Re: [Repeater-Builder] Re: Rohn 25g Tower
Just a brief note on two towers I had installed for over 35 years. I used three of the Radio Shack mast base mounts in the ground to support the tower with Rhon house brackets. These units consisted of a square metal plate, about six inches, with an 18 inch piece of sharpened angle welded to the bottom and a piece of round tubing about six inches long welded to the top. Over the years I had to loosen the U bolts holding the house bracket to the tower and move them up the tower to compensate for the tower settling into the ground. The towers were 40 and 60 ft, and the 60 ft supported an tri band beam and vertical antenna while the 40 ft tower supported a DB-224 and a tri band beam. I started with American tower but lost both towers due to sheer in a tornado at about the level of the house bracket. The towers did not come down but were tilted about 30 degrees off vertical. I replaced them with Rhon 25G and had no more problems. The American tower did not have any diagonal bracing. 73 - Jim W5ZIT Al Wolfe [EMAIL PROTECTED] wrote: Normally, putting ANY concrete under a properly house bracketed tower is a mistake. There used to be a Rohn letter out about it. Had to do with two immovable objects, that is, the house and the concrete base and the motion of the tower between them. Towers do flex in the wind and change dimensions with temperature. Rohn said that house bracketing any tower on a concrete base compromised it's strength. This is not an issue with guyed towers not using a house bracket. Back in the 1960's as a poor college student one of my part time jobs was with a company who did TV towers installs. (This was when we sold Rohn 25 straight sections for $7.50 each.) The company did literally hundreds of Rohn 25 installs to typically thirty to fifty feet. The rule was to go twenty feet above the house bracket. None were guyed. We never used any concrete. The house bracket did the work and was installed first into something substantial, usually a backing board or plate in the attic. A plumb line was dropped from the house bracket and a hole was dug about two feet deep. We then put in a couple of inches of pea gravel for drainage and two bricks for the tower to set on. The tower up to the house bracket was then installed and plumbed. The hole was filled and tamped. Then the tower sections above the house bracket and the antenna, rotor, twinlead, etc. were installed. We never had a house bracket or tower failure using these methods. Some of these towers from forty years ago are still around although most are gone because of cable or rust, but none ever failed because of the installation method. I have two towers installed this way here at my home, one 50 feet and one 40 feet, that have been up since 1979. Other than needing a little paint, they are still perfect. Al, K9SI - Got a little couch potato? Check out fun summer activities for kids.
Re: [Repeater-Builder] Using SPLAT or RM to reverse plot a repeater?
On Tue, 31 Jul 2007, Bill Powell wrote: Looking for experience and advice in using SPLAT or RM to reverse plot a repeater. What I'd like to do is identify holes in the current coverage and run a plot with SPLAT or RM with the holes as the center point to identify potential repeater sites. Do I use mobile parameters (antenna height) at the hole or do I use an estimated height of 100' assuming that I'll have a 100' tower at the new site? Restated - how do I insure that reciprocal results are reliable? You're gonna need a lot of computing power. A LOT of computing power. -- Kris Kirby, KE4AHR [EMAIL PROTECTED] * WAR IS PEACE * FREEDOM IS SLAVERY * * IGNORANCE IS STRENGTH * KETCHUP IS * * A VEGETABLE *
Re: [Repeater-Builder] Using SPLAT or RM to reverse plot a repeater?
* Bill Powell [EMAIL PROTECTED] [2007 Jul 30 20:34 -0500]: Looking for experience and advice in using SPLAT or RM to reverse plot a repeater. What I'd like to do is identify holes in the current coverage and run a plot with SPLAT or RM with the holes as the center point to identify potential repeater sites. Do I use mobile parameters (antenna height) at the hole or do I use an estimated height of 100' assuming that I'll have a 100' tower at the new site? I would start with mobile parameters and the hole as the center point and do a coverage plat to an antenna at 100' AGL. With most versions of SPLAT! this will show theoretical line of sight. You should clearly see the results of earth elevation changes. You can also tell later versions of SPLAT! to use a Longley-Rice model that more approximates an RF path than line of sight. Restated - how do I insure that reciprocal results are reliable? That is tough to do as the computer programs can't account for foliage and man made structures that will cause further path loss. Up until the last release or so SPLAT! only calculated line of sight. Now it includes a longley-Rice model option I think John is working on other algorithms for the current version. Have you sent John an email about this? He is quite responsive and would know as well as any one how you might approach your problem with SPLAT!. - 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] Using SPLAT or RM to reverse plot a repeater?
