Jump to content


Photo

New Design Hills Band 4+ Yagis


  • Please log in to reply
42 replies to this topic

#1 alanh

alanh

    AV Forum Member

  • Senior Member
  • 12,648 posts

Posted 26 February 2012 - 01:55 AM

http://newsletter.hi...SLETTER-P4.html
TSP2851
TSF2851
http://www.hillsante...&ProductID=3020

The TSF2851 performs better than the TMX20B4+ (channel range 28 - 52)

http://www.hillsante...ing%20Machinery


They also have a new masthead amplifier http://www.hillsante...8&ProductID=945
Q amp Digital frequency range 174- 230, 520 - 860 MHz. channels 6 - 12, 27 - 75

Alanh

Edited by alanh, 26 February 2012 - 02:02 AM.


#2 Canuck Eh!

Canuck Eh!

    AV Forum Member

  • Member
  • 13 posts

Posted 28 February 2012 - 06:23 AM

The above hills antenna doesn't provide the gain curve across the frequency range but it is not flat.

For interest for those who like to tinker the link below shows how to take the basic Gray Hoverman antenna and build it to your own specific requirements. Depending on the gain you desire you add reflector elements & do some other tweaking. It may be used as either UHF only or be adding tophat NARODS turn it into a VHF & UHFantenna. NOTE that the gain & SWR is almost flat across the whole band and speak for themselves. Best of all you can build it yourself for cheap since no aluminum tubing or boom is required. All measurements & site instructions on on the page. Enjoy exploring.
http://clients.teksa...km/gh_n_uV.html
Regards
Warren

#3 alanh

alanh

    AV Forum Member

  • Senior Member
  • 12,648 posts

Posted 28 February 2012 - 08:16 PM

Warren,
These antennas would be ideal for UHF digital TV in Canada because North America is limiting UHF TV to 470 - 698 MHz the higher frequencies to be used for cell phones and Wifi.

If you look at the present UHF range there are models designed for band 4 526 - 589 (Ca channels 24 - 32) band 4+ 526 - 680 (24 - 48) and band 5 582 - 820 (34 - 78) MHz.
The higher the frequency the higher the gain required.
This is because the gain is referred to a dipole resonant at that frequency.

A 150 MHz has a half wavelength of 1 metre. This is the total length of a resonant dipole
600 MHz so the half wavelength is 250 mm. This is the total length of a resonant dipole

If the field strength from these transmitters are identical then the 600 MHz signal will be a quarter of the voltage of the 150 MHz because the dipole is shorter.

dB = 20 x log 4 = 12 db extra gain is required for the same signal voltage. To ease the load most Australian UHF transmitters have 4 times the radiated power which is an increase of 6 dB. So midband UHF antennas need 6 db more gain than a band3 or VHF hi antenna.


http://www.dtvforum....na&fromsearch=1

AlanH

Edited by alanh, 28 February 2012 - 08:41 PM.


#4 Canuck Eh!

Canuck Eh!

    AV Forum Member

  • Member
  • 13 posts

Posted 29 February 2012 - 06:24 AM

Alan

If YOU look at:
1) the specs for the antenna you posted it is rated at 9.5 - 16 db gain for channels 28 - 51 (there are no graphs to indicate where these gains occur)....forget any stuff about other channels or bafflegab .... that is their posted specs unless I downloaded the incorrect antenna. ONCE AGAIN channel 28-51. http://www.hillsante...&ProductID=3020

2) the specs for the antenna I linked, for comparison, are shown across the channel 28-51 frequency range & MORE plus the gain is FLAT & equals or beats the gain of your new antenna .... (UHF best is minimum 14.5 the whole range to channel 51....VHF gain up to 7 across the band, IF YOU WISH to add VHF but can be built without it) no argument just facts. You MAY not need more than 1 antenna to cover your frequency range up to channel 51 which will be your new cut off for TV as I understand it unless you need greater VHF gain.

There are also bow tie antennas for UHF that can easily be tuned for any range with almost the same gain characteristics. Similar to the UTube antennas people mention but built to the correct dimensions and at a minimum meet the similar commercial versions but for a fraction of the cost.

