[Repeater-Builder] Cable length
Hi guys Just updating on the 6mc450s style notch duplexer problem.We found one of the 6 tuning insulators inside were burnt through the insulator so we got the local engineering group to lave another insulator out of nylon rod and have put it back together and tested it on the service monitor and it comes up perfect on it and tested it with a maxon pm150 and we are now getting 40 watt output of the duplexer instead of 4-10watt so I think we have fixed it .We will know when we install it back into the repeater. Thank You, Ian Wells, Kerinvale Comaudio, 361 Camboon Road.Biloela.4715 Phone 0749922574 or 0409159932 www.kerinvalecomaudio.com.au
[Repeater-Builder] Cable length
Hi again guys .This has been brought up before I know but I thought I need to ask this .With the length between the transmitter and diplexer should we keep the cable as short as possible because I seem to find I have more loss with longer rg223u cables (aprox 1 meter ) .I tried a isolator inline and it produced lower output than the cable did.Should I be using shorter lengths so to lower the loss .Maybe I should try heavier cable like hard line and see how much loss I get from that Thank You, Ian Wells, Kerinvale Comaudio, 361 Camboon Road.Biloela.4715 Phone 0749922574 or 0409159932 www.kerinvalecomaudio.com.au
Re: [Repeater-Builder] Cable length for NOTCH cavity?
I trust you plan to do this with the Radius owner's blessing, and with him present? If not, DON'T touch his radio or feedline - you're setting yourself up for a world of legal trouble if he has problems down the line! 73, George, KA3HSW / WQGJ413 - Original Message - From: "Bill Powell" <[EMAIL PROTECTED]> To: Sent: Saturday, July 26, 2008 9:29 PM Subject: [Repeater-Builder] Cable length for NOTCH cavity? [snip] So... I tuned a spare can as a notch (~19db) at freq X and intend to place it in-line with the Radius in hopes of removing (lowering) the level of freq X getting into the Radius transmitter. A 20 dB reduction "should" reduce the intermod by 40 dB IF the mixing is happening in the Radius. I hope. I intend to remove the antenna cable from the Radius, plug it into the T at the can and run a double-shielded cable from the can to the Radius.
RE: [Repeater-Builder] Cable length for NOTCH cavity?
> So... I tuned a spare can as a notch (~19db) at freq X and intend to > place it in-line with the Radius in hopes of removing (lowering) the > level of freq X getting into the Radius transmitter. A 20 dB > reduction "should" reduce the intermod by 40 dB IF the mixing is > happening in the Radius. > I hope. > > I intend to remove the antenna cable from the Radius, plug it into the > T at the can and run a double-shielded cable from the can to > the Radius. > > Does the length of the added cable matter? For the most part, no, it won't matter. If you were putting multiple cavities in series, with the notches all on the same frequency, cable lengths would be more critical. As long as the notch cavity is high-Q enough, and its return loss is high at the Radius' Tx and Rx frequencies, there won't be a problem. A more definitive test would be to just stick an isolator (dual stage preferably) between the Radius and the antenna. Key up the Radius and transmitter X, see if your receiver Y hears it. Sure, the receiver is going to be deaf while you do the test, but it will conclusive, and will only take a minute or so to run the test... --- Jeff WN3A
[Repeater-Builder] Cable length for NOTCH cavity?
In an attempt to address a hard 3rd order issue apparently being caused by a Motorola Radius repeater (no circulator and a cheapie internal notch "duplexer"). Background: Repeaters A and B share a properly engineered combiner system which is working well at 4 other sites. At this site a repeater we don't control (the Radius) shares the tower but NOT the combiner or antenna system. Repeater A transmits on freq X, Repeater B receives on freq Y, The Radius transmits on freq Z. The issue: 2X - Z = Y We believe the mix is happening in the Radius transmitter. We don't own or control the Radius and will need to "prove" the issue before we can get it's owner to address the problem. So... I tuned a spare can as a notch (~19db) at freq X and intend to place it in-line with the Radius in hopes of removing (lowering) the level of freq X getting into the Radius transmitter. A 20 dB reduction "should" reduce the intermod by 40 dB IF the mixing is happening in the Radius. I hope. I intend to remove the antenna cable from the Radius, plug it into the T at the can and run a double-shielded cable from the can to the Radius. Does the length of the added cable matter? If so, what should it be: fractional wavelength at X or Z? Something else? TIA, Bill - WB1GOT
RE: [Repeater-Builder] cable length
I keep hearing about these "Z-Matchers". Who makes them, and are they expensive?
