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Wacom WP-639 Duplexer question
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RichardK
Good evening, our club has a Wacom WP-639 four can duplexer as part of our repeater system. Input Fq is 147.915 and Output Fq is 147.315. We have a 600kHz (+) offset. Very simply, our main problem is when we run the transmitter at full power 100 watts, there is a HUGE desense on the receive side of things. When we drop the transmitter power level to around 20-50 watts, the receive side opens WAY up to a large area where people can get into the repeater. As we begin to bring up the transmitter power, "white noise" begins to appear and the receive side starts to desense again. All the cables have been switched to double sheilded cables and all the same wavelength in length. We have the duplexer seperated & sheilded from the transmitter & preamp parts. We have not replaced the antenna feed coax with double sheilded coax yet. Antenna is a Hustler G7 atop a 55' mast. The duplexer was retuned just over 1 year ago. Any suggestions as to what we could look into next? Some of us believe the problem is with the tuning of the duplexer receive cans. Thank you very much.
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开云体育What repeater are you running? Is it a GE Mastr II by chance? ? Andy ? From: Repeater-Builder@... [mailto:Repeater-Builder@...] On Behalf Of RichardK
Sent: Wednesday, September 08, 2010 3:11 PM To: Repeater-Builder@... Subject: [Repeater-Builder] Wacom WP-639 Duplexer question ? ? Good evening, our club has a Wacom WP-639 four can duplexer as part of our repeater system. Input Fq is 147.915 and Output Fq is 147.315. We have a 600kHz (+) offset. Very simply, our main problem is when we run the transmitter at full power 100 watts, there is a HUGE desense on the receive side of things. When we drop the transmitter power level to around 20-50 watts, the receive side opens WAY up to a large area where people can get into the repeater. As we begin to bring up the transmitter power, "white noise" begins to appear and the receive side starts to desense again. All the cables have been switched to double sheilded cables and all the same wavelength in length. We have the duplexer seperated & sheilded from the transmitter & preamp parts. We have not replaced the antenna feed coax with double sheilded coax yet. Antenna is a Hustler G7 atop a 55' mast. The duplexer was retuned just over 1 year ago. Any suggestions as to what we could look into next? Some of us believe the problem is with the tuning of the duplexer receive cans. Thank you very much. |
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Ken Arck
At 03:11 PM 9/8/2010, RichardK wrote:
<---The WP-639 is spec'd at only 80 db of isolation @ a 600 kHz split. At 100 watts, that simply isn't enough to prevent desense. You need more isolation Ken ------------------------------------------------------------------------------ President and CTO - Arcom Communications Makers of repeater controllers and accessories. Authorized Dealers for Kenwood and Telewave and we offer complete repeater packages! AH6LE/R - IRLP Node 3000 "We don't just make 'em. We use 'em!" |
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Ken Arck
At 04:38 PM 9/8/2010, Andrew Seybold wrote:
<---You hinting at the issue of Mastr II amp going spurious when the power is turned down too far? Ken ------------------------------------------------------------------------------ President and CTO - Arcom Communications Makers of repeater controllers and accessories. Authorized Dealers for Kenwood and Telewave and we offer complete repeater packages! AH6LE/R - IRLP Node 3000 "We don't just make 'em. We use 'em!" |
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Richard Kelly
开云体育?i'm at work right now--I will get that info tomorrow!!? Rich K W2RRK ?x ? To: Repeater-Builder@... From: aseybold@... Date: Wed, 8 Sep 2010 16:38:49 -0700 Subject: RE: [Repeater-Builder] Wacom WP-639 Duplexer question What repeater are you running? Is it a GE Mastr II by chance? ? Andy ? From: Repeater-Builder@... [mailto:Repeater-Builder@...] On Behalf Of RichardK
