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Atmospherics (merged) (Part 3)


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Old 27-04-2014, 15:06
DDaveBB
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.........
I have ordered a 9-element Yagi myself, based on Peter Körner's 9.2 design, in preparation for an overhaul of my aerial system. Next will be a rotator and assorted accessories. As I plan to have the 9.2 on top of a chimney-mounted 20ft pole, it will need guying to stabilise it during windy weather. Does anyone here know what sort of costs guying will incur? This overhaul is going to be expensive but it'll be worth it, particularly if it minimises the disruption caused by my ongoing interference problem.
.

Hi Nick,

I liked the thought of the Korner 9.2 - but for what I wanted to do I decided on the self build 5ele Yagi. Guying is likely to be expensive but definitely needs to be done professionally - and of course you'll need to get formal planning permission due to the height and prominence of the proposal. I've just checked and Havant County Council have a decent page on their web site (unlike my local council) explaining their approach.

I keep thinking about a 'proper' un-guyed tilt over support to give me an overall height of say 26ft - 20ft away from the house. But I it requires a 3ft x 3ft x 3ft concrete filled hole in which to bury or bolt on the base - so an expensive option. Current support is 18.5ft high and tilt-over - the new 5 ele is the biggest I dare put on it - but will be dropping it horizontal when winds above 50mph are prdicted - as I did this past winter.

Rgds

Davi
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Old 27-04-2014, 15:33
DDaveBB
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Nice to hear about your antenna David, it looks very nice, do you have a how to build guide that you could link me to as I'd be interested in upgrading from my FM3.

Also do you know if you can do what I have done with the FM3 to the FM5 which is to have both Horizontal and Vertical elements on one boom?

Nothing to report DX wise yet, hopefully the Sporadic E season will be starting soon!
I don't have any build guide - I 'just' worked out the hole positions for the element supports from the dimensions on the K6STI web-site. I'd be happy to send you detail as to how I constructed it in a private e-mail including a parts list and where I bought the materials from.

As for mounting two as horizontal/vertical on the same boom - I gather there has been a lot of argument about what this does to the antenna radiation pattern i.e. having a vertical pole in front of the driven element. Having said that, as already posted, it's been done with theTriax FM5 - a picture of which is also on the K6STI web-site. The person who did this (John Faulkner) carried out extensive tests to satisfy himself that it didn't cause any adverse effects.

With the K6STI yagi the 'problem' would be the box protecting the connections to the driven element which takes up some space but just eyeballing the aerial out of the bedroom window I can see there is enough space to fit a second box in between it and the first director. The boom length would need to be extend by 4 inches / 100mm and the vertical elements offset that amount in front of the corresponding elements.

As for SpE DX - the opening on the 26th passed my by - I was out but was tuned to 87.6 with the aerial facing south. Nothing logged on RDSSpy - but I'm monitoring!


Rgds

David

Last edited by DDaveBB : 27-04-2014 at 15:42. Reason: added info
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Old 27-04-2014, 15:35
radioredcat
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Hi Andy,

I've lost your email address! this web site has all the dimensions for the Triax FM5 http://www.ham-radio.com/k6sti/ just need to work it out - folding the dipole and getting it just right would be the difficult bit but have a look at the "Small 5-element Yagi" - much better front/rear spec than the Antiference/Triax.

Rgds

David
Hi David sorry I forgot to reply to your post as I have been busy lately anyway thanks for the link.

Andy
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Old 27-04-2014, 16:00
radioredcat
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A harmonic from Sutton Coldfield in St Helens, Merseyside? Or just a mixing of signals?

I still want to experiment with vertical polarisation, but it's just the hassle and expense, as I don't have my own ladders and paid a local aerial company to install it last October. It has stood up to severe high winds and just about clears my roof, but as I am not very high, I consider the results a let down.
It was just overload causing this problem it doesn't happen that often I used to get the same on analogue TV from Sutton back in the good old days.


Andy
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Old 27-04-2014, 19:34
radioredcat
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I have been busy with my aerials I made a dipole with a parasitic element which David very kindly gave to me and I replaced this with the 98 Mhz dipole.
The result of this was Today FM 101.4 the strongest Irish signal here was gone it was there before I swapped the dipoles.
I then put the 98 Mhz dipole back with the 2 element dipole spaced about 2 ft and Today FM was back but on 16/04/14 I received Klara 90.4 better on the 2 element dipole.

Last week I got a Triax FM 5 and have now replaced the Antiference FM 3 with the FM 5 and the result of that is much better directivity which is a boon here in overload alley.
I am going to try the Anti FM 3 low down vertical at the Eastside of the house for now for Dutch/Belgian stations as at this position Ireland won't be present if it works then it can stay there if not then I will put it vertical at the top of my mast.