* Kris Kirby [EMAIL PROTECTED] [2007 Jul 31 04:41 -0500]: On Tue, 31 Jul 2007, Bill Powell wrote: Looking for experience and advice in using SPLAT or RM to reverse plot a repeater. What I'd like to do is identify holes in the current coverage and run a plot with SPLAT or RM with the holes as the center point to identify potential repeater sites. Do I use mobile parameters (antenna height) at the hole or do I use an estimated height of 100' assuming that I'll have a 100' tower at the new site? Restated - how do I insure that reciprocal results are reliable? You're gonna need a lot of computing power. A LOT of computing power. As compared to? I routinely run SPLAT! coverage plots on my trusty 1.333 GHz Pentium III based T23 laptop. Yes, it may take a couple of minutes to chew through some of the more demanding plots. For SPLAT! purposes, enough computing power is available on the used market for even the most frugal ham. Even in the case of SPLAT!, memory is more important than CPU speed. I have 768 MiB in the laptop and a full GiB wouldn't hurt, but it really isn't worth tossing a 256 MiB chip for a 512 MiB one. Opening the PPM files generated by GNU Plot in the Gimp is no problem for my T23 either. I do this work on a Slackware partition which is quite a bit leaner than my Debian partition which I have set up for as a rich desktop. 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] Using SPLAT or RM to reverse plot a repeater?
Nate Bargmann wrote: * Kris Kirby [EMAIL PROTECTED] [2007 Jul 31 04:41 -0500]: On Tue, 31 Jul 2007, Bill Powell wrote: Looking for experience and advice in using SPLAT or RM to reverse plot a repeater. What I'd like to do is identify holes in the current coverage and run a plot with SPLAT or RM with the holes as the center point to identify potential repeater sites. Do I use mobile parameters (antenna height) at the hole or do I use an estimated height of 100' assuming that I'll have a 100' tower at the new site? Restated - how do I insure that reciprocal results are reliable? You're gonna need a lot of computing power. A LOT of computing power. As compared to? I routinely run SPLAT! coverage plots on my trusty 1.333 GHz Pentium III based T23 laptop. Yes, it may take a couple of minutes to chew through some of the more demanding plots. For SPLAT! purposes, enough computing power is available on the used market for even the most frugal ham. Even in the case of SPLAT!, memory is more important than CPU speed. I have 768 MiB in the laptop and a full GiB wouldn't hurt, but it really isn't worth tossing a 256 MiB chip for a 512 MiB one. Opening the PPM files generated by GNU Plot in the Gimp is no problem for my T23 either. I do this work on a Slackware partition which is quite a bit leaner than my Debian partition which I have set up for as a rich desktop. 73, de Nate Oh, duh, missed your OS...;cP -- Jim Barbour WD8CHL
Re: [Repeater-Builder] Using SPLAT or RM to reverse plot a repeater?
Nate Bargmann wrote: Even in the case of SPLAT!, memory is more important than CPU speed. I have 768 MiB in the laptop and a full GiB wouldn't hurt, but it really isn't worth tossing a 256 MiB chip for a 512 MiB one. Opening the PPM files generated by GNU Plot in the Gimp is no problem for my T23 either. I do this work on a Slackware partition which is quite a bit leaner than my Debian partition which I have set up for as a rich desktop. 73, de Nate Especially since I remember seeing somewhere that Win98 won't correctly allocate more then 512M of RAM. -- Jim Barbour WD8CHL
[Repeater-Builder] Micor Repeater
It has been suggested that before one adds a controller to the repeater it is best to have it repeat in it's original configuration. This unit was part of the VHF Provincial Mobile Telephone system and in its present form I can get it to repeat only after dialing the code that puts the transmitter on continuously. Eventually after being quiet for a time (no COS) the transmitter times out and you have to dial up to get it to operate again. Presently it has the following cards installed, left to right, Decoder filter STLN89HDT, TC Logic, Logic Module STLN932, Squelch Gate TLN4662A, Jackfield Module, Time Out Timer TRN8684A, Tel. Interface, Station control module TLN4635B, Line Driver Module. I am sure there is a reader to tell me that most of this stuff can be pulled out and a jumper changed here or there will get it going in a normal fashion. I hate to put a quick and dirty COS gate and relay on the Back Plane when a simple change to a plug in module will get it going. Receiver and Transmitter tuned up on the 144/145 band perfectly. Lots of good reading on this site, thanks for this opportunity, 73, Gordon.