Unless antennas are compared in the real world side by side under the same conditions the question which antenna is "better" for a given location is all conjecture.

I don't post for arguement purposes but only to show that there are equally good or better options for consideration IF A PERSON WISHES to save money & build their own. As a famous cartoon character says "Bada bada That's all Folks". Life is full of choices, look at the information available & make your own choices, I've got no dog in the hunt.

Regards

#5 dig2all

dig2all

    AV Forum Member

  • Member
  • PipPipPip
  • 314 posts

Posted 29 February 2012 - 08:42 PM

why is it that they see the need to release new models every couple of years?

#6 alanh

alanh

    AV Forum Member

  • Senior Member
  • 12,648 posts

Posted 29 February 2012 - 09:39 PM

Warren,
I am not disputing the cost of making your own compared to a manufacturing cost + taxes and profits.

Since the design you refer to is basically a phased array then like should be compared with like so look at http://www.hillsante...08542_FLYER.pdf There are others as well such as Wisi (German)http://www.wisi.de/c...g.pl?prod_id=36
Note that the horizontal beam angle is much greater than the vertical beam angle. This makes this antenna good for blocked including long distance paths with horizontal polarisation. Mounting this antenna on its side makes it directional in the horizontal plane for vertically polarised signals which is good in strong signal areas.ou

So your comment about testing on site is affected by reflected or delayed signals and blocked paths. For horizontal polarisation the horizontal plane directivity is good for rejecting reflections from surrounding structures where as for signals coming over the horizon a wide horizontal directivity is re quired but important to have a very narrow vertical directivity. Just check out the sun just rising/setting over the ocean

Neither the antenna you refer to and the antennas above are tuned to a narrow frequency range. The Q.pdf I linked to shows how the sensitivity drastically increases. This means that a set of half wave length horizontal bars phased together at a quarter wavelenth apart will be much more sensitive to a small range of channels. This is occuring in Darwin and regional areas of West Australia already.

The problem with circular dipoles is that they cannot discriminate between transmitters using horizontal and another using vertically polarised signals such as those used in Single Frequency Networks such as used in the Central Coast North of Sydney.

I have no wish to argue with you.

dig2all
Hills were the first to bring out a band 3/4 antenna for metropolitan areas to minimise impulse interference, more gain for the metal work used and little interference from strong channel 0 - 5A transmitters including FM.

The reason for the latest type is because the digital dividend means that channels 51 - 69 will be used for Wifi. There is serious considerations about interference being a problem for antennas designed for channels above 51.The restack of all digital transmitters into consecutive channels on each site commences in 2014. In the meantime the commercial DTV rollout in regional areas of WA are all using consecutive channels. In some cases ABC and SBS may catchup later.


If you look at the Matchmaster catalogue has also many new models.

The European manufacturers are yet to make new models for their digital dividend. The Asian importers are only using sales as a guide.
I still see in estates being built many antennas designed to receive channels below channel 6. Considering that the analog switchoff is well under way this is unacceptable.

I have no financial interest in any antenna manufacturer.

AlanH

Edited by alanh, 29 February 2012 - 09:49 PM.


#7 Canuck Eh!

Canuck Eh!

    AV Forum Member

  • Member
  • 13 posts

Posted 01 March 2012 - 04:24 AM

Alan
Again for interest only. Reading for the curious and builders to see what options are available.

On this side of the pond what you refer to as phased array (as you linked) we commonly call Bow Tie antennas. A gentleman name of Mclapp has investigated, designed & refined these antennas (with a great deal of feedback from other testers, builders, etc). They range from 2 bay to 4 bay and up to 8 bay when stacked (also available commercially). However what is unique is that they provide information on tine lengths & angles, bay separation, material choices plus hands on testing for various frequency ranges. They have also investigated curved reflectors and swept forward tines and reflector / element spacing plus some activity in the VHF high as a added benefit. The result being that generally speaking you can easily (very easily) build one of these for your specific requirements and usually beat the performance (and the quality dependent on origin) of a mass produced version.

link to a discussion & feedback thread http://www.digitalho...ad.php?t=100137
a build directory of various models http://www.frontiern...nnas/4baystuff/
data for different build configurations & bands (you don't get this detail from manufacturers) http://www.frontiern...are11-23-08.xls

The Gray Hoverman is a completely different animal build wise and has characteristics different from either bow ties or yagis. They are not commercially available anywhere.
Quote from Digital Home website.....

