Yagi 18B and Yagi10K / Yagi 18K aerial performance reports

NOTE: many of these reports are from the pre switchover low power digital + analogue era, but that doesn't make them any less relevant as regards aerial performance, if anything it makes them more so because aerial performance was actually better assessed when using analogue signals due to the "all or nothing" nature of digital TV reception.

Analogue v Digital pictures - how they degrade 310W L5

Yagi 18B

Yagi18B gain curve compared to other relevant aerials.

Note : many of these reports are from the analogue era, but that actually makes them more valid because of the "all or nothing" nature of digital reception.

Yagi 18 TV aerial 220W L10 4kB

G Moat-Brown  (Keelylang Hill Transmitter - Orkney)
I had an aerial in the loft but it didn't work too well so bought a Yagi18B and installed it outside on the chimney using one of your 6 foot cranked poles, an 8 inch mitre bracket and a lash kit, plus recabled in your good quality satellite cable. I also fitted a folded dipole FM aerial at the same time, I went for the this aerial rather than the half wave dipole because we live in a pretty exposed location. The Yagi 18B worked pretty well though some of the programmes do still intermittently break up. It is far better than the old aerial though obviously that was in the loft so at a bit of a disadvantage. I note your advice to try a mast head amp in an effort to further improve the signal but to be frank we don,t watch much TV so can cope with it how it is!
Unfortunately just the other week we had a 110 mph gale up here in Orkney which cracked the pole on the bend so it now needs replacing. Interestingly the pole had survived gusts of similar speed before but this gale did last about an hour! After all this extreme weather the only thing wrong with the [Yagi18B] aerial is one of the directors has developed a bit of a rattle but I'll tighten up the screw when I get round to it [fitting a slightly larger diameter self tapper if necessary]. I've decided to fit the aerial on the wall this time because the high winds have caused the corner pieces of the lashing kit to start to digging into the masonry on the corners of the stack, the actual chimney bracket was fine. I,m also going to use your 5 foot long inch and a half diameter pole satellite pole and not one but two 6 inch by 9 inch wall brackets, it shouldn't ever fail then!
As a bit of a footnote, when the installation got blow down the wind blew the aerials (by now hanging off by the cable) against the wall for a while and the dipole cover of the FM aerial was worn through. I feared that would mean a new aerial but fortunately I'd bought it from ATV and they sent me a spare one! So thanks for that, and also thanks for offering to supply the replacement mast free and for writing the only aerial website which actually made sense.

1.25in diameter pole snapped in 110mph wind 221Sq L5 kB

Left :
I can believe the wind was 100mph, it's snapped a 1.25 inch 16G (1.6mm thick) pole !

Right :
Note worn through dipole cover.

Worn through dipole cover 221Sq L5 kB

If any pole we sell * fails in use (provided it's used as we recommend) just send us a pic of the errant install and we'll replace the pole free (though you will have to pay the carriage). Despite George's experience I'd still recommend one of our 6ft x 1.25in cranks for a Yagi18, in fact, from memory, we've never had one fail on any install we've ever done. Actually that's wrong, after high winds we once had a 6ft crank split open longitudinally on the bend, it was very odd, I'd never seen it before (or since). I think in George's case the prolonged extreme Orkney wind combined with the additional wind loading of the Folded Dipole (higher wind loading than a Half Wave don't forget) was too much for the pole.
* Excludes the 6ft x 1.0" x 1.2mm 

As of May 2013 we've extended the lifetime warranty to any bracket we sell. Again it has to be used as per our recommendations but if any bracket we sell fails send us a picture of the failed installation and we'll replace the bracket free (excluding the carriage cost).
It's good to hear just how robust the Yagi18s are, I've always thought they were well made but 110mph! Incidentally, as George says, if the elements on a Yagi18 (or a DM Log come to that) do become loose [which I have to say is a rare event] you don't have to scrap the aerial, just tighten up the screw. If the screw won't tighten because the thread is stripped just put a slightly bigger gauge screw in, that usually sorts it!
We do try to supply spares for aerials purchased from us, which happily helped George here!