Re: [Repeater-Builder] Re: Radius M120
On Tue, 31 Jul 2007 10:14:10 jwpauler [EMAIL PROTECTED] wrote: Jay, Ed All... Thanks for the pinout list and RSS advice, I'll try all of that tonight. In case it matters... The RSS I'm using is for the GM300's, which works great for those radios, I can program the option pins on the accessory connector with this software; when connecting a M120 and using the same software, I have the ability to program the radio, but I loose the option to customize the pins! This doesn't make sense! [...] Justin The M120 has the 2-layer logic board whereas the GM300 has the 4-layer logic board. On the 2-layer board the functions of the accessory pins are not software-programmable. -- === Rodney S Baker VK5ZTV [EMAIL PROTECTED] ===
[Repeater-Builder] Com Spec TS-32HB
Does anyone have the data sheet on a TS-32HB CTCSS unit ? It is a very small unit with a 4 and an 8 pin header, and a 5 section dip switch to set the tones. It looks very different from the normal TS-32 Com Spec has it in their Fax back list but I can't get my fax to receive calls manually. They don't have it as a regular download. 73 John VE3AMZ
RE: [Repeater-Builder] Using SPLAT or RM to reverse plot - where to get?
Judging from the variety of responses to this thread, there seems to be far too much confidence placed in low-cost or free coverage plotting software. Even the professional-grade programs like ComStudy share the same limitation: They can estimate coverage area and dead spots based upon input data, but they are not perfect. You can plug in a digital elevation model that is supposedly accurate to 30 meters or better, but it is not perfect. Such models do not include trees, sand dunes, buildings, or similar dips and peaks that may throw off the calculations. It is a mistake to assume that the coverage or lack thereof will be perfectly modeled by computer software- regardless of the computing power. Even though I own ComStudy 2.2, including the high-resolution digital elevation models, I still use a BVS Coyote instrument to determine actual coverage. This unit contains modular receivers that are calibrated for measuring input signal level. The Coyote also contains a GPS receiver for logging the position and time. A low-power transmitter, usually about one watt, is placed in continuous operation at the site to be plotted. The Coyote is put in a vehicle that has a simple omni whip antenna on the roof, positioned so that the direction of arrival of the test signal has relatively little effect. The car is then driven around the intended coverage area, while the Coyote is measuring and recording the received signal strength and storing same onto a memory card. Later, the data are processed to create a map showing the signal strength in color along the routes of travel. Although the Coyote pretty much agreed with the ComStudy plots, there were many coverage holes that appeared in the Coyote data that were invisible in the ComStudy data. There's not much I can do to correct such dead spots, other than move the transmitter to a different site. Moreover, these drive tests often prove that the best coverage is not always achieved from the highest site in the area. 73, Eric Lemmon WB6FLY Looking for experience and advice in using SPLAT or RM to reverse plot a repeater. What I'd like to do is identify holes in the current coverage and run a plot with SPLAT or RM with the holes as the center point to identify potential repeater sites. Do I use mobile parameters (antenna height) at the hole or do I use an estimated height of 100' assuming that I'll have a 100' tower at the new site? Restated - how do I insure that reciprocal results are reliable?
RE: [Repeater-Builder] Com Spec TS-32HB
John, Perhaps it's just as well- the data sheet on Com-Spec's fax-back service is incorrect, page 4 is a duplicate of page 2. The complete TS-32HB Instruction Sheet will be posted on the RBTIP site soon. I am sending you a copy directly. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of John J. Riddell Sent: Tuesday, July 31, 2007 8:22 AM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Com Spec TS-32HB Does anyone have the data sheet on a TS-32HB CTCSS unit ? It is a very small unit with a 4 and an 8 pin header, and a 5 section dip switch to set the tones. It looks very different from the normal TS-32 Com Spec has it in their Fax back list but I can't get my fax to receive calls manually. They don't have it as a regular download. 73 John VE3AMZ
[Repeater-Builder] LVD 75 Amp Relay Source.
