788 replies to this topic

[craigread]

alanh, on Apr 1 2005, 09:19 PM, said:

Craig,
I suggest you go for a drive up Belmont Av. I have been in your area, but I do not live anywhere near you.  North could easily be a possibility.

Phased Arrays
This type of antenna is much more directional in the horizontal direction when used for vertical polarisation. The longest axis of the whole antenna will be horizontal.

If you use a yagi, and the transmitter antenna is above you don't forget to point the antenna upwards, because it is much more directional in the vertical direction

AlanH

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Ok, now I'm totally stumped and frustrated.  I purchased the masthead amplifier you listed and mounted it about 50mm from a brand new phased array antenna.  The signal has improved maybe 1% max.  Channel 9 still breaks up and HDTV is still unwatchable.

Any ideas of anything else I could try?

[kiwi_aus]

craig  I'm just over the hill from you off old belgrave rd
email me and I'll give you my mobile #     I have a LARGE phased array you can try if you like
did you alter the aspect of the phased array  ie changed the way it sits on the pole, you need "vertical" orientation which would be the oposite to how it came packaged

Quote

Ok, now I'm totally stumped and frustrated.  I purchased the masthead amplifier you listed and mounted it about 50mm from a brand new phased array antenna.  The signal has improved maybe 1% max.  Channel 9 still breaks up and HDTV is still unwatchable.

Any ideas of anything else I could try?

<{POST_SNAPBACK}>

[antennaiq]

You will find that claimed gain figures and the actual figures are quite different.  These results also vary according to the scenario.  Things like impedence match, capture area (especially for UHF) and front to back also come into the equation, even for digital!  Claimed gain figures become almost like a my engine is bigger than your engine type competition.

[RLR]

Craig,

The Belmont Av tower is only about 500m from you in a straight line and should be nnw based on the your description of where you live.

[antennaiq]

or go for a vertically polarised phased array, think a Wisi or Fracarro P54 phased arrays have a narrower beamwidth when vertically polarised.

[antennaiq]

Yarra Valley, if you have too much signal on Analogue ABC use a low band attenuator, then use a smaller amplifer, because if you use a big fella you might end up with more signal than the amp can handle.  This will vary so use common sense.  Sometimes a big amp is necessary, but in my opinion 44dB is just too much.

The other question, ever though of using a band 3 yagi???  Most of these Fracarro 6E512, BLV6, Hills DY14 peak on channel 12, which is what we all want.  Then again horses for courses, and sometimes you need a B3 phased array.

darulezy, on Jan 7 2005, 11:35 AM, said:

alanh, on Dec 1 2004, 11:57 PM, said:

Could you also find out if they intend to modify the Band 3 phased array to increase its sensitivity on channels 11 & 12. It would have applications for long distance and blocked path sites where digital band 3 is used.

<{POST_SNAPBACK}>

YES!
I  need something like that to further improve my reception, last time I looked there was no suitable antenna. Ideally this antenna would have a matched masthead amplifier with variable gain for each band, and a shielded masthead amp would be prefered. One input would be ok, since I only intend on using a combined antenna.

EDIT: Oh and I'm sick of terminating co-ax, so a package solution would be nice (ie. antenna, masthead and terminated co-ax supplied in one pretty cardboard box)  

<{POST_SNAPBACK}>

[alanh]

Craig,
Is your STB tuned to the following;
HSV(7) channel 41 620.5 MHz
GTV(9) 44 641.5 MHz
ABV(2) 47 662.5 MHz
SBS(3) 50 683.5 MHz
ATV(1) 54 711.5 MHz.

What are channels 41, and 45+?

Note these frequencies are also being used by Selby & Ferntree Gully These are single frequency networks Selby is horizontally polarised and more powerful. Selby is 250 W each where as Upwey is 65 W So you could be getting some signal from Selby and some from Upwey.

