Kaul 6.5

[colbec]

In an earlier thread (Adventures while dish hunting) I mentioned a dish I had retrieved but had no pics since camera was dead. Here is an update.

The dish is a Kaul-tronics 6.5 foot. This is a bit puzzling, I see all kinds of references to the Kaul 7.5 but not a 6.5.

Some details:

Diameter 78", depth 12", focal distance 31.7", f/D is 0.406
Strings cross perfectly in the middle, no warp
Mesh is Ku compatible

While setting up I was having a hard time since I did not have my lnbf correctly oriented in the scalar ring for vertical polarity. The skew markings on the lnb case were evidently for H polarity. In order to find my south satellite I just swapped a Ku band lnb into the scalar ring and had no problem finding signals at 94% plus. No question this dish will get Ku!

Initial C-Band results good. Somewhat more sensitive to rain fade than the Channel Master 10 foot on the same bird which was expected, but generally pulls in a very decent signal. More experiments later when I have replaced the actuator with a good threaded rod system.

 

[linuxman]

Nice looking dish Colbec!!

With it being only a 6.5 footer, you may have some problems with some signals.

It is a pretty flat dish with a .40 F/D ratio though, it should give you some nice gain.

Good find!

Fred

 

[mikekohl]

I have one of those KTI antennas of the same size, parked on 139 West
for monitoring any MPEG-2 audio channels that might be there.
Used an ADL RP-1 C-band feed, with polarizer, to minimize sidelobe issues
on such a small antenna. Interesting thing is that the audio signals on
139 are much stronger than any nearby video MPEG-2 from 137, so despite
the small size of the antenna, it works. Since this thing is over 30 feet in the air,
I would rather not have anything larger!

 

[tvropro]

I have one of those KTI antennas of the same size, parked on 139 West
for monitoring any MPEG-2 audio channels that might be there.
Used an ADL RP-1 C-band feed, with polarizer, to minimize sidelobe issues
on such a small antenna. Interesting thing is that the audio signals on
139 are much stronger than any nearby video MPEG-2 from 137, so despite
the small size of the antenna, it works. Since this thing is over 30 feet in the air,
I would rather not have anything larger!

So your saying the ADL RP-1 C band feed plays better than the Chaparral for adjacent satellite rejection. Interesting, I have one on my 12 foot dish and always like it's performance. I have a Chaparral PR 1 A/S in a box from years ago and always wondered if it would work better than the ADL.

 

[mikekohl]

WHEN they were available, the RP-1 series of feedhorns from ADL was much better than Chaparral in performance. I can honestly say that I have never had a situation in which the proper model of ADL feed (RP-1 or RP-2) could not make a significant improvement over an existing installation with a Chaparral.

What I did find in my many years with Orbitron was that many satellite dealers had no clue about properly installing feedhorns. An adjustable scalar such as the Chaparral PR1E, Corotor 2 or ADL RP-3 might allow them to get away with breaking the rules, but when using a FIXED non-adjustable feed such as the
ADL RP-1 and RP-2, many complained about poor results. Rule number one is
to set the F/D ratio on your feed for the antenna being used. In the case of the
RP-1 or RP-2, that was non adjustable. The RP-1 was designed for 0.335 to 0.425 f/d ratios, with the RP-2 specializing in 0.275 to 0.335. It was also about 7/8 inch thicker in the feed plate, so that had to be compensated for. The next step is to
install and adjust the focal length properly. The Orbitron devised solution was to
install four 3-inch slotted round-head machine bolts and 12 1/4 inch nuts.
Push the machine bolts through the feed plate, spin and wrench tight one set
of nuts on the back of the feedhorn. Spin another nut onto each of these "legs"
Install this assembly into the Quad Legs, and spin the last nut on back side to secure the feed. Now, carefully adjust the middle nut with your fingers for the
proper focal length and wrench the last nut tight to secure.