The Gray-Hoverman is the world's finest build-it-yourself UHF TV antenna, created and developed here at Digital Home. Retired and hobbyist antenna engineers such as old sparks, DogT, oneolddude, DjiPi, Kro, 99gecko, myself (as moderator), Keo, and others, working together under the leadership and effort of Autofils, have taken an obscure 1950s UHF TV antenna called the Hoverman and subjected the design to modern software-based computer modeling in hopes of optimizing its middling performance.

The result: the new Gray-Hoverman antenna is more powerful than similar commercially manufactured consumer antennas in every category, sometimes by whopping amounts. We've released the design, diagrams, and schematics, Copyright 2008, under the GPLv3 license so that anyone can roll their own.

Link to Gray Hoverman introduction thread http://www.digitalho...ead.php?t=81982
there are many more threads with in depth testing, build configurations and computer models.

Aside comment: It really surprises me that with the digital changeover there doesn't appear to be forums or sections of forums dedicated to experimentation, refining and building antennas in Australia or New Zealand. It is just so darn enjoyable, rewarding & cost effective especially when the support of fellow builders are available for help and direction.

Enjoy
Warren

#8 dig2all

dig2all

    AV Forum Member

  • Member
  • PipPipPip
  • 314 posts

Posted 02 March 2012 - 10:18 AM

dig2all
Hills were the first to bring out a band 3/4 antenna for metropolitan areas to minimise impulse interference, more gain for the metal work used and little interference from strong channel 0 - 5A transmitters including FM.

The reason for the latest type is because the digital dividend means that channels 51 - 69 will be used for Wifi. There is serious considerations about interference being a problem for antennas designed for channels above 51.The restack of all digital transmitters into consecutive channels on each site commences in 2014. In the meantime the commercial DTV rollout in regional areas of WA are all using consecutive channels. In some cases ABC and SBS may catchup later.

The European manufacturers are yet to make new models for their digital dividend. I still see in estates being built many antennas designed to receive channels below channel 6. Considering that the analog switchoff is well under way this is unacceptable.

AlanH


unsure you have your facts right. the hills combination band 3/4 antennas you mention might seem mechanically interesting but their performance is awful - is this a reference antenna for anything?

there is only 1 european manufacturer with significant presence in australia. have a closer look, you will find they are a step beyond hills with several antennas for digital dividend channel groups. instead of their wide band (28 - 52) approach they have models for specific channel groups that guarantee better rejection of lte 4g signals.

antenna selection (and installation practice) has always and continues to depend on who each installer talks to. do they offer clear facts or part information, possibly aimed at selling what's in the store.

Edited by dig2all, 02 March 2012 - 10:29 AM.


#9 alanh

alanh

    AV Forum Member

  • Senior Member
  • 12,648 posts

Posted 03 March 2012 - 04:11 AM

Dig2all,
From now in Hobart, either after the middle of next year in Perth and Brisbane or in 2014 in the other capital city main transmitters will be all band 3. There will be no need or want for any UHF. This will be for about 50 % of the Australian population.

Interesting that the European manufacturer to which you refer does not make a band 3 only log periodic antenna where as the Australian manufacturers use log periodics in their VHF sections, including the band 3 part of combo antennas. This is is interesting since your company has been singing the praises of LPAs for years. Remember that the gain in the European manufacturers' catalogues is 2.1 dB higher than the gains used in Australia because they use dipole as a reference rather than equal sensitivity in all directions in 3 dimensions.

Your favorite European manufacturer does not make any band 3 phased arrays.

When the digital restack occurs in 2014, there will be no need for band 3 and UHF antennas combinations because group A contains channels 6 - 8, 10 - 12 horizontally polarised, which will be used by all main transmitter sites in State Capital cities. Some regional sites will use group A but vertically polarised.