M Ward (Emley Moor Transmitter)
Thanks for all your help with my new installation, it's working great, very pleased.
We live in a valley with no line of sight to Emley Moor which is some 20 miles away. Previously I had a Maxview XB5 type aerial from the local DIY store mounted on a 6ft pole with satellite grade alloy foil type cable (about 12m) in good condition. Running one set reception wasn't great and we had quite a lot of picture break up due to lots of trees in the way. We could only pick up the local relay transmitter at Todmorden which doesn't have all the channels on it. There was no signal from Emley Moor even after switchover.
I've now fitted a Yagi18B, a 10ft 2" mast, a single output masthead amp and a four way splitter. The Yagi18B blows the old aerial clean out of the water, signal strength is very good, we only needed the masthead amp because of the four points in the house.

R Green (Hannington Transmitter)
We have just finished a house refurb in Micheldever. The original 16-element contract aerial (with wobbly reflector) was mounted on a 10ft pole on the chimney, and worked quite well, but after the refurb we no longer have a chimney and using the same length pole on a gable end lose about 6ft aerial height.Though only 9 miles from Hannington, we are at the bottom of a hill with surrounding  trees and have a bungalow so looking at the great info in your site, a Yagi 18B seemed appropriate. I purchased from ATV the Yagi, a 1/2 wave VHF dipole, some 18" T/K brackets, the 6-way distribution amplifier, a reel of coax, two diplexer faceplates and some sundry items. I mounted the aerials on a 10ft pole on a gable end. The quality of the aerials are good, and the faceplates are particularly good quality. Assembly and fitting was easy. Freeview is working excellently, but I have not tested analogue yet as we don't intend to use it. Thanks for the great service and very good web site full of helpful tips. I enjoyed reading the Cowboys Locker section! Oh and thanks for the free box of black cable clips, after I accidentally ordered brown ones!!  (our pleasure)

T Foster (Sutton Coldfield Transmitter)
I just wanted to say how embarrassed I was, when I found your website, detailing why I shouldn’t have purchased and installed my old wideband TV aerial (an XB10 type). It was a poor quality B&Q special. Not particularly cheap if I recall. It was very flimsy, and supplied with an indoor roof space mounting  kit, AND I mounted to the fascia board outside (slapped wrists). It lasted about five years with barely acceptable performance, with VERY poor reception for the last year, prompting replacement.
I eventually purchased one of your Yagi18B aerials with your mounting kit last week, and fitted it today. The kit is great (everything you need) and the aerial was easy to assemble.
1. Fantastic delivery: Ordered Friday, delivered Monday -Thanks.
2. As you can see from my pics, I have mounted the new aerial much more professionally this time, thanks to your site. I don’t like heights, and so did not mount on the chimney, it is too high  for me/my ladders.
3. The new Yagi18B out performs my old aerial at its best, and even brings in the MUX on (pre switchover) CH55 which is out of band. Reception is far less choppy and interrupted, even on the weaker MUXes. BBC1 analogue which was very snowy on the old aerial, is now perfect, along with the other analogue channels.
4. We use the Sutton Coldfield Transmitter, which was on low power for most of last summer, due to the temporary antenna build. Power is now up again, except for two of the MUXes, although I can receive them all perfectly now.
5. I have an indoor aerial amplifier/distributor, which I may need to switch off after DSO, when the power shoots up, we’ll see.

P Hind (Sutton Coldfield Transmitter)
Although I can't compare the aerial to another one because it's a new installation I can report that its performance is perfect and the build quality of the aerial is better than any B n'Q aerial I ever bought! The only reason I took time out to send this email is because I was VERY impressed with your service and quality of your goods, a big thankyou.

