Re: Radome for Red Rocket LNB Dual Feed?

Barry Chambers


I have a single Rocket LNB coupled up to the dual band feed via a 22mm compression pipe coupler. When you remove the red plastic end of the LNB, saw off the flange at the end of the pipe and slide the pipe into one end of the coupler. Since the LNB pipe outer diameter is about 21mm, it will need some packing to ensure a tight fit. I used a piece of thin brass sheet formed into a deformed circle whose ends were bent slightly to form sharp horns (image a cow's face) and this then grips the LNB pipe tightly, even before you fit the compression joint "olive" and locking nut.

My Rocket LNB has a 25MHz xtal and a PLL chip. As is, it the LNB is tuning about 500kHz low (poor quality xtal in the LNB). I am now locking mine using a LeoBodnar GPS oscillator set to its lowest  output level. The connections to the LNB are shown in the photos. The locking signal to the LNB should be fed via a low-pass filter. A suitable design is given on the BATC QO100 Wiki LNB page. The UKuG Chipbank stocks suitable variable inductors.

Hope this helps.


Barry, G8AGN
On 07/04/2019 08:03, Adrian G4UVZ via Groups.Io wrote:

Assuming that a way can be found to fit the plate feed to the Red Rocket LNB......maybe splitting the two elements in half and bolting together?
Has anyone considered '3D Printing' a Radome?  
Outside of my field of expertise ...not sure what the RF properties are of the various plastic filaments?   but the front window could be very thin?

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