Here is a picture of the aerials now showing the FM 5 and UHF logs and the 2 dipoles.
http://i593.photobucket.com/albums/t...psc3baa1bc.jpg

The 18 element UHF TV aerial is nothing to with me a f****** cowboy installer decided that he would save the price of a lashing kit as this aerial belongs to a neighbour 2 doors away oh and it's a second hand aerial as well.

You can't get the staff these days.

Andy
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Old 28-04-2014, 10:24
DDaveBB
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I have been busy with my aerials I made a dipole with a parasitic element which David very kindly gave to me and I replaced this with the 98 Mhz dipole.
The result of this was Today FM 101.4 the strongest Irish signal here was gone it was there before I swapped the dipoles.
I then put the 98 Mhz dipole back with the 2 element dipole spaced about 2 ft and Today FM was back but on 16/04/14 I received Klara 90.4 better on the 2 element dipole.......

Andy
Hi Andy,

I've modelled the set up shown in your photo using 4nec2 and what is happening is that the 98MHz dipole and the wideband dipole are interacting and having a big effect on the radiation pattern of each antenna. I can only make the assumption that one dipole at a time is being fed maybe someone else is more expert and can model the effect of each dipole with attached feed line.

So in a nutshell - just the wide-band dipole with parasitic element at 25ft gives a nice circular pattern across the whole band - with 4dBi gain including ground effect.
Stick a 98 MHz dipole (assumed 56 inch total element) 2 feet away and you end up with a 2 element array.

This means if you are taking the signal from the wideband dipole the 98MHz dipole acts as a director at the low end of the band but becomes a reflector at the low end of the band.

But if you take the signal from the 98MHz dipole then the wideband dipole acts as a reflector at the low end of the band but loses its effect at the higher end of the band becoming virtually non directive above 102MHz.

So maybe why you lost Today FM with just the wideband dipole is because you lost the gain imparted by having two dipoles spaced at 2 feet apart. Peak gain from your set up could be 5dB over the dipole

BTW - is that an old Stolle rotator? I had one back at the beginning of the 80's through to the 90's.

Rgds

David
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Old 28-04-2014, 16:27
radioredcat
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Hi Andy,

I've modelled the set up shown in your photo using 4nec2 and what is happening is that the 98MHz dipole and the wideband dipole are interacting and having a big effect on the radiation pattern of each antenna. I can only make the assumption that one dipole at a time is being fed maybe someone else is more expert and can model the effect of each dipole with attached feed line.

So in a nutshell - just the wide-band dipole with parasitic element at 25ft gives a nice circular pattern across the whole band - with 4dBi gain including ground effect.
Stick a 98 MHz dipole (assumed 56 inch total element) 2 feet away and you end up with a 2 element array.

This means if you are taking the signal from the wideband dipole the 98MHz dipole acts as a director at the low end of the band but becomes a reflector at the low end of the band.

But if you take the signal from the 98MHz dipole then the wideband dipole acts as a reflector at the low end of the band but loses its effect at the higher end of the band becoming virtually non directive above 102MHz.

So maybe why you lost Today FM with just the wideband dipole is because you lost the gain imparted by having two dipoles spaced at 2 feet apart. Peak gain from your set up could be 5dB over the dipole

BTW - is that an old Stolle rotator? I had one back at the beginning of the 80's through to the 90's.

Rgds

David
Thanks for that David I did remove the 98 Mhz dipole when I put the 2 element dipole up and it does work better at the lower end so when I put the 98 Mhz dipole back in the position it is now Today FM was back as it normally is.

Anyway now I have the Anti FM 3 spare I will use that for vertical work.

The rotator is a hirschmann formerly Stolle so basically the same and bought it in 1985 and still rotates ok I have heard people say they they don't last long.
My rotator has always had a support bearing which I think is why it has lasted so long and believe me it has done some hard labour rotating in it's time.
I have been thinking about taking it down and servicing it but I am thinking as it is a lot of work taking it down and then trying to take it apart as there's usually always one screw that breaks.
Anyway there's the old adage "don't fix what aint broke" and then the maintenance bit the grease must have gone hard by now so I will carry on thinking about that.


Andy
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Old 04-05-2014, 21:09
DDaveBB
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A nice enhancement is developing with a number of the low powered Belgain stations such as Club FM, Radio Kompas and Top Radio coming through clearly. Not much in the way of more distant signals although Fr Inter on 94.9 from Bourges-Nevy (470km) was present with noise at 20:45 local time.

Plenty of SpE except for us in the UK - lets hope it drifts our way tomorrow.

