BSC 621 issues

[gabshere]

Joe it sounds like a busy time hopefully it wont disturb the wife & her hand.
i'm trying to think of everything , i re read everything you have one thing i can note thats different on my setup is i'm not using the internal 22k switch i'm just running two coaxes. but like you I have two satellites set up for g10 one for ku and one for c band.

when i work on all my dishes i set up out at the dish and run short cables so i can move the dish and watch the signal levels on my coolsat with a live transponder. the reason i do it this way is you can make on the spot corrections , small adjustments and lock down a good signal.

now 1/8 isn't much but touching is desired..

1/4 ' off on the scaler was this just to the scaler or to inside the feedhorn.
and as long as you feel the scaler is centered and equal lenghts that should be ok

this is the main point to try
70% on c band dvb channel ?? on G10 your signals should be in the 90's
ok i suspect that the dish is slightly off (and if its off a bit you won't get ku signals) so while you have 70 readings on a channel ?? (see if you got the outdoor channel 4181H i get 96 signal & 97 Quality) you need to push or pull on a side while someone can watch the signal meter on the receiver.remember small incraments up to 1 inch movement at the most. If this doesn't improve your signal you need to goto the bottom of the dish and slightly lift up or push down to see if you gain any signal. unless you have your setup out at the dish it will require two people. I suspect you will have to raise or lower you elevation a bit. once you have gotten your c band signal levels up in the 90's peeked best you can then you should try to switch to ku.

if you can't obtain higher signals then a adjustment or more adjustment on the scaler & feedhorn are in order.

hopefully this will help. it only seems hard i love working on these old dishes.
this is the hand crank dish right? hopefully this will get it tuned in and you can really start enjoying this dish

 

[kb2kir]

Gabs,
Thanks for the info, I'm off to the hospital with the wife (7am here), so more later.
Joe

 

[MrTim]

I beg to differ on the multiple focal point theory. The more logical is the onion theory.

A parabolic reflector reflects everything that bounces off it to one focal point. It's not frequency dependant.

Your correct, the focal point is not frequency dependant, however the reflection follows a path that narrows as distance increases. Positioning the opening of the waveguide at the optimum distance improves it's signal gathering capabilities.

 

[MrTim]

I am not an average Joe on satellite. I have been in the hobby for at least 15 years plus.

No, I certainly didn't mean to come off that way and I apologize if it sounded that way. I just wanted to make sure you had the information we provide, because we do recognize the Ku LNBF can easily be out of polarity alignment.

 

[colbec]

As one who is trying to follow the arguments here, I am finding that my thinking comes back to the nature of the onion we are using as an example.

Strictly, an onion is a bulb with leaves growing outwards from a basal plate. As such it is quite possible to imagine multiple focal points with the last one at the highest frequencies at the apex of the reflected rays since the layers of the onion are not concentric. The picture in Mr Tim's illustration would be in accord with such an approach, and we are still talking about an onion theory.

If we are speaking less of an onion and more of a (forgive the example, comes from my childhood somewhere) a gobstopper (it's a large candy, built up layer on layer evenly on all sides), then all the spheres are concentric. For this to happen there must be some effect produced inside the feedhorn that would narrow the focus more rapidly than it would naturally.

 

[caddata]

...a bulb with leaves growing outwards from a basal plate...

To explain further in respect to an onion, the focused electromagnetic waves (microwaves) are in a sphere at the focal point. Within that sphere, as in layers of an onion, are the higher frequencies towards the center and lower frequencies towards the outside. Of course, the collected electrical energy is oriented vertical, horizontal, and circular (left and right) depending on the transmitting antenna orientation.

The "onion" we're looking for is the C band onion, and we want it to be just inside the mouth of the waveguide. The wave guide will be a resonate cavity for 3.7 to 4.2 Ghz. Once inside the resonate cavity, the C band signal seeks the C band antenna to go to ground. The Ku signals, still inside the C band resonate cavity seek the Ku resonate cavity. Once inside the Ku resonate cavity, the signals seek the Ku antenna to go to ground.

Harold

 

[ftarock]

MrTim,
No offend taken. Please excuse me if my post sounds offended to you. A combo C and Ku lnbf is a great idea, no doubt about that. I am also glad that it's a success of your company. Now if you can make C-band lnbf for offset, that will be another hot product...
Thanks

No, I certainly didn't mean to come off that way and I apologize if it sounded that way. I just wanted to make sure you had the information we provide, because we do recognize the Ku LNBF can easily be out of polarity alignment.

