| reply to Mr_DNS
Re: Minimum cable length I was told it is 75'. The resistance is needed to decrease voltage/DBs to prevent overload of the modem.
That said mine is 45';) |
|
 Rfsjr2Shop on TopPremium
join:2001-08-11
Ferndale, WA | said by jlester:I was told it is 75'. The resistance is needed to decrease voltage/DBs to prevent overload of the modem. That said mine is 45';) So if I were to give WB a shot, and I only really need a 10' run, what am I supposed to do with the other 65' of cable?
--
*Frank* Startouch Wireless Internet. Waverider EUM3003, TRENDnet TEW-411BRP+, 900MHz NLOS. |
|
| reply to blacksheep9
It is with out a doubt BS. I have run these systems day in and day out on 8' test sets with no ill effect.
There are too many variables here for one person's experience to be a final proof of anything.
But that doesn't stop the ignorant from insisting on their experience as final proof. |
|
 grohgregDunno. Ask The Chief
join:2001-07-05
Dawson Springs, KY
4 edits | reply to jlester
said by jlester: The resistance is needed to decrease voltage/DBs to prevent overload of the modem Given the loss variances in those "approved cable" lists, that's simply asinine. Even if that did make any sense, the technically correct (and probably cheaper) solution is a coaxial attenuator - not "more cable".
//greg// |
|
| reply to oldengineer
said by oldengineer :
It is with out a doubt BS. I have run these systems day in and day out on 8' test sets with no ill effect.
There are too many variables here for one person's experience to be a final proof of anything.
But that doesn't stop the ignorant from insisting on their experience as final proof.
You may be correct. That being said,I have seen nothing in WB's documentation that requires attenuation except during signal acquisition. In this case a 10 dB and 20 dB DC-power passing attenuation pad are cascaded to complete the test and then removed from the system.:) |
|
Mr_DNS
join:2005-09-07
Laredo, TX | reply to grohgreg
said by grohgreg:and probably cheaper) solution is a coaxial attenuator - not "more cable". I hinted I was using a surge protector, like others are too.
Don't know the specs of it, but it must handle less than 40 Volts DC on transmit side. Maybe one to several tenths of a dB loss [equivalent cable loss].
.
. |
|
Mr_DNS
join:2005-09-07
Laredo, TX | reply to randyvsatus
Horsefeathers...1. Someone didn't configure the amplifier requirement....says it all.
BTW, last I knew, cable companies don't supply amps to customers...and if so in your area...hmmm, another consumer self-induced problem...:D
. |
|
1 edit | said by Mr_DNS:BTW, last I knew, cable companies don't supply amps to customers...and if so in your area.... Don't take my word for it (you wouldn't anyway:D)...call Adelphia - they are the one's who put it in when the signal was too low and took it out when the signal was too high...I wouldn't even know what to buy on my own. I don't believe you even read my original post, or you wouldn't have said that. |
|
grohgregDunno. Ask The Chief
join:2001-07-05
Dawson Springs, KY
1 edit | reply to Mr_DNS
said by Mr_DNS:I hinted I was using a surge protector, like others are too. Don't know the specs of it, but it must handle less than 40 Volts DC on transmit side. Maybe one to several tenths of a dB loss [equivalent cable loss]. Are you trying to tap dance around a concept that the surge suppressor represents a coaxial attenuator? If so, I don't believe you understand the working principles.
Besides that, it's inconsistent in the face of increasing reports of WB/TeleSat advising customers and installers to remove them from problematic installations.
//greg// |
|
Mr_DNS
join:2005-09-07
Laredo, TX | said by grohgreg:Are you trying to tap dance around a concept that the surge suppressor represents a coaxial attenuator? .
.
Who me...not really...I just stated an empirical FACT, according to one surge protector company, their fact sheet.
But, since NRTC had these units designed with WB specs [I am told], and since I don't have these surge specs, I can say [as based upon another company's spec sheet] that you have a 0.1 dB attenuator when coaxial cables go via surge connectors.
Now, this company's spec sheet was not based upon these higher voltages/currents [I understand] that WB uses; hence, the attenuation may be higher...may!
Ok Chief? |
|
Mr_DNS
join:2005-09-07
Laredo, TX | reply to grohgreg
said by grohgreg:Besides that, it's inconsistent in the face of increasing reports of WB/TeleSat advising customers and installers to remove them from problematic installations. PS: I skimmed the NRTC Manual, and so far, no minimun was mentioned....hence, if true, then you can't "fire" a "problematic" installer, if they did not provide the facts. |
|
Mr_DNS
join:2005-09-07
Laredo, TX | reply to randyvsatus
said by randyvsatus:they are the one's who put it in when the signal was too low... Well, back to my original point...Someone didn't configure the amplifier requirement...after they cleaned up their mess.