Sent: Wednesday, September 08, 2010 3:11 PM To: Repeater-Builder@... Subject: [Repeater-Builder] Wacom WP-639 Duplexer question ? ? Good evening, our club has a Wacom WP-639 four can duplexer as part of our repeater system. Input Fq is 147.915 and Output Fq is 147.315. We have a 600kHz (+) offset. Very simply, our main problem is when we run the transmitter at full power 100 watts, there is a HUGE desense on the receive side of things. When we drop the transmitter power level to around 20-50 watts, the receive side opens WAY up to a large area where people can get into the repeater. As we begin to bring up the transmitter power, "white noise" begins to appear and the receive side starts to desense again. All the cables have been switched to double sheilded cables and all the same wavelength in length. We have the duplexer seperated & sheilded from the transmitter & preamp parts. We have not replaced the antenna feed coax with double sheilded coax yet. Antenna is a Hustler G7 atop a 55' mast. The duplexer was retuned just over 1 year ago. Any suggestions as to what we could look into next? Some of us believe the problem is with the tuning of the duplexer receive cans. Thank you very much. |
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On 9/8/2010 6:11 PM, RichardK wrote:
Good evening, our club has a Wacom WP-639 four can duplexer as part of our repeater system. Input Fq is 147.915 and Output Fq is 147.315. We have a 600kHz (+) offset. Very simply, our main problem is when we run the transmitter at full power 100 watts, there is a HUGE desense on the receive side of things. When we drop the transmitter power level to around 20-50 watts, the receive side opens WAY up to a large area where people can get into the repeater. As we begin to bring up the transmitter power, "white noise" begins to appear and the receive side starts to desense again. All the cables have been switched to double sheilded cables and all the same wavelength in length. We have the duplexer seperated& sheilded from the transmitter& preamp parts. We have not replaced the antenna feed coax with double sheilded coax yet. Antenna is a Hustler G7 atop a 55' mast. The duplexer was retuned just over 1 year ago. Any suggestions as to what we could look into next? Some of us believe the problem is with the tuning of the duplexer receive cans. Thank you very much. The Wacom WP-639 is insufficient for 100 solid state watts, unless you run a GE MASTR II PLL exciter and no preamp. You will either need to replace the duplexer with another unit capable of properly isolating 100 solid state watts, add additional filters, change to a less noisy transmitter and amplifier (tubes are better - no I'm not kidding). Kevin Custer - W3KKC |
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I'm not surprised- you're asking too much of a duplexer that has four 5"
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cans. According to my CommShop program, a duplexer with an 80 dB spec is more suitable with transmitter power in the 10-15 watt range, assuming a solid-state PA and a receiver sensitivity around 0.35 uV at 12 dB SINAD. On a 100 watt repeater, I'd expect something like a WP-642, which has six 8" cans. BTDT, got the T-shirt and mug... 73, Eric Lemmon WB6FLY -----Original Message-----
From: Repeater-Builder@... [mailto:Repeater-Builder@...] On Behalf Of RichardK Sent: Wednesday, September 08, 2010 3:11 PM To: Repeater-Builder@... Subject: [Repeater-Builder] Wacom WP-639 Duplexer question Good evening, our club has a Wacom WP-639 four can duplexer as part of our repeater system. Input Fq is 147.915 and Output Fq is 147.315. We have a 600kHz (+) offset. Very simply, our main problem is when we run the transmitter at full power 100 watts, there is a HUGE desense on the receive side of things. When we drop the transmitter power level to around 20-50 watts, the receive side opens WAY up to a large area where people can get into the repeater. As we begin to bring up the transmitter power, "white noise" begins to appear and the receive side starts to desense again. All the cables have been switched to double sheilded cables and all the same wavelength in length. We have the duplexer seperated & sheilded from the transmitter & preamp parts. We have not replaced the antenna feed coax with double sheilded coax yet. Antenna is a Hustler G7 atop a 55' mast. The duplexer was retuned just over 1 year ago. Any suggestions as to what we could look into next? Some of us believe the problem is with the tuning of the duplexer receive cans. Thank you very much. |
