Supplied RB antenna

[oceans777]

So after trying my new RB 2009 with a very expensive Dressler active antenna (ARA2000HDX) for a week and not getting the results I'd expect, my wife said "Why don't you just try the one it came with, up on the roof?"

Don't be ridiculous, I scoffed, there is way too much cable loss and just to show her how silly her idea was I climbed up and attached the little RB antenna directly to my 60 feet of LMR-400 coax.

"Wow, is 300 messages any better?" she said as I came back in. Sure enough, no amp, no monolithic, low noise voodoo with diplexer and attenuation control, blah blah blah, the little RB whip even with two adapters temporarily installed at the antenna side, it is easily outperforming the Dressler.

It can finally see aircraft at much lower altitudes - the Dressler never saw anything until it reached at least FL10. Range is not drastically improved but is better. With high mountains all around, much better than I expected. There are many more messages now too - I was averaging 80-90 before, today it was up around 250-300 for many hours.

Makes it  harder for me to justify the ADS-B antenna and amp I'll probably buy later but the results are amazing so far...

[tarbat]

But the ARA2000HDX is not specifically tuned to 1090MHz, it's a general purpose 50-2000MHz active antenna.  I would expect that to perform very badly for 1090MHz use.

[Storm]

the little RB whip even with two adapters temporarily installed at the antenna side

WOW!!! I'd like to try that, what kind of adapters do I need to connect it to my 12 meter ecoflex?

Thanks.

[flightchecker]

Makes it  harder for me to justify the ADS-B antenna and amp I'll probably buy later but the results are amazing so far...

As tarbat already says, the ARA2000HDX is a "broadband", not a "tuned" antenna as are
antennas (AND !!! preamplifiers) designed for ADS-B applications.
The ARA2000HDX will (by its specs) receive a wide spectrum of signals, even amplifies all of them, thus finally leading to an "overdriven" receiver input, (that, by its circuitry, only expects the rather narrow [and small] ADS-B signal spectrum) and the receiver finally appears to be insensitive.
An "ADS-B antenna" (whilst tuned) and a "suited" preamp (by its filtering behavior) will prevent the above.
 
Problems though may arise if an aircraft appears to be very close to the receiving antenna / preamp setup, as the (relativly high) fieldstrenght generated by a transponder under this circumstances might have the same effect as described before.

Regards


Karl

[oceans777]

Yes that is exactly correct - the difference is clearly in eliminating the broaband aspect. I was just surprised the little antenna did so well. The ARA did ok actually - ranged out to about 130 miles but I look forward to using an ADS-B specific pre-amp and antenna soon. 
I  did think the attenuation of the 60 foot LMR-400, though relatively low, along with having to use adapters would yield far worse performance than it actually is.

[oceans777]

Storm,

I think you would need a female N-connector to a female SMA connector at the antenna, that is assuming the antenna end of your Ecoflex is an N-connector. Your Ecoflex has slightly higher loss I think than LMR-400 or about the same so you would be using half the distance I am - should get decent results!

Should look like this:

[CoastGuardJon]

As a matter of interest, I recently bought an ICOM IC-R7000 and a Dressler ARA 1500 from a work mate (her late father's, been sat collecting dust for 18 years).   No PSU for the Dressler, but decided to risk 12v+ to the 3.5 connector tip, immediate 20+db increase on the S-meter, but it isn't anything like as clean to listen to as my Royal 7000 discone, this with both antennas in the loft.    A good exterior twig with masthead amp has to be the way to go.   I've never noticed hugely different improvements with reception aerials, just the higher the better, but for transmitting it's a whole different ball game, the antenna must be closely tuned to the frequency, or the actual amount of signal radiating from the antenna can be minimal (VSWR).    If you've got other, very strong RF signals close by, then the closer an antenna is tuned or trapped to the desired signal the better.

[oceans777]

I have Dressler ARA-100 HDX and the 2000, both have been a big disappointment. The100 HDX is easily outperformed by a wire hanging from a window and any discone will significantly outperform my ARA2000 across the range.
We've tried them in quieter RF environments and noisier - nothing seems to coax anything near the performance they claim.

They can run the signal meter off   the scale but ours just overload or the reception is so noisy it's of no use. Evern the AOR AR5000A+3 and Icom IC-R8500 won't handle them.

[oceans777]

Jon,

I don't know what the ARA1500 power rating is (actually didnt know there was an ARA 1500!) but both of mine just use 12-13.5v, center tip positive and the psu's are regulated, 1000 mA. My understanding is the amp only uses 100 to 300 mA but is rated up to 1000. The actual diplexer says "250 mA max" on it, so that's odd but tried it with several 250 mA psu's - no difference really.

I'll shut up about Dressler now since this is the RB forum.

[CoastGuardJon]

Hi oceans777, thanks for the info, it all seems to be working OK, but I don't find it as useful a signal source as the spoked discone with base loaded vertical.   The Dressler ARA-1500 is long obsolete, designed for use up to 1500Mhz, and they were rather expensive - the active and aerial part is a white plastic tube 50cm long and 9cm diameter.   Although this is an RB site, I'm sure no-one will mind a discussion on antennas, I'll be trying all and everything with my Christmas prezzie (an RB!) and will post results.    In the short time I've been using this site, I've found AN support and all forum members very helpful and tolerant, even to constructive criticism which is taken on board, without topics being locked down!   But, I'm sorry if you feel I've hijacked your thread - not my intention!

[oceans777]

Hey not feeling hijacked at all - glad to hear from another Dressler user -  you're the only other person I've heard from who has one!
I too am experimenting with antennas until I can afford a proper ADS-B setup, so the forum has been a huge help and source of info.
I'm glad it's not restrictive or locked down like many are.

Look forward to hearing your results!

[Storm]

Thanks oceans!