andrewlace

This is a really good thread. Sorry I got in so late. Generally for digital modulators they run 80+ dB signal levels. I would advise not have a splitter going into two amps. A dw42 works fine but as a rule there are better launch amps out there but at three times the price (you're paying for the extra headroom and channel load). Dw42 offers the best bang for buck. With that channel load don't expect any higher output than 108dB on the highest channel before overdriving the amplifier. A band pass filter on the antenna side will help improve mer and reduce noise. A splitter is an awful way to mix signals. At least they have increased the isolation by using an amplifier on the antenna, but at the same time increasing distortion on the Fta channels. I would be cascading some drop taps (directional couplers) reversed to mix the antenna and balance signal levels. Assuming the antenna feed is 60+ dB you shouldn't need a masthead amplifier. If you do need a masthead amplifier put a band pass filter on the input stage (after an amplifier may work with the launch amplifier but is not ideal). You could also use a diplexer, however you'll likely find that the channel levels from the modulators are too high and need to be brought down. Three basic amplifiers for this system and no filtering is not ideal. A reversed tap means the input becomes the output and vice versa. They also have a better impedence match and heaps better port to Port isolation. For four digital modulators I'd be using a four way tap into the tap sides for the modulator and assuming the levels are high enough 62+dB into band pass filter (if not put the band pass filter on the masthead amplifier input feed) then feed the aerial into the labelled output on the tap. The labelled input (becomes your output) on the tap then feeds into the distribution amplifier. Choose a suitable tap value based on the difference between the antenna input levels and modulator input levels. Sorry I didn't catch this sooner I hope this helps in the future. What brand of modulator are they? What are your levels? Let me know if this helps. I've found on a lot of systems a mda20 is better than a dw42. It has less noise and more headroom, but no gain adjustment but a lot less gain. Kingray makes both products and if you don't need the extra gain the mda20 is an outstanding product and incredible value for money. Most good antenna wholesalers should be able to supply you.

The fracarro phased array is a good suggestion. James has suggested the mda20u I can verify that their range on amplifiers works where nothing else has. It may be worth seeing if anyone on the forum covers your area. I use a unaohm ap01 as a meter and the number of times I've done a job where 3 other guys couldn't get results and didn't know what a spectrum analyzer is our how to use one is bewildering. A good meter and technician is obviously crucial. I recommend in weak signal areas to only add filtering as absolutely necessary. The narrow band Yagi's that fracarro make do amazing things. Some of the new wisis have a LTE filter inbuilt which brings

Six years later and filtering still does not reduce the errors. It reduces noise which may or may not be the issue. There are narrow band aerials which have higher gain and good band selectiveness, narrower beamwidth etc, and there are products like the mda which now have additional filtering built in. I've used heaps of kingray mda20l and the low noise design, high headroom and little or no filtering has meant I've used it for amplifying c band satellite at a stretch and FM in weak signal areas with little harmonics. The audiophile customer was blown away and I was very happy too. Band pass filters are now cheap and very effective you can choose which channel block you need. Lacey's TV have these.

Forgot to mention the yagi brought the my Dandenong up 6dB and the lte down about 20dB

Forgot to mention the yagi brought the weakest mount Dandenong signals up 6dB and the lte down about 20 dB

At the lte issue ran across another one today. 43dB channel 7 and 10 digital Melbourne, Cheap low gain combination 3 4 antenna with low gain. Chucked a yagi and took a cheap distribution amp out. Lte was at 70 dB no amp no worries ? dang shame I followed my GPS getting there though. Lol.

Good points MLXXX, a few people stopped getting excited about this forum due to the stupidity of others. Forum moderators are responsible for this mainly, I've also seen much advice and no field experience coming from said person. I don't like being told "remember" hey I do this job everyday. I have some great friends who are former broadcast engineers. I like to study different products to come up with viable solutions to simple issues. But I know I can be arrogant hence my comment about my experience the ones on here that seem to know the most only use it when necessary and with discernment, rather than pretending to be an authority.