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Richard Kelly
开云体育Good evening Eric,? Maybe this is why when the trasmit power is dropped to the 20-50 watt range, the receive opens way up like it should.? However, according to the spec sheets regarding the Wacom SP-639 Duplexer, it is rated for 200 watts.? So, again, not sure what's going on.? We will be trying other things such as adding a second ground rod outside the shack instead of the single one we use now.? We will also try isolating the amp some more and replacing the coax feed line with hard line.? Thank you very much.? We will be contacting?Wacom directly tomorrow. ? Rich Kelly, W2RRK ?x ? > To: Repeater-Builder@... > From: wb6fly@... > Date: Wed, 8 Sep 2010 18:10:44 -0700 > Subject: RE: [Repeater-Builder] Wacom WP-639 Duplexer question > > I'm not surprised- you're asking too much of a duplexer that has four 5" > cans. According to my CommShop program, a duplexer with an 80 dB spec is > more suitable with transmitter power in the 10-15 watt range, assuming a > solid-state PA and a receiver sensitivity around 0.35 uV at 12 dB SINAD. On > a 100 watt repeater, I'd expect something like a WP-642, which has six 8" > cans. BTDT, got the T-shirt and mug... > > 73, Eric Lemmon WB6FLY > > > -----Original Message-----
> From: Repeater-Builder@... > [mailto:Repeater-Builder@...] On Behalf Of RichardK > Sent: Wednesday, September 08, 2010 3:11 PM > To: Repeater-Builder@... > Subject: [Repeater-Builder] Wacom WP-639 Duplexer question > > > > Good evening, our club has a Wacom WP-639 four can duplexer as part of our > repeater system. Input Fq is 147.915 and Output Fq is 147.315. We have a > 600kHz (+) offset. Very simply, our main problem is when we run the > transmitter at full power 100 watts, there is a HUGE desense on the receive > side of things. When we drop the transmitter power level to around 20-50 > watts, the receive side opens WAY up to a large area where people can get > into the repeater. As we begin to bring up the transmitter power, "white > noise" begins to appear and the receive side starts to desense again. All > the cables have been switched to double sheilded cables and all the same > wavelength in length. We have the duplexer seperated & sheilded from the > transmitter & preamp parts. We have not replaced the antenna feed coax with > double sheilded coax yet. Antenna is a Hustler G7 atop a 55' mast. The > duplexer was retuned just over 1 year ago. Any suggestions as to what we > could look into next? Some of us believe the problem is with the tuning of > the duplexer receive cans. Thank you very much. > > > > ------------------------------------ > > > > Yahoo! Groups Links > > <*> To visit your group on the web, go to: > http://groups.yahoo.com/group/Repeater-Builder/ > > <*> Your email settings: > Individual Email | Traditional > > <*> To change settings online go to: > http://groups.yahoo.com/group/Repeater-Builder/join > (Yahoo! ID required) > > <*> To change settings via email: > Repeater-Builder-digest@... > Repeater-Builder-fullfeatured@... > > <*> To unsubscribe from this group, send an email to: > Repeater-Builder-unsubscribe@... > > <*> Your use of Yahoo! Groups is subject to: > http://docs.yahoo.com/info/terms/ > |
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Ken Arck
At 06:18 PM 9/8/2010, Richard Kelly wrote:
<--That is a complete waste of time as that is not the problem. Your duplexer simply cannot provide enough isolation for the power level you're trying to run. More grounding and replacing coax with hardline (unless your coax isn't doubleshield to start with) will buy you nothing. Ken ------------------------------------------------------------------------------ President and CTO - Arcom Communications Makers of repeater controllers and accessories. Authorized Dealers for Kenwood and Telewave and we offer complete repeater packages! AH6LE/R - IRLP Node 3000 "We don't just make 'em. We use 'em!" |
