Signal strength issue, anyone help?

Nelbert

Hi guys,

Picked up a new aerial and have it set up.... Problem is the signal isn't great but I'm limited on adjusting the aerial direction or position much more.

I'm using a dvb-t dongle which spits out minimal power (I assume) however I connected an old Ariva 150 and then used its loop out to connect to the dongle and the signal is perfect.

What do I need to replace the 150 in this scenario and make it so I can then split the signal into a second dongle? I'm confused about mast head amp vs one of those amplifier / booster splitters.

Any advice on what would be best for this? (From my minimal knowledge a bit of signal gain and split is essentially what I need but not sure how to achieve this).

The Cush

What type of aerial did you install and where?

A properly installed outdoor aerial, correctly aligned on the nearest transmitter shouldn't necessarily require amplification for a single TV point.

What transmitter does the Saorview coverage checker recommend for your location - https://www.saorview.ie/en/get/coverage

A standard 2 output distribution amp will feed 2 TV points, examples http://www.freetv.ie/saorview/tv-distribution/amplifier.html

Nelbert

The Cush wrote: »

What type of aerial did you install and where?

A properly installed outdoor aerial, correctly aligned on the nearest transmitter shouldn't necessarily require amplification for a single TV point.

What transmitter does the Saorview coverage checker recommend for your location - https://www.saorview.ie/en/get/coverage

A standard 2 output distribution amp will feed 2 TV points, examples http://www.freetv.ie/saorview/tv-distribution/amplifier.html

A relatively small one I picked up in power city for €15 or so (approx 25cm long).... I've pointed it in roughly the same direction as a neighbours aerial.... It is behind the sat dish though and probably not quite pointed directly at three Rock.

They signal is nearly there just not quite.

Tvheadend reporting SNR of approx 21dB and signal strength of approx -86dBm

Reports similar levels without the Ariva but suffers picture breakup without it......

Aesthetically this aerial is better for wife approval factor..... Do I need something more substantial realistically? I'm in north Dublin if that helps....

The Cush

Nelbert wrote: »

Aesthetically this aerial is better for wife approval factor..... Do I need something more substantial realistically? I'm in north Dublin if that helps....

Which transmitter does the Saorview coverage checker recommend? I assume Kippure, a Group T aerial will be required.

Thurston?

Nelbert wrote: »

A relatively small one I picked up in power city for €15 or so (approx 25cm long).... I've pointed it in roughly the same direction as a neighbours aerial.... It is behind the sat dish though and probably not quite pointed directly at three Rock.

Tvheadend reporting SNR of approx 21dB and signal strength of approx -86dBm

..... Do I need something more substantial realistically?

This aerial?

No matter, with any aerial, you need to put it where it can actually get a 'sniff' of a signal. 'Behind the sat. dish' doesn't sound ideal ...

-86 dBm is a very poor signal level.

Nelbert

Thurston? wrote: »

This aerial?

No matter, with any aerial, you need to put it where it can actually get a 'sniff' of a signal. 'Behind the sat. dish' doesn't sound ideal ...

-86 dBm is a very poor signal level.

Yeah that's the one....

Is height a big issue? It's only about 10-12 feet off the ground. I could mount it on top of the shed for a clearer line of sight but would be about the same height.

Thurston?

Nelbert wrote: »

Is height a big issue? It's only about 10-12 feet off the ground. I could mount it on top of the shed for a clearer line of sight but would be about the same height.

Yeah, there's such a thing as 'height gain' with terrestrial transmission, & also take into account obstacles in the direction of the transmitter. (Though an exception to this might be a tall tree, where there could be a clearer signal path lower down.)

If you can't get a satisfactory result in the outdoor locations you're willing to use, do you have an attic? Could be worth a try there, if it offers extra height.

Nelbert

Thurston? wrote: »

Yeah, there's such a thing as 'height gain' with terrestrial transmission, & also take into account obstacles in the direction of the transmitter. (Though an exception to this might be a tall tree, where there could be a clearer signal path lower down.)