The current sites which use vertically polarised band 3 and horizontally polarised UHF such as Canberra, Manning River, Wide Bay, Gladstone and Goulburn Valley will either go purely group A vertically polarised only or will go UHF horizontally polarised only.


UHF will not need band 3 at all.
Group B 28 - 33 in horizontal and vertical polarisations
Group C 34 - 39 in horizontal and vertical polarisations
Group D 40 - 45 in horizontal and vertical polarisations
Group E 46 - 51 in horizontal and vertical polarisations
All transmitters on a single site will be allocated all the channels of a group and they will all have the same polarisation.

Using antennas where all of the elements are close to the same length and spacing makes them more sensitive to a smaller range of channels than an antenna designed for a wide range of channels.

A European manufacturer's Yagi channel group antennas are made for the following channel groups

E21 - E26 470 - 518 MHz Not used for TV in Australia
E26 - E34 518 - 582 MHz = AU 27 - 35
E34 - E46 582 - 678 MHz = AU 36 - 48
E46 - E69 678 - 862 MHz Will not be used for TV in Australia after the restack

Phased arrays (panel antennas) are designed for Au channels 20 - 75 or 40 - 75 If these antennas removed the X dipoles and used straight dipoles at the correct spacing their sensitivity would greatly increase.

As you can see these antennas do not match our channel groups.

To show the effect http://www.dtvforum....howtopic=101239

The above effect does not apply to Log Periodic Antennas. The narrower the channel range the smaller the LPA antenna. The maximum gain is much less than a narrow band Yagi-Uda.

You should be selling antennas which comply with AS 1417.1(Int)-2011. This standard expires on 24th February next year. This is to give time to rewrite the standard to match the grouping of channels described above. http://infostore.sai...oductID=1452023. The cost is tax deductible on your business.

Complying with the standard ensures the best performance in Australia antennas must match our widespread use of vertical polarisation, single frequency networks along with our 7 MHz wide UHF channels and our restricted range of UHF frequencies.This applies to all manufacturers selling into the Australian market. This is not the case in Europe or the USA.

AlanH

Edited by alanh, 03 March 2012 - 04:21 AM.


#10 dig2all

dig2all

    AV Forum Member

  • Member
  • PipPipPip
  • 314 posts

Posted 03 March 2012 - 09:45 AM

what are you trying to say?

narrow band antennas must do a better job of rejecting the dangerous lte 4g signal than all band antennas.

fracarro has been successful in this sector in australia for a long time and some of those products will suit the new channel groups much better than what you propose. of course the overall technical requirements in australia differ from europe and most other countries - so the numbers don't always translate. regret that brings me to one of our old sticking points; until you put some of these products on a meter and do some comparative testing, you will not understand.

this thread was about uhf antennas, now you change it to include band 3. fracarro has 5 different all band 3 antennas on the australian market with perhaps 20 other narrow band b3 models - see catalogue page 12: http://www.laceys.tv...L_D1_lowres.pdf
page 11 shows the very band 3 phased arrays you mention. don't bucket it because it doesn't mention the post switch off channel groupings - its last years book.

last word?

#11 alanh

alanh

    AV Forum Member

  • Senior Member
  • 12,648 posts

Posted 03 March 2012 - 06:22 PM

dig2all,

I went to the Fracarro website not yours.

The following antennas fail AS 1417.1(Int)-2011;
Al6HD, Al18HD, Al23HD, Al30HD, Hills DL3, DL4, CA16GL, Fracarro 4E2, 4E3, 4DF (not Au ch6 but Au ch 2) Remove them from sale.There is now no locations which require any channel below channel 6 provided they have a digital receiver or set top box.

Fracarro 6E5 - 6E12, 11D5 - 11E12 single channel antennas are only suitable for monitoring individual transmitters,and the worst case large MATV systems which would be rare.


When I go to your website I wish to make the following comments which applies after the digital restack.

Your entire Log periodic range becomes redundant.

The broadband band 3 Yagi-Uda antennas are fine for group A, except for band 3 UHF combination which will not be required. Sigma combo is one of those.

