Jump to content


Welcome to DBSTalk


Sign In 

Create Account
Welcome to DBSTalk. Our community covers all aspects of video delivery solutions including: Direct Broadcast Satellite (DBS), Cable Television, and Internet Protocol Television (IPTV). We also have forums to discuss popular television programs, home theater equipment, and internet streaming service providers. Members of our community include experts who can help you solve technical problems, industry professionals, company representatives, and novices who are here to learn.

Like most online communities you must register to view or post in our community. Sign-up is a free and simple process that requires minimal information. Be a part of our community by signing in or creating an account. The Digital Bit Stream starts here!
  • Reply to existing topics or start a discussion of your own
  • Subscribe to topics and forums and get email updates
  • Send private personal messages (PM) to other forum members
  • Customize your profile page and make new friends
 
Guest Message by DevFuse

Photo
- - - - -

genie high-frequency connectors


  • Please log in to reply
46 replies to this topic

#21 OFFLINE   peds48

peds48

    🙈🙉🙊📡

  • DBSTalk Club
  • 12,281 posts
  • LocationLong Island, NY
Joined: Jan 10, 2008

Posted 11 April 2014 - 04:17 PM

You may want to reread the article.

my bad.   :(


Here’s to the crazy ones.
The misfits. The rebels.
The the troublemakers.
The round pegs in the square holes.

The ones who see things different.
They’re not fond of rules, and they have no respect for the status quo.


Think Differently 

...Ads Help To Support This SIte...

#22 OFFLINE   veryoldschool

veryoldschool

    Lifetime Achiever

  • Moderators
  • 41,984 posts
Joined: Dec 09, 2006

Posted 11 April 2014 - 04:52 PM

VOS's argument of loss as a function of the length of the barrel is not sound. The issues are with "insertion loss" and "return loss" those have more to do with impedance matching, reflection and scattering as opposed to voltage drop.

"If you only knew" what you were posting about, but it's clear you haven't worked with a network analyzer very much.

How do you think the scattering parameters are measured?


A.K.A VOS

#23 OFFLINE   veryoldschool

veryoldschool

    Lifetime Achiever

  • Moderators
  • 41,984 posts
Joined: Dec 09, 2006

Posted 11 April 2014 - 05:07 PM

adding 2 cents:

 

and physically the two cuts of polypropylene around central wire will create two air gaps - here is the catch: impedance changed four times there,

so it will creat a loss and reflections on sat signals;perhaps that .5 dB at each connection

 

while the barrel itself could show 1/10 loss in lab tests, when that expensive connectors made precisely to eliminate/reduce measurement's error

If the connectors are worn, there can be some merit to this.

How much may be questionable.

The connectors in question were the F 81 & 71, where any "air gap" is going to be in the thousandth of an inch, with the dielectric constant only changing from 2.2ish to 1, where the difference of one degree of the wavelength is only 0.006" at 1.8 GHz.

The connectors on the RG6 are going to have much more to do with "air gaps" if they're not installed correctly, than the F 81.


A.K.A VOS

#24 OFFLINE   veryoldschool

veryoldschool

    Lifetime Achiever

  • Moderators
  • 41,984 posts
Joined: Dec 09, 2006

Posted 11 April 2014 - 05:54 PM

For your reading pleasures... Is it better to use barrels on your wall plates or just run the cable straight through? (Solid Signal Blog)

 

Insightful comments from fellow staff member VOS are also included.  :grin:  :)

This seems to be an example of how poorly people read these days.

I questioned two things:

  1. That a F81 connector adds 1 dB of loss.
  2. Measuring 0.1 dB of loss.

To say anything else merely points to how poorly one comprehends what they read.


A.K.A VOS

#25 ONLINE   P Smith

P Smith

    Mr. FixAnything

  • Registered
  • 20,051 posts
  • LocationMediterranean Sea
Joined: Jul 25, 2002

Posted 11 April 2014 - 06:20 PM

If the connectors are worn, there can be some merit to this.

How much may be questionable.

The connectors in question were the F 81 & 71, where any "air gap" is going to be in the thousandth of an inch, with the dielectric constant only changing from 2.2ish to 1, where the difference of one degree of the wavelength is only 0.006" at 1.8 GHz.