AlanH

[craigread]

alanh, on Apr 9 2005, 12:54 AM, said:

Craig,
Is your STB tuned to the following;
HSV(7) channel 41 620.5 MHz
GTV(9) 44 641.5 MHz
ABV(2) 47 662.5 MHz
SBS(3) 50 683.5 MHz
ATV(1) 54 711.5 MHz.

What are channels 41, and 45+?

Note these frequencies are also being used by Selby & Ferntree Gully These are single frequency networks Selby is horizontally polarised and more powerful. Selby is 250 W each where as Upwey is 65 W So you could be getting some signal from Selby and some from Upwey.

AlanH

<{POST_SNAPBACK}>

Alan,

The STB does auto channel search and tuning.  The frequencies I've used for testing on my PVR are as you've specified them.  It also has an auto-tuning function.  I have no idea what you're referring to in regards to channels 41 and 45+.

I tried mounting the antenna the other way (for horizontal polarisation) and checked it in all directions (360 degrees).  With vertical polarisation I get ~ 5700 signal strength (pointing roughly NNE) on the PVR and with horizontal, I get ~5200 (regardless of direction).  Either way, I get a SNR of ~5800.  The scale of the readings are hexadecimal with a supposed maximum value of FFFF.  The STB always reads 90%+ on strength and quality even when the signal is breaking up (so it's totally useless for testing).

Even though the indicated signal strength is lower (5200 hex compared to 5700 hex) the actual picture quality is pretty much identical.  Nine on SD still breaks up on the PVR (all SD channels are fine on the STB) and Seven HD breaks up a lot.

[poidahl]

[quote name='craigread' date='Apr 8 2005, 09:04 PM']
[/quote]
Ok, now I'm totally stumped and frustrated.  I purchased the masthead amplifier you listed and mounted it about 50mm from a brand new phased array antenna.  The signal has improved maybe 1% max.  Channel 9 still breaks up and HDTV is still unwatchable.

Any ideas of anything else I could try?
[right]<{POST_SNAPBACK}>[/right]
[/quote]

Laceys.tv has recently decided to start a Signal Level Meter rental service of their basic TC870 that could assist.  Craig should be able to help you.

[alanh]

poidahl,
That is a service which will be good for members of this forum.

Craig,
I would like to remind Craig, the maximum output for each digital transmitter at Upway is only 60W which is tiny.


I must apologise for "What are channels 41, and 45+?" Too late at night!

What I would like to know is, Do you get good pictures on analog reception from Uwey. You can use the same antenna mounted for vertical polarisation.
Upwey

ATV Analog 48, Digital 54
ABV Analog 39, Digital 47
SBS Analog 51, Digital 50
HSV Analog 42, Digital 41
GTV Analog 45, Digital 44

Try aligning your antenna using an analog signal.

What signal strength do you get without the antenna connected at all?

AlanH

[Hilly]

Does anyone know how good the reception is in diamond creek!

As i am about to get a HD set top box any recommendations would be good.

[kiwi_aus]

alanh
could part of craigs problem be.....  he is below the upwey transmitter, which is slightly over the hill from him ( other side ) and the low power combineing to give him a week signal, there would be a lot of leaf / tree matter also  ???

grant


ps I'm more enclined to think selby would be a better option

I tried using a phased array with direct line of sight albeit with LOTS of large trees in between at upwey and didn't have a great signal, also boosted with kingray mast amp sam204dp split 3 ways at masthead
my phased array was a double, compared to craigs
I also had varied results with selby with the phased array

I changed to a 91 element antsig antenna band 4&5 channels 21-69 ( only $35 from Arlec factory shop )
directed at selby
and now get a good signal,
I have a higher and better line to selby than craig

as for extra signals  I think I get upwey / mt dandy / selby / fentree gully
always a great mix for problems !

alanh, on Apr 11 2005, 08:34 PM, said:

poidahl,
That is a service which will be good for members of this forum.

Craig,
I would like to remind Craig, the maximum output for each digital transmitter at Upway is only 60W which is tiny.

AlanH

<{POST_SNAPBACK}>

[craigread]

alanh, on Apr 11 2005, 08:34 PM, said:

poidahl,
That is a service which will be good for members of this forum.