The band 3 phased array you sell is not Fracarro, but Hills.

The Laceys catalogue shows the following Fracarro products which do not appear in the Fracarro international catalogue

10 GAMMA/R Au ch. 20-31 11dB gain 24dB f/b ratio.

10 DELTA Au ch. 24-36 11dB gain 20dB f/b ratio.

10 DELTA/R Au ch. 24-36 11dB gain 24dB f/b ratio.

10/3539/R Au ch. 28-42 11dB gain 24dB f/b ratio.

10/4046/R Au ch. 34-49 11dB gain 24dB f/b ratio.

10/4753/R Au ch. 40-57 11dB gain 24dB f/b ratio.

10/5461/R Au ch. 46-67 11dB gain 24dB f/b ratio.

10/6269/R Au ch. 55-75 11dB gain 24dB f/b ratio.

The only ones on the Fracarro catalogue narrower than Au channel 20 - 75
E21 - E26 470 - 518 MHz Not used for TV in Australia
E26 - E34 518 - 582 MHz = AU 27 - 35
E34 - E46 582 - 678 MHz = AU 36 - 48
E46 - E69 678 - 862 MHz Will not be used for TV in Australia after the restack

are shown in the Fracarro international catalogue.

None of the above frequency ranges match individual UHF groups or even pairs of groups.

Their new range using circular elements are a worry here because Fracarro do not quote the vertical and horizontal beam width. These antennas may have trouble rejecting signals of the other polarisation on the same channels.

Masthead amplifiers
No amplifier should now amplify any frequency below 174 MHz, outside the range 526 - 820 MHz which will have to change the UHF top limit to 694 MHz when the the restack occurs.


"Tech Tip:

A Fracarro channel cut antenna provides substantial improvements in gain,

front to back ratio and beamwidth, providing results where other antennas fail."
http://www.laceys.tv...L_D1_lowres.pdf page 11


"the hills combination band 3/4 antennas you mention might seem mechanically interesting but their performance is awful - is this a reference antenna for anything?"
Lastly do not rubbish any competitor unless you can backup your claim. What characteristic of their performance is awful and what is the comparison reading?
As for reference antennas if you go to the CAI's website the LPAs were the worst performers. The UK has no band 3 TV and considering that 50 % of the Australian population require band 3 makes your claim largely irrelevant. An antenna is not a reference antenna unless the frequency range and polarisation matches the transmitter being used.
Fracarro is not the only manufacturer making wideband UHF antennas and none should be used here. This may become increasingly important as the broadcasters try and put more programs into the existing digital TV channels.
Alanh

#12 James T Kirk

James T Kirk

    AV Forum Member

  • Member
  • PipPipPipPip
  • 764 posts

Posted 03 March 2012 - 09:01 PM

Hello Canuck Eh! and dig2all

It is worth remembering that alanh has very little practical experience and once he gets a "bee in his bonnet" will go on at infinitum repeating himself and making many rash claims.

This present fuss over not using antennas that work above above 700MHz is a lot of hot air really. As usual and demonstrated on innumerable occasions, alanh has a very blinkered view of the world and it applies here too. When the restack occurs and no DTV services will operate above 700MHz I can guarantee that all those people out there with Band IV/V antenna that work well up to almost 900MHz will not be rushing out and buying new antennas and that is because the huge majority will have no trouble at all. The very very few that do will simply install a low pass filter.

Rule of thumb: Debating this stuff with alanh is never beneficial to anyone, either the informed or those seeking knowledge.

Canuck Eh!
By the way, I love the term "I've got no dog in the hunt" and it was nicely used.

Don't worry about any risk of lack experimenters here, there are many of us here with real experience who make our own antennas, matching networks stubs, filters and all else needed in this game.
Enjoyment of creativity is alive and well here, there are just a few "stick in the mud's" that need to be ignored until they become problematic and then we expose them for what they are as and when needed.

