[Repeater-Builder] Diode Squelch AND Gate Circuit
I've been reading on the Repeater Builder's website about using an AND gate to cure squelch ills. I believe this may be what I need to try on our system running for RX's and one TX's. All the CTCSS boards are in the RX's before they go to the voter, and hence the controller cannot do the AND gating. Below is the circuit mentioned on another website as to build up a diode AND gate. Anyone got ideas on component values? V+ | | | o-|| | | | o-|| |o OUTPUT RESISTOR | o GROUND Scott NA4IT
[Repeater-Builder] Re: Diode Squelch AND Gate Circuit
Well, the circuit did look right. Both diodes should be shifted left. Guess Yahoo can't handle plain text... Scott NA4IT --- In Repeater-Builder@yahoogroups.com, Scott [EMAIL PROTECTED] wrote: I've been reading on the Repeater Builder's website about using an AND gate to cure squelch ills. I believe this may be what I need to try on our system running for RX's and one TX's. All the CTCSS boards are in the RX's before they go to the voter, and hence the controller cannot do the AND gating. Below is the circuit mentioned on another website as to build up a diode AND gate. Anyone got ideas on component values? V+ | | | o-|| | | | o-|| |o OUTPUT RESISTOR | o GROUND Scott NA4IT
RE: [Repeater-Builder] Intermod
I would strongly suspect that new preamp to be the culprit. 73 Gary K4FMX _ From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Nate Duehr Sent: Saturday, February 03, 2007 2:35 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Intermod On 2/3/07, Jeff DePolo [EMAIL PROTECTED] mailto:jeff%40depolo.net net wrote: I think I see how Steve's logic is leaning, and I agree - I don't see any logical mix here until you include a user's transmission on one of the repeater's inputs. Fred - do you hear ALL 147.33 transmitter activity coming in on the 147.765 input, or just when there is actually a user keyed up on 147.93? If the latter, that's a big clue... --- Jeff Yep, that's going to be the key... been there done that... Ye olde 600 KHz split on VHF problem. It creates perfect mixes with users and the repeaters themselves that fall right smack on the input of the next repeater along the band. A close-in high-powered user to a VHF repeater can mix with it with bad results for the next in line machine. Requiring CTCSS on a different tone than the original machine and users will cover up the problem, but not fix it, of course... not a permanent fix, but sometimes necessary. If Jeff's observation is correct, and you only hear input activity... try to find a ham who's rig causes the issue consistently (and you'll probably find that HT users don't, also -- they're usually just too weak to create a strong-enough mix). Then you can have that person lower their power and see if the problem signal on the repeater's input seems to drop out quickly or get much weaker, since you're looking for a mix that would drop off rapidly as one of the transmitter's power levels was lowered. If that's not it... have a 600 KHz AM station in your town? There's always the possibility of other mixes as well... Jeff's test is the kicker to start with -- do you hear the full TX tail of the other repeater or just user input? Does it do it on ALL transmissions or just certain users? Anyone involved in the situation live real close to either repeater, who you know has high gain antennas and runs lots of power? Nate WY0X
[Repeater-Builder] Mastr II Station Power Supply Problem?
I'm setting up a Mastr II VHF station for a 2 meter repeater and when I got to the power amp to check everything I can only get about 86 watts out of the 110watt PA. I noticed that the power supply starts to fold over at about 20 watts out and when I get to 80 watts the supply is only at around 8 to 9 volts. This Mastr II station has the PLL exciter but they gave me a 4 transistor power amp the original amp was missing. This is the newer type station with the IDA controller. I looked up the model number of the supply and it's a PL19D430272G1 Rev 4 which shows to be the right power supply for the station. I don't have my spectrum analyzer at the moment so I can't tell if the power amp is spurring although station metering shows below rated current on transmit. Any clues? Bill...
Re: [Repeater-Builder] Effects of doubling RF output on UHF repeater?
I'm sure you will get a few more more educated replies than mine- Here's my two cents. Double the power, the most you would theoretically get is 3db more signal. Will the end users notice- probably not very significantly. I have heard and experienced systems that ran *high powered* amplifiers on their repeaters, one in particular failed but only the users 50 miles away noticed a difference (and that was on pure exciter power). What are the downsides- consume more power, potentially introduce more de-sense. You will create more heat in the cabinet as well. Is it worth it? You could probably argue it either way. If the money is sitting there to burn and it makes some people happy, what the heck, give it a shot and let us know your results. Is it going to make the machine full-quieting 60dB over S-9 OM everywhere it hears? Likely not. Remember, the next complaint from the other people is I hear it full scale but I cant get in! and your next post is about voters! Tom W9SRV - Original Message From: Tony L. [EMAIL PROTECTED] To: Repeater-Builder@yahoogroups.com Sent: Monday, February 5, 2007 8:47:34 AM Subject: [Repeater-Builder] Effects of doubling RF output on UHF repeater? One of our 70cm Amateur Radio repeaters is currently outputting 50 watts into the duplexer. We're considering replacing the existing RF power amp with a 100 watt model. Current draw on the 50 watt unit is 8 amps. The 100 watt unit will draw 20 amps. Our power supply is rated at 36 amps continuous, and the duplexer is rated at 250 watts. Half of our users believe that the repeater's output power is perfectly matched to its receiver. That is, users of high powered mobile radios generally lose repeater reception at about the same time the repeater's receiver loses them. However, the other half of our users believe doubling the repeater's power output would generate increased activity since the repeater could be heard more comfortably. We could upgrade without changing any of our other infrastructure. However, these questions arise: 1) Will the hundreds we pay to upgrade actually translate into significantly increased range? 2) Will we risk generating additional receiver noise by doubling our output power, thus losing coverage in the process? 3) Will using a higher power level shorten the life of other system components over time (e.g., power supply)? By the way, our frequency coordination would be valid even if we doubled our output power. Yahoo! Groups Links Looking for earth-friendly autos? Browse Top Cars by Green Rating at Yahoo! Autos' Green Center. http://autos.yahoo.com/green_center/
[Repeater-Builder] Re:HF Remote Base?
Not exactly a repeater controller, but take a look at Larry's website for ideas on remote control of radios: http://www.telepostinc.com/n8lp.html#top Mike AI4NS
Re: [Repeater-Builder] HF Remote Base?
Arcom, CAT and Link-Comm all make controllers that will control a modern HF radio. http://www.arcomcontrollers.com http://www.catauto.com http://www.link-comm.com I only have hands-on experience with the Link-comm's controlling a IC-706 and TS-570. -Sean On Feb 3, 2007, at 7:10 PM, drwoolweaver wrote: Any suggestions for a modern repeater controller that will also operate a frequency agile HF remote base? Thanks de David
[Repeater-Builder] Repeater antennas.
I am looking for opinions on what antenna is good for repeater use that are in the $200-250 dollar range. I am looking at the Antennx and the Hustler 270R. Opinoins? Thanks Dan/NØFPE
[Repeater-Builder] test
[Repeater-Builder] Re: Intermod
--- In Repeater-Builder@yahoogroups.com, Jeff DePolo [EMAIL PROTECTED] wrote: Some one heard the owner of 165 talk about having to keep the power down because of desense. A perfect example of bandaidsmanship. What about a band pass on 147.765? Nah, it would only buy you a couple of dB of attenuation at 147.93. It may take a crystal filter or just padding the input a little. I don't know what kind of preamp it is. If it's his repeater Tx overloading his preamp or Rx, an extra pass/reject cavity (pass 147.765, reject 147.165) before the preamp would likely fix the 33 issue, and possibly help, if not cure, his desense problem as well, unless the desense is being caused by transmitter noise, in which more filtering on the Tx would be necessary. --- Jeff I agree with Jeff. Put a notch cavity ahead of the preamp tuned to it's 165 transmitter. I bet removing the preamp would cure the whole problem. I am having trouble with my posts showing up. I tried earlier via email but it didn't make it. This is from the group board. 73 Gary K4FMX
[Repeater-Builder] Re: EFJ Challenger as Repeater
Really nice site. I am still getting some conflicting info. The unit that we are considering is the EF Johnson CR600 desktop repeater/base. I have had a hard time finding information on that particular model. Some specific questions: Is it crystal controlled or synthesized. If the latter, what sort of interface and software is out there. Is it easily brought down to the ham bands Are the built-in duplexers readily tuned to the ham bands Does anyone have a manual/schematic? steve WA4BVO KB3OKL repeater --- In Repeater-Builder@yahoogroups.com, skipp025 [EMAIL PROTECTED] wrote: Great stuff Joel! great job. I thought I was flying solo with the EF Johnson Challengers. cheers, skipp Huntley, Joel jhuntley@ wrote: Here's some info on the Challenger stuff if you're interested... http://www.ccdx.org/zedyx/mods/challenger.htm 73 de Joel - WA1ZYX
[Repeater-Builder] RLN-4008 RIB Clones
Good Morning everyone, Has anyone used the RIB clone offered by Valley Enterprises on that auction place? Opinions welcome on that one and on RIB clones in general. And before anyone sends that reply reminding me I can roll my own RLN-4008 from the diagram on batlabsthank you...I have considered that often, but considering the time and effort to gather and assemble the price asked for the clones is *very* attractive. Yes, I am lazy at heart. :) Thanks for your comments. Dennis -- Dennis L. Wade KG6ZI Carmichael, CA
[Repeater-Builder] mobile repeater setup
I drive a truck OTR and at times work with FEMA. Would it be possible to put together a mobile repeater system that could be used in areas without power? I have a generator system in my truck so I have 110 power available. My interest would be in something semi permanently installed without need for putting antennas up or down. I realize it would have a rather limited reach but would theoretically allow an ht user 5 miles east of the truck to talk to an ht user 5 miles west of the truck when they wouldn't be able to talk simplex. With mobiles the effective radius presumably would be greater as well. My questions are is this feasible and reasonable? What would be the least expensive system I could put together to do this job? Thanks in advance for all suggestions. 73 Leo K5LDB
Re: [Repeater-Builder] Effects of doubling RF output on UHF repeater?