Craig,
I would like to remind Craig, the maximum output for each digital transmitter at Upway is only 60W which is tiny.


I must apologise for "What are channels 41, and 45+?" Too late at night!

What I would like to know is, Do you get good pictures on analog reception from Uwey. You can use the same antenna mounted for vertical polarisation.
Upwey

ATV Analog 48, Digital 54
ABV Analog 39, Digital 47
SBS Analog 51, Digital 50
HSV Analog 42, Digital 41 
GTV Analog 45, Digital 44

Try aligning your antenna using an analog signal.

What signal strength do you get without the antenna connected at all?

AlanH

<{POST_SNAPBACK}>

Alan, the pictures on Analog are woeful (always have been).  There's lots of black and white, audio drop-outs and a LOT of ghosting (and that's in good weather).  In poor weather the signal can totally drop out.  My SD digital signal is infintely better.

When setting the antenna up for Vertical polarisation (to try Selby and FTG) there was zero difference regardless of the direction I pointed the antenna in.  The signal had the same strength even when pointing it south (a direction there shouldn't be a signal from).  I also tried the frequencies for Mt. Dandenong (using the linuxtv scan and tzap programs), but couldn't lock a signal on those frequencies.

I think the problem here is my location in the valley.  Even though Upwey is only 60w and I'm not getting line-of-sight, it is definitely the strongest signal I get.  I may just need to petition the local govt to raise the transmitter (in both height and power).

[darulezy]

antennaiq, I have put reception issues on hold for the time, television content being the major issue (boring content and infested with advertising material).

I certainly do not have any strong signals where I am, I have a blocked signal path for the tv channels 2,9 and 10 from the Mt Dandenong tower. and channel 7 and SBS are just inside operating range.

Its the way it is, its the way its always been and no amount of digital technology will radiate a signal though a mountain.

A masthead amplifier of any sort will drive a longer cable, will increase the signal to noise ratio but won't help me make a signal out of nothing, hence I have not purchased a newer masthead than what I currently have.

There is a repeater at Mt Victorio that I've tried but that also has issues.

I could try the band 3 antenna you have mentioned at a later date.

[kiwi_aus]

wrong way around craig
upwey is vertical and selby is horizontal
horizontal polarisation is the way the antenna bracket would have been in when purchased
the main backbone of the phased array is vertical but a "horizontal polarisation"
as per my alteration to your email picture

change the bracket to swing the rest of the antenna 90 degrees to get vertical polarisation for upwey

Quote

When setting the antenna up for Vertical polarisation (to try Selby and FTG) there was zero difference regardless of the direction I pointed the antenna in.  The signal had the same strength even when pointing it south (a direction there shouldn't be a signal from).  I also tried the frequencies for Mt. Dandenong (using the linuxtv scan and tzap programs), but couldn't lock a signal on those frequencies.

I think the problem here is my location in the valley.  Even though Upwey is only 60w and I'm not getting line-of-sight, it is definitely the strongest signal I get.  I may just need to petition the local govt to raise the transmitter (in both height and power).

<{POST_SNAPBACK}>

[craigread]

kiwi_aus, on Apr 13 2005, 12:25 AM, said:

wrong way around craig
upwey is vertical and selby is horizontal
horizontal polarisation is the way the antenna bracket would have been in when purchased
the main backbone of the phased array is vertical but a "horizontal polarisation"
as per my alteration to your email picture

change the bracket to swing the rest of the antenna 90 degrees to get vertical polarisation for upwey

Yes, that's the way I had it setup kiwi_aus.  It was my post that was wrong.

I found an article on signal loss here that indicates that the number of splits I have may be a much more significant issue than I originally thought.  I have the cable from the antenna going under the house to a power injector, then to a 4 way splitter and then there is a 3 way splitter after the point in the living room.  All of them use F-type connectors, but there'd still be signal loss from each one.

