when you phase couple two identical antennas.

And the mast location has been accounted for in it's design.

 

[zorrin]

Your only going to get an additional 3 dB of signal strength when you phase couple two identical antennas.

And the mast location has been accounted for in it's design.

The two antennas cost me a total of 20 euros...
And I need the 3dB for my project.
I already know that I can receive the TNT signal from Brussels in Belgium in Paris with my current small installation (only one time...)
I would like to try to receive it continuously.
It's a bit crazy but I'll do it!

Now the coupler is my problem.

 

[Channel Hopper]

Your only going to get an additional 3 dB of signal strength when you phase couple two identical antennas.

And the mast location has been accounted for in it's design.

3dB is good for the initial cost.

 

[Channel Hopper]

Hello,
I found 2 UHF antennas and I would like to couple them.

View attachment 145523

What type of coupler should I use ?

View attachment 145524


To fix them together on a horizontal tube, I decided to move the fixing from the back to the center of the antennas.
The weight would be better distributed between the front and the rear.

View attachment 145525

In this photo the vertical tube passes through the center of the antenna.

Do you think this is blocking reception?

View attachment 145526G

Use quality sub GHz combiners and keep all cables between the two antennas at an identical length.

Are you looking to capture just horizontal polarity ?

 

[zorrin]

Use quality sub GHz combiners and keep all cables between the two antennas at an identical length.

Are you looking to capture just horizontal polarity ?

Are you talking about that?



Not this one (don't need adjustment) ?


Or something else ?

 

[Adam792]

Have you managed to receive the RTBF on UHF channel E56 since the launch of 700MHz 5G in France? I saw recently that this is now causing signal issues even near the border between France and Wallonia.

Apparently the RTBF mux will move to DVB-T2 HD (HEVC like the German channels) in spring 2023, and at the same time switch to channel 42.

 

[Terryl]

Try looking for one of these hummers.....

https://www.channelmaster.com/products/jointenna-tv-antenna-combiner-cm-0500

And your still going to have to match the coax lengths between the antennas.

 

[zorrin]

Have you managed to receive the RTBF on UHF channel E56 since the launch of 700MHz 5G in France? I saw recently that this is now causing signal issues even near the border between France and Wallonia.

Apparently the RTBF mux will move to DVB-T2 HD (HEVC like the German channels) in spring 2023, and at the same time switch to channel 42.

My Sony TV has a permanent automatic search function.
Very quickly I saw the names of unknown
channels appear that I identified as coming from Belgium on channel 56.
But I had never seen an image before last September.
The quality was very good but the channels and radios slowly disappeared 30mins later.

Channel 42 would not be a problem for me, only the Eiffel Tower, which is the opposite of Belgium from me, uses this frequency.
My Sony TV has a permanent automatic search function.
Very quickly I saw the names of unknown channels appear that I identified as coming from Belgium on channel 56.
But I had never seen an image before last September.
The quality was very good but the channels and radios slowly disappeared 30mins later.

Channel 42 would not be a problem for me, only the Eiffel Tower, which is the opposite of Belgium from me, uses this frequency.

 

[zorrin]

Try looking for one of these hummers.....

https://www.channelmaster.com/products/jointenna-tv-antenna-combiner-cm-0500

And your still going to have to match the coax lengths between the antennas.

Yes, I suspected that requirement

 

[zorrin]

There are 251 km between my house and the transmitter.
I am at an altitude of 132m and the transmitter at 172m.

The maximum height is 174m between us.
It's a problem but not too much I think.

 

[zorrin]

I will of course put a rotator for the fine adjustment but also to see if I wouldn't be able to catch you too

 

[Adam792]

Interesting stuff

The nearest Francophone Belgian DVB-T transmitter to Paris is Tournai/Froidmont. That's 40kW but in V polarisation. The high powered transmitter near Brussels (Wavre) is 80kW H. Both currently use channel 56 in SFN.

Looks like from the Paris region that the terrain profile is more favourable towards Brussels than Tournai.

 

[ozumo]

There are 251 km between my house and the transmitter.
I am at an altitude of 132m and the transmitter at 172m.

The maximum height is 174m between us.
It's a problem but not too much I think.

View attachment 145546

Looks more like 32m than 132m on that chart? This line-of-sight calculator allows you to enter antenna heights (Wavre is 232m according to wikipedia):

https://www.scadacore.com/tools/rf-path/rf-line-of-sight/

 

[zorrin]

Looks more like 32m than 132m on that chart? This line-of-sight calculator allows you to enter antenna heights (Wavre is 232m according to wikipedia):

https://www.scadacore.com/tools/rf-path/rf-line-of-sight/

No, I'm sure of my position.
I am at one of the highest places near Paris.
I based myself on the transmitter of the tower of Brusseles not the Wavre one.
But I believe that you are right for that.
I will recalculate today

 

[Adam792]

The central Bruxelles/Tour des Finances transmitter looks like it’s only a few kW in power from the info I found, and is V polarisation like Tournai rather than H like Wavre. All are using channel 56.

On the other hand, once the switch to channel 42 happens next year, V pol may be better for you as it would give you better rejection of the H pol transmission on E42 from the Eiffel Tower transmitter.

 

[Adam792]

There's also Anderlues/Mont-Sainte-Geneviève (80kW H @ 157m), and Profondeville/Rivière (50kW H @ 157m) also on channel 56.

Source: fmscan.org

 

[LeBelge]

The two antennas cost me a total of 20 euros...
And I need the 3dB for my project.

I think that you need a better antenna like that one:



I bought it from castorama.fr ( in France )