Re: [Repeater-Builder] Adding Remote Base to a Repeater
At 1/20/2007 08:42, you wrote: >Hi all, > >I've been working on this problem for a while and have not come up >with any good solutions. So I'm hoping to find someone that has "been >there, done that" with some suggestions. > >The issue is that I want to add a same-band remote base to an >existing repeater. The main problem is that the remote base is a >transceiver and I can't find a way to provide proper isolation >to/from the repeater. > >Here are the frequencies, but it looks like it really doesn't matter >all that much. The repeater transmits on 443.300, receives on >443.800. We're using a typical UHF pass-reject duplexer with about 70 >db of isolation between those two freqs. The remote base will >transmit on 444.225 and receive on 449.225. > >I can put two antennas on the tower, but my horizontal space will be >less than 20 feet. That's not going to help much unless you use a Yagi for the rmt. base antenna & put the side null into the rptr. ant. You really need vertical isolation. >If the remote base had a separate tx and rx, then a band pass can >with a notch can (on the repeater freqs) on each side would probably >work fine. > >Anyone have a good solution? A friend of mine actually brought the RX input of a Kenwood TM-241 out separately so it could be connected to a community RX antenna some 60 ft. away from the 2 meter repeater TX antennas. We were also able to add an isolator to the TX (to be a good neighbor) & filters & pads to the RX line until the IMD dropped to minimal levels. The 241 has rather poor dynamic range. Bob NO6B
Re: [Repeater-Builder] Adding Remote Base to a Repeater
Dwayne, 2 possible answers: 1) Eliminate the current T/R switching so that you can bring out a seperate TX and RX path, then add the filtering as needed and then go to a new T/R relay. OR get behind the current T/R switching and take the individual paths thru the necessary filtering before connecting to the TX and RX. In this case I would try for something with a T/R relay and avoid diode RF switching. 2) Use a seperate radio or receiver for RX and use the existing transceiver for TX. Two pipes, two sets of filtering devices. 443.3 TX and 448.3 RX for the repeater, with the remote base on an inverted pair at 444.225 TX and 449.225 RX gives you a seperation of 5.925 MHz, should be easy with a second pass notch duplexer. I'd probably use a Yagi antenna for the remote base freq. rather than try to combine everything onto one antenna. _ \/ Omni | _^__\/_|_\/__^_ | | circulator | | | 443.3 448.3 TX RX ^ = pass cavity, \/ = notch cavity |-| -|-|-> Yagi | _^__\/__|__\/__^_ 2 radio setup for remote base using seperate ||Yagi. || 444.225 || 449.225 || TX RX How about using something like a Mitreck and taking a seperate lead to the RX input for the remote base. You might be able to do a one antenna system with a split from the antenna feeding a couple of notch cans on each leg, then split each leg thru pass cans and add circulators to both TX legs. _ \/ Omni | __\/__\/__|__\/__\/_ | | __^__^__|__^__^__ __^__^__|__^__^__ || | | circcirc | | || | | 443.3 444.225448.3 449.225 You will still need a way to seperate the RX and TX on the remote base. Fair amount of loss in the cans. Just a couple of ideas that might help. Of course as others have said I could be wrong. Milt N3LTQ - Original Message - From: "ldgelectronics" <[EMAIL PROTECTED]> To: Sent: Saturday, January 20, 2007 11:42 AM Subject: [Repeater-Builder] Adding Remote Base to a Repeater > Hi all, > > I've been working on this problem for a while and have not come up > with any good solutions. So I'm hoping to find someone that has "been > there, done that" with some suggestions. > > The issue is that I want to add a same-band remote base to an > existing repeater. The main problem is that the remote base is a > transceiver and I can't find a way to provide proper isolation > to/from the repeater. > > Here are the frequencies, but it looks like it really doesn't matter > all that much. The repeater transmits on 443.300, receives on > 443.800. We're using a typical UHF pass-reject duplexer with about 70 > db of isolation between those two freqs. The remote base will > transmit on 444.225 and receive on 449.225. > > I can put two antennas on the tower, but my horizontal space will be > less than 20 feet. > > From the pile of spare parts, I