Using C-band or ku-band reflector

[visionman]

As uhf has a "reflector" behind its antenna, has anyone ever tried using a c-band or ku dish to reflect signal into an antenna? Such as placing the uhf antenna at the focal point facing the dish surface?

 

[Trip]

I just got a CM4251 antenna from someone who was giving theirs away, and it operates on the same principle. I don't have it up for testing yet.

- Trip

 

[boba]

The CM4251 was a UHF antenna with a 7' reflector. Most "C" band dishes were 8-10' so it could serve as a reflector. Due to the wave length of VHF Channels 2-13 are probably out of the question. Channels 14-69 could probably be picked up with a 2 bay bow tie if you can mount it at the focal point.

Now how and where do you mount this monsterocity, you need to be a serious hobbiest.

 

[FaT Air]

I just got a CM4251 antenna from someone who was giving theirs away

If they got another, send 'em my way.

 

[kittyhas1000legs]

I'm actually using a 1M ku dish right now for OTA. I have a single bowtie around 6ish inches from the center of the dish. The reflector blocks the massive amount of interference from my apartment (and probably surrounding apartments) in order to get a couple certain channels out of Springfield, MA (I'm in New Britain, CT).

 

[FaT Air]

Think the Ku dish is too small to add any approachable gain if the active element is at the focal point. Think it would be better to place the active element at 1/4 wave from the dish's surface. (spacing same as a yagi reflector) Would also afford better F/B ratio.(??) Maybe put some (yagi) directors 'out front'.(??)
Now if the dish is a 6 to 10 ft BUD, the focal point may be the 'way to go' for a UHF directional antenna.
All the above is IMHO, BTW, haven't 'played' with it.

 

[visionman]

I was a TVRO dealer (BUD) for 18 years. Have some old equipment still laying around. We get a few ota channels but since digital, I've had that urge to see if it could be done. Some interesting ideas posted here. Makes me feel it could be possible. I do wonder what funneling the waves to the focal point would do to that signal. The 1/4 wave from surface might be the better idea though.

 

[Trip]

If they got another, send 'em my way.

He just had the one. He had owned it for 15 years and was getting away with a smaller antenna with success. Now it's mine!

- Trip

 

[FaT Air]

Lucky Dog.

 

[primestar31]

Man, that's an antenna to KILL for!

 

[Cham]

Man, that's an antenna to KILL for!

You could likely build one, parabolic doesn't need to be as accurate as C or especially Ku band, maybe chicken wire or stucco wire with something to support it in a parabolic shape shape... and make up a dual driven element array with reflectors behind them for the feed point. The two driven elements are good to have due to the broadband frequency required for the UHF band TVRO spectrum... maybe each centered to cover the most of the band. Would have to do some antenna modeling to figure out, and build for your area and consider the specific station(s) you want to receive.

Issue would be getting it high enough for a clear shot to the horizon... and you would certainly want to have the assembly aimable (rotator!).

 

[FaT Air]

Around here I think stowable would be a required/nice feature. Think there were many gusts over 60mph last night. Repurpose a beat up 6 to 8 ft mesh BUD?