开云体育Rich, ? Eric speaks the truth.? The will HANDLE 200 watts without arcing, etc, but do not provide nearly enough isolation at 600 KHz spacing to handle 100 watts.? For a 35 watt transmitter, I run cans that provide around 96 dB of isolation… the 85 dB your cans can provide just ain’t gonna cut it. ? 73, ? Mike WM4B ? From: Repeater-Builder@... [mailto:Repeater-Builder@...] On Behalf Of Richard Kelly
Sent: Wednesday, September 08, 2010 9:19 PM To: repeater-builder@... Subject: RE: [Repeater-Builder] Wacom WP-639 Duplexer question ? ? Good
evening Eric, |
开云体育I'm afraid your wasting your time.? According to the document for the Wacom 639 duplexer, this is what it says:MIN. FREQ. SPACING: 600 KHz POWER: TO 200 WATTS Notice that it says "TO 200 watts".? That would be if you were at 2MHz of spacing or more.? You are only at 600KHz spacing, so you power level will be much less.? I know it's not what you want to hear, but I believe you have the wrong duplexer for a 100 watt solid state repeater. 73, Joe, K1ike On 9/8/2010 9:18 PM, Richard Kelly wrote: Good evening Eric, |
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Richard Kelly
开云体育Hello again Ken,? Thank you for replying with more info, we appreciate it.? My email address if you want to get off this?posting is w2rrk@... ? How?would we go about providing MORE isolation than?what we?have done so far?? ? Rich Kelly W2RRK ?x ? > To: Repeater-Builder@... > From: ah6le@... > Date: Wed, 8 Sep 2010 18:24:41 -0700 > Subject: RE: [Repeater-Builder] Wacom WP-639 Duplexer question > > At 06:18 PM 9/8/2010, Richard Kelly wrote: > > > > > > We will be trying other things such as adding a second ground rod > > outside the shack instead of the single one we use now. We will > > also try isolating the amp some more and replacing the coax feed > > line with hard line. > > > <--That is a complete waste of time as that is not the problem. Your > duplexer simply cannot provide enough isolation for the power level > you're trying to run. > > More grounding and replacing coax with hardline (unless your coax > isn't doubleshield to start with) will buy you nothing. > > Ken > > ------------------------------------------------------------------------------ > President and CTO - Arcom Communications > Makers of repeater controllers and accessories. > http://www.arcomcontrollers.com/ > Authorized Dealers for Kenwood and Telewave and > we offer complete repeater packages! > AH6LE/R - IRLP Node 3000 > http://www.irlp.net > "We don't just make 'em. We use 'em!" > > > > ------------------------------------ > > > > Yahoo! Groups Links > > <*> To visit your group on the web, go to: > http://groups.yahoo.com/group/Repeater-Builder/ > > <*> Your email settings: > Individual Email | Traditional > > <*> To change settings online go to: > http://groups.yahoo.com/group/Repeater-Builder/join > (Yahoo! ID required) > > <*> To change settings via email: > Repeater-Builder-digest@... > Repeater-Builder-fullfeatured@... > > <*> To unsubscribe from this group, send an email to: > Repeater-Builder-unsubscribe@... > > <*> Your use of Yahoo! Groups is subject to: > http://docs.yahoo.com/info/terms/ > |
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At 9/8/2010 18:24, you wrote:
At 06:18 PM 9/8/2010, Richard Kelly wrote:Replacing copper-braided coax with RG-214 or hardline is hardly a waste of time. The duplexer isolation may not be quite enough, but that can be easily remedied by adding an extra pass cavity to the TX. Just another 10 to 15 dB of TX noise suppression is likely all you need. RG-8, RG-213 or LMR-400 antenna feed, OTOH, will make any duplexer moot due to all the desense it will generate, sooner or later. Bob NO6B |
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NORM KNAPP
I got a set of 4 sinclair cans, like a Q202g on a GE mastr II running 100 watts with pll exciter and GE preamp with no desense. Antenna is roughly 300' away fed with LDF7-50A. Is this a miracle or typical?
