Masthead Pre-amp

[neroon79]

so would a digital tv masthead amp work? 32db gain unit with f type connectors, i know the freq only goes to 860mhz but should still boost the signal?

You gave the answer by yourself: The amp is designed frequencies up to 860MHz. Above this frequencies amps usually going relatively quick from amplification to attenuation. Further these amps usually allowing a higher Signal noise than the amps specially designed for our needs (high gain, narrow bandwidth, low noise, Installation in the "wild weather"). Further the CA-TV or SAT-TV amps are designed for Signal-Modulation-Types, which may cause additional negative effects too.

EDIT: I just forgot: TV has an Cable-Wave-Resistance of 75Ohm, RB and the 1090MHz Antennas using 50Ohm. Connecting 50Ohm to 75Ohm will produce reflections and interferences, which both are very bad for the Signal you want to receive.

Short:Better you keep your hands off from such experiments. ;-)

[jaskel]

ROGER THAT THANKS FOR THE INFO, I CANT SEEM TO FIND A AMP UNDER 150 AUD damn caps lock..sorry.

Anyone know where to get one at a decent price?

[CoastGuardJon]

Hi Jaskel, as stated on your other post a pre-amp will only boost signals , so are best used to overcome losses on a long co-ax run.

[MW0CVW]

Hello,

I must comment on the general electrical and mechanicial construction of the ELAD mast head amplifier and bias tree was poor.

The first unit received from W&S was faulty which was returned and replaced.

The second unit worked for about two weeks then failed.

I returned this back to W@S for a full refund.

The system has now been replaced with the Kuhne LNA 1090MHZ mast head amplifier and bias tree.

This system has a better noise figure then the Elad and additional band pass filtering on the pre-amplifier antenna input, so out of band signals (1090mhz) will not  be amplified and reduce amplifier performance.

Kuhne also added some additional static protection on the amplifier RF stages and advised an antenna with  DC ground would be the preferred option.

far better mechanical construction for outside applications.

I have posted polar diagram showing my coverage using the SSJ 1090MHZ antenna system.

Hope you find these comments helpful.

Kind Regards

Paul

MW0CVW

EGGP/EGNR

[Dana]

Hi everybody,
After trying the JIM M75 amp without success I ordered a KU LNA 1090 A TM amplifier.
I have a question regarding the length of coaxial cable between antenna and amplifier….which is the optimal length ? I read that the usually length is 1m , is a problem if the length is shorter or a bit longer ? Also I would like to know if the type of coaxial cable used between the antenna and amplifier have to be the same type with the coaxial used between amplifier and power supply or I can use also other type of 50 Ohm low loss coax ? I am afraid that the length of cable that I bought is not longer enough to use it also between amplifier and antenna.
Thank you very much

[nortonbeak]

From antenna to pre-amp the cable needs to be as short as possible without putting any strain on to the connectors. About one metre ought to be sufficient. A high quality low loss cable should be used.

[MW0CVW]

Dana,

I am not surprised the performance to the Jim 75 amplifier was poor as this is a broadband amplifier with high noise figure.

The KU LNA 1090 which is be signed for mast antenna mounting, and with the bias tree located at the bottom of the coax you can power the LNA via the coax cable NO ADDITIONAL WIRES FOR POWER (12V) REQUIRED.

Buy the best coax possible LMR 400 (15m) or Echo Flex cable run from the LNA to the Airnav receiver is 15 meters.

LMR 400 from the antenna (SSJ) to the KU 1090 LNA amplifier.

This cable length is about 1.5 meters which includes a drip loop and N-type connectors rubber covers to stop any moisture ingress via the coax into the RF Connectors.

Don't have to be to critical on cable length above within a couple of meters will be fine.

The LNA small bandwidth good gain and low noise figure will improve your reception and take coax cable losses of signal into account.

Hope this information helps you out.

Regards

Paul

mw0cvw

EGGP/EGNR

[Dana]

thanks guys :)

[Dana]

Hi,

   I just installed a KU LNA 1090 pre-amp and unfortunately I noticed a important loss of signal then before without pre-amp, shorter distance and less contacts with about 10-15%. I am using  10 m of Ecoflex 10 and GP1090 antenna outside about 17m high no obstacles around . Can anyone give me an explanation for that less contacts , please ?
Thank you.

[Budgie]

I had this initially with a second hand pre-amp and in my case it turned out to be the power supply.
The bias-tee needed centre + supply but the one supplied was centre -
So just check that you have the correct type of power supply for it. 

[Dana]

I don't use any bias-tee, I feed the amplifier with direct power supply 12V as KU LNA 1020 allow it as an alternative instead to use a bias-tee.

[jaskel]

sounds like the supply u feed your amp is dead!

[nortonbeak]

sounds like the supply u feed your amp is dead!

... or wrong polarity ?

[neroon79]

Did you buy KU LNA BB 1020 A or the KU LNA 1090 A TM. The last one is a specially designed for narrow-bandwidth ultra low noise Amp for ADS-B signals, as the other Amplifier is a wide-bandwidth Amp with a higher noise figure and no out of band suppression.

[Dana]

I am using a KU LNA 1090 A TM . The polarity is right one.....All connectors are O.K.  So, I have no explanation for loss signal using pre-amp:(.
Maybe  the short lenght of coaxial cable ( 10m Ecoflex 10) to be the reason?