LVD 75 Amp Relay Source. Per my post regarding the Low Voltage Disconnect information. I was able to locate the Bosch 75 Amp Relay from the www.solarseller.com web site, which appears to have a lot of goodies, which might prove handy for repeater dc back up systems. http://www.solarseller.com/dc_photoswitch__dc_timer__voltage_controlled_switch_dc_relay.htm Tyco bought Bosch so going forward all new parts will have the Tyco label. cheers, skipp
[Repeater-Builder] UHF motorola maxtracs
Hey guys, Alright, I need your help. Anyone know of a good supplier with some UHF maxtracs? I need a handfull of them. I need the ones with the 16 pin connecter. Thanks, Jed
[Repeater-Builder] Help finding LBI's for a Delta
I have a Delta table top base (low band) that I am trying to find out which lbis apply to it. So far I know that the id plate says that it is a N3A016. I will dig into it more shortly to try and id the main modules in the radio itself shortly. Gale
Re: [Repeater-Builder] Micor Repeater
Have done a Micor repeater using the CAT-200 controller. It's really quite easy to do. Pull all the cards except the Station Control and the F1 PL Decoder. A mid split PA will work if the output is 147.00 but I don't think a high split PA will last very long. Strongly suggest if yours is not a low split machine you contact Kevin Custer and get the receiver front end recoiled. Guarantee it will make at least .25 microvolts difference in sensitivity. Well worth the money. Have my diagram of the backplane of how and where COR, CTSS, Audio and power are picked off. Will .pdf and send it to you if you need it. There's a couple of other things you need to do to turn it into a repeater if its configured as a base unit but no problem. Hope this helps. Dave, W7GK Gordon [EMAIL PROTECTED] wrote: It has been suggested that before one adds a controller to the repeater it is best to have it repeat in it's original configuration. This unit was part of the VHF Provincial Mobile Telephone system and in its present form I can get it to repeat only after dialing the code that puts the transmitter on continuously. Eventually after being quiet for a time (no COS) the transmitter times out and you have to dial up to get it to operate again. Presently it has the following cards installed, left to right, Decoder filter STLN89HDT, TC Logic, Logic Module STLN932, Squelch Gate TLN4662A, Jackfield Module, Time Out Timer TRN8684A, Tel. Interface, Station control module TLN4635B, Line Driver Module. I am sure there is a reader to tell me that most of this stuff can be pulled out and a jumper changed here or there will get it going in a normal fashion. I hate to put a quick and dirty COS gate and relay on the Back Plane when a simple change to a plug in module will get it going. Receiver and Transmitter tuned up on the 144/145 band perfectly. Lots of good reading on this site, thanks for this opportunity, 73, Gordon. - Fussy? Opinionated? Impossible to please? Perfect. Join Yahoo!'s user panel and lay it on us.
RE: [Repeater-Builder] Help finding LBI's for a Delta
Gale, I looked up N3A016 in my GE microfiche file, and I believe that it is a Package Number which was often used in place of a combination number when it was a standard model. However, the package number listing begins at N3A101 which raises the possibility that the number may not be correct. Package numbers in that general range are mostly Delta mobile radios, not stations. Please double-check the number, and also pass along other numbers and markings on the station. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Tuesday, July 31, 2007 12:55 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Help finding LBI's for a Delta I have a Delta table top base (low band) that I am trying to find out which lbis apply to it. So far I know that the id plate says that it is a N3A016. I will dig into it more shortly to try and id the main modules in the radio itself shortly. Gale
Re: [Repeater-Builder] Micor Repeater
Want to fire me off a copy as well. I like to see the different ways it is done. Maybe then I will pull the micor back out and see how I did it!!! Thanks! Corey N3FE - Original Message - From: Dave Hough To: Repeater-Builder@yahoogroups.com Sent: Tuesday, July 31, 2007 4:08 PM Subject: Re: [Repeater-Builder] Micor Repeater Have done a Micor repeater using the CAT-200 controller. It's really quite easy to do. Pull all the cards except the Station Control and the F1 PL Decoder. A mid split PA will work if the output is 147.00 but I don't think a high split PA will last very long. Strongly suggest if yours is not a low split machine you contact Kevin Custer and get the receiver front end recoiled. Guarantee it will make at least .25 microvolts difference in sensitivity. Well worth the money. Have my diagram of the backplane of how and where COR, CTSS, Audio and power are picked off. Will .pdf and send it to you if you need it. There's a couple of other things you need to do to turn it into a repeater if its configured as a base unit but no problem. Hope this helps. Dave, W7GK Gordon [EMAIL PROTECTED] wrote: It has been suggested that before one adds a controller to the repeater it is best to have it repeat in it's original