I've been meaning to update the house to a structured configuration, which could get me quite a bit of signal back.  That would involve one 8-way splitter and running three separate cables from there to the living room (for STB, PVR and Analogue).  The splitter would also feed another three analogue TV's scattered around the house with two points for later expansion.

I'm going to contact Laceys.tv later this week about hiring a signal strength meter and use it to check the signal at each point.  That will give me an idea of how soon I should update the cabling.

[kiwi_aus]

ahhhhh  didn't realise you had split to so many points

check the signal on a single down lead first to see if you receive enough signal to allow splitting when you get the meter


I still think your phased array may be too small, and also selby with a bigger yagi would be better

Upwey comment via my own experiance with the same size and larger, phased array with a better line of sight than you to the transmitter (and only split 3x at the powered masthead, ie: 3 downleads )  the larger phased array helped though

[craigread]

kiwi_aus, on Apr 13 2005, 01:51 PM, said:

ahhhhh  didn't realise you had split to so many points

check the signal on a single down lead first to see if you receive enough signal to allow splitting when you get the meter

<{POST_SNAPBACK}>

Yep, I'll be heading down to pick one up from Laceys tomorrow.  I'll check the down-lead and each point after the split.  I'll also check on the old Yagi I had.

kiwi_aus, on Apr 13 2005, 01:51 PM, said:

I still think your phased array may be too small, and also selby with a bigger yagi would be better

<{POST_SNAPBACK}>

Bugger!  I hate spending money on something one week, to have it be useless the following week.  I still doubt Selby will be better as I have probably less line-of-site to it than Upwey and from my testing so far (pointing in that direction and switching the polarisation of my antenna) the signal is less than what I'm getting from Upwey.  When I get the field strength meter I'll test to see where I get the strongest signals from.

kiwi_aus, on Apr 13 2005, 01:51 PM, said:

Upwey comment via my own experiance with the same size and larger, phased array with a better line of sight than you to the transmitter (and only split 3x at the powered masthead, ie: 3 downleads )  the larger phased array helped though

<{POST_SNAPBACK}>

One of the problems with my installation is there is >12m of cable from the masthead amp to the power injector.  There is no roof cavity to speak of, so the cable runs down the 6m pole, across the roof, down the side of the house to under the house to where the nearest power point resides.

To give a clearer picture, my cabling is currently like this:

Antenna
|___Power Injector
      |___F-Type Splitter
            |___Living Room
            |     |___F-Type Splitter
            |           |___VCR
            |           |___STB
            |           |___PVR
            |___Front Bedroom
            |     |___Television
            |___Rear of house
                  |___Rear Bedroom
                        |___RF Splitter
                              |___Television
                              |___Study
                                    |___TV Tuner (with VGA Output)

Yup, got to be a heap of signal loss by the end of that mess.  Even with everything disconnected except for 1 point in the living room, the signal isn't great.

I'm going to be recabling and aiming for this:

Antenna
|___Power Injector in Utility Cupboard
      |___F-Type Splitter in Utility Cupboard
            |___Living Room - VCR
            |___Living Room - STB
            |___Living Room - PVR
            |___Front Bedroom - TV
            |___Rear Bedroom - TV
            |___Study - TV Tuner

The Utility cupboard will also end up housing my ADSL modem, switch, linux server (file server and lighting control with http://w3.misterhouse.net:81/) and the backend for the PVR with all network and video cabling being routed through there.  Eventually, speaker cabling will also be routed through there as well.

I'll post the measurements from the field strength meter so everyone can see what a difference this makes.

[kiwi_aus]

a waste

[kiwi_aus]

my offer of a loan of my spare antenna still stands if you wish to try it over the weekend

[craigread]

kiwi_aus, on Apr 15 2005, 12:00 AM, said:

my offer of a loan of my spare antenna still stands if you wish to try it over the weekend

<{POST_SNAPBACK}>

Thanks, I appreciate the offer kiwi_aus.  I might give you a call tomorrow.