The connectors on the RG6 are going to have much more to do with "air gaps" if they're not installed correctly, than the F 81.

my points are :

- the barrel in not last thing in the part of cabling: we must add two F-connectors to count the loss

- how big the gap is widely vary, I'm know usually it's 1 mm or so in case of proper F-connector or more if you'll do it by yourself, plus if occasionally pull it, then it will come to more then 2 mm



#26 OFFLINE   veryoldschool

veryoldschool

    Lifetime Achiever

  • Moderators
  • 41,984 posts
Joined: Dec 09, 2006

Posted 11 April 2014 - 07:01 PM

my points are :

- the barrel in not last thing in the part of cabling: we must add two F-connectors to count the loss

- how big the gap is widely vary, I'm know usually it's 1 mm or so in case of proper F-connector or more if you'll do it by yourself, plus if occasionally pull it, then it will come to more then 2 mm

I thought you might have more to add, so I looked at what the lack of a dielectric would do to the impedance.

The impedance changes from 75 ohms to about 90 ohms, which would have an RL of 20.83 dB & load mismatch attenuation of 0.036 dB.

 

So, while it can be calculated, its impact is negligible.


A.K.A VOS

#27 OFFLINE   harsh

harsh

    Beware the Attack Basset

  • Registered
  • 19,399 posts
  • LocationSalem, OR
Joined: Jun 14, 2003

Posted 11 April 2014 - 08:58 PM

So, while it can be calculated, its impact is negligible.

While negligible, it is additive.

Too often we enjoy the comfort of opinion without the discomfort of thought. -- JFK


#28 ONLINE   P Smith

P Smith

    Mr. FixAnything

  • Registered
  • 20,051 posts
  • LocationMediterranean Sea
Joined: Jul 25, 2002

Posted 11 April 2014 - 09:00 PM

I would check on real connections if my SA will register the difference ... while seen may times: typical loss on each F-connector is 0.5 dB (from dish 'white' papers)



#29 OFFLINE   veryoldschool

veryoldschool

    Lifetime Achiever

  • Moderators
  • 41,984 posts
Joined: Dec 09, 2006

Posted 11 April 2014 - 09:32 PM

I would check on real connections if my SA will register the difference ... while seen may times: typical loss on each F-connector is 0.5 dB (from dish 'white' papers)

I was also waiting for a comment about a F connector. Given it's no more than an outer shell on the RG6, where does any loss come from?

Poor mating, or simply the lack of accuracy of your SA ?


A.K.A VOS

#30 OFFLINE   veryoldschool

veryoldschool

    Lifetime Achiever

  • Moderators
  • 41,984 posts
Joined: Dec 09, 2006

Posted 11 April 2014 - 09:35 PM

While negligible, it is additive.

not that much when it falls below the system levels, and you've got to "add up" an a lot to have 0.036 dB become anything meaningful.

 

"Someday" you'll get into a discussion that  you know something about, but today isn't it.


A.K.A VOS

#31 OFFLINE   slice1900

slice1900

    AllStar

  • Registered
  • 2,937 posts
  • LocationIowa
Joined: Feb 14, 2013

Posted 12 April 2014 - 12:28 AM

While negligible, it is additive.

 

You seem to delight in making comments that while technically true, are totally irrelevant. If you're so close to the margin that this makes a difference, you'd probably find that temperature/humidity differences, static electricity and the phase of the moon also affected the stability of your system. Only a fool would worry about a fraction of a db when it takes a drop of dozens of db prior to the receiver to reach the margin where a fraction could theoretically matter.

 

You are familiar with the phrase "penny wise, pound foolish", I trust?


SL5, PI-6S, SA-6AL 3xSWM16, 21 H20-100, 1 H20-600, 7 H24-700/AM21


#32 OFFLINE   veryoldschool

veryoldschool

    Lifetime Achiever

  • Moderators
  • 41,984 posts
Joined: Dec 09, 2006

Posted 12 April 2014 - 02:07 AM

You seem to delight in making comments that while technically true, are totally irrelevant. If you're so close to the margin that this makes a difference, you'd probably find that temperature/humidity differences, static electricity and the phase of the moon also affected the stability of your system. Only a fool would worry about a fraction of a db when it takes a drop of dozens of db prior to the receiver to reach the margin where a fraction could theoretically matter.

 

You are familiar with the phrase "penny wise, pound foolish", I trust?

Don't limit him to "technically true", as he doesn't himself.

You know he merely posts crap until painted into a corner and then simply fades away to post some crap in another thread.

Pretty much SOP for him on the forum.


A.K.A VOS

#33 OFFLINE   matty8199

matty8199

    Icon

  • Topic Starter
  • Registered
  • 741 posts
Joined: Dec 04, 2005

Posted 12 April 2014 - 01:37 PM

alright...so should i replace with the high frequency connectors i bought at lowes or return them and go back to the ones that were in the wall when i bought the house in october?  again, brand new from the builder...i have one genie mini on the original house wall plate connectors right now and it seems to be working fine.



