Re: [Repeater-Builder] Looking for a UHF Circulator and load

2005-11-23 Thread Bob M.
I would agree that it's good practice. However in this situation, the only other equipment at the site is cellphone stuff. And if they lose an antenna and the amp goes, they'll just have to get it all fixed. I don't know how long the repeater would continue to transmit without an antenna anyway, bu

Re: [Repeater-Builder] Looking for a UHF Circulator and load

2005-11-23 Thread k7pfj
Hi Ken,   It  is always a good practice to use a isolator in com sites. Look at it this way if you loose an antenna you most likley save your amp. Not to mention if your in a site with public safety it is a good idea.   Mike K7PFJ   -- Original message -- > At 06:00 AM 11

Re: [Repeater-Builder] Looking for a UHF Circulator and load

2005-11-23 Thread Bob M.
I don't know how long the site has been alive, nor do I know the bands it's running in, but I do recall seeing signals in the 850-890 MHz segment. My SA only goes up to 1.5 GHz; other than a frequency counter, I have nothing else that goes over 1 GHz. We did put the SA directly on the antenna and

Re: [Repeater-Builder] Looking for a UHF Circulator and load

2005-11-22 Thread Eric Lemmon
Bob, Depending upon the frequency band and the modulation being used, it's possible that the cellular transmitter is radiating a low-level spurious signal. All cellular telephone sites transmit one or more control channels continuously, and the associated mobile units home on this channel to rece

Re: [Repeater-Builder] Looking for a UHF Circulator and load

2005-11-22 Thread Mathew Quaife
Not me, but could have been.  I went to buy a piece of 7/8" hardline a few years back, thought the deal was to good to be, then found it was Radian.  No the other guy put up 150' of it, only to find it would not work.   Mathew Chuck Kelsey <[EMAIL PROTECTED]> wrote: So how much did you end u

RE: [Repeater-Builder] Looking for a UHF Circulator and load

2005-11-22 Thread Bob M.
I don't think this is a dupe. The amp IS a Henry 20in/200out job, brand new. It has its own switching power supply mounted on the back. I think they're using 24V MOSFETs now. My 10in/100out amp uses ordinary 14VDC and bipolar transistors. I didn't look directly at the PA output. I do remember loo

RE: [Repeater-Builder] Looking for a UHF Circulator and load

2005-11-22 Thread 'Jeff DePolo WN3A'
(having email "issues" today, so if this is a dupe, please ignore) RE: cell mixes and 440 repeater I had a 440 repeater at a site with no other UHF transmitters for probably a mile or two. On an adjacent tower was a cell site (this was back in the early 90's AMPS days). When certain cell chann

Re: [Repeater-Builder] Looking for a UHF Circulator and load

2005-11-22 Thread Chuck Kelsey
So how much did you end up with? LOL. Chuck WB2EDV Mathew Quaife wrote: > Just out of curiosity, where did the hardline come from, also, it is not > Radian by any chance? I heard of that happening once to a guy who > bought some cheap hardline, so he thought. Just kicking idea's around >

Re: [Repeater-Builder] Looking for a UHF Circulator and load

2005-11-22 Thread Bob M.
I don't know the brand or where it came from, except that it's supposed to be new stuff. Everything else is brand new and ordered specifically for the amateur band. Bob M. == --- Mathew Quaife <[EMAIL PROTECTED]> wrote: > Just out of curiosity, where did the hardline come > from, also, it is

Re: [Repeater-Builder] Looking for a UHF Circulator and load

2005-11-22 Thread Bob M.
The inside jumper is 1/2 inch Heliax. We put the dummy load at the end of that and had no desense either. The outside jumper is whatever came with the Super Stationmaster antenna, hopefully good quality RG-214, but I don't know what they normally supply. Bob M. == --- Bob Dengler <[EMAIL PROT

Re: [Repeater-Builder] Looking for a UHF Circulator and load

2005-11-22 Thread Mathew Quaife
Just out of curiosity, where did the hardline come from, also, it is not Radian by any chance?  I heard of that happening once to a guy who bought some cheap hardline, so he thought.  Just kicking idea's around here.    Mathew "Bob M." <[EMAIL PROTECTED]> wrote: I looked at the duplexer wit

Re: [Repeater-Builder] Looking for a UHF Circulator and load

2005-11-22 Thread Neil McKie
... only when you hold it out the window ... Neil Ken Arck wrote: > > At 09:09 AM 11/22/2005 -0800, you wrote: > > > > The resistive load isn't an antenna either. > > <---I generally face little resistance when it comes to antennae... > > Ken Yahoo! Groups Links <*> To visit y

Re: [Repeater-Builder] Looking for a UHF Circulator and load

2005-11-22 Thread Bob Dengler
At 11/22/2005 11:04 AM, you wrote: >If it weren't so hard to move, we'd take the entire >repeater to my site and connect it to my coax and >identical antenna. Unfortunately, that still tells us >it's a problem with the existing coax/antenna setup. >Could be a connector. Could be the short jumper f

Re: [Repeater-Builder] Looking for a UHF Circulator and load

2005-11-22 Thread Bob M.
The antenna/coax is showing 0.05w reflected (1/2 of the first minor division) on a 5W element in a Bird 43 with 200 watts feeding the duplexer. From a purely VSWR standpoint, that's acceptable. Whether or not it's 50 ohms is something we did not check yet. Future steps include sweeping the antenna