LJ
-Original Message- From: Eric Lemmon <[EMAIL PROTECTED]>Sent: Jan 23, 2006 9:06 PM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] cable length
Ian,
The cable length is more important on the TX side than on the RX side. However, since the impedances of the power amplifier output and of the duplexer TX input are seldom known with any certainty, it is impossible to know in advance what length that jumper cable should be. The TX jumper cable acts as a linear impedance transformer, depending upon its length in relation to the wavelength of the TX carrier. The chances that any random length of cable will result in a perfect match are slim.
The method I use is to make up a cable that fits the installation neatly, and then measure the power going to the antenna from the duplexer with a Bird wattmeter. Then I install an impedance matcher ("Z-matcher") at the output of the PA. If tuning the Z-matcher makes a significant improvement in the forward power, I know that the jumper cable is probably not the ideal length. I now have two choices: I can start experimenting with longer and shorter cables until I find the optimum length, or I can set the Z-matcher for the optimum setting and close up the cabinet, turn out the lights, and head home. Opinions vary greatly on this issue...
73, Eric Lemmon WB6FLY
From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Ian WellsSent: Monday, January 23, 2006 4:34 PMTo: Repeater-Builder@yahoogroups.comSubject: [Norton AntiSpam] [Repeater-Builder] cable length
Is it nessary to have the correct length coax from the diplexer to the rx and tx or is there a formular that can show the correct length .I am currently using RG223 coax for these links
Thank You,
Ian Wells,
Kerinvale Comaudio,
www.kerinvalecomaudio.com.au
YAHOO! GROUPS LINKS
Visit your group "Repeater-Builder" on the web.
To unsubscribe from this group, send an email to: [EMAIL PROTECTED]
Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
YAHOO! GROUPS LINKS
Visit your group "Repeater-Builder" on the web.
To unsubscribe from this group, send an email to: [EMAIL PROTECTED]
Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
RE: [Repeater-Builder] cable length
I thank you for the response .I don't usually set the TX cable at one length and it varies at all my sites .most of the sites may be around aprox 1 meter or so
Thank You,
Ian Wells,
Kerinvale Comaudio,
www.kerinvalecomaudio.com.au
---Original Message---
From: Eric Lemmon
Date: 01/24/06 15:06:34
To: Repeater-Builder@yahoogroups.com
Subject: RE: [Repeater-Builder] cable length
Ian,
The cable length is more important on the TX side than on the RX side. However, since the impedances of the power amplifier output and of the duplexer TX input are seldom known with any certainty, it is impossible to know in advance what length that jumper cable should be. The TX jumper cable acts as a linear impedance transformer, depending upon its length in relation to the wavelength of the TX carrier. The chances that any random length of cable will result in a perfect match are slim.
The method I use is to make up a cable that fits the installation neatly, and then measure the power going to the antenna from the duplexer with a Bird wattmeter. Then I install an impedance matcher ("Z-matcher") at the output of the PA. If tuning the Z-matcher makes a significant improvement in the forward power, I know that the jumper cable is probably not the ideal length. I now have two choices: I can start experimenting with longer and shorter cables until I find the optimum length, or I can set the Z-matcher for the optimum setting and close up the cabinet, turn out the lights, and head home. Opinions vary greatly on this issue...
73, Eric Lemmon WB6FLY
From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Ian WellsSent: Monday, January 23, 2006 4:34 PMTo: Repeater-Builder@yahoogroups.comSubject: [Norton AntiSpam] [Repeater-Builder] cable length
Is it nessary to have the correct length coax from the diplexer to the rx and tx or is there a formular that can show the correct length .I am currently using RG223 coax for these links
Thank You,
Ian Wells,
Kerinvale Comaudio,
www.kerinvalecomaudio.com.au
YAHOO! GROUPS LINKS
Visit your group "Repeater-Builder" on the web.