double the power is a 3DB increase, which will result in 1/2 S-unit increase in signal. There will be very little, if any, difference. Unless you can do the upgrade for free, it is not worth it. -- Original Message -- Received: Mon, 05 Feb 2007 08:47:45 AM CST From: Tony L. [EMAIL PROTECTED] To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Effects of doubling RF output on UHF repeater? One of our 70cm Amateur Radio repeaters is currently outputting 50 watts into the duplexer. We're considering replacing the existing RF power amp with a 100 watt model. Current draw on the 50 watt unit is 8 amps. The 100 watt unit will draw 20 amps. Our power supply is rated at 36 amps continuous, and the duplexer is rated at 250 watts. Half of our users believe that the repeater's output power is perfectly matched to its receiver. That is, users of high powered mobile radios generally lose repeater reception at about the same time the repeater's receiver loses them. However, the other half of our users believe doubling the repeater's power output would generate increased activity since the repeater could be heard more comfortably. We could upgrade without changing any of our other infrastructure. However, these questions arise: 1) Will the hundreds we pay to upgrade actually translate into significantly increased range? 2) Will we risk generating additional receiver noise by doubling our output power, thus losing coverage in the process? 3) Will using a higher power level shorten the life of other system components over time (e.g., power supply)? By the way, our frequency coordination would be valid even if we doubled our output power.
RE: [Repeater-Builder] Effects of doubling RF output on UHF repeater?
1) No 2) Yes 3) Probably not. Fred N4GER -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Tony L. Sent: Monday, February 05, 2007 8:48 AM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Effects of doubling RF output on UHF repeater? One of our 70cm Amateur Radio repeaters is currently outputting 50 watts into the duplexer. We're considering replacing the existing RF power amp with a 100 watt model. Current draw on the 50 watt unit is 8 amps. The 100 watt unit will draw 20 amps. Our power supply is rated at 36 amps continuous, and the duplexer is rated at 250 watts. Half of our users believe that the repeater's output power is perfectly matched to its receiver. That is, users of high powered mobile radios generally lose repeater reception at about the same time the repeater's receiver loses them. However, the other half of our users believe doubling the repeater's power output would generate increased activity since the repeater could be heard more comfortably. We could upgrade without changing any of our other infrastructure. However, these questions arise: 1) Will the hundreds we pay to upgrade actually translate into significantly increased range? 2) Will we risk generating additional receiver noise by doubling our output power, thus losing coverage in the process? 3) Will using a higher power level shorten the life of other system components over time (e.g., power supply)? By the way, our frequency coordination would be valid even if we doubled our output power. Yahoo! Groups Links
RE: [SPAM] RE: [Repeater-Builder] Intermod
I have come to the same conclusion. Fred N4GER -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Gary Schafer Sent: Saturday, February 03, 2007 2:05 PM To: Repeater-Builder@yahoogroups.com Subject: [SPAM] RE: [Repeater-Builder] Intermod I would strongly suspect that new preamp to be the culprit. 73 Gary K4FMX _ From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Nate Duehr Sent: Saturday, February 03, 2007 2:35 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Intermod On 2/3/07, Jeff DePolo [EMAIL PROTECTED] mailto:jeff%40depolo.net net wrote: I think I see how Steve's logic is leaning, and I agree - I don't see any logical mix here until you include a user's transmission on one of the repeater's inputs. Fred - do you hear ALL 147.33 transmitter activity coming in on the 147.765 input, or just when there is actually a user keyed up on 147.93? If the latter, that's a big clue... --- Jeff Yep, that's going to be the key... been there done that... Ye olde 600 KHz split on VHF problem. It creates perfect mixes with users and the repeaters themselves that fall right smack on the input of the next repeater along the band. A close-in high-powered user to a VHF repeater can mix with it with bad results for the next in line machine. Requiring CTCSS on a different tone than the original machine and users will cover up the problem, but not fix it, of course... not a permanent fix, but sometimes necessary. If Jeff's observation is correct, and you only hear input activity... try to find a ham who's rig causes the issue consistently (and you'll probably find that HT users don't, also -- they're usually just too weak to create a strong-enough mix). Then you can have that person lower their power and see if the problem signal on the repeater's input seems to drop out quickly or get much weaker, since you're looking for a mix that would drop off rapidly as one of the transmitter's power levels was lowered. If that's not it... have a 600 KHz AM station in your town? There's always the possibility of other mixes as well... Jeff's test is the kicker to start with -- do you hear the full TX tail of the other repeater or just user input? Does it do it on ALL transmissions or just certain users? Anyone involved in the situation live real close to either repeater, who you know has high gain antennas and runs lots of power? Nate WY0X
Re: [Repeater-Builder] mobile repeater setup
Leo: Look around for a used Motorola GR300 repeater. They have a footprint of about one square foot and about 14 high and are quite reliable. I have a couple of them running in the 70 cm ham band. They usually come with a 120 VSAC power supply, but they run off of 13.8 VDC, so you can bypass the supply and run them directly from yoiur rig's DC source. I set mine for 20 W XMT power to keep a limit on final amp heat. They'll fit neatly into a small space in the sleeper area with room to spare. They include a built-in duplexer (UHF). There might be some on the Bay. Also, I have a Moto UHF suitcase repeater that includes a duplexer. 73, Dick W1NMZ - Original Message - From: texasexpediter To: Repeater-Builder@yahoogroups.com Sent: 04 February, 2007 15:16 Subject: [Repeater-Builder] mobile repeater setup I drive a truck OTR and at times work with FEMA. Would it be possible to put together a mobile repeater system that could be used in areas without power? I have a generator system in my truck so I have 110 power available. My interest would be in something semi permanently installed without need for putting antennas up or down. I realize it would have a rather limited reach but would theoretically allow an ht user 5 miles east of the truck to talk to an ht user 5 miles west of the truck when they wouldn't be able to talk simplex. With mobiles the effective radius presumably would be greater as well. My questions are is this feasible and reasonable? What would be the least expensive system I could put together to do this job? Thanks in advance for all suggestions. 73 Leo K5LDB
RE: [SPAM] RE: [Repeater-Builder] Intermod
You're right, however I have no control over the 165 repeater. The owner has been informed. I have no clue what he is going to do. I'm willing to help, however the monkey is on his back. Fred N4GER -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Gary Schafer Sent: Saturday, February 03, 2007 5:02 PM To: Repeater-Builder@yahoogroups.com Subject: [SPAM] RE: [Repeater-Builder] Intermod The 165 repeater needs an additional notch in its transmitter. 73 Gary K4FMX _ From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Fred Flowers Sent: Saturday, February 03, 2007 5:04 PM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Intermod Steve, Jeff, Nate, Ya'll are on the right track. I did some additional tests. It not the 147.765 subscriber it's the 147.93 subscriber that is throwing the stinky stuff into the fan. Keying the 33 repeater does not cause the 165 repeater to come up. However, when both repeaters are on the air 33 will keep 165 keyed the 33 audio can be heard on the 165 repeater. As soon as the 33 subscriber unkeys the interfering signal on 165 goes away. I a ham not infected with ctcss phobia, therefore 33 (which I built) has RX TX tone. This lets me TX on 33's input not key the repeater. The 165 repeater is not interfered with. Also lowering the power of the 147.930 TX clears the problem. 174.33, 147.93 147.165 have to be on the air to cause the problem in the 147.765 RX. I assume it is in the 147.765 RX, I don't have access to look at RX audio on the 147.165 repeater. Is it valid to add 600 kHz to the intermod calculator? I get an interesting fifth order when I do. 147.9300 MHz - 147.3300 MHz - 147.1650 MHz - 0.6000 MHz - 0.6000 MHz = 147.7650 MHz Right on the 147.165 input. As I said before, the owner may have added a preamp to 147.165 a day or two ago. This problem just came to light last night. These two repeaters have been on the air for years. I was wrong about the spacing, they are 4 miles apart. The 33 repeater equipment was getting tired I replaced it with a Mastr II station repeater two weeks ago. I can't say for sure if the problem started with new 33 equipment or the preamp on 165. It looks to me like the cure is to notch 147.930 at the 147.756 receiver. Anyone have any thoughts. Fred N4GER -Original Message- From: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com [mailto:Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com] On Behalf Of Nate Duehr Sent: Saturday, February 03, 2007 1:35 PM To: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com Subject: Re: [Repeater-Builder] Intermod On 2/3/07, Jeff DePolo [EMAIL PROTECTED] mailto:jeff%40depolo.net net wrote: I think I see how Steve's logic is leaning, and I agree - I don't see any logical mix here until you include a user's transmission on one of the repeater's inputs. Fred - do you hear ALL 147.33 transmitter activity coming in on the 147.765 input, or just when there is actually a user keyed up on 147.93? If the latter, that's a big clue... --- Jeff Yep, that's going to be the key... been there done that... Ye olde 600 KHz split on VHF problem. It creates perfect mixes with users and the repeaters themselves that fall right smack on the input of the next repeater along the band. A close-in high-powered user to a VHF repeater can mix with it with bad results for the next in line machine. Requiring CTCSS on a different tone than the original machine and users will cover up the problem, but not fix it, of course... not a permanent fix, but sometimes necessary. If Jeff's observation is correct, and you only hear input activity... try to find a ham who's rig causes the issue consistently (and you'll probably find that HT users don't, also -- they're usually just too weak to create a strong-enough mix). Then you can have that person lower their power and see if the problem signal on the repeater's input seems to drop out quickly or get much weaker, since you're looking for a mix that would drop off rapidly as one of the transmitter's power levels was lowered. If that's not it... have a 600 KHz AM station in your town? There's always the possibility of other mixes as well... Jeff's test is the kicker to start with -- do you hear the full TX tail of the other repeater or just user input? Does it do it on ALL transmissions or just certain users? Anyone involved in the situation live real close to either repeater, who you know has high gain antennas and runs lots of power? Nate WY0X Yahoo! Groups Links
RE: [Repeater-Builder] Effects of doubling RF output on UHF repeater?
