Invacom LNBFs?

[Lone Gunman]

I recently picked up an old Janiel Junion 6 ft SOLID aluminum dish and polarmount. It has been sitting for a very long time and the scaler ring is corroded and bolts are rusted and a couple wrung off when I tried to remove them.

What I want is to use an Invacom LNBF on this primarily for Ku and some C stuff along with having the capability of receiving circular stuff too.

So I've been looking at both the QPF-031 and QPH-031 and I bought of of those adapters to mount an Invacom on with the 40mm clamp.

So which one of these two LNBFs is suppose to work with this dish/mount?

Does either need that scaler ring that the bolts broke off in?

Here is a picture of what I have to work with.

Thanks

 

[gabshere]

with what i can see of your setup , your dish is a prime focus dish and would need a lnbf that is also primefocus ( that counts the QPH-031 out) the qpf-031 is usually bought with their scaler ring and would probably need the adaptor plate sold by most FTA dealers for a prime focus dish.

other options you can consider , depending if your trying for c band also cause the qpf & qph are quad ku lnb & lnbf other options are the 741 and the 621 c & ku

your setup looks like it has a support arm ring with a scaler ring attached to that . use some penetrating oil ( i like PB Blaster) on it and wire brush.

now with all that said ... you can hook up a qph-031 to a prime focus dish just you will lose some signal quality

 

[Lone Gunman]

with what i can see of your setup , your dish is a prime focus dish and would need a lnbf that is also primefocus ( that counts the QPH-031 out) the qpf-031 is usually bought with their scaler ring and would probably need the adaptor plate sold by most FTA dealers for a prime focus dish.

other options you can consider , depending if your trying for c band also cause the qpf & qph are quad ku lnb & lnbf other options are the 741 and the 621 c & ku

your setup looks like it has a support arm ring with a scaler ring attached to that . use some penetrating oil ( i like PB Blaster) on it and wire brush.

now with all that said ... you can hook up a qph-031 to a prime focus dish just you will lose some signal quality

The penetrating oil didn't do much as two of the three broke off in the scaler ring. If needed I can probably save it though as I got a milling machine in my shop. So right now there's no scaler ring on that mount.

Had though about the 741 but it won't do circular and I can hit 40.5W. Don't know anything about the 621 but can find out.

I see the QPF-031s are a bit higher than the QPHs is the reason I was asking. Fleabay has the QPHs for less than $60 but the QPFs are over a C note. That and I've see some kind of what appears to be an extension tube/scaler ring assembly that goes for another $25+? Is that part needed for the QPF or can I just use the adapter bracket I bought?

 

[Anole]

I can't see birds that far east, so pardon my confusion.

However, 40°w bird is circular C-band.
The Ck1 and DMX741 can do circular C-band with the dielectric insert.
Whether a 6' dish is large enough, I couldn't say.
However, if you rig an LNBF for circular, it's not optimized for linear.
So you either need two Siamese twin LNBFs, or another solution.

Getting a Ck-1 or DMX741 to perform well on KU, on a prime focus dish, will require very careful alignment.
Also, due to the limited field of view, it won't see the entire dish.
So an alternative would be a better choice if maximum signal is a requirement.
The simple GeoSatPro SL1P would perform better.

Yes, the QPF-031 (F=Flange to attach to a feedhorn, H=includes feed Horn) is matched to the prime focus dish with an AF-120 feedhorn, which sells for about $25.
But, if you mount the QPF-031 at the dish's focus, then it's Ku-only.

Lastly, I'm not seeing a lot of use for circular Ku these days...

Might want to rethink or re-describe the goals, and we can maybe come up with ideas more matched to your needs. -

 

[Lone Gunman]

Thanks for your reply.

Although I've had a 10 ft BUD since 1988 I'm a little bit ignorant about this FTA/DVB stuff and mainly depend on others that are "in the know" for advice/guidance on what to get so you'll have to bear with me.

As far as goals go, I want it all on one dish. While I realize that this 6 footer won't get all the Cband stuff that's up there, some guys say it will get some of it. I'll still have a 10 or 12 foot mesh dish and my GI920 as a mover for that.

The 6 footer will start out with an old Echostar 7000 receiver that I originally got with my BUD in 88 as a dish mover only. Later on will probably migrate to something different to move the dish but to begin with I can use the Echostar as a dish mover with the FTA AZBox slaved to it or just connected to the coax by itself. Have to wait to see how that turns out. Using an LNBF will also eliminate the need for polarity changes by the receiver, which is a few less wires to run.

The reason for circular is that sometimes there's ITC feeds on some sats that are primarily circular, ie, 40.5W and a few others. Had a couple of guys recommend that Invacom on another board but gave few specific reasons for that choice other than it's a good unit.

So far the only thing I've bought for this 6 footer is the adapter ring to hold the LNBF but after looking at the Cband LNB that came off that thing I may need that LNBF scaler ring extension thingie to get the focal depth right.

So yeah, any suggestions you got, I'm all ears so let'r fly! And I do like to hear opinions from others as well.