have a multitude of UHF band pass and > notch filters. I would also not be opposed to adding something like a > pass-notch duplexer if there is a way to configure it to work. > > From my testing, it seems that the real issue is that the remote base > is a transceiver and there is pretty much no way to add anything > except notch filtering. Adding band pass cans will filter either the > tx or the rx, but not in any combination (that I can find) to do both. > > If the remote base had a separate tx and rx, then a band pass can > with a notch can (on the repeater freqs) on each side would probably > work fine. > > Anyone have a good solution? > > Dwayne Kincaid > WD8OYG > > > > > > > > Yahoo! Groups Links > > >
Re: [Repeater-Builder] Adding Remote Base to a Repeater
ldgelectronics wrote: > Hi all, > > I've been working on this problem for a while and have not come up > with any good solutions. So I'm hoping to find someone that has "been > there, done that" with some suggestions. > > The issue is that I want to add a same-band remote base to an > existing repeater. The main problem is that the remote base is a > transceiver and I can't find a way to provide proper isolation > to/from the repeater. > > Here are the frequencies, but it looks like it really doesn't matter > all that much. The repeater transmits on 443.300, receives on > 443.800. Did you mean something else? That's a 500 kc split > We're using a typical UHF pass-reject duplexer with about 70 > db of isolation between those two freqs. The remote base will > transmit on 444.225 and receive on 449.225. > > I can put two antennas on the tower, but my horizontal space will be > less than 20 feet. > Did you mean vertical? That should be plenty of vertical spacing. > >From the pile of spare parts, I have a multitude of UHF band pass and > notch filters. I would also not be opposed to adding something like a > pass-notch duplexer if there is a way to configure it to work. > > >From my testing, it seems that the real issue is that the remote base > is a transceiver and there is pretty much no way to add anything > except notch filtering. Adding band pass cans will filter either the > tx or the rx, but not in any combination (that I can find) to do both. > > If the remote base had a separate tx and rx, then a band pass can > with a notch can (on the repeater freqs) on each side would probably > work fine. > > Anyone have a good solution? Nothing beats antenna separation for a cheap way out, vertical is best for vertically polarized antennas. I have a repeater on 443.925 TX and 448.925 RX I have a remote base on 443.950 RX and 443.950 TX. There is 100 feet of vertical separation, the repeater is a Micor with the AFC disabled. Link is Radius M120 at 4 watts, no desense either way. (that's 25 kc of spacing!!!) The repeater is running a preamp, and no it is not deaf Kevin Custer
[Repeater-Builder] Adding Remote Base to a Repeater
Hi all, I've been working on this problem for a while and have not come up with any good solutions. So I'm hoping to find someone that has "been there, done that" with some suggestions. The issue is that I want to add a same-band remote base to an existing repeater. The main problem is that the remote base is a transceiver and I can't find a way to provide proper isolation to/from the repeater. Here are the frequencies, but it looks like it really doesn't matter all that much. The repeater transmits on 443.300, receives on 443.800. We're using a typical UHF pass-reject duplexer with about 70 db of isolation between those two freqs. The remote base will transmit on 444.225 and receive on 449.225. I can put two antennas on the tower, but my horizontal space will be less than 20 feet. >From the pile of spare parts, I have a multitude of UHF band pass and notch filters. I would also not be opposed to adding something like a pass-notch duplexer if there is a way to configure it to work. >From my testing, it seems that the real issue is that the remote base is a transceiver and there is pretty much no way to add anything except notch filtering. Adding band pass cans will filter either the tx or the rx, but not in any combination (that I can find) to do both. If the remote base had a separate tx and rx, then a band pass can with a notch can (on the repeater freqs) on each side would probably work fine. Anyone have a good solution? Dwayne Kincaid WD8OYG