M George (Emley Moor Transmitter)
I live at the bottom of a valley so reception is not great. Before getting a digital TV I wanted to maximise my analogue picture quality which would normally do the same for the digital signal.
I was sold a Vision V10-481 (a model of XB10WB) but the picture was still far from perfect.
Swapping to the Yagi18B gave us the best picture we,ve ever had, I was very pleased, but that was only on 1 to 4 because Channel 5 was no better for some reason!
I don't really understand that either, possibly co-channel interference?

J Wozniac (Sutton Coldfield Transmitter)
Thanks for a very prompt and efficient service recently. I bought a Yagi18B aerial and variable gain 4 way mast head amplifier together with a fixing kit recently. The aerial and parts were all of good quality and I found it easy to install. I would like to say how  useful the information on the website was in helping me to choose the right equipment. I am tuned into Sutton Coldfield but the tall buildings and electronics of Birmingham City Centre are directly between us and the Transmitter, so reception has been a bit difficult even though we are only 10 miles away. The new aerial produces a signal with 100% quality and 70% strength (with gain turned up) as measured on the Humax 9300T, much better than the old one [a 12 element Yagi type] which is actually in a better position. Anyway many thanks for your efforts on the website as it made the choice much easier.

D Hancock (Black Hill Transmitter)
Have just purchased one of your Yagi 18B aerials as our old one (a Yagi 12? ) , was 25 yrs old and bits falling off.  Wanted reception of Black Hill whilst we are down behind a very large rise in Lanark. Used your cable replacing ordinary brown sheath.Aerial mounted about 1.5 metres above the chimney.Results approx 2db improvement over digital channels 41 to 51 and nearer 15db at 55 (Mux5); nothing at Mux6, as expected (pre DSO - Jun 2011 - Black Hill was an E group). No actual field strength figures available ( no meter ) but analogue signal fair and better than it ever was with little noise and echoes. I'm quite satisfied with the build quality, hope it stands up to gas central heating and  coal fire. Like your web site - very informative; however, have mux identifications not been revised by Ofcom? (See MUX names and renames).

ATV (Emley Moor Transmitter)
Now, partly due to the fact it was the summer (better weather and we weren't as busy * ), partly because it was only a mile down the road and partly because it was on a wall [i.e. easier access], I decided to use this as a research exercise. We went back at least four times, changing one thing at a time, all for free (other then the materials).....
First we tried it on other Transmitters, i.e. Crosspool and Belmont. No joy.
Next we tried increasing/reducing the amplification of the amp [always buy a variable gain amp....] to higher than optimum, then less than optimum setting, but hey, we were struggling ! Zero improvement.....
Next we put the install on a 10ft pole, thus increasing the height over the roof by about three and a half feet. This improved things but a week or two later the customer was back on.....
Next we swapped the Log40 for a Yagi18B. This improved things the most. We left site and waited with bated breath to see if the phone would ring. No telephone call was forthcoming. Eventually my sense of curiosity (and my impatience) got the better of me, so I phoned the customer. They replied that whilst it wasn't perfect it was much better and they could cope with it OK. I said we may be able to improve it further with an XB16B (but that'd cost an extra £30, no labour, that's just for the aerial ! ) and to contact us if they needed it doing.
No call yet though!

Log Periodics should be used wherever possible, but they're not universal!
If you need more gain make sure it's significantly more than a Log would give you, so as to make up for what you're losing in swapping from a Log. In this case it was a B group Transmitter so we didn't prat about with a wideband Yagi, we went for a high gain B group.
And it worked!

* You'll always get better service from an aerial installer if you have the job done in the summer (usually April to August/September) ! Not only will the better weather mean he's likely to be in a better mood ( ! ) but he's likely to have less work on as well. It's the same for TV repairs etc, it's always slacker in the summer. The theory is the better weather and longer nights mean people watch less TV, and so are less bothered about a crap picture!

