JIM m-75 Pre-Amp

[steveb25]

Hi all

Is anybody using a JIM M-75 preamp on the airnav box.

Would appreciate any info that you have, i.e what connections did you need 2 x addaptors etc

Thanks

Steve

[Dec]

Hi Steve,

I was using a JIM m75 pre-amp with a SBS-1 until I got the Radarbox, and there was some improvement,
However there has been some talk on the forum from time to time about pre-amps, and the fact that they amplify
the things you don't want (noise),
I think its up to the individual user at the end of the day, if the end result works for you then happy days,

I myself have not tried the Jim m75 pre-amp with the Radar box yet, but I will eventually,
the connectors you will need are widely available on the net for a couple of quid, try Ebay or maplins and there is many more,
the connectors are,  SMA Male to BNC Female Adapter this is fitted between the pre-amp and radarbox,
and SMA Female TO BNC Male Adaptor, this is fitted between your antenna and the pre-amp,


Hope this is of some help,

Regards Dec.

[Roadrunner]

However there has been some talk on the forum from time to time about pre-amps, and the fact that they amplify
the things you don't want (noise),
I think its up to the individual user at the end of the day, if the end result works for you then happy days

It is only wide band pre-amps that will cause unwanted noise, one dedicated to the 1090 Mhz frequency of RB should be fine, only problem is these dedicated pre-amps are a little pricey :-(

[steveb25]

Thanks for the info guys

I think getting my AE higher in the first place might help to start with

[Edwards]

Hi Steve,

I am using a Jim M-75 Pre-amp with my radarbox. I find it works quite well. It certainly raises the message rate by another 30-50 messages a second on average. It has some limited filtering by means of selecting 3 bands but these bands are quite wide and its not great as you can't specifically set 1090mhz.

The best thing to do before considering using one is to ensure that you have an antenna with high gain specifically tuned for 1090mhz and as you say ensure its as high as possible as raising it above obstructions makes a dramatic difference and will certainly increase performance a lot more than a pre-amp can.

Im using the MyDel BS1100 kit with the AS1105 High gain whip. I have found this antenna to work relatively well with the Jim Preamp. Ensuring the antenna is away from electical noise sources such as computers and electric heaters also helps, especially when using a pre-amp. As roadrunner and Dec say the preamp can increase this noise too resulting in no overall improvement.

Hope this helps.

Edwards

[steveb25]

Thanks Edward

Just doing a little bit of experimenting at the moment.

As usual my problem is getting the AE high enough. Notice that by just raising it a few feet, it increased the range out to the west by between 10-15 miles.

Next step the roof!!!