The biggest stupid installer mistake was in simply bolting on a feedhorn scalar
plate to the quad legs, and adjusting the movable center part in and out for
best signal. This bad habit blinded their minds to the concept of first adjusting
the f/d ratio, and using the quad legs (with or without external adjusters) to
get the focal point perfected. While one may find the hot spot of the focal point,
unless the f/d ratio is set properly on the feedhorn, precious signal will be lost due to a mismatch with the antenna.

 

[tvropro]

WHEN they were available, the RP-1 series of feedhorns from ADL was much better than Chaparral in performance. I can honestly say that I have never had a situation in which the proper model of ADL feed (RP-1 or RP-2) could not make a significant improvement over an existing installation with a Chaparral.

What I did find in my many years with Orbitron was that many satellite dealers had no clue about properly installing feedhorns. An adjustable scalar such as the Chaparral PR1E, Corotor 2 or ADL RP-3 might allow them to get away with breaking the rules, but when using a FIXED non-adjustable feed such as the
ADL RP-1 and RP-2, many complained about poor results. Rule number one is
to set the F/D ratio on your feed for the antenna being used. In the case of the
RP-1 or RP-2, that was non adjustable. The RP-1 was designed for 0.335 to 0.425 f/d ratios, with the RP-2 specializing in 0.275 to 0.335. It was also about 7/8 inch thicker in the feed plate, so that had to be compensated for. The next step is to
install and adjust the focal length properly. The Orbitron devised solution was to
install four 3-inch slotted round-head machine bolts and 12 1/4 inch nuts.
Push the machine bolts through the feed plate, spin and wrench tight one set
of nuts on the back of the feedhorn. Spin another nut onto each of these "legs"
Install this assembly into the Quad Legs, and spin the last nut on back side to secure the feed. Now, carefully adjust the middle nut with your fingers for the
proper focal length and wrench the last nut tight to secure.

The biggest stupid installer mistake was in simply bolting on a feedhorn scalar
plate to the quad legs, and adjusting the movable center part in and out for
best signal. This bad habit blinded their minds to the concept of first adjusting
the f/d ratio, and using the quad legs (with or without external adjusters) to
get the focal point perfected. While one may find the hot spot of the focal point,
unless the f/d ratio is set properly on the feedhorn, precious signal will be lost due to a mismatch with the antenna.

Thank's Mike, I'll stick with my ADL and leave the Chapparral in the box it's in.

 

[gabshere]

thanks Mike as always great information. i've noticed that on three of the four dishes i've recovered the FD was set incorrectly for the dish , which i believe was mainly cause c-band reception was easier to gain than ku and those dishes were set up mainly for c-band only. but could also been through being installed improperly, or just tweaked for c-band.

 

[tvropro]

thanks Mike as always great information. i've noticed that on three of the four dishes i've recovered the FD was set incorrectly for the dish , which i believe was mainly cause c-band reception was easier to gain than ku and those dishes were set up mainly for c-band only. but could also been through being installed improperly, or just tweaked for c-band.

: I'll take an educated guess that alot of c band systems were never set up optimally, since analog had room to play. Digital especially with minimal error correction rates don't have that option and will tell you so bigtime. I've seen where even a small adjustment can make a big difference.

 

[Likvid]

Actually it's the opposite with digital broadcasts these days, you don't need as much knowledge as you did in the old analog days, everything is so forgiving now.

Everything these days are so easy compared to the old days.

In the old days a small misalignment showed up with no mercy, with digital it doesn't matter if you are 5dB C/N above threshold or 1dB above, the picture quality will be the same, yes BER will be worse closer to threshold but J6P won't take notice of it.

 

[tvropro]

Actually it's the opposite with digital broadcasts these days, you don't need as much knowledge as you did in the old analog days, everything is so forgiving now.

Everything these days are so easy compared to the old days.

In the old days a small misalignment showed up with no mercy, with digital it doesn't matter if you are 5dB C/N above threshold or 1dB above, the picture quality will be the same, yes BER will be worse closer to threshold but J6P won't take notice of it.

What you say is true because digital is all or nothing. But if your C/N is at threshold under good conditions, you have nothing when adverse weather etc hits. Your still better off getting all the signal you can especially with a 7/8 FEC channel such as HBO.