Rf amp yes or no ?

[G4LOH]

Well that saw lasted two weeks so have now orded amp and separate fiter, let's see how they go.
so anybody reading this the saw above is probably not a good idea.

Which parts have you ordered please?

Are you placing the amplifier ahead of the filter or after it?

I recommend a cavity filter like this one:

https://shop.sysmocom.de/1090-MHz-cavity-filter-for-Mode-S-ADS-B/cf1090-kt30

Several other manufacturers also offer cavity filters.

[Col@home]

Well I got a 40db amp and filter gave me 180nm less than she saw, so I got another active saw with 21db and back up to 230nm but still 120nm les than haywats that says so am going to have a play with different antennas and amps on a Windows setup in my workroom.

[G4LOH]

Putting an amplifier *before* the filter will reduce the ability of your system to handle strong unwanted signals.....

Ebay/Amazon amplifiers will see mobile phone signals, OFDM TV signals, even WiFi which are already FAR louder than distant aicraft signals, they amplify them and overload themselves... the signals all get mixed up and the "noise" it makes blocks reception of the distant 1090MHz signals you're interested in.

Because you're seeing lower range with the higher gain amplifier, I *think* that's probably what's happening to you. If you can post more details of the filters/amplifiers you have, I could comment further.

A low-loss cavity filter fitted between the antenna and the amplifier stops the overloading problem.

A SAW type filter cannot be used for this because its internal losses are too high.

I found several suppliers of "1090MHz Cavity Filter" :

https://acasom.com/fr/products/1090mhz-outdoor-cavity-filter-ads-b-flight-tracker-ads-transponder-radarcape-receiver-flarm

https://www.aliexpress.com/i/1005005021376424.html

https://webshop.jetvision.de/en/product/filter-1090-mhz-bundle/?v=79cba1185463

https://shop.sysmocom.de/1090-MHz-cavity-filter-for-Mode-S-ADS-B/cf1090-kt30

Can't see any on Ebay or Amazon

I understand they're a bit pricey but for some locations, they are essential.

I use a cavity filter myself because of a strong local interferer, my range is always maxxed out at 349nm.

Tim

[Col@home]

This is what I have now home brew 4 radial spider @9mtr high with 3mtr double sheld 75 ohm coax 150 nm stand alone 180 nm with https://www.ebay.co.uk/itm/405172981...mis&media=COPY and filter first.
230 nm with https://www.ebay.co.uk/itm/355970094...mis&media=COPY

[G4LOH]

This is what I have now home brew 4 radial spider @9mtr high with 3mtr double shelf 75 ohm coax 150 nm stand alone 180 nm with https://www.ebay.co.uk/itm/405172981...mis&media=COPY and filter first.
230 nm with https://www.ebay.co.uk/itm/355970094...mis&media=COPY

OK thanks.

The 40dB amplifier is way too much gain, especially with the "active SAW" which has 21dB gain itself, don't use these two items together.

The "active SAW" alone is the best of what you have but:
The active SAW uses a Golledge SAW device with 2.3dB loss and Qorvo amplifier with 1.4dB Noise figure.... so your overall Noise Figure will be ~4dB

4dB is high for a Noise Figure but it's filtering will help if local signals are indeed the problem you have.

The best option, which would completely stop local interferers, and lower the noise figure to ~ 1dB would be:

Antenna something like this: (As high up and clear of obstacles obvs)

https://thepihut.com/products/60cm-1090mhz-antenna-for-ads-b?variant=41103129215171&currency=GBP&utm_medium=product_sync&utm_source=google&utm_content=sag_organic&utm_campaign=sag_organic&gad_source=1&gclid=CjwKCAjw3624BhBAEiwAkxgTOulVmzUirwA2WO8QVw_GbNGHqLjrQhQ-P98j5RxNoCRbZ4_gw0XBWRoCqTEQAvD_BwE

Then a cavity filter someting like this:

https://www.aliexpress.com/i/1005005021376424.html

Then this low noise figure preamplifier (0.6dB) or equivalent

https://www.ebay.co.uk/itm/116247064342?_skw=low+noise+amplifier+board&itmmeta=01JA3HY5DYGAMNF9ST6EC03CWY&hash=item1b10dd6f16:g:yMUAAOSwtBhmjeLl&itmprp=enc%3AAQAJAAAA0HoV3kP08IDx%2BKZ9MfhVJKlD%2BpEXrdeud6Z0QFQXS4zxwaI7o%2F8lsED9bD2TR1tX%2Fyfwa%2BX9B8fkbVRBoqjponZqiAiH6ZCUHSv9NBbgG4hpQ4Jd8bRyoLnM68O1UE3iRQk5sGNKFDPQZ2Vzfpp%2BqrPTtzVILiyCG1gvsdg7MC9QzS%2BfWminT1IXDaa81cQvgrduGbWigVjIoRfzM0%2FSKyKx0xImp5QnC9rc7RrGZk37vOKda5%2F5%2B4sZEa7S%2FmS%2F694UoUJQ6bngFFFISjoTfI4%3D%7Ctkp%3ABk9SR6DX-PHQZA

I have the filter and amplifier in a weatherproof box right up the pole at the antenna which also helps.


