Auroras back in stock

[chipp1968]

yes i have realised that is a possibility ,but i still think another may be usefull .still thinking about it at moment its more likely when i have a few more sets working and may be in different rooms too

[garfy]

Hello,
A good idea would be a AMTV VHF transmitter.
I have a Transmitter kit which i ordered some months ago from America, but have not got round to it yet as moving house has set this back somewhat.
All you need then is a set top V aerial.
Regards,
Garfy.

[chipp1968]

I didnt think that was legal ?

[Kat Manton]

Hi,

Originally Posted by chipp1968

I didnt think that was legal ?

Correct, in the UK you're not allowed to transmit anywhere unless you either hold a licence or a specific exemption exists. If I end up with enough sets to justify it, I'll be distributing the signal(s) with a distribution amp, cable, and tap points for each set. With a bit of thought and filtering several channels on various standards could be fed down the same bit of wire; a bit less dodgy than transmitting them all...

Regards, Kat

[ppppenguin]

It is illegal to transmit like this in the UK.

I believe that a member of this forum (I'm certainly not going to name him) has experimented with using a CATV distrbution amp to bring the modulator output up a bit and feed it to a simple dipole. This could give easy reception around a house with indoor "rabbits ears" aerials.

I would much rather adopt Kat's method, either with proper professional distribution kit or with cheap and cheerful domestic stuff. The only thing to watch out for is that some modern distribution equipment is rolling off at the lower end of Band I which could compromise channel 1.

[Kat Manton]

Hi,

I already have a Vision V52-100, (remarkably, both cheap and cheerful and professional) which, with a roll of CB100, a bucket of F-types and a tap per set would do the job nicely for enough sets for me. For more sets, beefier amps are available, and corresponding taps with greater attenuation.

Disclaimer, I have no connection with DAS other than having bought gear from them which I'm very happy with.

Regards, Kat

[chipp1968]

how many sets could a standard aurora drive without amplification if any more than one ?

[ppppenguin]

Depends on sensitivity of sets but there will be no problem splitting 2 ways. 4 ways will probably work but not with a deaf set.

If you want to experiment then just put an attenuator in the aerial feed. If you can put in 12dB and the picture is still OK then you can split 4 ways.

[garfy]

Hello,
Of course it`s ilegal,but only low power enough for the house.
Regards,
Garfy.
PS I also have a low power AM radio transmitter.

[chipp1968]

I also have an am transmitter too of v low power .
I will try feeding 2 sets with aurora when i get some proper splitter leads etc

[DoctorWho]

I have a cabled system throughout the house, there are approximately 24 sets connected throughout the house via distribution amps and co-ax outlets. The UHF and VHF signals are combined by a distribution unit and then sent all around the house. Even thought this is purely a cabled system 405 can be picked up indoors on a set with a set top aerial! Amusingly the 7 modern colour sets also connected up are also being fed with a VHF signal as well as UHF, sadly though even those with VHF tuners do not tuen down low enough to pick up even the audio.

The one and only problem with the whole system is that, when 405 is switched on, it causes interference on UHF channels, any ideas how this can be overcome as, ideally, I would like to have 405 on all of the time?

I also use a Gizmo MW (AM) transmitter to put VHF stations back on to MW, it just runs to a simple loft aerial and allows the various radios around the house to pick up whatever I want to transmit, this can also be fun if you want to play vintage radio recordings on to old sets, even crystal sets or early external horn speaker sets, but I followed the manufacturers instructions with this so as to remain legal, it only transmits a few feet as far as I am aware, just enough to feed around the house.

Peter.

[Sean Williams]

Hi Peter,

The problem you are getting is a result of mixing and harmonics upsetting the UHF sets - Probably best to start a new thread for this - we are well off the track for this discussion.

Cheers
Sean

[DoctorWho]

You're probably right Sean, good idea.

Ta muchly.

Peter.

[ScreenSaver]

Originally Posted by ppppenguin

Has anyone really been charged £50? I thought the maximum was about £30 which is actually fair, even if you don't like the rules. Anything under £25 and you have done OK. most of us seem to have paid £16 to £30.

Well for the record - and maybe it is a record? - I've just been fleeced for £31.55 to receive mine. That's £18.05 VAT plus the standard £13.50 demand for money with menaces.

Maybe I can get in the Guiness Book of records....unless someone is intent on outdoing me by paying more Oh well, the kids wont miss a couple of meals...

ScreenSaver

PS: I thought I'd just add, that the Aurora is still, in my opinion, good value for money, even with the charges. It's the apparent abitrary nature of their application by HMRC which is frustrating.