Yeah I'm on the peninsula replaced a 5 year old one a week ago. There are heaps of them here. Every time someone says it goes nuts at any time, amp is an am126 on the mornington peninsula they were a best seller. I want my installations to be working when I can't.

Yeah I'm on the peninsula replaced a 5 year old one a week ago. There are heaps of them here. Every time someone says it goes nuts at any time, amp is an am126 on the mornington peninsula they were a best seller. I want my installations to be working when I can't.

Hi this is a duplicate post. Recommend not using that amp. According to the box it has 100dB gainhttp://www.bunnings.com.au/antsig-8-way-indoor-vhf-uhf-distribution-amplifier_p4360394 ROFL this product is another example of why there is always going to be a market for quality antenna technicians 10dB x 8 is approximately 26dB gain. If the amplifier's not a low noise solution and has a split or mixed input. Kingray and fracarro both make excellent amplifier solutions, aerial industries also have lte filtered amplifiers.

Can definitely be done but will require either a dedicated commercial solution for iptv or raspberry pi and xbmc type solution. I'd be worried about sufficient bandwidth. If you can run optic fibre data and tv should be a doodle fibre is a lot cheaper than what it was and much faster than wifi even using a dedicated apn and won't need a bunch of raspberry pi units abs external tuners configured to stream to other raspberry pi units. Coax degrades much faster than fibre. You can run data and tv and numerous satellite services down the one fibre. You can even get the ends preterminated. I'd hate tti set it all up and find I don't have the bandwidth to do several HD channels.

According to the box it has 100dB gain http://www.bunnings.com.au/antsig-8-way-indoor-vhf-uhf-distribution-amplifier_p4360394 ROFL this product is another example of why there is always going to be a market for quality antenna technicians 10dB x 8 is approximately 22dB gain, high noise 12dB insertion loss. As your amplifiers from bunnings if your aerial is from there I'd suggest going passive (no amp). Try a Fracarro terza6hd from Laceys.tv Brisbane. Say G'day to Ash, he's a top bloke and knows his stuff. The antsig products are definitely not in the same class. If you can run a system with a good aerial and no amp your laughing. They have a range of quality splitters. I love bunnings for their range of hardware, but they are not an industry specialist. Ash will likely know the good local technicians as he is a smart guy. I do install work in Melbourne.

Hi beeblebrox, yeah I like the cast casing on the old mda20. I've seen a few pcb only Kingray's fail due to corrosion. It's an expensive case to manufacture though. I know almost every amplifier has the same issues unless you go nuts with silicone lol. Which alcad are you using?

Oh dear I went out there over 18 months ago so it wasn't lte that was the issue. I was there for about 15 minutes and never charged for my time. Grant is in an area known by locals for for being difficult. A lot of the homes are built on the side of a hill. LTE is an issue, not the issue. Kingray do not filter out cb bands on all their amplifiers. I know this as a lot of pubs use their amps to run s band analogue. You should run a noise gen and spectrum analyser to test a product before declaring then effective as filters. I have said it before narrow band yagis are a great cost effective way of filtering lte, cb radio and most interference. A wideband uhf yagi or log periodic is not advisable. Most filtered lte amps are greatly inferior to many dedicated lte filters on the market. That said agreed it is not wise to rehash don't use a log periodic, use a lte filter, trust me on the sunscreen speech. Kingray make some excellent amplifiers but filtering out anything out of the tv band magically and with low noise, even their budget products, that they don't do so well. As previously discussed the mda20 is vastly superior but with little or no filtering. Melbourne doesn't use block e so a narrow band yagi can smash most lte issues. We need to remind ourselves that a lot of issues are resolved with the correct antenna and no amplifier. A cheap amplifier and antenna is an expensive solution to a simple problem. Most interference issues can be resolved by removing amplifiers and installation of a suitable quality antenna. As I saw earlier with a chap trying to get Melbourne cbd transmitter off a terrible combination antenna polarized horizontally (cbd needs 40-44 vertical from memory). It would be cheaper and simpler to put a narrow band yagi on designed for block e 10/4046r does an awesome job at this and can be used for either polarity (oddly enough I used to use these for Gippsland back in the day). With grants place someone needs to do a full site test. Grant was keen to point out access issues, as with anything if you can't safely get to the masthead amplifier and aerial you don't do the job. That's how you stay in the industry. What was wrong on Grant's job is an issue of conjecture until someone gets access abc fixes it. This may have already happened (could have been an intermittent amplifier) as is often the case. Half the sites on the peninsula with amplifiers use alcad am126, a product which is legendary for going intermittent after a few years. I'm an active forum member and have been for years.