Good idea and when you install the amplifier you will want to install this filter pre amp at the same time. http://www.anglelinear.com/custom/custom.html they are worth there money and the results are unbelievable. Oregon Repeater Linking Group Mike Mullarkey 6539 E Street Springfield, OR 97478 [EMAIL PROTECTED] www.orlg.org -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Tony L. Sent: Monday, February 05, 2007 6:48 AM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Effects of doubling RF output on UHF repeater? One of our 70cm Amateur Radio repeaters is currently outputting 50 watts into the duplexer. We're considering replacing the existing RF power amp with a 100 watt model. Current draw on the 50 watt unit is 8 amps. The 100 watt unit will draw 20 amps. Our power supply is rated at 36 amps continuous, and the duplexer is rated at 250 watts. Half of our users believe that the repeater's output power is perfectly matched to its receiver. That is, users of high powered mobile radios generally lose repeater reception at about the same time the repeater's receiver loses them. However, the other half of our users believe doubling the repeater's power output would generate increased activity since the repeater could be heard more comfortably. We could upgrade without changing any of our other infrastructure. However, these questions arise: 1) Will the hundreds we pay to upgrade actually translate into significantly increased range? 2) Will we risk generating additional receiver noise by doubling our output power, thus losing coverage in the process? 3) Will using a higher power level shorten the life of other system components over time (e.g., power supply)? By the way, our frequency coordination would be valid even if we doubled our output power.
RE: [Repeater-Builder] mobile repeater setup
Yes, it's easy to do. I have one 440. You don't need 110v, 12v works just fine. Check out this site. http://www.nhrc.net/nhrc-4mvp/ Fred N4GER -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of texasexpediter Sent: Sunday, February 04, 2007 5:17 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] mobile repeater setup I drive a truck OTR and at times work with FEMA. Would it be possible to put together a mobile repeater system that could be used in areas without power? I have a generator system in my truck so I have 110 power available. My interest would be in something semi permanently installed without need for putting antennas up or down. I realize it would have a rather limited reach but would theoretically allow an ht user 5 miles east of the truck to talk to an ht user 5 miles west of the truck when they wouldn't be able to talk simplex. With mobiles the effective radius presumably would be greater as well. My questions are is this feasible and reasonable? What would be the least expensive system I could put together to do this job? Thanks in advance for all suggestions. 73 Leo K5LDB Yahoo! Groups Links
RE: [Repeater-Builder] Mastr II Station Power Supply Problem?
I'm setting up a Mastr II VHF station for a 2 meter repeater and when I got to the power amp to check everything I can only get about 86 watts out of the 110watt PA. I noticed that the power supply starts to fold over at about 20 watts out and when I get to 80 watts the supply is only at around 8 to 9 volts. If this station is using the stock Mastr II supply, my first bet is that the capacitor in the ferro circuit (7.5 uF IIRC) is bad. What's the voltage without load? --- Jeff
Re: [Repeater-Builder] Diode Squelch AND Gate Circuit
At 2/5/2007 05:35, you wrote: I've been reading on the Repeater Builder's website about using an AND gate to cure squelch ills. I believe this may be what I need to try on our system running for RX's and one TX's. All the CTCSS boards are in the RX's before they go to the voter, and hence the controller cannot do the AND gating. Below is the circuit mentioned on another website as to build up a diode AND gate. Anyone got ideas on component values? V+ | | | o-|| | | | o-|| |o OUTPUT RESISTOR | o GROUND Looks like your diodes are in a position to short out your V+ if the CTCSS or COS output goes to ground. The resistor (10 k or so) should go between V+ the output/diode anodes, there is no connection to ground. This assumes both the CTCSS COS outputs are active high, your voter's COS input is fairly high impedance. If it requires TTL-compatible inputs, some buffering will be needed. Bob NO6B
Re: [Repeater-Builder] Effects of doubling RF output ...
Tony L. wrote: 1) Will the hundreds we pay to upgrade actually translate into significantly increased range? As others have said -- not significant. But there'll always be someone who'll want to argue the point here ya go: Envision pouring a cup of water on a table top -- it makes a puddle of X radius (range) and (PI * R^2) area. Pouring on a second cup will double the area (at the same depth) .. but the radius increases by only 1/3 at best. Doubling the radius (range) requires LOTS more water. Let the naysayer figure out how much. g /.
Re: [Repeater-Builder] Effects of doubling RF output on UHF repeater?
You've already gotten reasonable answers that I won't rehash. Let's consider this, assuming that bumping the power up to 100 Watts doesn't degrade your receiver, how do the users perceive things? Flea powered HTs are the bane of repeater builders (or, at least, me), but people love them. Most are designed with rather hot receivers that give reasonable receive range with their small rubber-duck antennas. Now let's assume that your current setup works such that as the repeater is getting noisy in their receiver that they are dropping out of the repeater, i.e. the repeater is still balanced (do you see where I'm going?). Now you bump the power and suddenly the HT user is hearing the repeater full-quieting. Naturally he'll assume that he's in a better coverage area but will find that he's dropping out (as before) even though he's hearing the machine so much better. Of course, the complaints begin. What has been gained? A different set of complaints (from personal experience). It sounds to me like your repeater is reasonably balanced and I wouldn't do anything to upset that. I would leave it up to those that need the needle pinned to improve their own stations. 73, de Nate -- Wireless | Amateur Radio Station N0NB | Successfully Microsoft Amateur radio exams; ham radio; Linux info @ | free since January 1998. http://www.qsl.net/n0nb/ | Debian, the choice of My Kawasaki KZ-650 SR @| a GNU generation! http://www.networksplus.net/n0nb/ | http://www.debian.org
Re: [Repeater-Builder] RLN-4008 RIB Clones
we have a regular rib and a smartrib, we also have one of those aftermarket clones. the moto ribs read everything, but we had problems with the 'clone', we had problems reading some moiles. I'd give it a try if money is an issue and you don't have a bajillion customer radios and need to depend on it to work on all of 'em. Dennis Wade [EMAIL PROTECTED] wrote: Good Morning everyone, Has anyone used the RIB clone offered by Valley Enterprises on that auction place? Opinions welcome on that one and on RIB clones in general. And before anyone sends that reply reminding me I can roll my own RLN-4008 from the diagram on batlabsthank you...I have considered that often, but considering the time and effort to gather and assemble the price asked for the clones is *very* attractive. Yes, I am lazy at heart. :) Thanks for your comments. Dennis -- Dennis L. Wade KG6ZI Carmichael, CA - Any questions? Get answers on any topic at Yahoo! Answers. Try it now.