To unsubscribe from this group, send an email to: [EMAIL PROTECTED]
Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
RE: [Repeater-Builder] cable length
Ian,
The cable
length is more important on the TX side than on the RX side. However,
since the impedances of the power amplifier output and of the duplexer TX input
are seldom known with any certainty, it is impossible to know in advance what
length that jumper cable should be. The TX jumper cable acts as a linear
impedance transformer, depending upon its length in relation to the wavelength
of the TX carrier. The chances that any random length of cable will result
in a perfect match are slim.
The method I
use is to make up a cable that fits the installation neatly, and then measure
the power going to the antenna from the duplexer with a Bird wattmeter.
Then I install an impedance matcher ("Z-matcher") at the output of the PA.
If tuning the Z-matcher makes a significant improvement in the forward power, I
know that the jumper cable is probably not the ideal length. I now have
two choices: I can start experimenting with longer and shorter cables
until I find the optimum length, or I can set the Z-matcher for the optimum
setting and close up the cabinet, turn out the lights, and head home.
Opinions vary greatly on this issue...
73, Eric Lemmon WB6FLY
From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Ian
WellsSent: Monday, January 23, 2006 4:34 PMTo:
Repeater-Builder@yahoogroups.comSubject: [Norton AntiSpam]
[Repeater-Builder] cable length
Is it nessary to have the correct length coax from the diplexer
to the rx and tx or is there a formular that can show the correct
length .I am currently using RG223 coax for these links
Thank You,
Ian Wells,
Kerinvale Comaudio,
www.kerinvalecomaudio.com.au
YAHOO! GROUPS LINKS
Visit your group "Repeater-Builder" on the web.
To unsubscribe from this group, send an email to: [EMAIL PROTECTED]
Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
[Repeater-Builder] cable length
Is it nessary to have the correct length coax from the diplexer to the rx and tx or is there a formular that can show the correct length .I am currently using RG223 coax for these links Thank You, Ian Wells, Kerinvale Comaudio, www.kerinvalecomaudio.com.au YAHOO! GROUPS LINKS Visit your group "Repeater-Builder" on the web. To unsubscribe from this group, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
[Repeater-Builder] Cable length for DB4076W Duplexer
Hello there, I'm looking for some help with a UHF Decibel Products DB4076W Duplexer, in specific the coax cable lengths if one of you can measure and provide them from your same model unit. This duplexer is Decibel's round UHF BpBr "four bottle" assembly, the suffix -004 (dash no) is for standard 450-470 Mhz operation. I received this duplexer less (missing) the two center to the N tee coax jumpers. The jumpers between the bottles are still in place and not the same length. Decibel assigns letters to each jumper, which correspond to a part number. The coax is the classic (tan/brown in colour) PTFE (Teflon) (high quality) type. There are various methods to measure the coax cable lengths. Some people use the coax length plus 1/2 inch for the connector. Some people use the connector "tip to tip" (yes even with N connectors). It doesn't matter to me which method you use. All I ask is that you please tell me which method you use in your reply. Using the tip to tip method, the High-pass, notch low side jumper (between the two high pass bottles), is ~ 6 inches long and has the Decibel Part Number of 048350-032 The Low-pass, notch high side jumper (between the two low pass bottles) is ~ 12 inches long and has the Decibel Part Number of 048350-010 The limited Decibel paperwork (I have here) shows the jumper from the Low-pass, notch high bottle to the N tee connector has the same part number as just above. So half the battle is won. What I need is the length of jumper from the High-pass, notch low bottle to the N tee connector. Decibel's part number for this item is 048350-001 Can any of you help? Is there a method to convert Decibels part number scheme to a length value? I understand there are various methods to make your own duplexer cables. I've found these type Decibel Duplexers work better with the original manufactures cable length value in place. If you can help, I'd appreciate it very much. My files have many recorded mfgrs cable length values (which are available to anyone who needs the information), just not this one Decibel Duplexer Model (yet). Again thanks, please reply direct or with a follow up post. Cheers, skipp skipp025 at yahoo.com Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