configuration. This unit was part of the VHF Provincial Mobile Telephone system and in its present form I can get it to repeat only after dialing the code that puts the transmitter on continuously. Eventually after being quiet for a time (no COS) the transmitter times out and you have to dial up to get it to operate again. Presently it has the following cards installed, left to right, Decoder filter STLN89HDT, TC Logic, Logic Module STLN932, Squelch Gate TLN4662A, Jackfield Module, Time Out Timer TRN8684A, Tel. Interface, Station control module TLN4635B, Line Driver Module. I am sure there is a reader to tell me that most of this stuff can be pulled out and a jumper changed here or there will get it going in a normal fashion. I hate to put a quick and dirty COS gate and relay on the Back Plane when a simple change to a plug in module will get it going. Receiver and Transmitter tuned up on the 144/145 band perfectly. Lots of good reading on this site, thanks for this opportunity, 73, Gordon. -- Fussy? Opinionated? Impossible to please? Perfect. Join Yahoo!'s user panel and lay it on us. -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.476 / Virus Database: 269.11.0/927 - Release Date: 7/30/2007 5:02 PM -- I am using the free version of SPAMfighter for private users. It has removed 2241 spam emails to date. Paying users do not have this message in their emails. Get the free SPAMfighter here: http://www.spamfighter.com/len
[Repeater-Builder] GE Receivers Plus Power Supplies
I have a couple of GE ER-41C VHF (138-174 MHz) FM receivers complete with EP-39A -110vac power supplies for the cost of shipping. Both receivers and power supplies work fine. If anyone is interested, please contact me off list. Doug VE7DRF dkdavies at telus dot net
Re: [Repeater-Builder] Re: Coax length between added cavity and duplexer
Nate wrote: For the record, the interference appears as an on frequency signal (leading me to initially suspect intermod of some type) with clear audio of the dispatcher and officers. At first I thought I heard a second level of audio as well that I haven't been able to identify it whether it is background or another transmitter--partly due to catching it at the right time, and partly because my QTH doesn't allow me to hear it very well. KC0MLS thought receiver overload may be the issue so that's why we're trying the Celwave cavity. Hi Nate... Just to be clear (because it helps figure it out), do you hear every transmission, or only parts of transmissions? (Mixing with something else that goes on and off air, would come and go during a longer transmission on the system you're hearing in your repeater. Often you can find the thing you're mixing with if it's on-site by watching TX LED's and taking along a few receivers... Okay the dispatcher is on-air, and hey there's the interference, and the red TX LED just came on over here on this panel... and then... there it's gone and the TX LED went out... You get the idea... Also seeing what's really coming down the RX side of things with a Spectrum Analyzer may be enlightening. Nate WY0X
[Repeater-Builder] 23 Centimeter D-Star Innards
Pictures of the insides of the ID1, RP2V and RP2D at http://www.bosshardradio.com/dstar/23cm_innards or on the dstar_digital photos section. The RP2D is very similar to the ID-1 except the ID-1 has an additional LSI chip and clock crystal - same radio casting. The RP2V has a fan on the transmitter and none on the receiver. Will take some photos of the antenna and combiner when they arrive. Steve NU5D
Re: [Repeater-Builder] UHF motorola maxtracs
Jed i have here and GM300 UHF i am looking for an GM300 vhf in exchange i dont need the uhf anymore 73/s gervais ve2ckn - Original Message - From: Jed Barton To: repeater-builder@yahoogroups.com Sent: Tuesday, July 31, 2007 1:29 PM Subject: [Repeater-Builder] UHF motorola maxtracs Hey guys, Alright, I need your help. Anyone know of a good supplier with some UHF maxtracs? I need a handfull of them. I need the ones with the 16 pin connecter. Thanks, Jed
[Repeater-Builder] Intermodulation Interference
That last comment about the spectrum analyzer is an excellent suggestion. Trying to solve such interference problems with cavities or isolators may involve far more effort and expense than necessary. Here's a case in point: I was getting some severe interference to my reception of an Amateur repeater on 147.210 MHz, but not on other Ham repeaters. My base radio at the time was a Kenwood TK-760K2, which is a low-tier commercial product. The interference was sometimes voice, and sometimes data. I could almost eliminate the interference by putting a DCI bandpass filter in the feedline, but then I couldn't receive or transmit on the commercial frequencies used by other VHF repeaters I control. So, I pulled out my trusty Hameg digital spectrum analyzer, and set it to sweep the 140-160 MHz band. As soon as the interference began, I had the answer: 3rd order intermodulation with two local paging systems. Two paging transmitters on a hilltop a few miles from my house were each running about 3.5kW ERP- one on 152.480 MHz and the other on 157.740 MHz. The interference only occurred when the two paging transmitters were on the air