Re: [Repeater-Builder] mobile repeater setup
If your going to use two mobiles as a repeater (such as the GM300 series, or any other mid powered mobile radios) you must consider these radios are not meant for heavy / continuous duty use. If you are going to have moderate traffic, 20W is fine (with a fan). If your going to have heavy traffic, I'd turn the power down to no more than 12 watts and add a nice heavy muffin fan. I work as a two way radio technician and have seen my share of toasted Mobile PA's. Paul Metzger KQ6EH --- On Feb 4, 2007, at 15:16, texasexpediter wrote: I drive a truck OTR and at times work with FEMA. Would it be possible to put together a mobile repeater system that could be used in areas without power? I have a generator system in my truck so I have 110 power available. My interest would be in something semi permanently installed without need for putting antennas up or down. I realize it would have a rather limited reach but would theoretically allow an ht user 5 miles east of the truck to talk to an ht user 5 miles west of the truck when they wouldn't be able to talk simplex. With mobiles the effective radius presumably would be greater as well. My questions are is this feasible and reasonable? What would be the least expensive system I could put together to do this job? Thanks in advance for all suggestions. 73 Leo K5LDB
RE: [Repeater-Builder] Intermod
Oops I meant to say needs a notch in the receiver tuned to its transmitter. 73 Gary K4FMX _ From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Gary Schafer Sent: Saturday, February 03, 2007 6:02 PM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Intermod The 165 repeater needs an additional notch in its transmitter. 73 Gary K4FMX _ From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Fred Flowers Sent: Saturday, February 03, 2007 5:04 PM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Intermod Steve, Jeff, Nate, Ya'll are on the right track. I did some additional tests. It not the 147.765 subscriber it's the 147.93 subscriber that is throwing the stinky stuff into the fan. Keying the 33 repeater does not cause the 165 repeater to come up. However, when both repeaters are on the air 33 will keep 165 keyed the 33 audio can be heard on the 165 repeater. As soon as the 33 subscriber unkeys the interfering signal on 165 goes away. I a ham not infected with ctcss phobia, therefore 33 (which I built) has RX TX tone. This lets me TX on 33's input not key the repeater. The 165 repeater is not interfered with. Also lowering the power of the 147.930 TX clears the problem. 174.33, 147.93 147.165 have to be on the air to cause the problem in the 147.765 RX. I assume it is in the 147.765 RX, I don't have access to look at RX audio on the 147.165 repeater. Is it valid to add 600 kHz to the intermod calculator? I get an interesting fifth order when I do. 147.9300 MHz - 147.3300 MHz - 147.1650 MHz - 0.6000 MHz - 0.6000 MHz = 147.7650 MHz Right on the 147.165 input. As I said before, the owner may have added a preamp to 147.165 a day or two ago. This problem just came to light last night. These two repeaters have been on the air for years. I was wrong about the spacing, they are 4 miles apart. The 33 repeater equipment was getting tired I replaced it with a Mastr II station repeater two weeks ago. I can't say for sure if the problem started with new 33 equipment or the preamp on 165. It looks to me like the cure is to notch 147.930 at the 147.756 receiver. Anyone have any thoughts. Fred N4GER -Original Message- From: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com [mailto:Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com] On Behalf Of Nate Duehr Sent: Saturday, February 03, 2007 1:35 PM To: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com Subject: Re: [Repeater-Builder] Intermod On 2/3/07, Jeff DePolo [EMAIL PROTECTED] mailto:jeff%40depolo.net net wrote: I think I see how Steve's logic is leaning, and I agree - I don't see any logical mix here until you include a user's transmission on one of the repeater's inputs. Fred - do you hear ALL 147.33 transmitter activity coming in on the 147.765 input, or just when there is actually a user keyed up on 147.93? If the latter, that's a big clue... --- Jeff Yep, that's going to be the key... been there done that... Ye olde 600 KHz split on VHF problem. It creates perfect mixes with users and the repeaters themselves that fall right smack on the input of the next repeater along the band. A close-in high-powered user to a VHF repeater can mix with it with bad results for the next in line machine. Requiring CTCSS on a different tone than the original machine and users will cover up the problem, but not fix it, of course... not a permanent fix, but sometimes necessary. If Jeff's observation is correct, and you only hear input activity... try to find a ham who's rig causes the issue consistently (and you'll probably find that HT users don't, also -- they're usually just too weak to create a strong-enough mix). Then you can have that person lower their power and see if the problem signal on the repeater's input seems to drop out quickly or get much weaker, since you're looking for a mix that would drop off rapidly as one of the transmitter's power levels was lowered. If that's not it... have a 600 KHz AM station in your town? There's always the possibility of other mixes as well... Jeff's test is the kicker to start with -- do you hear the full TX tail of the other repeater or just user input? Does it do it on ALL transmissions or just certain users? Anyone involved in the situation live real close to either repeater, who you know has high gain antennas and runs lots of power? Nate WY0X Yahoo! Groups Links
Re: [Repeater-Builder] mobile repeater setup
On 2/5/07, Dick [EMAIL PROTECTED] wrote: Look around for a used Motorola GR300 repeater. They have a footprint of about one square foot and about 14 high and are quite reliable. A friend has a GR1225 which is Moto's tiny little single radio solution for this type of thing also. Works well. Nate WY0X
Re: [Repeater-Builder] Effects of doubling RF output ...
Tony, Not kowing your system and where it is located and what is at the site. But if you were to make a signaficant increese for the portable performance like 3-6db from what you are using would that be worth the cost. Mike -- Original message -- From: [EMAIL PROTECTED] Tony L. wrote: 1) Will the hundreds we pay to upgrade actually translate into significantly increased range? As others have said -- not significant. But there'll always be someone who'll want to argue the point here ya go: Envision pouring a cup of water on a table top -- it makes a puddle of X radius (range) and (PI * R^2) area. Pouring on a second cup will double the area (at the same depth) .. but the radius increases by only 1/3 at best. Doubling the radius (range) requires LOTS more water. Let the naysayer figure out how much. g /.
[Repeater-Builder] Re: Spam-filters WAS: Intermod
Bob M. wrote: I configured my Yahoo mailbox so it put spam into the BULK folder rather than immediately deleting it. I found this message between 1200 and 1226 EST. So nice of Yahoo to consider this SPAM ! I would surmise that this is why I'm not seeing any of Kevin's messages. Bob M. == It's gotta have something to do with content of the messages, not where they came from, I think. Most spam filters don't like HTML email, which is why I so emphatically encourage people to just use plain text, and NOT HTML. Another thing they look for is image files, .gif's, .jpg's, etc. They also look for certain words and phrases, which is pretty subjective, IMHO. Course, I use Thunderbird and set it so that it converts everything to plain text anyway. MUCH safer that way. And it's adaptive filters work much better then any ISP's filtering. -- Jim Barbour WD8CHL
[Repeater-Builder] Re: Effects of doubling RF output on UHF repeater?
Hello back, Should be a nice change Tony... but you're going to need the proper equipment in place and to consider all the issues before you make the change. Half of our users believe that the repeater's output power is perfectly matched to its receiver. That is, users of high powered mobile radios generally lose repeater reception at about the same time the repeater's receiver loses them. Man are you going to mix up a lot of opinions with the above... We like to call some repeaters alligator machines all mouth and no ears. :-) You didn't say if many of your users have portables or if mobile/base operation is primary for most folks on your system. Some repeater owner/ops don't like/want portables as the primary means to access machine. But keep in mind there are ways to increase the receive side of your repeater. If you improve one side you could also improve the other side... Also remember the antenna is the first and probably only/best free lunch improvement you can make to a repeater. However, the other half of our users believe doubling the repeater's power output would generate increased activity since the repeater could be heard more comfortably. It will... but in some cases you might not want the extra users. Just depends on your user base and what they really want to have on the repeater. 1) Will the hundreds we pay to upgrade actually translate into significantly increased range? Only if the increase can be done without hosing up the receiver performance. Yes if you also increase the repeater performance in most directions. 2) Will we risk generating additional receiver noise by doubling our output power, thus losing coverage in the process? Sure if you don't properly protect the receiver. But keep in mind that jumping to 100 watts is done all the time so you're not just out there on your own. 3) Will using a higher power level shorten the life of other system components over time (e.g., power supply)? Probably not if you play by the rules... By the way, our frequency coordination would be valid even if we doubled our output power. If you don't have a co-channel horses-behind to deal with... great! cheers, skipp
RE: [Repeater-Builder] Effects of doubling RF output on UHF repeater?
Upping the power changes the balance , if you really need to fiddle with it improve the antenna for a boost both ways and at no additional running cost . From: Tony L. [EMAIL PROTECTED] Reply-To: Repeater-Builder@yahoogroups.com To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Effects of doubling RF output on UHF repeater? Date: Mon, 05 Feb 2007 14:47:34 - One of our 70cm Amateur Radio repeaters is currently outputting 50 watts into the duplexer. We're considering replacing the existing RF power amp with a 100 watt model. Current draw on the 50 watt unit is 8 amps. The 100 watt unit will draw 20 amps. Our power supply is rated at 36 amps continuous, and the duplexer is rated at 250 watts. Half of our users believe that the repeater's output power is perfectly matched to its receiver. That is, users of high powered mobile radios generally lose repeater reception at about the same time the repeater's receiver loses them. However, the other half of our users believe doubling the repeater's power output would generate increased activity since the repeater could be heard more comfortably. We could upgrade without changing any of our other infrastructure. However, these questions arise: 1) Will the hundreds we pay to upgrade actually translate into significantly increased range? 2) Will we risk generating additional receiver noise by doubling our output power, thus losing coverage in the process? 3) Will using a higher power level shorten the life of other system components over time (e.g., power supply)? By the way, our frequency coordination would be valid even if we doubled our output power. _ Advertisement: 50% off on Xbox 360, PS and Nintendo Wii titles! http://www.play-asia.com/SOap-23-83-4lab-71-bn-49-en-84-k-40-extended.html
RE: [Repeater-Builder] Mastr II Station Power Supply Problem?