James

#13 alanh

alanh

    AV Forum Member

  • Senior Member
  • 12,648 posts

Posted 03 March 2012 - 09:34 PM

dig2all,
I omitted to say that many companies are still selling antennas which fail the Australian standard requirement to not be designed for any channel below channel 6

James,
Why rs the ACMA currently testing interference between the new LTE Wifi in frequencies just above channel 51 because they are concerned about it. Also you live in an area where you do not use the upper end of band 5. LTE is yet to be used in Australia outside this test in Victoria.

AlanH

#14 James T Kirk

James T Kirk

    AV Forum Member

  • Member
  • PipPipPipPip
  • 764 posts

Posted 03 March 2012 - 10:06 PM

Re: Why rs the ACMA currently testing interference between the new LTE Wifi in frequencies just above channel 51 because they are concerned about it.
Answer: It is because changed conditions always prompts an investigation, it is routine.

Re: Also you live in an area where you do not use the upper end of band 5.
Answer: You are in error.

For Canuck Eh!
Above are examples of what was stated earlier.

James

Edited by James T Kirk, 03 March 2012 - 10:11 PM.


#15 nbound

nbound

    AV Forum Member

  • Member
  • PipPipPipPip
  • 778 posts

Posted 03 March 2012 - 10:29 PM

James,
Why rs the ACMA currently testing interference between the new LTE Wifi in frequencies just above channel 51 because they are concerned about it. Also you live in an area where you do not use the upper end of band 5. LTE is yet to be used in Australia outside this test in Victoria.

AlanH


Considering the number of wideband UHF aerials installed by people its not going to matter too much what the previous channel plan was, and I agree with James' surmisation on the topic. Just for an example one of the transmitters I use broadcasts on 56-68, I can often see the little NextG/3G bumps at 850 and 900Mhz on the spectrum analyser of my meter. Im yet to have any problems with them though, with or without a masthead, even though some of my mastheads will amplify upto 860Mhz.

#16 alanh

alanh

    AV Forum Member

  • Senior Member
  • 12,648 posts

Posted 04 March 2012 - 01:36 AM

nbound,
One aspect is interference and the other is that the narrower the bandwidth of the antenna the greater the gain for no extra metal work.

Hence the attached graph.


"Tech Tip:

A Fracarro channel cut antenna provides substantial improvements in gain,
front to back ratio and beamwidth, providing results where other antennas fail."
http://www.laceys.tv...L_D1_lowres.pdf page 11

Note: All gain figures quoted by antenna manufacturers are referenced to a dipole or an isotopic antenna at that frequency. They don't tell you about the drop in sensitivity caused by the shortening of the dipole as the frequency rises.


AlanH

Edited by alanh, 04 March 2012 - 01:44 AM.


#17 Canuck Eh!

Canuck Eh!

    AV Forum Member

  • Member
  • 13 posts

Posted 04 March 2012 - 04:53 AM

CONTENT EDITED

Hello Canuck Eh! and dig2all

It is worth remembering that alanh has very little practical experience and once he gets a "bee in his bonnet" will go on at infinitum repeating himself and making many rash claims.

Rule of thumb: Debating this stuff with alanh is never beneficial to anyone, either the informed or those seeking knowledge.

James


I've pretty much come to the same conclusion. He's probably well intentioned but it does get a bit much.

Regards

#18 alanh

alanh

    AV Forum Member

  • Senior Member
  • 12,648 posts

Posted 04 March 2012 - 01:42 PM

nbound,
The effect of interference from mobile phones will only become obvious where the band 5 signals are weak and the mobile phone repeater is next door.

Others,
When I joined the original forum 8 years ago, I was pushing to stop the installation of antennas designed for channels below channel 6 because they were never to be used for digital. I have never told any poster to replace their antenna if they have reliable reception. These people usually don't post anyway. I have only recommended this for new installations and for those with unreliable reception. It turns out that if only band 3 reception is included on a medium gain antenna only 1/3 of the VHF antenna is required for the same performance. This considerably reduces the price because all that extra alumininium and labour is not required. In addition there is much less pick up of interference from power lines, other powerful broadcasters such as analog TV and FM radio. Even now new installations are occuring with these large antennas when the switchoff date is less than 2 years away with some areas within 6 months. This is either a lack of knowledge or the attraction of repeat business when the large elements bend and fall off.