Richard P      Malvern transmitter
I originally ordered an XB10K to receive Malvern (Worcs.) 13.2 km from my house. Unfortunately a Yagi10K was delivered by mistake. Justin at once agreed to replace it but suggested that the Yagi10K would probably be satisfactory with enough gain as Malvern muxes are 400W and the distance is only 13.2km, plus the smaller aerial is more suitable for end mounting.  The path is a clear LOS.  Malvern is vertically polarised and it is always preferable to mount the antenna behind its reflector to avoid the vertical support pole from affecting its radiation pattern in these cases.  This is easy to do with the Yagi10K as the boom is not too long.  The XB10K can be mounted for VP either behind its reflector or with its support cradle at the point of centre of gravity.  The former is better electrically, but the aerial is quite heavy and this is not good mechanically [we agree].  The centre of gravity technique is better mechanically, but the vertical support pole is bound to affect the radiation pattern.   So, I tried the Yagi10K.  It is a well built aerial – much better than contract aerials, and it will probably last longer than an XB10K too.  The Yagi10K is mounted quite high at 40ft AGL and performs extremely well receiving Malvern so I have decided to keep this aerial.  It is mounted on a 2” od aluminium scaffold pole supported using T and K brackets.  This pole is needed as it also supports a 3 element Band II (VHF FM) Yagi (HP) and also a DAB yagi (VP) mounted behind its reflector.
Background info :  Malvern used to be aerial group C/D in the old analogue days.  Many tv aerials round here are still C/D despite going digital and there being no DTT muxes above 700MHz with the “700MHz clearance” making spectrum available for 5G.  This is why I have changed mine.  It has taken me a long time to get around to doing it!  Malvern muxes are now ch.29 to ch.47.  Because I wanted to try receiving lower frequency muxes from Ridge Hill, Sutton Coldfield, and a low power relay in Worcester as well I plumped for a group K.  The other common problem with installed tv aerials here is that they have been installed with the wrong polarization.  I suspect this is a common problem throughout the UK.
So, I would recommend the Yagi10K provided you are not a great distance from the tx where a higher gain would be advised.
ATV is also a friendly and knowledgeable company to deal with. Thank you and best wishes, Richard P

We definitely agree that only relatively small aerials (e.g. Yagi 10K or Logs) should be end mounted. It puts extra twisting forces on the install and all the wind load is put through one piece of the boom which is almost always only 15mm alloy box section. In fact it's ironic that the aerial with the highest wind loading (a Tri Boom) is end mounted !
The 3 element FM aerial in the accompanying picture is of interest, it looks like a professional quality item, these are usually end mounted, ironically so in view of the comments above.... Note that in the case of these types of aerial the booms are extra strong and so are the mountings, i.e. steel transmitter towers !  Technically end mounting an aerial removes the possibility of the mast interfering with the signa
l, though in the real world when the polarity is opposite it doesn't actually make that difference.
Last point of interest : notice the pigeon on the aerial ? It's less common to find birds perching on vertically polarised aerials, for obvious reasons, I'm told "they don't like it up 'em"...... Seriously though, birds can damage aerials, particularly weakly constructed ones, Bacofoil aerials being particularly susceptible But there's no chance any bird would damage a Yagi10K, well OK, possibly an Ostrich, but how would it get up there (apart from the fact we're not in South Africa, obviously...) ?

Yagi10K plus FM3 plus DAB aerial install 302W L5

Yagi 18K

Yagi18K gain curve compared to other relevant aerials.

Note : many of these reports are from the analogue era, but that actually makes them more valid because of the "all or nothing" nature of digital reception.