The use of the field strength meter has really made it obvious where some significant problems are.  I took measurements without the power transformer and got zero signal, but with it I get 78 dB (before the splitter).  After the first splitter I get 71 dB and lose almost 1 dB at the point in the living room.  After the splitter in the living room, I'm down to 64 dB.

If the article I linked in an earlier post (http://www.swhowto.com/VideoLoss.htm) is correct (and I'm interpreting it correctly), a 10 dB loss is ~ 1/10th the input signal and an 8-way splitter loses 11 dB of signal.  Considering I'm losing 14 dB of signal, an 8-way splitter would put me ahead by 3 dB (or give me 100% more signal).

All of these splitters are supposed to be high quality F-Type splitters, but they have a great deal of signal loss.  I'm going to take the field strength meter to the place where I purchased the splitters and ask to test other splitters they have.  Hopefully, they have something that could split the signal with much less loss of signal.

At 69-71 dB, Channel 9 still breaks up (but is watchable) via the PVR.  So I'm sure part of it is signal quality (rather than strength).  By eliminating as much signal loss as possible, I might be able to turn the amp down on the mast head and improve the signal quality.  I'm not 100% sure on that one though.  Tomorrow, I'll try taking all of the splitters out and see what the signal quality is like.

This thread started as a guide on how to get the best reception.  I've well and truly hijacked the thread, so I hope all this stuff I'm going through is helping some others.  

[kiwi_aus]

craig

how much is it costing to hire the signal meter and for what time period ??

where are Laceys

[craigread]

kiwi_aus, on Apr 16 2005, 02:56 PM, said:

craig

how much is it costing to hire the signal meter and for what time period ??

where are Laceys

<{POST_SNAPBACK}>

The signal meter is $59 for 1 week.
Laceys are in Frankston.

[mtv]

If you had the amp connected without power applied to it when you took the measurement, that would give you a 0 reading, as the unpowered amp would have blocked the signal.

What was the signal reading directly from the antenna before it enters the amp?

With digital, amps are the very last resort and they should only be used to overcome cable/distribution losses, not to perform magic by increasing signal that isn't there. As a general guide, you need to be receiving 40 - 50dBuV at the input to the amp, so you need to "capture" as much signal as possible before considering anything else. Choice of antenna is therefore critical.

Cheers

Col

[craigread]

mtv, on Apr 24 2005, 01:45 AM, said:

If you had the amp connected without power applied to it when you took the measurement, that would give you a 0 reading, as the unpowered amp would have blocked the signal.

What was the signal reading directly from the antenna before it enters the amp?

With digital, amps are the very last resort and they should only be used to overcome cable/distribution losses, not to perform magic by increasing signal that isn't there. As a general guide, you need to be receiving 40 - 50dBuV at the input to the amp, so you need to "capture" as much signal as possible before considering anything else. Choice of antenna is therefore critical.

Cheers

Col

<{POST_SNAPBACK}>

Ah, I didn't realise that about the amp.  I have already returned the meter, so can't measure the signal from the antenna prior to putting an amp in.  I can tell you that with an amp that supposedly provides 45dB, I'm only getting ~78dB of signal (before any splitters) so that could suggest that I'm only getting ~33dB of signal at the antenna.

I was finding that with the antenna setup for horizontal polarisation, it didn't make a lot of difference which direction I pointed the antenna in.  My measurements indicated about a ~30dB drop in signal when trying for a horizontal poloarised signal (which is pretty close to no unamplified signal at all).

Also, the meter they provide only measures the signal at a single frequency point (a digital signal should be sampled from a number of frequencies and the results averaged), so with signal break up across the band it wasn't even useful for getting the direction of the antenna correct (unless I wanted to sit down and do a heap of samples each time I turned the antenna).  When testing for the frequencies published on the dba website or the frequencies programmed into the meter, it appeared that signal for some channels were stronger in one direction than signal for other channels.  They're all transmitted from the one tower, so that's a good indication of the scattering effect the trees are having on the signal I'm getting.

From discussing the results I've had with the guys from Laceys, I've decided to get somebody with more experience (and professional digital equipment) to take a look at this.