at the same time as the 147.210 MHz repeater. This was third-order IM because two times 152.480 MHz minus one times 157.740 MHz (three times involved) equals 147.220 MHz, close enough to 147.210 MHz to obliterate the latter. The mixing was occurring in the front end of my base radio, AKA receiver IM. One of the simple solutions to receiver IM is the local-distant function that is frequently available in the programming software. The local position adds a small amount of attenuation in the front end, which can make a huge difference in IM rejection. In my case, however, the 147.210 MHz repeater is a distant station that I must use the distant setting to receive. The interference went away after I upgraded my base radio to a Motorola CDM1550-LS. Sometimes, an interference issue affects only certain designs, models, or brands. I readily acknowledge that my situation might be exceptional, with two very powerful paging transmitters at a nearby site. What if I had a repeater at the same site as the paging transmitters? That would definitely be a problem faced by repeater owners, over and over again! Back to the original premise, that of seeing what other signals are on the air at the same time the interference occurs, is of major benefit to an interference investigation. A spectrum analyzer is the instrument of choice for that task. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Nate Duehr Sent: Tuesday, July 31, 2007 2:54 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: Coax length between added cavity and duplexer Nate wrote: For the record, the interference appears as an on frequency signal (leading me to initially suspect intermod of some type) with clear audio of the dispatcher and officers. At first I thought I heard a second level of audio as well that I haven't been able to identify it whether it is background or another transmitter--partly due to catching it at the right time, and partly because my QTH doesn't allow me to hear it very well. KC0MLS thought receiver overload may be the issue so that's why we're trying the Celwave cavity. Hi Nate... Just to be clear (because it helps figure it out), do you hear every transmission, or only parts of transmissions? (Mixing with something else that goes on and off air, would come and go during a longer transmission on the system you're hearing in your repeater. Often you can find the thing you're mixing with if it's on-site by watching TX LED's and taking along a few receivers... Okay the dispatcher is on-air, and hey there's the interference, and the red TX LED just came on over here on this panel... and then... there it's gone and the TX LED went out... You get the idea... Also seeing what's really coming down the RX side of things with a Spectrum Analyzer may be enlightening. Nate WY0X
Re: [Repeater-Builder] Your old work bench - shop pictures are on ebay!
Wow... that's old. The best is the T44ransmitter.. 450 mhz, 12 watts with a pair of 2C39's. and a 41V receiver.with the 60KHZ if filter still in! Lance N2HBA - Original Message - From: skipp025 To: Repeater-Builder@yahoogroups.com Sent: Tuesday, July 31, 2007 6:11 PM Subject: [Repeater-Builder] Your old work bench - shop pictures are on ebay! Your old work-bench and/or shop pictures on ebay! In case you didn't take any pictures of your bench or shop in years past... some of your equipment found its way onto ebay. :-) LOT OF TUBE GENERAL ELECTRIC MOTOROLA PARTS Ebay Item number: 140143649238 enjoy... s.
[Repeater-Builder] Kenwood TKR-901 Ham Mod
Ok, Here is a good one for the group. Has anybody been successful at modifying the TKR-901 900Mhz repeater to go into the ham bands 902-928Mhz. I have such a unit and am very familiar with Kenwood equipment but never herd of anybody being successful at getting one of these to play at the desired band. If you have been successful please email me how you modified the unit. Thanks, Mike Mullarkey K7PFJ 6886 Sage Ave Firestone Co, 80504
Re: [Repeater-Builder] Intermodulation Interference
Eric Your experience reads like an O.Henry short story and punch line. Right up till the end, I was convinced that you were going to find an external mix producing on-channel junk. Haven't most of those high power pagers moved up to 800 Mhz or higher? Bruce K7IJ ** Get a sneak peek of the all-new AOL at http://discover.aol.com/memed/aolcom30tour
[Repeater-Builder] GE Datafile Bulletin 10008-5
All, I am hopeful that someone out there has a clear and complete paper copy of GE Datafile Bulletin 10008-5, entitled Measuring FM Deviation by the Bessel Null Method. This is an eight-page document authored by Jim Carrington, back in November 1967. Although I have a copy of this document on microfiche, its quality is far below that expected for publication on the GE Master List. If you will allow me to borrow your paper copy for scanning, please contact me at my call at verizon dot net. Please be aware that this is NOT a request for general information about the Bessel Null theory or its application; it is a request for a single and specific document published by General Electric. I must add this caveat, because I constantly receive replies from well-meaning folk who send me links to general information about the Bessel Null, but not to the specific GE Datafile 10008-5. Thanks for your help! 73, Eric Lemmon WB6FLY