Yagi 18 TV aerial 220W L10 4kB

Paul R (Bilsdale Transmitter)
My original "wideband" aerial was chimney fitted some 15 years ago and looking to Bilsdale Transmitter; signal strength where I am should be good. Recent storms battered the aerial. The signal was still ok'ish but quality was poor and the next big wind was going to see the aerial achieving lift off and scaring the next door neighbours cat ( a positive point). I was running 4 tv's from a signal amplifier.  Using the advice on this  brilliant web site I  got rid of the unshielded wall plates. 5 minutes work. On Justin's email advice purchased a Yagi 18K aerial. Was just getting the ladders out when I though hang on let's first see how this works in the loft (age certainly does not improve my appetite for heights and what I had read on the site made me think it was a worth a go) Long story short. Signal strength now 90 to 100% across nearly all channels ( channel 37 low but the Transmitter power is a lot lower on that one I believe). Signal quality now 100% across the board..AND no amplifier - just a splitter!  My guess? Wall plate removal helped. Coax cable length reduced by about 5 metres ( and new cable obviously). Significant gain improvement from new aerial and strong signal area. I would not have achieved this result without the information on this website and Justin's help. If you use this site and then go off and buy somewhere else then you really should be ashamed. Although if you're that way inclined I doubt you will...
Just need somebody to volunteer to take the old aerial down... probably a cat lover...

I Thomas (Sandy Transmitter)
Location: Small village near Cambridge. The Transmitter for much of Cambs and Beds area is Sandy Heath, Bedfordshire. According to Atv-website, Sandy Heath analogue signal aerial was an A-band, but after digital switch over optimum aerial should have been K-band. Bought a new 32" Samsung Flat Screen HD Tv last month with built-in Tv Tuner to replace >15 yr old 24" Sony Trinton CRT Tv with Hitachi Freeview set-top box.The old Tv always suffered from random pixelation after Digital Switch Over, but with the new larger screen Tv,  the wife increasingly complained about the random pixelation, so action had to be taken ("at last", she said!).
- Original: >10 yr old unidentifiable 12-element aerial (it looks like a wideband 10 bay DY type) situated on the far side of house (easiest access), cabled with contract-quality ("low loss") tv cable by builders >10 yrs ago. Cable length approx 25m via one wall plate socket, unscreened but not, I don,t think, isolated.  On the new Samsung Tv, the in-built menu signal quality display showed 68->73 percent signal strength, and a range of Signal Bit Errors from 0 -> 505 (very variable over time, an average of about 200 signal bit errors). I bought and used a Fringe Electronics Pro Tv & Sat Signal Finder to check new aerial alignment which has a 12-led visual + audible signal strength display, and it seemed to work well for me. On the old aerial it showed a 52 dBuV reading at the wall plate socket.
- New: ATV-supplied 18-element Yagi 18K aerial situated on nearside of house (access via neighbours property) newly cabled with Atv-supplied satellite-quality tv cable. Cable length is now a bit shorter at approx 15m and with no wall plate socket. The signal reading on the new Samsung Tv, the in-built menu signal quality display showed 93->94 percent signal strength, and always 0 (zero) signal bit errors for the New Aerial. The Pro Tv Signal Finder showed a 70 dBuV reading at the plug (no wall plate).
So the meter showed a relative +18 dBuV signal increase Old Aerial->New Aerial signals. No visible pixelation now seen. Wife happy. Job done.Congratulations to Atv on a most informative website. Good comprehensive aerial kit supplied; all parts seemed to be of good quality.
Obviously the most important observation by far  in the above report is "wife happy".
We don't usually recommend the purchase of signal meters, we don't think they're really required for aligning your aerial and so for most people they're a bit of a waste of money. However in this particular case it does at least mean we've got an second set of readings over and above the TV's !
A Yagi18K will outperform most widebands (and it's better made then any of them.....) but an 18dB increase in signal is huge and cannot really be explained by just the aerial. The wall plate wasn't isolated so is unlikely to be the problem, so that just leaves the cable, or aerial positioning.
Interesting...

W Ridsdale (Caradon Hill Transmitter)

We had a tri boom type aerial before but never had much joy with it, the signal quality on our TV only being about 5 out of 10. In fact as an experiment I compared it to an old 10 element wideband aerial, and even that worked a bit better than the tri boom*.
I looked on UK Free TV and they said Caradon was a K group (since corrected by them to an A group) so I bought a Yagi18K and wired it up into my signal strength meter. Rather disappointingly it only lit one LED! However when I plugged it into the TV it worked fine (i.e. cheap signal meters aren't worth having ! ), the picture is much more reliable now. I can't really explain that because both the tri boom and the Yagi18K are mounted in the same place and use the same cable.
* That's a bit strange actually. I'd expect a 10 element A group to work just as well (or even a bit better) than a wideband Tri Boom, but one of the latter should work at least as well or a bit better than a 10 element wideband, but then again, RF is a black art isn't it !