[ppppenguin]

Sorry to hear that you've set a record

$275 is about £150 at current rates so VAT at 17.5% is £26.25. The lowest handling charge I've seen is the Post Office at £3.50. So anything up to £29.75 would seem OK. Unpleasant but acceptable. That's about what I paid on my first Aurora.

I don't think it's worth trying to understand HMRC Unless you are doing a lot of import/export business when it's essential to pay the correct rates.

[channel405]

I have spent a week now playing my Aurora and think it’s simply superb! It is now my prized possession!

I have connected it to a number of different kit and tried all sorts of things. Currently, the main 625 source is a DTT receiver that supplies off air BBC (no commercial rubbish here please!) albeit in 16x9. Despite not being true to original 405 specs I tend not to put the box into 4x3 or letterbox mode as this reduces the resolution- the Aurora retains the 720 pixels per line of the 625 signal. The output of the DTT box is RGB and that goes to a digital recorder. The out put of the recorder (DVD RAM or DVCAM deck) is component so the Y (luminance) has no subcarrier (I know the Aurora strips this anyway) then into a JVC video corrector unit. With this I can boost the high frequency of the 625 video prior to the Aurora input. The result is a very sharp and crisp 405 picture. In fact, I would say the difference in detail between the original 625 and the converted 405 picture is negligible. That is to say the difference is almost imperceptible, and this is using a high resolution Sony broadcast monitor for the 625 picture! Admittedly the 405 line set has only a small screen, but this just goes to show that the old system is still worthy of very good results.

With the lower line rate and therefore reduced bandwidth, 405 line colour would record very well on a component recording system like Beta SP. Because the R-Y and B-Y signals would be less “compressed” the colours would look richer than on 625. So, thus proving the number of lines isn’t everything!

[ppppenguin]

Apart from grumbles about import tax has anyone got anything to say against the Aurora? We know about the harmonics on the output and I made a couple of minor criticisms in my review. I suppose it's so small that it can get lost or the dog can swallow it whole

It's not often that a product has been so well received. A splendid bit of work by Darryl.

In fact, I would say the difference in detail between the original 625 and the converted 405 picture is negligible.

The 405 system always did have more horizontal resolution than was strictly justified by the number of lines. When we look at colour pictures on coarse pitch CRTs via PAL decoders that cut off everything much above 3.5MHz it's not surprising that 405 looks sharp.

[channel405]

Originally Posted by ppppenguin

When we look at colour pictures on coarse pitch CRTs via PAL decoders that cut off everything much above 3.5MHz it's not surprising that 405 looks sharp.

Thats the whole point, I am using a fine pitch broadcast monitor and yet the 405 picture has very near the same level of details. Whereas I have a small colour JVC monitor with very coarse dot pitch and the level of detail of the 625 picture is far below that of the 405, I'd say nearer 2.5Mhz!

Just a shame about the poor DC clamping on my current 405 set!

[ppppenguin]

Each MHz of bandwidth at 405 is worth (approx) 99/64 of a MHz at 625. So 3.5MHz at 405 is worth 5.4MHz at 625. In other words the H resolutions of the 2 systems are almost identical. It's not surprising that if all other things are equal, they will look equally sharp. It certainly seems like that on my dual standard Prowest monitor.

Of course I'm using the Aurora to do the conversion and that measures pretty much flat over the entire band when checked with multiburst so it's clearly doing it's job properly.

[murphyv310]

Great reading everyone
The Aurora's are wonderful converters, I use the multistandard converter and the basic one is also excellent except for the harmonics.
I built a Steve Mcavoy modulator and modded it with x-tals for a stable output. I have retained double sidebands but have made up filters to cut off above 50mhz. the results into my Murphy 310 & Ekco TMB272 are truly excellent, with no noticeable reduction in horizontal resolution compared to 625 (see my other threads). I have fed the output into a high output distibution amp (60's valve type) & then to a dipole this give a range of about 1km, VERY NAUGHTY I know and NOT used now. I had to move house at the turn of the year and the "new" house was empty for 7 weeks so I set up a 625 camera up via the Aurora and modulator to the amp and to a chopped DV27 CB aerial, this was then monitored on My Sony TV990UB 800meters away with excellent results.
I had no complaints either from residents or the orthorities, 45mhz is basically unused, so I didnt worry too much as my signal is harmonic free not affecting 90mhz FM.

Please do NOT try to copy what I have done it's not allowed in the UK

Trevor