#34 OFFLINE   Bill Broderick

Bill Broderick

    Icon

  • Registered
  • 1,509 posts
  • LocationLong Island
Joined: Aug 25, 2006

Posted 12 April 2014 - 02:36 PM

Try using the original wall plates.  If they work, continue to use them.  If not, don't.



#35 OFFLINE   peds48

peds48

    🙈🙉🙊📡

  • DBSTalk Club
  • 12,281 posts
  • LocationLong Island, NY
Joined: Jan 10, 2008

Posted 12 April 2014 - 04:16 PM

Try using the original wall plates.  If they work, continue to use them.  If not, don't.

Or wait for DirecTV to go to your house and change them.... :rotfl:


Here’s to the crazy ones.
The misfits. The rebels.
The the troublemakers.
The round pegs in the square holes.

The ones who see things different.
They’re not fond of rules, and they have no respect for the status quo.


Think Differently 

#36 OFFLINE   peds48

peds48

    🙈🙉🙊📡

  • DBSTalk Club
  • 12,281 posts
  • LocationLong Island, NY
Joined: Jan 10, 2008

Posted 12 April 2014 - 04:17 PM

 

You know he merely posts crap until painted into a corner and then simply fades away to post some crap in another thread.

Pretty much SOP for him on the forum.

Yep, like the "RC71 thread" discussion....


Here’s to the crazy ones.
The misfits. The rebels.
The the troublemakers.
The round pegs in the square holes.

The ones who see things different.
They’re not fond of rules, and they have no respect for the status quo.


Think Differently 

#37 OFFLINE   veryoldschool

veryoldschool

    Lifetime Achiever

  • Moderators
  • 41,984 posts
Joined: Dec 09, 2006

Posted 12 April 2014 - 05:31 PM

alright...so should i replace with the high frequency connectors i bought at lowes or return them and go back to the ones that were in the wall when i bought the house in october?  again, brand new from the builder...i have one genie mini on the original house wall plate connectors right now and it seems to be working fine.

 

 

Try using the original wall plates.  If they work, continue to use them.  If not, don't.

Bill has given a good answer.

"The truth is" there are no "high frequency" connectors. Just connectors labeled as such.

The Genie "mini" uses the coax networking, which is in the OTA antenna range and hard to call "high frequency".


A.K.A VOS

#38 OFFLINE   TomCat

TomCat

    Broadcast Engineer

  • Registered
  • 3,642 posts
Joined: Aug 31, 2002

Posted 13 April 2014 - 11:55 AM

P. Smith and VOS are both right. What the what? Call CNN!

 

It is not so much a signal loss issue per se, as it is an impedance matching or VSWR issue. There is virtually no resistance to attenuate signal in any connector, but signal can be attenuated by bad impedance matching. And this is exactly why some connectors, once cut onto a cable, will exhibit anywhere from .1 to 1 dB of loss. Even identical connectors by the same person. As someone who has connectorized over 25,000 RF and video cables I can assure you, it's a fact of life.

 

In a perfect world, connectors would not be problematic, and in the real world they mostly are not. Still, it is difficult to simulate all of the aspects of coax through a connector, although the old F-81 is pretty perfect already. We all did have to stop using crimp connectors because they showed reflections above about 1.8 GHz or so, and the newer SWM systems use a higher L-Band frequency than the conventional distribution, so a better connector was needed. Sensible.

 

I do not fault DBS companies for putting the highest standards in place for connectors, in fact I consider that good engineering. But the potential for problems is actually microscopic, so unless your system is already marginal, pretty much any connector will be just fine. IOW, use what you have or what you can get, and don't fret if it doesn't fit the perfect connector's parameters. But if you are a pro installer, use the best.


Edited by TomCat, 13 April 2014 - 12:00 PM.

It's usually safe to talk honestly and openly with people because they typically are not really listening anyway.

#39 OFFLINE   veryoldschool

veryoldschool

    Lifetime Achiever

  • Moderators
  • 41,984 posts
Joined: Dec 09, 2006

Posted 13 April 2014 - 06:06 PM

 We all did have to stop using crimp connectors because they showed reflections above about 1.8 GHz or so, and the newer SWM systems use a higher L-Band frequency than the conventional distribution, so a better connector was needed.

I don't know of any SWM that is above 1.8 GHz.


A.K.A VOS

#40 OFFLINE   texasbrit

texasbrit

    Hall Of Fame

  • DBSTalk Club
  • 4,215 posts
Joined: Aug 09, 2006

Posted 13 April 2014 - 06:22 PM

I don't know of any SWM that is above 1.8 GHz.

Yes, SWM systems actually use LOWER frequencies than traditional DirecTV systems....






Protected By... spam firewall...And...