TV Aerial for 4G

[friendly1uk]

I have a project to consider.
My vodafone 4G is in the 900-950mhz region. Top band c/d (green ends) TV aerials.
I use an MR600 4G router

This is 4G+ which means I have two connections, hence two aerials, generally cross polarised as the towers do.

My intention is to remove the radiating element of a TV aerial, and simply position my 4G modem in it's space. In the loft, where it doesn't rain so often.

I have seen a youtube where a guy does similar, but for wifi. Using a wifi dongle where the radiating element of a wifi yagi would be. Results were better than my efforts with a wifi yagi replacing my wifi dongles removable aerial. Actually... his results were good.

Now I come to choosing the TV aerial. Locally we left top band a couple of years back, so finding a group c/d would be easy. However, the newer aerials sold as wideband, tend to have directors that are little crosses, not flat bar. I'm unsure if digital TV is in fact cross polarised. As my router is. It would seem to make sense that I get the more recent wideband style, then reposition the elements, rather than have the log arrangement. I can get one of these that's just been in a loft for a tenner. Plus a tenner to fetch it, at today's fuel costs.

So that's where I'm on the fence. On one side, a top band yagi has good gain where I need it. The log has the nice crosses but poor gain in top band specifically. Though I would move the elements about (having done a little maths) to perhaps target my band even better than the c/d

My fastest download has been 80Mbps on band 8. Spec: 880 – 915 UL / 925 – 960 DL (45mhz bandwidth)
I get much better reception of a band 20 mast, but it's never over 40Mbps. Spec: 832 – 862 UL / 791 – 821 DL (30mhz bandwidth)
I can see a band 1, but that is 1920 – 1980 UL / 2110 – 2170 DL (60mhz)
I can also see a BAND 7 choice.

These choices of 1,7,8,20 are just what it can see now. It doesn't give mast ID number though, so I can't see them on mapping software. My phone can list all the masts it can see, and it's generally quite a few. I'm in the city so it's a bit congested, but I can see 10 miles out from my roof space. I hope to find a less used mast 'out there' somewhere. So while I can select bands to use on my router, I need the extra selectivity of a beam like aerial.


I'm waffling. Do I mod the wideband log, or will all them crosses closely grouped be a problem?

[friendly1uk]

figuring pic posting

[grafter]

Group C/D TV aerials covered 690-860MHz and chances are most designs would of started to roll off aaround 820MHz. Above that gain, FB ratio and polar response dropped like a stone and by the time they got to 950MHz were probably no more efficient than a dipole. Scrap the TV aerial and buy some LTE log periodics.

[friendly1uk]

Band 20 LTE is channel 61 to 69


The obsolete DY14WB looked interesting

I think shuffling a wideband about might be the better option. Decreasing the gaps, to raise the frequency a little. Tonight I put a 100mm fan grill ahead of the router and saw gains in both signal and snr of about 4db. Just with a poorly placed circular director.


I do have a lot of wire coat hangers, and some white PVC pipe or mini trunking for a beam. Keeping with the homebrew project I fancy a crack at.

[friendly1uk]

The tri-beams look a bit peaky, but the wideband yagi's actually look okay. I expected a more even performance across the TV band, but they actually excel in the top band. All of them.


Look at the contract 10WB. It's climbing as it leaves our view. Channel 75 (960) seems reasonable. Giving band 8 LTE coverage, not just band 20 which is covered on these graphs.

[grafter]

Band 20 LTE is channel 61 to 69

I know but you started the thread by saying your router starts at 900MHz

My vodafone 4G is in the 900-950mhz region.

[friendly1uk]

Yes, I had chosen to use band 8, which extends to 960, around channel 77 perhaps. Extrapolating from the test data above, coverage should be possible. I'm just torn between a linear yagi build, or a log. The more I look, the log might be more suitable. Perhaps even the shorter wideband types. Partly because my band choices cover quite a range. The yagi is a bit focused, and I'm unsure which band I will settle with. Band 8 was not great yesterday, and I saw a record low of 8Mbps. Better than the various 24bps adsl services I've had still.

I feel a lot more comfortable making a yagi, if it comes to a self build. The wideband's have quite a reflector though. The sheer number of 4G masts and handsets transmitting is quite something. Blocking out noise might clean up my reception. Having a greater effect than the beaming. I'm a CB radio guy, taking on a digital project. Where signal to noise concerns need as much thought as outright power.

[pienari]

I think swr is not good but sure you can test effect.

I have built 18el lte band 3 (1.9m boom 1800MHz) yagis and those monsters can reach really high speeds long distance.

7km from mast.
Huawei router external antennas inside house 4/0.1Mbit at band3
I installed yagi beams to 9m high.
238/42Mbit

Worth to try

https://aijaa.com/oMwCUt