Re: [Repeater-Builder] Kenwood TKR-901 Ham Mod
Mike; I have looked at it, here is the dilemma. The channels are pre-programmed into the tx and rx decks. There are rotary channel switches to select the channel( at least in the ones I have) . Valid channel numbers are 1-400. 401 unlocks the vco. Both tx and rx react same. The only way I think it is going to work is if someone engineers a micro-controller to interrupt the pll and the cpu to modify the load data. Separate processes will be needed for the tx and rx. The leads are relatively accessible on the platters. The PLL chip is documented. I have some pc scope captures of the load process. I do not have time to develop a solution.. I will provide what I have if someone wants to pick up the ball. Pete N2MCI and I have both eyed this one and really just do not have the cpu cycles to spare... Doug KD8B At 08:32 PM 7/31/2007, you wrote: Ok, Here is a good one for the group. Has anybody been successful at modifying the TKR-901 900Mhz repeater to go into the ham bands 902-928Mhz. I have such a unit and am very familiar with Kenwood equipment but never herd of anybody being successful at getting one of these to play at the desired band. If you have been successful please email me how you modified the unit. Thanks, Mike Mullarkey K7PFJ 6886 Sage Ave Firestone Co, 80504 inline: a1d251b.jpg
Re: [Repeater-Builder] Intermodulation Interference
Eric Look up the pager intermod filters that PAR Electronics sellsI have had good luck using them to fix a similar situation here-I think that one would have fixed your problem. Scott - Original Message - From: Eric Lemmon To: Repeater-Builder@yahoogroups.com Sent: Tuesday, July 31, 2007 4:17 PM Subject: [Repeater-Builder] Intermodulation Interference That last comment about the spectrum analyzer is an excellent suggestion. Trying to solve such interference problems with cavities or isolators may involve far more effort and expense than necessary. Here's a case in point: I was getting some severe interference to my reception of an Amateur repeater on 147.210 MHz, but not on other Ham repeaters. My base radio at the time was a Kenwood TK-760K2, which is a low-tier commercial product. The interference was sometimes voice, and sometimes data. I could almost eliminate the interference by putting a DCI bandpass filter in the feedline, but then I couldn't receive or transmit on the commercial frequencies used by other VHF repeaters I control. So, I pulled out my trusty Hameg digital spectrum analyzer, and set it to sweep the 140-160 MHz band. As soon as the interference began, I had the answer: 3rd order intermodulation with two local paging systems. Two paging transmitters on a hilltop a few miles from my house were each running about 3.5kW ERP- one on 152.480 MHz and the other on 157.740 MHz. The interference only occurred when the two paging transmitters were on the air at the same time as the 147.210 MHz repeater. This was third-order IM because two times 152.480 MHz minus one times 157.740 MHz (three times involved) equals 147.220 MHz, close enough to 147.210 MHz to obliterate the latter. The mixing was occurring in the front end of my base radio, AKA receiver IM. One of the simple solutions to receiver IM is the local-distant function that is frequently available in the programming software. The local position adds a small amount of attenuation in the front end, which can make a huge difference in IM rejection. In my case, however, the 147.210 MHz repeater is a distant station that I must use the distant setting to receive. The interference went away after I upgraded my base radio to a Motorola CDM1550-LS. Sometimes, an interference issue affects only certain designs, models, or brands. I readily acknowledge that my situation might be exceptional, with two very powerful paging transmitters at a nearby site. What if I had a repeater at the same site as the paging transmitters? That would definitely be a problem faced by repeater owners, over and over again! Back to the original premise, that of seeing what other signals are on the air at the same time the interference occurs, is of major benefit to an interference investigation. A spectrum analyzer is the instrument of choice for that task. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Nate Duehr Sent: Tuesday, July 31, 2007 2:54 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: Coax length between added cavity and duplexer Nate wrote: For the record, the interference appears as an on frequency signal (leading me to initially suspect intermod of some type) with clear audio of the dispatcher and officers. At first I thought I heard a second level of audio as well that I haven't been able to identify it whether it is background or another transmitter--partly due to catching it at the right time, and partly because my QTH doesn't allow me to hear it very well. KC0MLS thought receiver overload may be the issue so that's why we're trying the Celwave cavity. Hi Nate... Just to be clear (because it helps figure it out), do you hear every transmission, or only parts of transmissions? (Mixing with something else that goes on and off air, would come and go during a longer transmission on the system you're hearing in your repeater. Often you can find the thing you're mixing with if it's on-site by watching TX LED's and taking along a few receivers... Okay the dispatcher is on-air, and hey there's the interference, and the red TX LED just came on over here on this panel... and then... there it's gone and the TX LED went out... You get the idea... Also seeing what's really coming down the RX side of things with a Spectrum Analyzer may be enlightening. Nate WY0X