Good luck,
Tim

[Col@home]

ok I now have the pi hut Antenna up with the base at 7mtr same distance as spider (220nm) but 200 more messages with amp in, it drops by 30nm with no amp.
if I install the dump1090-fa and then the graphics will i still output to fr?
Are the below settings correct.
P.S. thank you both for your help (so far)
.Screenshot_20241016_145518_Edge.jpg

[G4LOH]

"200 more messages with amp in, it drops by 30nm with no amp"

I guess that's the "Active Saw" amp? ... It's hard to draw any conclusions, either the noise figure is being lowered, or the filtering is stopping local interferers.

The gain setting in the DVBT stick will affect this too, maybe try different values and see the impact?

I'm really a RF hardware guy, sorry can't advise about dump1090 software.

[wiedehopf]

I'll just relink this guide linked earlier in this thread:

https://github.com/wiedehopf/adsb-wiki/wiki/Raspbian-Lite:-ADS-B-receiver

The readsb install script will reconfigure fr24 to use it as a data source.

[abcd567]

I am using following setup for more than a month. There are no issues with the SAW Filter+21 dB Amplifier
My antenna is a magnetic base whip antenna, located indoors.
I live in an urban area in an apartment, so everything is indoors.
AS I am located in an urban area, there are lot of cell/mobile towers nearby, plus strong TV & FM transmissions


Filtered LNA DVB-T RPi.jpgmag-mount whip antenna 1090 mhz.png


skyaware-map.png

[Col@home]

sorry guys you may notice I have just deleted some posts.
I have just run heywatsthat on my pc and not mobile and have been given some completely different distances and it would appear 220nm is my max so it would seem all is good but thanks for your help.
https://www.heywhatsthat.com/?view=A613BRW7

Colin
1090.png

[abcd567]

What is your equipment with which achieved such a good performance?

I could achieve following range with indoor mag-mount antenna and low-cost LNA+SAW filter (photos attached below)

Max Range = 280 nm
Average Range = 200 nm

dump1090-localhost-range-24h-1.png



Filtered LNA DVB-T RPi.jpgmag-mount whip antenna 1090 mhz.png





.

[G4LOH]

I'm a bit confused about what you're trying to achieve range-wise.

Are you looking to climb the FR24 data sharer leader board? https://www.flightradar24.com/share-statistics

Perhaps you might tell me your radar name (and enable data sharing if not already done so?) There will be some clues in that data which will help work out what is happening.

Mine is T-EGHK-8 in the Country GBR listing

Cheers

Tim

[abcd567]

I'm a bit confused about what you're trying to achieve range-wise.

Are you looking to climb the FR24 data sharer leader board? https://www.flightradar24.com/share-statistics

Perhaps you might tell me your radar name (and enable data sharing if not already done so?) There will be some clues in that data which will help work out what is happening.

Mine is T-EGHK-8 in the Country GBR listing

Cheers

Tim

It is not clear from your post if it is addressed to me (abcd567) or Col@home

As far as I am concerned, competition is not at all my objective. The last I looked at "FR24 data sharer leader board" was about 5 years ago.

My objective is, and always was, to reach a low-cost harware-software solution to get a good performance at a cost affordable to most hobbyists.

[G4LOH]

The OP asked about "an LNA to improve his range". I assumed from this that he wanted to get the best possible range at his location which is, primarily, a hardware question.

To get the best range at any location relies on having the best possible antenna and LNA hardware.

No software can ever compensate for imperfect performance of the hardware.

The DVB-T dongles have quite poor performance as weak signal receivers, they have high "Noise Figure" and are extremely vulnerable to strong local signals which most users are never even aware of.

The Noise Figure may be improved with an LNA but very often, adding an LNA exacerbates the strong signal handling problem.

Many of the add-on parts on Ebay will actually make the performance worse. I haven't seen anything on there that might actually optimise the range for anyone.

Col@home, looking at your Heywhatsthat profile you have a pretty good radio location with your radio horizon being < 0.5 degrees in all directions.

A radio horizon of 0.5 degrees will limit the range a little but I would expect 250nm would still be possible. Here I have a radio horizon of 1.2degrees to the North-East and my range never exceeds 220nm in that direction as a result.

Tim

[abcd567]

G4LOH

Our objectives are different.

Your objective is Rolls Royce, Bentley, Jaguar, and Aston Martin
My objective is Ford, Kia, Nissan, and Volkswagon