SO what happens when you connect a larger power supply ? From: Bill [EMAIL PROTECTED] Reply-To: Repeater-Builder@yahoogroups.com To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Mastr II Station Power Supply Problem? Date: Sun, 04 Feb 2007 22:01:14 - I'm setting up a Mastr II VHF station for a 2 meter repeater and when I got to the power amp to check everything I can only get about 86 watts out of the 110watt PA. I noticed that the power supply starts to fold over at about 20 watts out and when I get to 80 watts the supply is only at around 8 to 9 volts. This Mastr II station has the PLL exciter but they gave me a 4 transistor power amp the original amp was missing. This is the newer type station with the IDA controller. I looked up the model number of the supply and it's a PL19D430272G1 Rev 4 which shows to be the right power supply for the station. I don't have my spectrum analyzer at the moment so I can't tell if the power amp is spurring although station metering shows below rated current on transmit. Any clues? Bill... _ Advertisement: It's simple! Sell your car for just $20 at carsales.com.au http://a.ninemsn.com.au/b.aspx?URL=http%3A%2F%2Fsecure%2Dau%2Eimrworldwide%2Ecom%2Fcgi%2Dbin%2Fa%2Fci%5F450304%2Fet%5F2%2Fcg%5F801577%2Fpi%5F1005244%2Fai%5F838588_t=757768878_r=endtext_simple_m=EXT
Re: [Repeater-Builder] Effects of doubling RF output on UHF repeater?
If you ever do install the amp, I would suggest lying to the users when it goes on line. Tell them that it is on low power when it is on high and vice versa but don't announce it the instant you change. Wait a while before announcing it. You will very quickly find out who can actually tell the difference. At least that is what we found about 20 years ago when we did a major rearrangement of antennas and lowering power. Nobody honestly could tell the difference and those who agreed with our false conditions were shown to not have a clue (I never did tell them what the experimental results were :-) Burt VE2BMQ Tony L. wrote: One of our 70cm Amateur Radio repeaters is currently outputting 50 watts into the duplexer. We're considering replacing the existing RF power amp with a 100 watt model. Current draw on the 50 watt unit is 8 amps. The 100 watt unit will draw 20 amps. Our power supply is rated at 36 amps continuous, and the duplexer is rated at 250 watts. Half of our users believe that the repeater's output power is perfectly matched to its receiver. That is, users of high powered mobile radios generally lose repeater reception at about the same time the repeater's receiver loses them. However, the other half of our users believe doubling the repeater's power output would generate increased activity since the repeater could be heard more comfortably. We could upgrade without changing any of our other infrastructure. However, these questions arise: 1) Will the hundreds we pay to upgrade actually translate into significantly increased range? 2) Will we risk generating additional receiver noise by doubling our output power, thus losing coverage in the process? 3) Will using a higher power level shorten the life of other system components over time (e.g., power supply)? By the way, our frequency coordination would be valid even if we doubled our output power.
RE: [Repeater-Builder] Mastr II Station Power Supply Problem?
Master II Base Station / Repeater Power Supplies come in four flavors. The most important information is: Two are fused at 15 Amps, and two are fused at 35 amps. If you have the high current model, it has a BUSS NON-35 AMP one-time FUSE (Class K5), and is 3 inches long. The 15 Amp fuse is a NON-15 (obviously), and is considerably smaller in size, and is 2 inches in length. It will be obvious when you look at the fuse holder / fuse. I could look up some model numbers, but this information will tell you if you have the smaller power supply in a BIG BOY application. Bill Hudson W6CBS Subject: RE: [Repeater-Builder] Mastr II Station Power Supply Problem? I'm setting up a Mastr II VHF station for a 2 meter repeater and when I got to the power amp to check everything I can only get about 86 watts . . . BEGIN:VCARD VERSION:2.1 N:;W6CBS FN:W6CBS ORG:Hudson Sports Productions TITLE:Broadcast Engineer TEL;WORK;VOICE:1-650-595-5566 TEL;PREF:1-650-595-5566 ADR;WORK:;1-650-595-5566;P O Box 7143;San Carlos;California;94070;USA LABEL;WORK;ENCODING=QUOTED-PRINTABLE:1-650-595-5566=0D=0AP O Box 7143=0D=0ASan Carlos, California 94070=0D=0AUSA EMAIL;PREF;INTERNET:[EMAIL PROTECTED] REV:20060508T165031Z END:VCARD
RE: [Repeater-Builder] Repeater antennas.
Hi Dan, I have a NOS still in original carton Sinclair SRL 334-2 for sale. $240.00 and it is UPS shippable as it has a 2 part mast. 73 Gary K4FMX _ From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Dan Sent: Saturday, February 03, 2007 8:48 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Repeater antennas. I am looking for opinions on what antenna is good for repeater use that are in the $200-250 dollar range. I am looking at the Antennx and the Hustler 270R. Opinoins? Thanks Dan/NØFPE
Re: [Repeater-Builder] Effects of doubling RF output on UHF repeater?
At 06:47 AM 02/05/07, you wrote: One of our 70cm Amateur Radio repeaters is currently outputting 50 watts into the duplexer. We're considering replacing the existing RF power amp with a 100 watt model. Might want to ask the knowledge base here for recommendations and/or warnings... This group has over 3,000 members and they can tell you what works or doesn't work. Current draw on the 50 watt unit is 8 amps. The 100 watt unit will draw 20 amps. Our power supply is rated at 36 amps continuous, and the duplexer is rated at 250 watts. OK, so the surrounding equipment can handle it. But can the receive side? Might want to mention what repeater you are using, and if you have any RF neighbors at the same site. This can be significant... for example if you have a 375w base on a UHF paging channel in the same building then our recommendations might be a bit different. Half of our users believe that the repeater's output power is perfectly matched to its receiver. That is, users of high powered mobile radios generally lose repeater reception at about the same time the repeater's receiver loses them. Good. Your system isn't an alligator (all mouth and no ears) or an elephant. However, the other half of our users believe doubling the repeater's power output would generate increased activity since the repeater could be heard more comfortably. Big question: Do you want/need the increased activity? The increased power will raise the signal strength out in the fringe areas, and make it easier to hear, but can the users out there get back in? Yes, 3db can be difference between the repeater being heard or not in a fringe area... but it makes ZERO difference if the user can't get into the repeater. That's where the receive side of your system comes into play. If it can't hear them, they all you've done is raise the frustration level because the users expect that if they can hear it then they can get back into it (and if they have supersensitive flea-powered HTs then the ball game is different than if they have 50w mobiles) If you don't meet those expectations then you will have a different set of complaints to handle. Years ago I worked with a midwest group that had a similar coverage problem on 2m. Their solution was unique: they were on a low-end 147MHz channel with a plus offset and simply added a minus offset receiver for the other end of town. They told the users that if they were on the east side to use plus offset and if on the west side to use minus offset. If you boost the transmit power and find yourself up against the physics in repeater receiver performance the only way to get back to a balanced system is to add outlying receivers and linking them back in and voting them. Note that going to a voted environment is a HUGE can of technical worms. See these two articles: http://www.repeater-builder.com/tech-info/remotereceivers.html http://www.repeater-builder.com/tech-info/votingcomparators.html We could upgrade without changing any of our other infrastructure. However, these questions arise: 1) Will the hundreds we pay to upgrade actually translate into significantly increased range? Is there another system at the same site (or nearby) that runs higher power? Can you use them as a test? For example, is there a UHF commercial repeater(even a police/fire one) that has the same or similar ERP of your 100w system? If so, do a coverage check on that channel. If you are friends with the tech people of that system they may already have done a plot. Maybe download a copy of Radio Mobile and do a set of plots for yourself. You will find that boosting the antenna system performance makes more of a change. Remember that 3db more gain or 3db less loss in the antenna system will help the receive side and the transmit side and do it as much as the transmit side gets by doubling the power, and without changing out the transmitter. Note that in many areas coverage can depend on your geography more than the power level. Locally one popular system is limited by the fact that it's in a valley. Twenty watts into 6db does a great job of covering it, but they use 40w only because that's what was on hand. You could boost it from the current 40 to 1,000 watts and all you would do is raise the s-meters (and get further into the underground parking garages). In that environment once you've covered the valley floor, all you end up doing is spinning the AC mains power meter faster. If you have a flat-as-a-pancake service area then increasing the power level makes your footprint larger. But picture this: if you double the area of the footprint (which the 3db won't do, but for simple math, lets say it does), how much larger is the radius? So the answer is, it depends, but usually not as much as you'd like. BTW, this question was asked on this group back in 2004 and answered in 2005... Check out http://www.repeater-builder.com/antenna/3db.html 2) Will we risk generating additional receiver noise by doubling our
[Spam] RE: [Repeater-Builder] Mastr II Station Power Supply Problem?