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----- Original Message -----
From: Repeater-Builder@... <Repeater-Builder@...> To: Repeater-Builder@... <Repeater-Builder@...> Sent: Wed Sep 08 20:10:44 2010 Subject: RE: [Repeater-Builder] Wacom WP-639 Duplexer question I'm not surprised- you're asking too much of a duplexer that has four 5" cans. According to my CommShop program, a duplexer with an 80 dB spec is more suitable with transmitter power in the 10-15 watt range, assuming a solid-state PA and a receiver sensitivity around 0.35 uV at 12 dB SINAD. On a 100 watt repeater, I'd expect something like a WP-642, which has six 8" cans. BTDT, got the T-shirt and mug... 73, Eric Lemmon WB6FLY -----Original Message----- From: Repeater-Builder@... <mailto:Repeater-Builder%40yahoogroups.com> [mailto:Repeater-Builder@... <mailto:Repeater-Builder%40yahoogroups.com> ] On Behalf Of RichardK Sent: Wednesday, September 08, 2010 3:11 PM To: Repeater-Builder@... <mailto:Repeater-Builder%40yahoogroups.com> Subject: [Repeater-Builder] Wacom WP-639 Duplexer question Good evening, our club has a Wacom WP-639 four can duplexer as part of our repeater system. Input Fq is 147.915 and Output Fq is 147.315. We have a 600kHz (+) offset. Very simply, our main problem is when we run the transmitter at full power 100 watts, there is a HUGE desense on the receive side of things. When we drop the transmitter power level to around 20-50 watts, the receive side opens WAY up to a large area where people can get into the repeater. As we begin to bring up the transmitter power, "white noise" begins to appear and the receive side starts to desense again. All the cables have been switched to double sheilded cables and all the same wavelength in length. We have the duplexer seperated & sheilded from the transmitter & preamp parts. We have not replaced the antenna feed coax with double sheilded coax yet. Antenna is a Hustler G7 atop a 55' mast. The duplexer was retuned just over 1 year ago. Any suggestions as to what we could look into next? Some of us believe the problem is with the tuning of the duplexer receive cans. Thank you very much. |
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Rich,
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The short answer is: You need to find a bigger duplexer. Four 8" cans would work well such as a Wacom WP-641. You could simply call and order one if Wacom was still in business. (RIP) Unfortunately Tx/Rx bought them years ago for the name and to quash competition. They can be found occasionally for around $600 or so on the used market. Other alternatives are as follows: 1) You can use two antennas and split the 639 duplexer so that 2 cans are in series between the TX and the TX antenna, and the other two are in series between the RX and the RX antenna. Terry WX3M a list member is doing this with VERY good results on one of his VHF machines. Of course this involves the expense of additional feedline and a second antenna. I think you said you had this machine on an 80' mast. 50' or so of vertical isolation coupled with the additional isolation of splitting the duplexer *may* be enough isolation to get rid of all the desense. TX goes on bottom, RX on top. 2) Buy additional Band Pass / Band Reject (BPBR) cans. You can add these additional cans between the Tx and/or Rx and the duplexer. These cans will give additional isolation. Even if you can find just Pass or Notch cavities, tune them and put them in the correct place. With both of the above options, you are looking to add to the isolation between your transmitter and receiver. You'll find you'll do best by adding cans to your transmitter that notch side-band noise at your receiver's frequency. In other words, do what you can to insure your receiver is not hearing your own transmitter's sideband noise on it's input. Pass cans tuned to the TX frequency or NOTCH cavities tuned to your *RX* frequency placed in the transmit line are your best hope. Good luck, Scott Scott Zimmerman Amateur Radio Call N3XCC 474 Barnett Road Boswell, PA 15531 On 9/8/2010 9:52 PM, Richard Kelly wrote:
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Ken Arck
At 08:21 PM 9/8/2010, no6b@... wrote:
? <--Notice I said: >More grounding and replacing coax with hardline (unless your coax >isn't doubleshield to start with) will buy you nothing. I was assuming he wasn't running something along the lines of RG-8 but I did think to qualify that. Ken
------------------------------------------------------------------------------
President and CTO - Arcom Communications
Makers of repeater controllers and accessories.
Authorized Dealers for Kenwood and Telewave and
we offer complete repeater packages!
AH6LE/R - IRLP Node 3000
"We don't just make 'em. We use 'em!"