The current investigations about LTE is not to find out if there is interference but how much frequency needs to be reserved above channel 51 to prevent interference to the LTE from TV transmitters and to the receivers. The smaller this reservation the greater the profits at the auction of channels 52 - 69.

It is only imported antennas which have the incorrect frequency ranges for Australia. The Australian manufacturers make their products for this market.
The first post in this strand demonstrates this by only covering channels 28 - 51. All of the elements in this antenna are designed for the channels we use and there is no redundant ones for channels we do not use.

AlanH

#19 dig2all

dig2all

    AV Forum Member

  • Member
  • PipPipPip
  • 314 posts

Posted 04 March 2012 - 02:45 PM

ok, canuck eh's content was edited - how about editing your vitriolic post alanh?

#20 bellotv

bellotv

    AV Forum Member

  • Member
  • PipPipPipPipPip
  • 1,631 posts

Posted 04 March 2012 - 05:57 PM

...........
When I go to your website I wish to make the following comments which applies after the digital restack.

Your entire Log periodic range becomes redundant.......

Alanh

You must have missed the LP4.

I've been testing this up here on Mt Moombil (Ch 30.33.36.38.39 ) and its got exactly the same performance as the LP45 on these channels .

Obviously this is as high as its going to work but its going to be fine for the B and C groups.

Yeah yeah yeah it doesn't have the same gain as a 10RD4 ( Fracarro10 element yagi that covers 28-40) on the same band ( about 1.5 -2dB lower ) but hay it was still pulling 80dBuV in one area I tested it in and a pad was still needed to bring it back to a reasonable level .

So why not ?

I didn't see 10RD4 on your list of UHF antennas avaialable from Laceys so I'm wondering how accurate your compilations are ?

Edited by bellotv, 04 March 2012 - 06:30 PM.


#21 alanh

alanh

    AV Forum Member

  • Senior Member
  • 12,648 posts

Posted 04 March 2012 - 09:02 PM

BelloTV,
Log Periodics were conceived as a wideband antenna of consisting of dipoles scattered throughout the design bandwidth. The low frequency end is determined by the length of the elements and at the high frequency end the accuracy construction including varying the diameter and spacing of the boom and elements as the frequencies rise. There is no focussing effect which occurs in Yagi-Udas. As a result once there is enough dipoles per bandwidth the gain will not rise. This is why you are getting the same signal strength from the LP4 and the LP45. The LP45 has more elements for the greater frequency range.

I did preface my comments as applying after the digital restack. The ACMA is yet to announce the restack channels for the North Coast NSW, however they usually include some of the existing channels. So Mt Moombil will be allocated either group B (channels 28, 29, 30, 32, 32, 33) or group B (channels 34, 35, 36, 37, 38, 39). I have not allocated 10RD4 because it covers 18 channels not 6 channels. The attached graphs show how the narrower the channel range the more sensitive the antenna becomes with an antenna for a single channel being the ultimate. The 10RD4F is rated for 470 - 606 MHz by Fracarro which is our channel 20 - 38 regardless of what Lacey's lead you to believe http://www.fracarro....L_BAND_10RD.pdf

http://www.fracarro....nel_grouped.pdf channel range in Australian channels is outlined in a previous post.

AlanH

The narrower the channel range the higher the gain, the better the directivity, the better the VSWR the Yagi-Uda becomes as it is truely a narrow band antenna. The ACMA had made it possible to limit the channel range to the number of transmitters with one spare on an individual site.

The ACMA is looking at doubling the data rate in the future, so to keep reception reliable better RF antenna performance will be required if there is no changes to transmitter power.

#22 James T Kirk

James T Kirk

    AV Forum Member

  • Member
  • PipPipPipPip
  • 764 posts

Posted 04 March 2012 - 09:45 PM

BelloTV,
Log Periodics ............. There is no focussing effect which occurs in Yagi-Udas.


alanh

If there is no "focussing effect" in log periodics, how is gain achieved?
This is a pretty simple one so please commence your response from the standpoint of this being that another of your statements is again quite wrong, otherwise no reply is preferred.

