scanSydney

Just wanted to start some discussion on using TV antennas for scanning.

Successfully using the TV antenna with an RTL-SDR stick - and streaming to http://www.broadcastify.com/listen/feed/15287

Only issue I've really discovered is that the seperate VHF & UHF antennas are directional and pointed to North Sydney. However it seems to have no issue picking up any local UHF. Only on 118.75 I've had issues picking up "Katoomba Base" which is the NPWS Katoomba office - however they're in a pretty poor spot for radios anyway, as they're surrounded nearly entirely by ridges much higher than their antenna mast.

Considering that I should be moving my Uniden 396T to use the TV antenna as SDRSharp suggests I get a better signal for most channels this way. My only concern is the Uniden is a 50ohm system, while the TV antenna is 75ohm. But it hasn't troubled the Uniden for using 75ohm TV coax for many years.

I've ordered a TV splitter amplifier today so I can get more TV antenna outlets - at least this will allow me to plug my TV in again (oops) and run more RTL-SDR sticks simultaneously.

Any thoughts or feedback on any of this?

Geez, are times that tough ?

A decent discone is under $200...

I use the TV aerial for my Horsley Park unitrunker control channel input.
Cant get a good signal on the magnetic base setup but it booms in on the TV aerial, even though it is 90 deg to the antenna direction


Grant

BerryV wrote:Geez, are times that tough ?

A decent discone is under $200...

Scanning doesn't interest me all that much these days. I only listen to my scanner during emergencies/crisis times, and I could do that successfully with the 25cm rubber ducky antenna that came with it. The only advantage for me having a fixed antenna is so other people can stream it via radioreference. Since nobody wants to participate with the costs of this, I'd rather invest a minimal amount of money into it also. But I'm more than happy to take up your suggestion if you pay for the antenna

The setup I have works perfectly fine however I'm looking at ways I can improve it at minimal costs.

I'm far more interested in satellite comms these days and would rather sink money into that hobby.

cartman wrote:I use the TV aerial for my Horsley Park unitrunker control channel input.
Cant get a good signal on the magnetic base setup but it booms in on the TV aerial, even though it is 90 deg to the antenna direction


Grant

Exactly what I'm experiencing with the RTL-SDR. Have a scanning antenna that performs ok, except the TV ant is at a higher elevation and is amplified, so the signal is significantly stronger, despite the tower being 150 deg off the antenna beam and the antenna missing more than half its elements after a wind storm a year ago.

Looking into the impedance mismatch today, apparently I *MAY* experience degraded strength on a 50ohm receiver but what I read suggested that it probably won't be measurable.

http://www.solred.com.ar/lu6etj/tecnicos/En_75.htm
http://www.ham-radio.com/k6sti/match.htm
http://www.antenna-theory.com/basics/impedance.php

Finally got the time to try this the other day... works significantly better than the Mobile One SCATX antenna I was using. The only downside is the introduction of mains hum from the scanners audio which appears to source from the amplifier.

Just watch with using TV antenna amplifiers.I used one once with a AOR1000 & believe it might have caused damage to the receive circuitry in the scanner.
The scanners receive sensitivity decreased over time. Don't get one with too high a gain.

John.