If you can't get a satisfactory result in the outdoor locations you're willing to use, do you have an attic? Could be worth a try there, if it offers extra height.

My biggest thing has been trying to avoid going near the "old" aerial on the back of the house as I didn't want to risk any of the roof tiles on the extension.... It fed a tv in the back room with soar view perfectly until the sky installer cut the cable and joined to it to run a sky box to the same point "sure you won't need it if you have sky"......

I may just bite the bullet.... It's one of the bigger types that you see all over Dublin beside dishes so I'm guessing if I can get a cable from it to my tvheadend box I should be all good....

Nelbert

Getting approx -55dBm (rte2 mux) and -66dBm (rte1 mux) off the aerial at the back of the house.........

Anyone know if this is a good, bad or indifferent signal?
Picture is perfectbut I need to split this signal so would a simple amplified splitter do the job?

Nelbert

66

Thurston? wrote: »

To convert a signal power in dBm (decibels referenced to milliwatt) to signal level in dBµV (decibels referenced to microvolt), add 107, so you have levels of 52 dBµV & 41 dBµV respectively.

Both of these should stand a 2-way split, but 41 is probably a bit on the low side for comfort.

Which frequencies are these being received on, & what direction is the aerial actually pointed?

Pointed at three rock best I can tell (it's fairly solidly put up, was here when we moved in) so -55dBm on 546MHz and -66dBm on 570MHz.

The Cush

Nelbert wrote: »

Getting approx -55dBm (rte2 mux) and -66dBm (rte1 mux) off the aerial at the back of the house.........

Anyone know if this is a good, bad or indifferent signal?
Picture is perfectbut I need to split this signal so would a simple amplified splitter do the job?

Any signal meter I've used measures the incoming signal in dBμV, using an online calculator the -66dBm (rte1 mux) converts to about 43 dBμV which is below the minimum accepted signal level of 50 dBμV. With a correctly aligned aerial both signal strength levels should be around similar levels.

Have you checked which transmitter you should be pointing at?

Thurston?

Your signal levels there, in dBµV (decibels referenced to 1 microvolt) are, to the best of my understanding, about 53dBµV & 43dBµV respectively. Both of these should stand a 2-way split without problem, although the latter is a bit towards the low side.

What frequencies are you getting these on, & which way is the aerial actually pointing?

Thurston?

Nelbert wrote: »

Pointed at three rock best I can tell (it's fairly solidly put up, was here when we moved in) so -55dBm on 546MHz and -66dBm on 570MHz.

Just if you're in north Dublin, thought it might be possible it's actually pointing north to Clermont Carn & Kilkeel.

Sorry about deleting the post you quoted, was looking at figures for 50 ohm impedence, although the difference in conversion isn't huge.

The Cush

Thurston? wrote: »

Just if you're in north Dublin, thought it might be possible it's actually pointing north to Clermont Carn & Kilkeel.

Sorry about deleting the post you quoted, was looking at figures for 50 ohm impedence, although the difference in conversion isn't huge.

This is the calculator I used and it came in at just under 43 dBμV for 75 ohms - http://www.qsl.net/pa2ohh/jsdbmdbu.htm. The DTG recommend a min. of 50 dBμV for reliable domestic reception to overcome degradation to multipath, impulsive and other interference..

I've asked the OP a few times to check which transmitter is recommended by the coverage checker, the aerial may simply require an adjustment towards Kippure.

Nelbert

The Cush wrote: »

This is the calculator I used and it came in at just under 43 dBμV for 75 ohms - http://www.qsl.net/pa2ohh/jsdbmdbu.htm. The DTG recommend a min. of 50 dBμV for reliable domestic reception to overcome degradation to multipath, impulsive and other interference..

I've asked the OP a few times to check which transmitter is recommended by the coverage checker, the aerial may simply require an adjustment towards Kippure.