Hi Jeff! Thanks for the reply. The no load voltage is about 14.1 volts. Bill... -Original message- From: Jeff DePolo [EMAIL PROTECTED] Date: Mon, 05 Feb 2007 16:28:07 -0800 To: Repeater-Builder@yahoogroups.com Subject: [Spam] RE: [Repeater-Builder] Mastr II Station Power Supply Problem? I'm setting up a Mastr II VHF station for a 2 meter repeater and when I got to the power amp to check everything I can only get about 86 watts out of the 110watt PA. I noticed that the power supply starts to fold over at about 20 watts out and when I get to 80 watts the supply is only at around 8 to 9 volts. If this station is using the stock Mastr II supply, my first bet is that the capacitor in the ferro circuit (7.5 uF IIRC) is bad. What's the voltage without load? --- Jeff
RE: [Spam] RE: [Repeater-Builder] Mastr II Station Power Supply Problem?
Pull out the ferro cap and test it. Or alternatively, take the cap out, tape up the leads that went to it, and fire up the supply again and see if you get the same amount of sag under load. If so, then it sure sounds like the cap is open. --- Jeff Hi Jeff! Thanks for the reply. The no load voltage is about 14.1 volts. Bill... -Original message- From: Jeff DePolo [EMAIL PROTECTED] Date: Mon, 05 Feb 2007 16:28:07 -0800 To: Repeater-Builder@yahoogroups.com Subject: [Spam] RE: [Repeater-Builder] Mastr II Station Power Supply Problem? I'm setting up a Mastr II VHF station for a 2 meter repeater and when I got to the power amp to check everything I can only get about 86 watts out of the 110watt PA. I noticed that the power supply starts to fold over at about 20 watts out and when I get to 80 watts the supply is only at around 8 to 9 volts. If this station is using the stock Mastr II supply, my first bet is that the capacitor in the ferro circuit (7.5 uF IIRC) is bad. What's the voltage without load? --- Jeff Yahoo! Groups Links -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.1.411 / Virus Database: 268.17.25/669 - Release Date: 2/4/2007
Re: [Repeater-Builder] Mastr II Station Power Supply Problem?
On 2/5/07, Bill Hudson [EMAIL PROTECTED] wrote: If you have the high current model, it has a BUSS NON-35 AMP one-time FUSE (Class K5), and is 3 inches long. The 15 Amp fuse is a NON-15 (obviously), and is considerably smaller in size, and is 2 inches in length. It will be obvious when you look at the fuse holder / fuse. I could look up some model numbers, but this information will tell you if you have the smaller power supply in a BIG BOY application. Visually, this is the black plastic soap dish fuse holder versus the larger fuse holder directly bolted on the back with a metal shield over it. I could probably take photos of both types given enough time, if someone badly wanted them. I just racked a soap dish into a very difficult rack to get things in and out of, though -- so it'd be no fun to pull it back out and shoot a digital pic... (sigh - bad timing, as always...). Nate WY0X
RE: [SPAM] RE: [Repeater-Builder] Intermod
I knew what you meant, thanks. Fred N4GER -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Gary Schafer Sent: Monday, February 05, 2007 11:43 AM To: Repeater-Builder@yahoogroups.com Subject: [SPAM] RE: [Repeater-Builder] Intermod Oops I meant to say needs a notch in the receiver tuned to its transmitter. 73 Gary K4FMX _ From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Gary Schafer Sent: Saturday, February 03, 2007 6:02 PM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Intermod The 165 repeater needs an additional notch in its transmitter. 73 Gary K4FMX _ From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Fred Flowers Sent: Saturday, February 03, 2007 5:04 PM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Intermod Steve, Jeff, Nate, Ya'll are on the right track. I did some additional tests. It not the 147.765 subscriber it's the 147.93 subscriber that is throwing the stinky stuff into the fan. Keying the 33 repeater does not cause the 165 repeater to come up. However, when both repeaters are on the air 33 will keep 165 keyed the 33 audio can be heard on the 165 repeater. As soon as the 33 subscriber unkeys the interfering signal on 165 goes away. I a ham not infected with ctcss phobia, therefore 33 (which I built) has RX TX tone. This lets me TX on 33's input not key the repeater. The 165 repeater is not interfered with. Also lowering the power of the 147.930 TX clears the problem. 174.33, 147.93 147.165 have to be on the air to cause the problem in the 147.765 RX. I assume it is in the 147.765 RX, I don't have access to look at RX audio on the 147.165 repeater. Is it valid to add 600 kHz to the intermod calculator? I get an interesting fifth order when I do. 147.9300 MHz - 147.3300 MHz - 147.1650 MHz - 0.6000 MHz - 0.6000 MHz = 147.7650 MHz Right on the 147.165 input. As I said before, the owner may have added a preamp to 147.165 a day or two ago. This problem just came to light last night. These two repeaters have been on the air for years. I was wrong about the spacing, they are 4 miles apart. The 33 repeater equipment was getting tired I replaced it with a Mastr II station repeater two weeks ago. I can't say for sure if the problem started with new 33 equipment or the preamp on 165. It looks to me like the cure is to notch 147.930 at the 147.756 receiver. Anyone have any thoughts. Fred N4GER -Original Message- From: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com [mailto:Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com] On Behalf Of Nate Duehr Sent: Saturday, February 03, 2007 1:35 PM To: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com Subject: Re: [Repeater-Builder] Intermod On 2/3/07, Jeff DePolo [EMAIL PROTECTED] mailto:jeff%40depolo.net net wrote: I think I see how Steve's logic is leaning, and I agree - I don't see any logical mix here until you include a user's transmission on one of the repeater's inputs. Fred - do you hear ALL 147.33 transmitter activity coming in on the 147.765 input, or just when there is actually a user keyed up on 147.93? If the latter, that's a big clue... --- Jeff Yep, that's going to be the key... been there done that... Ye olde 600 KHz split on VHF problem. It creates perfect mixes with users and the repeaters themselves that fall right smack on the input of the next repeater along the band. A close-in high-powered user to a VHF repeater can mix with it with bad results for the next in line machine. Requiring CTCSS on a different tone than the original machine and users will cover up the problem, but not fix it, of course... not a permanent fix, but sometimes necessary. If Jeff's observation is correct, and you only hear input activity... try to find a ham who's rig causes the issue consistently (and you'll probably find that HT users don't, also -- they're usually just too weak to create a strong-enough mix). Then you can have that person lower their power and see if the problem signal on the repeater's input seems to drop out quickly or get much weaker, since you're looking for a mix that would drop off rapidly as one of the transmitter's power levels was lowered. If that's not it... have a 600 KHz AM station in your town? There's always the possibility of other mixes as well... Jeff's test is the kicker to start with -- do you hear the full TX tail of the other repeater or just user input? Does it do it on ALL transmissions or just certain users? Anyone involved in the situation live real close to either repeater, who you know has high gain antennas and runs lots of power? Nate WY0X Yahoo! Groups Links
Re: [Repeater-Builder] Effects of doubling RF output on UHF repeater?
On 2/5/07, Burt Lang [EMAIL PROTECTED] wrote: If you ever do install the amp, I would suggest lying to the users when it goes on line. Tell them that it is on low power when it is on high and vice versa but don't announce it the instant you change. Wait a while before announcing it. You will very quickly find out who can actually tell the difference. At least that is what we found about 20 years ago when we did a major rearrangement of antennas and lowering power. Nobody honestly could tell the difference and those who agreed with our false conditions were shown to not have a clue (I never did tell them what the experimental results were :-) Burt VE2BMQ Agreed Burt -- or if not lying, not saying a word. Sounds dumb, but there are a million factors OTHER than the repeater that affect how a particular user is hearing the machine -- and many don't know how to logically remove the changes THEY'RE making from the changes happening to the repeater... if they THINK it sounds worse after a change... then they'll complain, even if the system is actually performing BETTER. Nate WY0X
Re: [Repeater-Builder] Effects of doubling RF output on UHF repeater?
On 2/5/07, Barry C' [EMAIL PROTECTED] wrote: Upping the power changes the balance , if you really need to fiddle with it improve the antenna for a boost both ways and at no additional running cost Unless you're running separate antennas, how would changing the gain of the antenna make a difference in additional gain for RX that wouldn't be also seen in additional gain for TX? But unless I'm missing something here (deep nulls and fading due to terrain or something?) the added gain of a better antenna on receive would translate to the same on TX, doesn't it? The only reasonable way to get more RX without affecting TX would be (pre-)amplification of the receive chain and additional filtering if necessary to avoid desense, etc. If there's a suspicion that the system isn't performing as absolutely well as it can on RX, a usable receiver sensitivity test with a weak signal injected into the RX chain with the antenna connected also, would be the way to find out. Jeff's article about measuring the sensitivity of a receiver WITHOUT the site noise/antenna connected is here: http://www.repeater-builder.com/tech-info/receiversensitivity.html And doing it WITH the site noise/antenna is here: http://www.repeater-builder.com/tech-info/effectivesens.html If there's 2 or 3 more dB available between the site noise floor and the receiver's best sensitivity measurements -- then sure, maybe you can squeak all of that out with better filters, a good LNA and balance the added TX power. That will take additional money/time/effort beyond just swapping the PA for a bigger one and checking for desense. And... no one's posted this here in the discussion yet... http://www.repeater-builder.com/antenna/3db.html ... which of course, is a good discussion of the situation too, since it actually starts with the same theoretical question (should I add 3dB to my transmitter?) and tackles the analysis of adding 3dB to a system mathematically. Hopefully the above articles help. And if you haven't done the Effective Sensitivity test, do it BEFORE you make any changes. It will give you a baseline so you know if relatively you're making things better, or worse, overall on RX. Nate WY0X
Re: [Repeater-Builder] Effects of doubling RF output on UHF repeater?