Thanks for posting that beeblebrox. Have you used many of these? I've still got a few mda20 series left. I've never seen an amp in this price range work as well. I'll have to see what to do when I get down on levels. External filters work great too.

Interesting reading. If you have spare elements on a yagi you probably don't have spare elements as each element is specific. Then again I've never installed one of these. I'd probably use a fracarro narrow band yagi, wisi, and johannson also make some good antennas. An aerial is a specifically engineered solution: from the mast clamp, reflectors, directors, balun everything needs to be well thought out. In order to get the best impedance match, return loss and out of band rejection a well designed yagi specific to your channels is advisable more often than not.

Hi Alanh, they are on the back of mount eliza where effectively every second house has access to Gippsland. It is a difficult area: reception can be patchy. I can't remember all the details but I think I went out there looked at access to the antenna. It is difficult.

Secret meetings happening hey?

Kewvic that antenna is designed for mount Dandenong, not the channel 10 building. Which transmitter are you pointing towards?

A fair number of customers in your area through the years have wound up getting tv reception off the channel 10 building. Because of the introduction of lte I'd be trying an old school narrow band yagi 10/4046/r yagi these can be mounted vertically polarised without extra hardware. If you have an amplifier you may need lte filtering as this has become a recent issue everywhere. If you do need an amplifier any of the Kingray mda series amplifiers are the best I've used: most headroom, least noise, most effective on weak signals, most impervious to interference.

Depending on signal in the area a good band34 log periodic may be fine. Generally when channel 7 digital is affected it may be due to corrosion or water damage of the aerial, this is not always the case. Depending on the cause of signal issues on SBS a phased array antenna such as a wisi or Fracarro pu4a etc may help as it has a larger capture area and reasonable gain to assist with trees and hills in the area. It may make more sense to have one system running both and potentially less maintenance. You may need a good technician to look at the system rather than buying the best bits to do it yourself without test equipment and training to make it work.

Could be summarised as buyer beware. An antenna with an unshielded inbuilt amplifier with no certainty about the RF performance of the amplifier. The +/- is the gain control. Potential to create a feedback loop is high. Hence why many manufacturers offer low noise pre balun amplifiers as optional other are offered at all. Suggest a proper crimp tool well almost set you back as much as a cheap aerial, a compression tool will cost you more again, but the right tools are essential to do am antenna properly.

Hi bello, glad you didn't get a VW the dealership try robbing you each time you come near. Did you get the petrol Hiace? I hear the engines in those go forever.

It may be worth looking into a good phased array antenna. A signal check by an experienced technician with a good meter would help. Brands that do make good phased arrays include wisi, fracarro, and alcad. The alcad ap369 comes with an optional low noise masthead amplifier if necessary. The only other low noise amplifier I can recommend is the aussie built Kingray MDA which is by all means a very nice GasFet masthead amplifier. When trees make the signals go crazy a phased array antenna has a larger capture area which usually helps a lot. M'bozo raises some excellent points:

Hi Chris, It sounds like you're going down the right path as far as using a phased array antenna. Usually is a customer has problems on UHF during inclement weather this is a good place to start. I would assume the cypress trees are your big issue. I have seen it several times where moving the antenna inches can make a huge difference. Detuning the antenna can make a difference also. Some may also have run accross the issue with fast growing tree foliage during the spring times. This seems to be the time of year in very well treed areas where tv reception is affected I believe due to the season. A nice feature of a higher resolution and faster spectrum analyser is the ability to see the distortion in the signal. Having bought an AP01 some three years ago, it's a really nice feature to have.