Rgds

David
Sittingbourne
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Old 05-05-2014, 13:26
Hybrid tellies
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On my DX set up, Grundig Satellite 700 and it's telescopic aerial, I heard my first French station this year. I think it was Lille on 105.2. As Wave 105, from Chilerton Down, faded out either Planet Rock from Sutton Coldfield or the French signal from Lille would fade in. Conditions not good with nothing else about.
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Old 05-05-2014, 15:09
KnobTwiddler
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I heard my first French station this year. I think it was Lille on 105.2........
That used to be the most regular of the French stations here at my location - that was until a bloody pirate squatted on the frequency here in London.
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Old 05-05-2014, 17:22
ACL777
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Conditions are up. It is probably the best of the year so far for me.I have also received my first 70cm Dutch repeater on 430.350 PI2HGL . Its very weak though.
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Old 05-05-2014, 19:54
ACL777
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Anybody on the east coast try 430.350 from Den Haag. Its belting through like a local repeater.
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Old 09-05-2014, 14:26
Brightonelectri
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Anybody on the east coast try 430.350 from Den Haag. Its belting through like a local repeater.
there is open access to the radio scanner located in the University of Twente,faculty of electrical engineering. Covers all freqs from 50Khz upwards. It appears that more than
200 people can access the system simultaneously, all listening to different
freqs. I tried it today and found a huge number of HF signals.

http//websdr.ewi.utwenete.nl.8901
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Old 09-05-2014, 22:48
KnobTwiddler
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there is open access to the radio scanner located in the University of Twente,faculty of electrical engineering. Covers all freqs from 50Khz upwards.
There are quite a few SDR's that you can use, here is a list that includes the Twente receiver which only goes up to 29.160 MHz, so it doesn't cover 70 cm.
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Old 10-05-2014, 17:14
Nick_G
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Hungary made it in here on 87.6 at around 1545 UTC for maybe 3 or 4 minutes: MR 1 Kossuth Rádió from Győr/Szabadhegy peaking at 2 bars with RDS. One or two very vague signals on other channels around the same time. That's it so far, but this is the first Es for me of 2014.

Let's hope it continues to improve.
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Old 10-05-2014, 19:01
ACL777
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Thanks for the heads up. I hope to Dx more repeaters both on 2m and 70cm.
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Old 10-05-2014, 22:07
KnobTwiddler
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Hungary made it in here on 87.6 at around 1545 UTC for maybe 3 or 4 minutes.............. this is the first Es for me of 2014.

Let's hope it continues to improve.
That's good news Nick, I've been waiting for some Es to test the homebrew loop aerial.
Although it works very well at nulling stations, with the pirate situation here I'm not sure if a 3 ele beam wouldn't be better with forward gain and a narrower beamwidth.

By the way what is the situation with your interference problem - is it still ongoing?
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Old 14-05-2014, 19:39
Les Wires
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Nice Es opening on 70MHz in to Spain at 1930bst, could be spreading to band II soon.
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Old 14-05-2014, 19:56
Nick_G
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That's good news Nick, I've been waiting for some Es to test the homebrew loop aerial.
Although it works very well at nulling stations, with the pirate situation here I'm not sure if a 3 ele beam wouldn't be better with forward gain and a narrower beamwidth.

By the way what is the situation with your interference problem - is it still ongoing?
It has improved greatly in the last few weeks. It makes me wonder if it is central heating-related but I am glad it has mostly gone in time for the Es season.

Speaking of which there has been a very patchy opening here with very intermittent reception. It has just been one signal at a time and they have been minimal. The few heard included Kiss FM on 88.0 from Romania, Morocco on 87.9 and probably Algeria on 87.6 and 87.7. Plus an unid Balkan language briefly on 89.4.
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Old 15-05-2014, 19:56
JonCollett
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Anyone getting any DX this evening? I have Ducth TV Muxs (West and Utrecht) active this evening, suggesting a lift over the Netherlands at the moment.
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Old 16-05-2014, 15:38
Nick_G
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Some good Es about this afternoon to central Europe and the Balkans. Highest frequency logged with an ID was Radio B92 on 103.2 from Serbia. Other countries heard include Bulgaria, Hungary, Croatia, Austria and Slovakia but there may have been others in the mix.
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Old 16-05-2014, 17:23
fmradiotuner1
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Lots of Dutch booming in here right now.
Dream 100.2 getting bad to from the station on 100.1 & also 100.4 LOL.
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Old 16-05-2014, 18:02
Hybrid tellies
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Nothing on FM here but have seen first TV pictures on band1 ch R1 from Ukrain. Very weak and did not long.
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Old 16-05-2014, 21:26
fmradiotuner1
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All Sudbury freeview is breaking up here.
Not tried London but they are having trouble with the main TV.

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Old 16-05-2014, 22:07
ACL777
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Anyone getting any DX this evening? I have Ducth TV Muxs (West and Utrecht) active this evening, suggesting a lift over the Netherlands at the moment.
Dutch 70cm repeaters are coming through. There are weak TV signals but nothing strong enough to pull in with a horizontal aerial. The usual Dutch band 2 suspects are all here at varying levels plus France. As usual though there is a complete block at my location of anything coming from Belgium. Have you received any Danish TV yet?I know I have asked you before. I am guessing you get better Dutch signals as your aerial is vertical. I remember last June I was getting more German muxes in just because of polarization if I remember rightly.
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