James

#23 bellotv

bellotv

    AV Forum Member

  • Member
  • PipPipPipPipPip
  • 1,631 posts

Posted 04 March 2012 - 10:38 PM

..... This is why you are getting the same signal strength from the LP4 and the LP45. The LP45 has more elements for the greater frequency range.

Yes I know this .
I was just letting you know that there IS A LOG PERIODIC available from Laceys that doesn't go up to the 4G band seeing as this seems to be a major concern to you.

I did preface my comments as applying after the digital restack. The ACMA is yet to announce the restack channels for the North Coast NSW, however they usually include some of the existing channels. So Mt Moombil will be allocated either group B (channels 28, 29, 30, 32, 32, 33) or group B (channels 34, 35, 36, 37, 38, 39). I have not allocated 10RD4 because it covers 18 channels not 6 channels. The attached graphs show how the narrower the channel range the more sensitive the antenna becomes with an antenna for a single channel being the ultimate. The 10RD4F is rated for 470 - 606 MHz by Fracarro which is our channel 20 - 38 regardless of what Lacey's lead you to believe http://www.fracarro....L_BAND_10RD.pdf
........

The channel plan I saw ( which I'm sure was a link provided by you) has Mt Moobil going to group C.(channels ,34,35,36,37,38,39) as this would require only Two transmitter changes (Your Typo accepted).

Regarding channels that the 10RD4 covers .I use them everyday and while you suggest that they only work up to channel 38 ,I'm not taking Laceys on their word, They bloody do go up to 39.!!!!!!

If they didn't I wouldn't use them FACT .

There is no measurable difference either Channel power or Channel BER between channels 36,38,39 using a 10RD4 ( antenna positioned for optimum reception)

A histogram reading on a meter is a valuable tool lets you see all these thing many times a day .Shame you can't afford one on your pension then you would be able to get out there and actually see for your self

And why would you not mention an antenna that covers 18 channels ( the 10RD4) when you started this about a band 4+ antenna to begin with ???.

Edited by bellotv, 04 March 2012 - 10:50 PM.


#24 alanh

alanh

    AV Forum Member

  • Senior Member
  • 12,648 posts

Posted 05 March 2012 - 04:19 PM

BelloTV,
Fracarro guarantees the high frequency end of the 10RD4F is 606 MHz. Australian channel 39 is 603 - 610 MHz. I had to ur on the side of caution so I eliminated channel 39. An examination of their frequency response graph, then channel 39 will be covered. However there is still considerable sensitivity down to channel 20. This sensitivity could be converted to more gain by making the elements shorter and closer together.

I am aware that the LP4 does not go up to the mobile phone band, but it like all of the European antennas go down to channel 20 except band 5 antennas. In Europe they need their channels 21 - 27 but we do not.

I am not on the pension, I am earning a salary.

I know what a histogram is and have found that when you measure the sensitivity of a 4 element band 3 Yagi it is more sensitive than the band 3 from an LP345.

I want an antenna designed for each group exclusively. This is to get a better Carrier to noise ratio and BER so that higher data rates can be used to provide better pictures (full HD which we don't get from broadcasters now).

The reason for this post is that an antenna designed for AU channels 28 - 51 is that it is better than a AU channel 28 - 69 or even worse channels 20 - 75. It is still true that there are antennas designed for channels AU band 4 28 - 36, band 4+ 28 - 52 band 5 38 - 69 wideband 28 - 69. As you can see none of these existing bands exacly fit the groups to be used, particularly foreign antennas. So for all manufacturers supplying our market redesign of antennas is required.

For Mt Moombil, there is currently no best antenna for the restacked channels.

AlanH

#25 nbound

nbound

    AV Forum Member

  • Member
  • PipPipPipPip
  • 778 posts

Posted 05 March 2012 - 04:49 PM

Problem is, alan, noone is going to buy them until after restack, as currently the channels almost always do not neatly conform ot any of the bands. Once the restack occurs im sure we'll see a switch to single band antennas almost exclusively (and dualband/wideband antennas for the areas with >6 broadcasters). Though I still imagine we'll still see some wideband antennas as some installers will use them for all UHF bands regardless.