Coverage checker says kippure for area but three rock if I go specific to my address . From where I am you are talking a couple of degrees in difference between kippure and three rock though so by eye it's tough to tell exactly which way it's pointing. Is it that sensitive?


Edit: aerial looks to be about 20 degrees off..... Looks like I'm climbing out the window again....

Thurston?

Nelbert wrote: »

Edit: aerial looks to be about 20 degrees off..... Looks like I'm climbing out the window again....

20 degrees? Can you post a pic. of the aerial, indicating which end is pointing where? (Or if it turns out it's vertically polarised, it will be pretty obvious where it's pointing.)

Nelbert

Thurston? wrote: »

20 degrees? Can you post a pic. of the aerial, indicating which end is pointing where? (Or if it turns out it's vertically polarised, it will be pretty obvious where it's pointing.)

It's pointing straight south (180 degrees ish) but according to soar view coverage site it should be at 199 degrees a bit westerly.

Though to get a picture (back camera on my phone is broken and I don't fancy an awkward selfie!).

From pole to black end cap goes north to south if that helps? It's horizontal

edit: have adjusted direction to 199 degrees south south west..... no real impact.

Thurston?

How did you rig up the cable: joined to the existing coming from the aerial, I presume?

How did you make the joint?

Nelbert

Thurston? wrote: »

How did you rig up the cable: joined to the existing coming from the aerial, I presume?

How did you make the joint?

Aerial is like the one one the right of this image:
http://m.imgur.com/bLbj8?r

Yeah. Cut a couple inches of the cable, then f connector and coupler.


edit: cut the cable back a bit more and signal on both transponders is now in the minus 50-55 range (sorry this is what tvheadend spits out signal strength wise). Should be splittable at that strength yes? Probably best to replace the cable when I get the splitter?

Thurston?

Yep, that's the proper way to join the cable, & weatherproof it if it's outside.

So the aerial is a log-periodic type, similar to the other one you were trying. (And it's pretty obvious which is the 'pointy' end of these.)

It's not fitted with an amplifier of any kind? (Some logs have them mounted on the aerial itself.) Three Rock analogue signal power wasn't anything special.

Thurston?

Nelbert wrote: »

... signal on both transponders is now in the minus 50-55 range (sorry this is what tvheadend spits out signal strength wise). Should be splittable at that strength yes? Probably best to replace the cable when I get the splitter?

They were splittable even at the original figures. Just the difference between the 2, I thought was worth probing a bit.

Nelbert

Thurston? wrote: »

Yep, that's the proper way to join the cable, & weatherproof it if it's outside.

So the aerial is a log-periodic type, similar to the other one you were trying. (And it's pretty obvious which is the 'pointy' end of these.)

It's not fitted with an amplifier of any kind? (Some logs have them mounted on the aerial itself.) Three Rock analogue signal power wasn't anything special.

The join is actually inside (only about 2 metres from not even needing the join).

No amplifier that I can see (just a regular f connector straight into the aerial at the other end.

A powered splitter is the best bet though I assume? Replace cable to remove join while I'm doing that (a job for next weekend I think....).

Thurston?

Nelbert wrote: »

No amplifier that I can see (just a regular f connector straight into the aerial at the other end.

A powered splitter is the best bet though I assume? Replace cable to remove join while I'm doing that (a job for next weekend I think....).

Yeah, thought the signal was a bit too good for the aerial to have been taken out of the equation due to an inactive amplifier. (Signal just being picked up on the cable.)

A passive splitter should be fine, & no need to get rid of the join in the cable if things keep working.

Nelbert

Thurston? wrote: »

Yeah, thought the signal was a bit too good for the aerial to have been taken out of the equation due to an inactive amplifier. (Signal just being picked up on the cable.)

A passive splitter should be fine, & no need to get rid of the join in the cable if things keep working.

spot on. passive splitter I have drops signal by 4dB but still fine. can reconnect second tuner now.