S Williams (Sandy Transmitter)
I recently bought a Yagi 18K from you. As requested, here are details of my usage and findings.
- Reason for Upgrade : Our 30 year-old contract aerial has coped reasonably well with digital switchover. Although we were unable to get some channels, I suspect that was down to frequency banding more than the age of the aerial. However, for other reasons we needed to move the TV to the other end of the living room, so it seemed a good time to change to a K-band aerial to get the other channels and to renew the cabling at the same time.
- Performance : The Yagi 18K seems to perform well on digital. Not used on analogue, which is now switched off on our  transmitter.
- Transmitter : We live near Newmarket and are using it on Sandy Heath, which Wolfbane reckons is 32 miles away on a bearing of 253.
- Comparison : I don’t have a professional signal strength meter. However the on-screen signal strength meter from my digibox shows approx 80% with the Yagi vs 60% with the old contract aerial on the channels we were able to receive before. In addition we are now able to receive more channels, presumably because of the Yagi’s wider response curve. Both aerials used with a signal booster (not a masthead amp).
- Build quality : Looks better than the old aerial.
Assembly : ... was easy.

R Greatorex (Riberac Transmitter, France [Department 24])
Some feedback for you ref. my Yagi 18k. Thanks to your very informative website and much trawling of the net otherwise to ascertain Transmitter frequencies, I was able to determine the appropriate aerial for my area in the Dordogne. It was reassuring that my findings matched the aerial previously fitted but which had suffered corrosion to the terminals and degradation of the plastic element connectors. It is apparent that the aerial is superior in respect to these points and in build quality generally.
Anyway, suffice to say that after positioning the new aerial in preparation for fine tuning, when I turned on the TV lo and behold a perfect picture even with HD.

R Booth (Bilsdale Transmitter)
Purchased a YAGI 18K to replace a 25 year old aerial (similar type but 10 element, probably an A group) located on a 10 foot pole on a chimney, on a neighbour's bungalow. Pointed at BILSDALE 118 degrees, used Wolfsbane to get this. The requirement was to improve digital performance only.
1. Retuned before installation (SONY Bravia) found 67 services, missing the MUX D which was the aim of the exercise. Subsequent retunes would occasionally finding 93 services - including the MUX D, but the service seemed to deteriorate at night.
2. Installed the ATV Yagi18K, replaced the down lead, and the wall plate with a new MK unit, and the fly lead, - Leads were all CAI approved satellite cable (i.e. copper/copper).
3. Retuned after new installation - it found 192 services, many of which were duplicates, the set assigned these to '800' channel numbers on the EPG. Wrong direction I know but could these duplicates be from Pontop Pike? (I would have thought so but the way to check is to identify the frequency that they're transmitted on then use this table to confirm which Transmitter it is. Alternatively some boxes/TVs give the Transmitter name in one of the menus).
Build quality was fine no problems at all. Your additional instructions on the cable routing were useful, though I never intended to straighten the inclined dipole so those additional instructions weren't quite so useful, but you must have all sorts as customers I suppose !
The web site is excellent, by far the best source of info on the web for this activity. In conjunction with the UK Free TV site. Loved the cowboys pictures.

E Corden (Bilsdale Transmitter)
Very good advice from a lady answering the phone and everything arrived when she said it would. The Yagi18K is pointing to Bilsdale seems fine on BT vision and our other TV's freeview box. Our picture is vastly improved and we now get all the channels we should.
The old aerial pointed to Emley Moor(?) and we didn't get any BBC channels on the BT vision box and suffered other interference on other channels too. So far so good, thank you.