Ireland

[Mark07]

Interesting comments from Mark at Rocket Radio and ones that make sense.  You either have success with a pre-amp or you don't.  

I have a question for you then Mark.  I currently run 20 m of Westflex from the pre-amp to the bias-T.  In terms of range if I were to cut the distance to my radarbox by 50-70% and make that a run of 7-10m coax would I see a 'significant' increase in flights and distance?

Many Thanks,
Mark

[Fenris]

I have a question for you then Mark.  I currently run 20 m of Westflex from the pre-amp to the bias-T.  In terms of range if I were to cut the distance to my radarbox by 50-70% and make that a run of 7-10m coax would I see a 'significant' increase in flights and distance?

Westflex 103 is about 1.3dB per 10m, so halving the run would decrease the loss by 1.3dB.

Since the NF and gain of the preamp remains the same, as does the RB sensitivity, a quick cascaded NF calculation suggests that the system NF would reduce by 0.1dB. That is effectively below the level at which you could measure the effect.

[CoastGuardJon]

Hi Brian, keep the technical stuff coming, but keep it as simple as possible for us less technically able - I'm planning on getting all my antennas outside later in the year - looking at buying a Diamond D-777 and VX-4000, plus a radar extender http://www.radioworld.co.uk/~radio/catalog/radarextender-external-antenna-radarbox-p-5965.html?osCsid=67c910deb8541fefea3256a3ea9dd2ef , to add to the collection.   I am/was planning to fit a mast-head amp. to the radar extender, and also have a Jim-M75 just inside the loft, where downleads come in, terminate each downlead with N-plugs for ease and speed of connecting/disconnecting for comparison and experimentation.   Certainly, with analogue signals at least, I've had results in the past, which contradict the theories sometimes, but this digital stuff does seem to be a rather different kettle of fish!

[30682g]

Planning on buying an external what would one recommend. I am looking at the Radar Extender -v- the Radar Rama which one is recommend. Hope someone can help - thanks - Mick

[Fenris]

Planning on buying an external what would one recommend. I am looking at the Radar Extender -v- the Radar Rama which one is recommend. Hope someone can help - thanks - Mick

I have bought a RadarRama, but not yet erected it.

The two are roughly comparable, note that the gain of the larger antenna is achieved by narrowing the vertical radiation pattern (so the "doughnut" shape of the 3D radiation pattern is thinner but of a larger outer diameter) which means it is a little more optimised for the horizontal and so less good at receiving signals that are at an angle above the horizon. How big this effect is I can't say for sure. It's probably not that large, but will be affected by the surroundings, so that's another reason to get the antenna clear of local obstructions if you can.

The Radar Extender is quite big and more conspicuous, that might be important if your neighbours are a bit awkward and don't like what they perceive as visual "blights" on their view!

[30682g]

Thanks Brian. one could chance putting the extender in the loft. I have a two storey house. By placing the RB antenna supplied out on the upstairs window I am recieving flights over Swansea(I am in North Cork). By placing the extender in the loft will probally give me the same maybe better results. I have several antenna's outside at the moment for radio - there will be war if more go up i could get my walking papers. thanks for the advice. I can get the Radar Rama + connectors to the door from uk for €60. I was just checking before making the purchase. All the best - Mick

[robbieinderry]

Hi Robbie,
Good to see another user in Ireland.  You should get good coverage across into Scotland from where you are.  I pick up the Ryanair flights into Derry on a regualr basis from my location both on Radar and Airband radio.

Cheers
Mark

thanks mark,over the moon with the airnav box,when i connect to my laptop outdoors its magic love it,two questions i am up at a good height line of sight is good, i am thinking of getting a outdoor aerial,what do you recommend and
what coax is best ,thanks roobbie

[viking9]

Mark,

Let us see a screenshot of your polar diagram. If you are in a really good position you may just need to try your whip antenna on a pole outside. If that gives better coverage then you may be better off buying an inexpensive antenna.

Tom