Virtual Radar Server - Trouble shooting!

[jeallen01]

A/S

Many thanks - will do.

 

[jeallen01]

It may be quiet over the weekend, but it's ruddy busy at this moment - a few minutes ago VRS was showing that it was tracking 40+ planes, although that has now rapidly dropped to around 28!

 

[Archive-8]

@jeallen01 what psu did you get to power the line amp please?

 

[jeallen01]

@jeallen01 what psu did you get to power the line amp please?

A combo of the following:
- a bog standard 230Vac/15V dc wallwart that I had lying around
- a home-brewed filter with heavy capacitive/inductive filtering to try to take out any EM crap from the PSU, and a 15V zener to make sure the o/p did not go above that - am actually getting about 13Vdc out of that & could probably have used a higher voltage PSU and an 18V zener to safely get more like 16-17Vdc o/p to the amp itself, which is a standard dc pass satellite unit for 47-2150MHz IIRC.
- an inline DC inserter module intended mainly for supplying head-amps for TV reception

Will provide more details of the filter and dc inserter module tomorrow if you want (just going to bed now).

Also, I aimed to be able to inject about 40mA into the inserter module in case I wanted to add a 2nd amp about 1/2 way along the cable as each amp consumes about 20mA.

However, I've since come across this unit which effectively combines all those with an inline amp to be used near the receiver - that's a lot cheaper and quicker, but would not work for me as my antennas are some way from the house, and I aimed to have the amp as close to them as possible.

 

[jeallen01]

FWIW, here is a list of components used:
Amp at antenna end of cable: SAC 20dB IN-LINE SATELLITE AMPLIFIER/SIGNAL BOOST. LOW NOISE- 4DB MAX BUYME
PS: the ad shows, and I received, an amp marked as 47-2400MHz
Also got another one on the way to insert about 1/2 way along the cable, to see if that helps.
DC Inserter: Axing 950 - 2200 MHz Remote Power Inserter Satellite - although the product title states 950-2200MHz, the unit is actually marked 5...2200MHz!
DC Input filter: See attached jpeg - all the electronic components came from CPC Farnell, and the metal box and veroboard stripboard from ebay
PS: Excuse the "old fashioned" symbols but I used Visio 2001 to build it, and don't see any need for anything more modern in the future!
PSU: Actually a 12V wallwart, but I've now found a 15V one and I'll try that to see if it boosts the amp gain, but, if I built another one, I might try to find something nearer 18V, with a matching (or thereabouts) zener on the board.

 

[jeallen01]

Just raised the collinear about 10ft and this is the sort of thing I am getting now:

Around 70 (was up to 75 a few minutes ago) planes at up to just over 130nm now (not shown on screen shot).

PS: It's pretty clear that the range to the West is restricted by all the housing (including ours!) in that direction, as raising the antenna has made virtually no difference on that side.

Thus, so far, the two largest gains have been from adding the in-line amp just below the antenna and raising that by about 10ft.

 

[Analoguesat]

Wow - nice going - Ive got two on my vrs display atm,

 

[jeallen01]

PS to the list of components used in the DC supply filter: If I was going to build another one, I would change the design to have 2x 22000uH chokes in parallel in both the +ve & -ve rails to give a more symmetrical response.

 

[jeallen01]

And now at around 12.55

 

[jeallen01]

Wow - nice going - Ive got two on my vrs display atm,

I think the airways are a "little" busier around here than where you are

 

[Analoguesat]

I think the airways are a "little" busier around here than where you are

Just a tad

Now at 7

 

[jeallen01]

14.15



Now showing up to around 175 miles to the SSE, but not much increase anywhere else (NE is probably limited because the top part of the antenna is now in the lower branches of the neighbours' very tall tree, and the trunk is to the NE of the antenna ).

So, overall, raising the antenna by 10ft appears to have virtually doubled the range in any direction where the line-of-sight is not impeded by "things".

 

[jeallen01]

14.59
Now changed the PSU for one with a nominal 15Vdc o/p, although it's around 23V unloaded, but that does not appear to have made much in the way, if any, of further range improvements. That's probably because the amp is a Sat line amp designed to work on 13V or 18V according to the requested polarity, and so has voltage regulation designed to equalise its internal rail voltages at a much lower level than either - so will now go back to the original PSU as the Filter enclosure is definitely warmer than before!

 

[Archive-8]

Wow @jeallen01 that was well worth moving the aerial.

 

[jeallen01]

Last thing to try is the second line amp (same type) about 1/2 way along the antenna cable - should be here about the end of this week.

BTW: the combiner used to combine the signal feeds from the antennas to the line amp is one of these Konig FC-COMB-SAT-KN units which combine 5-862MHz from one port & 950-2400MHz from the other (with dc power pass), and with no bandstop filters within those ranges - about £3.50 on eBay etc.

 

[jeallen01]

Last one tonight @ 19.38, with only 40+ planes (although I saw about 76 aroun 16.00) - slight changes over N.France

 

[jeallen01]

Last thing to try is the second line amp (same type) about 1/2 way along the antenna cable - should be here about the end of this week..

Just fitted the 2nd amp and all that seems to possibly have done is to reduce the number and range of planes tracked - possibly adding extra noise which "drowns out" the weaker transponders.

OTOH, we have moderately heavy fog all over S.E. England and I wondering if all that moisture in the atmosphere is what is reducing the signal - so, had anyone seen the effect of fog on 1090MHz transponder signals?

 

[jeallen01]

Edited - actually, apparently no improvement since I fitted the 2nd amp, and the attached is what I have got.

Will leave the system running overnight to see what I have in the morning - hopefully, by then the fog will have cleared and I will have a more realistic comparison.

 

[jeallen01]

Took the 2nd amp out this morning and the number planes immediately almost doubled from 30ish to around 65-70 - so the 2nd amp idea did not work, but the one directly below the antenna most certainly does.

These amps only cost around £5 and so the experiment was worth a try, and I will find another use for that 2nd amp.

 

[Archive-8]

Would this help?

50MHz-6GHz UHF 2.4G Broadband Low Noise Amplifier RF LNA Amp Module 20DB VHF HF