 

[Anole]

no kidding!

Now if you can make C-band lnbf for offset, that will be another hot product.

...or if all it requires is just a cone-shaped scaler ring, how 'bout offering that for $10?
Would certainly enhance the sales of the BSC621 family.

 

[scottc98]

Cone-shaped scaler ring is a must for the offset

Anole,

Just to update on my mod thread....no new updated or additional mods yet. Shift at work changes and has ruined my sat time outside. Inside....its still great! Been streaming Tribe games (STO) and EPSNNEWS (COX SPORTS TV) to myself at work Just got the Jones networks off AMC 8 going today. Just need to find a way to send multiple PIDS via DVBDREAM.

MrTim,

Great product IMO! WHile I agree that you may never get the sig quality that a C/KU feedhorn will give, it does provide a cheap solution for us "small" dish users I would highly recommend getting the conical scalar rings for your company. That is probably the one thing stoping people from getting into the Minibud project. Plus, a 1.5 or 1.8 offset would still be great for Cband.

I do sacrafice some KU signal, but I am use to 45-65 quality on most channels before I got my 120cm, so no biggie. 75% of my FTA surfing is now Cband anyways

 

[kb2kir]

Guys,
Got it working!!! Sort of...... Changed to Ia-6, separate cables, peeked dish on C-band and adjusted first the skew on C-band then loosened the nut on the Ku section and peeked the skew for it. Re-peeked the dish. Repeated.
I now have 87-90% on the C side and 63-66 on the Ku. I find 63 too low, (picture pixels out) but sometimes it rises to 66 and then it works.
more tuning and tweaking. Will play more tomorrow.
Oh, the Wife says thank you for your concern, it is rare that strangers wish others well. Nice bunch of fellows!!
She's doing well, the procedure took 25 minutes and she was stoned for 1 hour afterward. She's funny when she comes out of the anesthesia.
Joe

 

[kb2kir]

Ahha! I did a calculation on the focal point and found as I had suspected, the goons that set up the dish originally, had the scalar ring to dish distance off by
1.5" !!!
I re-adjusted for the formula derived measurement and VIOLA!! another 2 points of signal strength on C.
THis, however degraded the Ku to 25% signal. Raining now so more later...

 

[voomvoom]

I would suspect the Rain for the degradation of the ku signal. Wait till the rain stops and see if it doesn't improve. C is much more leanient than ku, when it comes to Rain. About as different as night and day?

Al

 

[Anole]

Okay, here's a test suggestion.
I realize not everyone can easily do it, nor will want to, but let's discuss it, nevertheless.

Pick one or more weak Ku bird/transponder pair for these tests, and stick with it/them.
By weak, I just mean one that's maybe 50% of the best you can get.
No need to look for one down around 20% for the first try, but you might repeat the test with a 20-30% if you want to.
Record your results so we can learn from your findings.

So you don't like the received quality on the BSC621 LNB, mounted on your BUD, when looking at a Ku signal?
Now, let's say you were to remove the '621, and replace it with a nominal 0.6db stock Ku-only LNB.
No fair using a hot LNB, as the point is to use one of modest performance.

Because the Ku-only LNB is optimized for a F/D like you'd find on an offset dish, it will only see the middle of your BUD, and should perform accordingly.
If you have an 8' BUD, maybe the LNB will see just a few feet in the middle of the dish.
Move that LNB in and out, and round-about, and record the signal quality you can obtain when peaked.
Now you have a base-line to shoot for when you put the '621 back on your BUD.
With the BSC621 installed and optimized properly, shouldn't it blow away the Ku-only LNB?
The '621 should be getting signal reflected from the entire BUD, if properly illuminated, so that's its secret weapon.

What sort of quality did that same Ku-only LNB achieve on your 30-40" dish when looking at the same weak bird?
If it got a much hotter signal, does that suggest the BUD is not performing well at Ku ?

Optional test: how does the '621 perform on Ku, when mounted on your 30-40" dish?

 

[colbec]

Here are some different data points in the BSC621-2 discussion. I just took delivery of a unit and have been testing it.

Mostly C-Band is identical to other reception on the same dish. Ku is different.

Here is my test apparatus: 6 foot Kaul dish on Von Weise actuator driven by a PC2000 analog receiver.
Coolsat 6000 receiver.
Dish is carefully measured for fd and f/d. No warp, mesh is smooth and regular.
I just use the analog receiver for push/pull and use the digital receiver to see what quality signal is coming in.
The two receivers are not slaved one to the other.