Spend the money on a more modern receiver designed for repeater ops, get a fresh antenna like a Station Master, and use the best run of heli-ax and premium connectors you can afford and you will see just as much improvement if not better. External power Amplifiers and more power output will do some things you might not like. Your receiver noise floor will increase. Any filters you have in line with the low power setting might now act up on the higher power output. Ditto with the coaxial connectors. You might see more intermod and have to install more gadgets that would go wrong or go wrong when you least want to. Ask yourself if you want a gadgety repeater or one that will operate when the lights go out or even when there is bad weather out there. I build a couple and learned the hard way. Adam Kb2jpd On 2/5/07, Nate Duehr [EMAIL PROTECTED] wrote: On 2/5/07, Barry C' [EMAIL PROTECTED] atec77%40hotmail.com wrote: Upping the power changes the balance , if you really need to fiddle with it improve the antenna for a boost both ways and at no additional running cost Unless you're running separate antennas, how would changing the gain of the antenna make a difference in additional gain for RX that wouldn't be also seen in additional gain for TX? But unless I'm missing something here (deep nulls and fading due to terrain or something?) the added gain of a better antenna on receive would translate to the same on TX, doesn't it? The only reasonable way to get more RX without affecting TX would be (pre-)amplification of the receive chain and additional filtering if necessary to avoid desense, etc. If there's a suspicion that the system isn't performing as absolutely well as it can on RX, a usable receiver sensitivity test with a weak signal injected into the RX chain with the antenna connected also, would be the way to find out. Jeff's article about measuring the sensitivity of a receiver WITHOUT the site noise/antenna connected is here: http://www.repeater-builder.com/tech-info/receiversensitivity.html And doing it WITH the site noise/antenna is here: http://www.repeater-builder.com/tech-info/effectivesens.html If there's 2 or 3 more dB available between the site noise floor and the receiver's best sensitivity measurements -- then sure, maybe you can squeak all of that out with better filters, a good LNA and balance the added TX power. That will take additional money/time/effort beyond just swapping the PA for a bigger one and checking for desense. And... no one's posted this here in the discussion yet... http://www.repeater-builder.com/antenna/3db.html ... which of course, is a good discussion of the situation too, since it actually starts with the same theoretical question (should I add 3dB to my transmitter?) and tackles the analysis of adding 3dB to a system mathematically. Hopefully the above articles help. And if you haven't done the Effective Sensitivity test, do it BEFORE you make any changes. It will give you a baseline so you know if relatively you're making things better, or worse, overall on RX. Nate WY0X
[Repeater-Builder] a tiny bit OT, but interesting (tower topples in Florida)
hope you're not in the shelter/building when one comes down! http://beradio.com/news/wcfb_tower_toppled/index.html
RE: [Repeater-Builder] Mastr II Station Power Supply Problem?
There's a safety note on the GE ferroresonant supply plus some info on fuse sizes here: http://www.repeater-builder.com/ge/mastr2/m2-arcing.html Mike WA6ILQ At 01:32 PM 02/05/07, you wrote: Master II Base Station / Repeater Power Supplies come in four flavors. The most important information is: Two are fused at 15 Amps, and two are fused at 35 amps. If you have the high current model, it has a BUSS NON-35 AMP one-time FUSE (Class K5), and is 3 inches long. The 15 Amp fuse is a NON-15 (obviously), and is considerably smaller in size, and is 2 inches in length. It will be obvious when you look at the fuse holder / fuse. I could look up some model numbers, but this information will tell you if you have the smaller power supply in a BIG BOY application. Bill Hudson W6CBS Subject: RE: [Repeater-Builder] Mastr II Station Power Supply Problem? I'm setting up a Mastr II VHF station for a 2 meter repeater and when I got to the power amp to check everything I can only get about 86 watts . . .
[Repeater-Builder] wanted: Low band, low split micor receiver
Searching for a friend.. Prefer rack mount. For use just above 30mhz or so.. Whatcha got? Buy, trade, etc.. df
RE: [Repeater-Builder] Effects of doubling RF output on UHF repeater?
Tony, As you can tell from the number of replies, this is a topic that generates a great deal of interest! I agree with the majority of posters who state that a power increase will have relatively minor positive effect, and MAY have significant negative effects. In fact, one fellow posted a comment a year or two ago, that his 50 watt PA died, and he connected the exciter directly to the duplexer in place of the PA for several weeks- a 100:1 change in power output- and none of the regular users noticed the difference! In this particular case, the repeater was far from being balanced. Nevertheless, it does lend credence to the oft-repeated statement that increased power does not equate to increased coverage. It has been stated many times on this and other sites that the primary limitation of repeater coverage is the ability of the repeater to hear the radios in the field. If the pipsqueak-power handheld portable radios in the field cannot reach the repeater's receiver, no amount of power increase will make any difference. Quite the contrary, as many have pointed out, more power will possibly increase receiver noise and/or desense, intermodulation, and other ills. These MAY have the effect of reducing the coverage area! I strongly suggest that a thorough analysis be performed on the entire system, to ensure that the feedline loss is as low as it can possibly be, the antenna gain and pattern is appropriate for its location, and the receive chain is as efficient and noise-free as possible. If your site noise floor is low, you MAY be able to profoundly improve your coverage with a couple of bandpass cavities followed by a very good preamp, between the duplexer output and the receiver input. A preamp is never the final answer but when appropriately filtered CAN result in a significant improvement. Please note that I have emphasized the words MAY and CAN. I have learned from experience that effective site engineering comes from a proper consideration of all factors. Moreover, the knee-jerk suggestion that an increase in power output will solve repeater coverage issues is laughably misguided. I sincerely hope that you can convince your repeater users that a careful analysis of the repeater operation may reveal other, more effective means to improve its coverage. 73, Eric Lemmon WB6FLY From: Tony L. [EMAIL PROTECTED] mailto:railtrailbiker%40yahoo.com Reply-To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Subject: [Repeater-Builder] Effects of doubling RF output on UHF repeater? Date: Mon, 05 Feb 2007 14:47:34 - One of our 70cm Amateur Radio repeaters is currently outputting 50 watts into the duplexer. We're considering replacing the existing RF power amp with a 100 watt model. Current draw on the 50 watt unit is 8 amps. The 100 watt unit will draw 20 amps. Our power supply is rated at 36 amps continuous, and the duplexer is rated at 250 watts. Half of our users believe that the repeater's output power is perfectly matched to its receiver. That is, users of high powered mobile radios generally lose repeater reception at about the same time the repeater's receiver loses them. However, the other half of our users believe doubling the repeater's power output would generate increased activity since the repeater could be heard more comfortably. We could upgrade without changing any of our other infrastructure. However, these questions arise: 1) Will the hundreds we pay to upgrade actually translate into significantly increased range? 2) Will we risk generating additional receiver noise by doubling our output power, thus losing coverage in the process? 3) Will using a higher power level shorten the life of other system components over time (e.g., power supply)? By the way, our frequency coordination would be valid even if we doubled our output power.
RE: [Repeater-Builder] Motorola R2600 Service Monitor Display Problem
James, I recently purchased an R2600D Service Monitor, and it has none of those problems. Since it has a color LCD display panel instead of a CRT, I have to wonder how it could act like that. If your unit has a CRT, perhaps it is the R2600C model. Regardless of the problem, contact Doyle Wofford at General Dynamics, the manufacturer of the R2600 series. His phone number is 480-441-0664, and his e-mail is [EMAIL PROTECTED] Doyle is the tech support engineer for the R2600 series. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of crackedofn0de Sent: Monday, February 05, 2007 6:16 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Motorola R2600 Service Monitor Display Problem I have an R2600D with a minor display problem. When first powered up, the picture wiggles, jiggles, and squeezes in and out ever so slightly both in the vertical and the horizontal. This problem doesn't affect readability of the display much, but it's at least annoying, and I'd rather not wait for it to get worse. Once the unit is warmed up, the situation improves and pretty much goes away. I could guess high voltage problem but could this by chance be a known problem for the R2600D with a common fix? James K7ICU
RE: [Repeater-Builder] Effects of doubling RF output on UHF repeater?