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The PLL exciter is why you're having such good success running a 4-cavity
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duplexer. If you had a PM exciter, chances are you'd be experiencing desense. The PLL exciter produces about 22 dB less noise at 600 kHz offset, reducing the noise supression requirement of the duplexer by a like amount. See: The OP also mentioned he was using a preamp - that's not helping his situation either. Even with a good receiver he's probably on the edge of crunching it with only a 4-pack. Personally, I'd never run a preamp with nothing but a 4-cavity duplexer on 2m, but if it works for you, God bless... A Q202G gives more isolation than a WP639 from what I've seen/measured, in part because the cavities are larger diameter (I think they're 7" versus 5"?). --- Jeff WN3A -----Original Message----- |
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Rich,
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While there have been a lot of good suggestions thrown at you, you are fighting an uphill battle without knowing the spec's that were obtained when the duplexer was re-tuned the last time or finding someone with a tracking generator or network analyzer to verify the duplexer tuning. Simple method to eliminate coax and/or antenna as possible source of your desense is to tune it up with a good VHF dummy load. I make the repeater work as good as possible running into a dummy load before I connect it to an antenna. If you discover that as others have stated and I also have found out the same results, that your duplexer may not have enough isolation, I recommend adding a 12" pass cavity between the transmitter and the duplexer as the first step. If you are still a little short on isolation, then the addition of another 12" pass cavity between the receiver and the duplexer may be necessary. I always try the cavity on the transmitter side first. For this you need a true pass cavity, one that has two connectors and no notch adjustment. Motorola, GE, and DB-Products for starters have made these 12" pass cavities since the 70's. These pass cavities can often be found used for a reasonable price. 600 KHz split repeaters can be a challenge. I personally like to see a little over 100 db of isolation, especially if you have a decent preamp added to the receiver. Kevin is dead-on about how clean tubes can be compared to solid state PA's. I can run our UHF Micor tube repeaters at 150 watts with a Angle Linear preamp on the receiver, with less isolation required from the duplexer, than the same Micor repeater with a 75 watt solid state PA requires for no desense. For example, I have a Motorola Micor 2 Meter 147.250/147.850 repeater running in my garage on my test duplexer, which is a Sinclair 6 can that has about 94 db of isolation. I have the transmitter set at 60 Watts. With no preamp, I have no desense and some headroom before any desense would occur. With the factory 12 db gain Micor preamp, I have no desense, and a little headroom before desense would occur. With a Angle Linear or ARR preamp with higher gain, I have about 5 db of desense. To eliminate the desense would require another 5 db of isolation from the duplexer, which would put it at just about 100 to 102 db of required isolation from the duplexer. Good luck and let us know how you are progressing. Joe - WA7JAW --- In Repeater-Builder@..., "RichardK" <shutterbug13856@...> wrote:
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An additional 20dB of isolation can be realized by replacing the
antenna Tee connector with a circulator. Port A to B tuned to the TX frequency, Port B to C tuned to the RX frequency. Connect TX to port A, antenna to B, Receiver to C. I'm using a set of WP-639 and with this setup I am seeing approx 102dB of rejection from the TX to RX port and 97dB the other way. On Wed, Sep 8, 2010 at 8:40 PM, Scott Zimmerman <n3xcc@...> wrote: Rich, |
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NORM KNAPP
Oh drat! I thought I was getting away with something.... :-)
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I am about to start on a 6m mastr ii with 1 meg split. It is a 110 watt cont duty station I am converting to a repeater. I don't think the exciter is a pll, way too many cans on the board and small icom.... About how much isolation will I need there? I don't know if I have a preamp for this one or not... But if I do, I would try to run it. 73 ----- Original Message -----
From: Repeater-Builder@... <Repeater-Builder@...> To: Repeater-Builder@... <Repeater-Builder@...> Sent: Wed Sep 08 23:08:38 2010 Subject: RE: [Repeater-Builder] Wacom WP-639 Duplexer question The PLL exciter is why you're having such good success running a 4-cavity duplexer. If you had a PM exciter, chances are you'd be experiencing desense. The PLL exciter produces about 22 dB less noise at 600 kHz offset, reducing the noise supression requirement of the duplexer by a like amount. See: The OP also mentioned he was using a preamp - that's not helping his situation either. Even with a good receiver he's probably on the edge of crunching it with only a 4-pack. Personally, I'd never run a preamp with nothing but a 4-cavity duplexer on 2m, but if it works for you, God bless... A Q202G gives more isolation than a WP639 from what I've seen/measured, in part because the cavities are larger diameter (I think they're 7" versus 5"?). --- Jeff WN3A -----Original Message----- |
Kevin Custer
Mike Besemer - WM4B
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