Example: using AMC-5

Test 1:
Using Digiwave universal lnb DGU-03U (just stuck into the scalar ring where it will stay put.)

11.740 V comes in at 87% SQ
12.184 H comes in at 66% SQ

That 66% is pretty good for my location, that is what I get on a tuned 36" Fortec with the same lnb.

Now change only the lnb, replace with BSC621-2. Tuning is approximate, still waiting on my signal meter:

11.740 V comes in at 87% SQ
12.184 H comes in at 5% SQ

5% means no picture, not even macroblocking. Various efforts to reposition the lnb in the scalar ring have no effect.

Aha! Theory #1: what about FEC?
Hypothesis 1: FEC(11.740 V) different from FEC(12.184 H)
Failed: 3/4 = 3/4.

Aha! Theory #2: anybody?

 

[colbec]

Adjustment

In answer to my own post 34 the solution appears to be quite simply adjustment of the lnb. I am now getting identical results from the BSC621-2 and the dedicated Ku band universal on the same dish.

As a point of reference, with the scalar ring positioned accurately at the FD, the plastic cover of the mouth of the lnb is exactly flush with the tops of the fins of the scalar ring.

I am now even less trusting of the Coolsat meter, which does not seem to be linear at all.

 

[Anole]

Since my post above, it has come to my attention that the F/D ratio of "the other" C/Ku dual-band LNB, is 0.6
If due to the mechanical design, the same is true of the 621, that could account for the Ku performance.
The Ku LNB just doesn't see the entire dish.


I'd always been baffled at why a 6, 8, or 10-foot dish couldn't outperform a 1m Primestar, or Fortec.

 

[kb2kir]

Anole How goes it?
I haven't played with it lately, I was intent on getting G10r with the GI commercial dish.
If you didn't read my post, I changed to an SNH 031 and played with the location. Now have 94% on strong x-ponders, and 79% on the weaker ones.
When I get back from the CGS Hawk owners fly-in in Ohio labor day weekend I am going to get the boss's auger and plant the C-bander. But due to trees I must pick a bird to lock it on and that's where it will stay.
Any suggetions??

 

[voomvoom]

I'd always been baffled at why a 6, 8, or 10-foot dish couldn't outperform a 1m Primestar, or Fortec.

That may be a matter of opinion. I've notice, and I'm refering to a 10' mesh as oposed to a 1.2m solid ku dish, that the 1.2m will blow the mesh away when it comes to signal strength. However, it won't blow it out of the water, if the rain gets hard enough. I've seen the 1.2m dish lose the signal, but I've never had the 10' mesh lose the signal from rain. It will get lower, but it's still there. Now the wind is a different factor. The 1.2m rarely is affected by wind, while the 10' mesh will definitely become a pain with a strong wind. I too am baffled, but the larger dishes have there moments.

Al

 

[scottc98]

That may be a matter of opinion. I've notice, and I'm refering to a 10' mesh as oposed to a 1.2m solid ku dish, that the 1.2m will blow the mesh away when it comes to signal strength. However, it won't blow it out of the water, if the rain gets hard enough. I've seen the 1.2m dish lose the signal, but I've never had the 10' mesh lose the signal from rain. It will get lower, but it's still there. Now the wind is a different factor. The 1.2m rarely is affected by wind, while the 10' mesh will definitely become a pain with a strong wind. I too am baffled, but the larger dishes have there moments.

Al

I wonder if the difference it due to mesh vs solid and not size? Widn will affect the solid dish more than the mesh . Of course, weight would come into factor there too. Maybe rain isn't as bad on a mesh.

what would be nice is to see a comparison between a 1.2m solid and 1.2m mesh (if they make one) for ku performance

 

[Anole]

I had hoped to get my hands on a 6-foot, Ku, solid, transmit-class, offset-fed dish by now.
One that's at home with .6 to .7 F/D LNBs.

Then, compare the BSC621 or GeoSat CK1, to stock/cheap/average Ku only LNBs.
(and maybe an Invacom, just for good measure)
Though, I'm not sure what bird you'd have to aim at to get a weak enough test signal for the 6' dish.
Maybe some unencrypted 7/8 FEC might help (?)

If rain were a requirement, I'd have to run the test for 365 days to accumulate even an inadequate bit of data.