Thus, I was right...all along:D |
|
Mr_DNS
join:2005-09-07
Laredo, TX | reply to grohgreg
Have you seen any around 3 dB loss at 950 Mhz, that could handle upto 40 Volts DC?
Here is spec sheet for Belden 1694
.
»www.bluejeanscable.com/pages/tec···tech.htm
. |
|
| reply to Mr_DNS
said by Mr_DNS:Thus, I was right...all along:D I'm going to let you have your way and send our snowstorm to Amarillo  |
|
|
|
grohgregDunno. Ask The Chief
join:2001-07-05
Dawson Springs, KY
3 edits | reply to Mr_DNS
said by Mr_DNS:Have you seen any around 3 dB loss at 950 Mhz, that could handle upto 40 Volts DC? Here is spec sheet for Belden 1694 No. First, because inherent cable loss and coaxial attenuators are apples and oranges. But more to the point, because I don't think there's an affordable (if any) RG6 manufactured that can produce 950MHz loss results that low. And RG6 is typically rated to handle 300v (RMS) anyway. So - what's your point ?
The Belden 1694A link you provided is further evidence that you're struggling here. Initially, becase Belden 1694A is not even on the WB "approved cable" list. I'd guess that's because it's not specified for Direct Bury applications. But primarily because the spec sheet clearly indicates a swept 5.00db/100ft loss at 750 MHz and a 5.89db/100ft loss at 1000MHz. Suggesting "around 3 dB loss at 950 Mhz" is illogical (if not impossible).
I once again respectfully suggest that you don't understand the working principles. You're the originator of this topic, asking others for answers to your original cable length question. Yet you seem bent upon rejecting all inputs, in favor of your own.
//greg// |
|
Mr_DNS
join:2005-09-07
Laredo, TX
1 edit | said by grohgreg:I once again respectfully suggest that you don't understand the working principles. Well, I've been around TVRO [BUD: Big Ugly Dish] since early 1980s, and have done a few installs for BUDs/Pizza_Dishes.
That cable cited was for an example; I do have the master spec sheet for approved WB cable. Your assumption above [i.e., "my ignorance"], as based upon your remarks about that cable, was pseudo. This cable was rated for 3 GHz, and as I recall, solid copper, which is what WB wants; but it was only an example given with respect to the dB loss vs frequecy, nothing more.
I also know you better watch out, when buying adapters, cause the Cable's Industries specs are different from WB's specs; most are rated around 1 GHz when spec'ed.
I have found a 3 dB attenuator, but I can not find the spec sheet [It may be for Cable Stuff]:
»www.twacomm.com/catalog/model_30···305A0424
Until I see a spec sheet for dB loss vs frequency, I will assume nothing...although in theory, this should be rated for about 1000 MHz signal...but..
.
|
|
Mr_DNS
join:2005-09-07
Laredo, TX
2 edits | reply to grohgreg
said by grohgreg:I once again respectfully suggest that you don't understand the working principles. .
.
Just the facts, from another surge company:
Antenna/Cable Attenuation (5MHz-950MHz) less than 1dB
.
»www.panamax.com/products.cfm?gro···270&ly=h
.
. |
|
Mr_DNS
join:2005-09-07
Laredo, TX | reply to grohgreg
said by grohgreg:The Belden 1694A link you provided is further evidence that you're struggling here. See this post here, and notice who's name is there:
»Re: [Canadian] Xplornet Ka has arrived
. |
|
Mr_DNS
join:2005-09-07
Laredo, TX
1 edit | reply to grohgreg
said by grohgreg:Given the loss variances in those "approved cable" lists... Solid Copper
1. Belden 1840AC - 1000 MHz @ 6 dB [WB Approved]
2. Belden 1694A - 1000 MHz @ 5.89 dB
I think you'll find Solid Copper is similar, and 0.11 dB loss is peanuts per 100'
1. »www.solidsignal.com/prod_display···BLK#MORE
2. »www.bluejeanscable.com/pages/tec···tech.htm |
|
| reply to randyvsatus
The reason that minimum cable length is a concern is tied to the Standing Wave Ratio (SWR) of the entire tranmission system , i.e., the transmitter, transmission line and antenna. SWR is a measure of how much transmitter power is reflected back to transmitter because of mis-matches in the transmission system. This link provides more detail and may help...
»radioproshop.com/swr.htm |
|