Re: [Repeater-Builder] Looking for a UHF Circulator and load

2005-11-22 Thread Ken Arck
At 10:54 AM 11/22/2005 -0800, you wrote: >If the PA and duplexer weren't happy together, >wouldn't I also get desense when running on the dummy >load also? Remember it's perfectly happy on a 500w >Bird load. <---You answered your own question. Suspect the antenna, feedline or both. Ken -

Re: [Repeater-Builder] Looking for a UHF Circulator and load

2005-11-22 Thread Ken Arck
At 10:47 AM 11/22/2005 -0800, you wrote: >If anything is coming back down the antennaand through >the duplexer and mixing in the PA, the circulator will >prevent or reduce that effect. <---Absolutely correct. BUT that is not the same thing as desense nor are the symptoms the same. You said the d

Re: [Repeater-Builder] Looking for a UHF Circulator and load

2005-11-22 Thread Bob M.
I looked at the duplexer with a spectrum analyzer and a return loss bridge. It's making spec (100dB rejection) on each side. PB loss is 1.1dB. I did notice that the return loss indication on the SA showed a very nice sharp deep null (over 60dB) when looking into one port, while the other port was q

Re: [Repeater-Builder] Looking for a UHF Circulator and load

2005-11-22 Thread Bob M.
If anything is coming back down the antennaand through the duplexer and mixing in the PA, the circulator will prevent or reduce that effect. Bob M. == --- Ken Arck <[EMAIL PROTECTED]> wrote: > At 06:00 AM 11/22/2005 -0800, you wrote: > > >I'd like to try a circulator before buying one, > sin

Re: [Repeater-Builder] Looking for a UHF Circulator and load

2005-11-22 Thread Bob M.
No, that has not been done. He did try a different Kenwood repeater - no help. He brought his duplexer to another site - no desense. He tried a different duplexer at his site - desense. The intermod with the cell system is a strong candidate. His antenna is on top of the platform that the cell ant

Re: [Repeater-Builder] Looking for a UHF Circulator and load

2005-11-22 Thread Ken Arck
At 09:09 AM 11/22/2005 -0800, you wrote: > > The resistive load isn't an antenna either. <---I generally face little resistance when it comes to antennae... Ken -- President and CTO - Arcom Communications Makers of stat

Re: [Repeater-Builder] Looking for a UHF Circulator and load

2005-11-22 Thread Neil McKie
The resistive load isn't an antenna either. Neil Ken Arck wrote: > > At 08:15 AM 11/22/2005 -0800, you wrote: > >I once had an Exec II RFPA that didn't "like" the duplexer load > >it was TXing into. Had massive desense unless there was a > >circulator between the TX & duplexer. > > <-

Re: [Repeater-Builder] Looking for a UHF Circulator and load

2005-11-22 Thread Ken Arck
At 08:15 AM 11/22/2005 -0800, you wrote: >I once had an Exec II RFPA that didn't "like" the duplexer load it was >TXing into. Had massive desense unless there was a circulator between the >TX & duplexer. <---Makes sense. I know all about PA's driving a reactive load :-) Ken ---

Re: [Repeater-Builder] Looking for a UHF Circulator and load

2005-11-22 Thread Ken Arck
At 04:27 PM 11/22/2005 +, you wrote: >Well, for one it will limit any locally generated mixing products >resulting from rectification in the PA transistors. <---Yes it will. But that is not the cause of desense, that is one of the causes of intermodulation products. Ken ---

Re: [Repeater-Builder] Looking for a UHF Circulator and load

2005-11-22 Thread Kris Kirby
On Tue, 22 Nov 2005, Ken Arck wrote: > >I'd like to try a circulator before buying one, since if it doesn't > >help the situation, it's a waste of money to have it there. > > <---Aside from presenting a pretty much constant 50 ohm load to your > xmtr, why do you think a circulator will make a di

Re: [Repeater-Builder] Looking for a UHF Circulator and load

2005-11-22 Thread no6b
At 08:09 11/22/2005, you wrote: >At 06:00 AM 11/22/2005 -0800, you wrote: > > >I'd like to try a circulator before buying one, since > >if it doesn't help the situation, it's a waste of > >money to have it there. > ><---Aside from presenting a pretty much constant 50 ohm load to your xmtr, >why do

Re: [Repeater-Builder] Looking for a UHF Circulator and load

2005-11-22 Thread Ken Arck
At 06:00 AM 11/22/2005 -0800, you wrote: >I'd like to try a circulator before buying one, since >if it doesn't help the situation, it's a waste of >money to have it there. <---Aside from presenting a pretty much constant 50 ohm load to your xmtr, why do you think a circulator will make a differen

Re: [Repeater-Builder] Looking for a UHF Circulator and load

2005-11-22 Thread Mathew Quaife
Bob, just a suggestion, has he taken the repeater away from the site, hooked it to another antenna to see if he might be riding along a frequency there at the tower site.  He could be pulling something in from a second harmonic there.  The only reason I mention this, is a friend of mine had a 44