I may as well chime in here too. When adding a pre-amp don't overlook the fact that you may not always get out of the addition of the pre-amp what you think you will. Every cavity that is ahead of the pre-amp has loss. Sometimes it requires additional cavities which increases the loss over what you had without the pre-amp. You may end up with a total receiver noise figure the same as when you started depending on how bad the receiver is in the first place. But in most cases it should help some. Be prepared to start chasing IM problems though! Not that a pre-amp is an IM generator but you will see many more problems that may have been hidden before. I think someone mentioned measuring site noise as a first step. If you don't do that you may waste many many hours chasing problems of why the pre-amp doesn't work that could have been easily discovered up front. Desense and site noise measurements are on the top of the list. 73 Gary K4FMX _ From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Eric Lemmon Sent: Monday, February 05, 2007 8:54 PM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Effects of doubling RF output on UHF repeater? Tony, As you can tell from the number of replies, this is a topic that generates a great deal of interest! I agree with the majority of posters who state that a power increase will have relatively minor positive effect, and MAY have significant negative effects. In fact, one fellow posted a comment a year or two ago, that his 50 watt PA died, and he connected the exciter directly to the duplexer in place of the PA for several weeks- a 100:1 change in power output- and none of the regular users noticed the difference! In this particular case, the repeater was far from being balanced. Nevertheless, it does lend credence to the oft-repeated statement that increased power does not equate to increased coverage. It has been stated many times on this and other sites that the primary limitation of repeater coverage is the ability of the repeater to hear the radios in the field. If the pipsqueak-power handheld portable radios in the field cannot reach the repeater's receiver, no amount of power increase will make any difference. Quite the contrary, as many have pointed out, more power will possibly increase receiver noise and/or desense, intermodulation, and other ills. These MAY have the effect of reducing the coverage area! I strongly suggest that a thorough analysis be performed on the entire system, to ensure that the feedline loss is as low as it can possibly be, the antenna gain and pattern is appropriate for its location, and the receive chain is as efficient and noise-free as possible. If your site noise floor is low, you MAY be able to profoundly improve your coverage with a couple of bandpass cavities followed by a very good preamp, between the duplexer output and the receiver input. A preamp is never the final answer but when appropriately filtered CAN result in a significant improvement. Please note that I have emphasized the words MAY and CAN. I have learned from experience that effective site engineering comes from a proper consideration of all factors. Moreover, the knee-jerk suggestion that an increase in power output will solve repeater coverage issues is laughably misguided. I sincerely hope that you can convince your repeater users that a careful analysis of the repeater operation may reveal other, more effective means to improve its coverage. 73, Eric Lemmon WB6FLY From: Tony L. railtrailbiker@ mailto:railtrailbiker%40yahoo.com yahoo.com mailto:railtrailbiker%40yahoo.com Reply-To: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com To: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Subject: [Repeater-Builder] Effects of doubling RF output on UHF repeater? Date: Mon, 05 Feb 2007 14:47:34 - One of our 70cm Amateur Radio repeaters is currently outputting 50 watts into the duplexer. We're considering replacing the existing RF power amp with a 100 watt model. Current draw on the 50 watt unit is 8 amps. The 100 watt unit will draw 20 amps. Our power supply is rated at 36 amps continuous, and the duplexer is rated at 250 watts. Half of our users believe that the repeater's output power is perfectly matched to its receiver. That is, users of high powered mobile radios generally lose repeater reception at about the same time the repeater's receiver loses them. However, the other half of our users believe doubling the repeater's power output would generate increased activity since the repeater could be heard more comfortably. We could upgrade without changing any of our other infrastructure. However, these questions arise: 1) Will the hundreds we pay to upgrade actually translate into significantly increased range? 2) Will we risk generating
[Repeater-Builder] Re: Motorola R2600 Service Monitor Display Problem
What do you know...I do indeed have a R2600B with the CRT. Says so on the bottom. Should have verified that first. I'll give Doyle a try tomorrow. It'll be interesting to see if fixing this is less expensive than just selling my B and buying a used D. (Still waiting for somebody to say Just replace C13 and you'll be good to go!) James K7ICU --- In Repeater-Builder@yahoogroups.com, Eric Lemmon [EMAIL PROTECTED] wrote: James, I recently purchased an R2600D Service Monitor, and it has none of those problems. Since it has a color LCD display panel instead of a CRT, I have to wonder how it could act like that. If your unit has a CRT, perhaps it is the R2600C model. Regardless of the problem, contact Doyle Wofford at General Dynamics, the manufacturer of the R2600 series. His phone number is 480-441-0664, and his e-mail is [EMAIL PROTECTED] Doyle is the tech support engineer for the R2600 series. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of crackedofn0de Sent: Monday, February 05, 2007 6:16 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Motorola R2600 Service Monitor Display Problem I have an R2600D with a minor display problem. When first powered up, the picture wiggles, jiggles, and squeezes in and out ever so slightly both in the vertical and the horizontal. This problem doesn't affect readability of the display much, but it's at least annoying, and I'd rather not wait for it to get worse. Once the unit is warmed up, the situation improves and pretty much goes away. I could guess high voltage problem but could this by chance be a known problem for the R2600D with a common fix? James K7ICU
Re: [Repeater-Builder] Motorola R2600 Service Monitor Display Problem
At 06:16 PM 02/05/07, you wrote: I have an R2600D with a minor display problem. When first powered up, the picture wiggles, jiggles, and squeezes in and out ever so slightly both in the vertical and the horizontal. This problem doesn't affect readability of the display much, but it's at least annoying, and I'd rather not wait for it to get worse. Once the unit is warmed up, the situation improves and pretty much goes away. I could guess high voltage problem but could this by chance be a known problem for the R2600D with a common fix? James K7ICU Check the power supply filter caps for leakage. And BTW, I'm looking for an R2600 service manual, if you know of anywhere I can get it. Even a PDF of one. Mike
[Repeater-Builder] Simplex repeater
Hi all what do I need to put together a simplex repeater without using a recording device.I would like to hook up 2 radios and antennas.Thanks for any input.KC0USN 73's Do simplex repeaters require Frequency cordinater to give frequency or can you pick your own?
RE: [Repeater-Builder] Simplex repeater
Hmm, maybe it's just syntax, but a simplex repeater uses ONE frequency (i.e.simplex) as opposed a duplex repeater using two frequencies. A simplex repeater MUST store and forward (record) since it is self defeating to transmit and receive on the same frequency at the same time from the same location. Since you say you are using two radios, I can only assume you want to receive and transmit at the same time on two different frequencies, thus a duplex repeater. You can quite easily do this with two radios and a small 'controller' such as the hamtronics products. Good luck N7HQR _ From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of IF YOUR NICE I MAY TELL YOU Sent: Monday, February 05, 2007 4:01 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Simplex repeater Hi all what do I need to put together a simplex repeater without using a recording device.I would like to hook up 2 radios and antennas.Thanks for any input.KC0USN 73's Do simplex repeaters require Frequency cordinater to give frequency or can you pick your own?
[Repeater-Builder] Trying to put together Vhf 2 meter repeater.
Hi all Im trying to put together a vhf 2 meter repeater as cheap as possible.If any one has any good parts to trade or such please email and let me know I got some trading material also.Thanks and 73's
[Repeater-Builder] Antenna separation article
I am rather new to this group and maybe shouldn't be critical of anything on the site at this stage but here it goes anyway. I notice in the below referenced article on antenna separation that it is stated that the graphs are misleading and no where near accurate for modern day solid state equipment. http://www.repeater http://www.repeater-builder.com/antenna/separation.html -builder.com/antenna/separation.html That is not correct as the graphs for antenna isolation show approximately how much isolation can be expected with a given amount of separation either vertically or horizontally. This has nothing to do with the amount of isolation NEEDED for proper duplex operation. The amount of isolation needed is a function of the transmitter and receiver being used. One type of tx-rx combination may need a different amount of isolation than another type used with the same antenna isolation. Maybe someone would want to correct the above? As another note in the article it suggested using a spectrum analyzer to tune the receiver's local oscillator chain for lowest noise. While that is one approach, an easier and probably more accurate way of doing it is to use a sinadder on the receiver while tuning it up. Tuning everything for best sinadd will result in best signal to noise performance of the receiver which would also include lowest noise out of the local oscillator chain. I hope I don't step on any toes here. 73 Gary K4FMX
Re: [Repeater-Builder] Antenna separation article
At 2/5/2007 19:51, you wrote: As another note in the article it suggested using a spectrum analyzer to tune the receiver s local oscillator chain for lowest noise. While that is one approach, an easier and probably more accurate way of doing it is to use a sinadder on the receiver while tuning it up. Tuning everything for best sinadd will result in best signal to noise performance of the receiver which would also include lowest noise out of the local oscillator chain. Yes, but there is another major consideration when talking about repeater receivers ( this is the Repeater-Builder list): dynamic range. Tuning the LO for best SINAD gives you best sensitivity, but if the LO has significant spurious content, that will translate into spurious responses in the receiver. The LO tuning instructions for the G.E. MVP/Exec II/Mastr II RXs do not take SINAD into consideration except for the final step, where you're allowed to make only minor tweaks to the LO tuning. This is probably to assure that the LO stays clean. Bob NO6B