RE: [Repeater-Builder] Intermodulation Interference
Scott, I did check the PAR Electronics site, and I am impressed with their designs and user kudos. However, it is not easy to notch out the pager at 152.480 MHz and not attenuate my commercial channel at 152.345 MHz. The point is now moot, because the Motorola CDM1550-LS can operate at 152.345 MHz and on all 2m frequencies without a hint of interference from either the 152.480 or 157.740 MHz pagers. I have not needed, nor have I installed, any filters once I switched radios. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Scott Overstreet Sent: Tuesday, July 31, 2007 6:52 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Intermodulation Interference Eric Look up the pager intermod filters that PAR Electronics sellsI have had good luck using them to fix a similar situation here-I think that one would have fixed your problem. Scott - Original Message - From: Eric Lemmon mailto:[EMAIL PROTECTED] To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder@yahoogroups.com Sent: Tuesday, July 31, 2007 4:17 PM Subject: [Repeater-Builder] Intermodulation Interference That last comment about the spectrum analyzer is an excellent suggestion. Trying to solve such interference problems with cavities or isolators may involve far more effort and expense than necessary. Here's a case in point: I was getting some severe interference to my reception of an Amateur repeater on 147.210 MHz, but not on other Ham repeaters. My base radio at the time was a Kenwood TK-760K2, which is a low-tier commercial product. The interference was sometimes voice, and sometimes data. I could almost eliminate the interference by putting a DCI bandpass filter in the feedline, but then I couldn't receive or transmit on the commercial frequencies used by other VHF repeaters I control. So, I pulled out my trusty Hameg digital spectrum analyzer, and set it to sweep the 140-160 MHz band. As soon as the interference began, I had the answer: 3rd order intermodulation with two local paging systems. Two paging transmitters on a hilltop a few miles from my house were each running about 3.5kW ERP- one on 152.480 MHz and the other on 157.740 MHz. The interference only occurred when the two paging transmitters were on the air at the same time as the 147.210 MHz repeater. This was third-order IM because two times 152.480 MHz minus one times 157.740 MHz (three times involved) equals 147.220 MHz, close enough to 147.210 MHz to obliterate the latter. The mixing was occurring in the front end of my base radio, AKA receiver IM. One of the simple solutions to receiver IM is the local-distant function that is frequently available in the programming software. The local position adds a small amount of attenuation in the front end, which can make a huge difference in IM rejection. In my case, however, the 147.210 MHz repeater is a distant station that I must use the distant setting to receive. The interference went away after I upgraded my base radio to a Motorola CDM1550-LS. Sometimes, an interference issue affects only certain designs, models, or brands. I readily acknowledge that my situation might be exceptional, with two very powerful paging transmitters at a nearby site. What if I had a repeater at the same site as the paging transmitters? That would definitely be a problem faced by repeater owners, over and over again! Back to the original premise, that of seeing what other signals are on the air at the same time the interference occurs, is of major benefit to an interference investigation. A spectrum analyzer is the instrument of choice for that task. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com [mailto:Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com ] On Behalf Of Nate Duehr Sent: Tuesday, July 31, 2007 2:54 PM To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Subject: Re: [Repeater-Builder] Re: Coax length between added cavity and duplexer Nate wrote: For the record, the interference appears as an on frequency signal (leading me to initially suspect intermod of some type) with clear audio of the dispatcher and officers. At first I thought I heard a second level of audio as well that I haven't been able to identify it whether it is background or another
Re: [Repeater-Builder] Your old work bench - shop pictures are on ebay!
You know you are getting old when you recognize that stuff as past project radios... At 04:11 PM 07/31/07, you wrote: Your old work-bench and/or shop pictures on ebay! In case you didn't take any pictures of your bench or shop in years past... some of your equipment found its way onto ebay. :-) LOT OF TUBE GENERAL ELECTRIC MOTOROLA PARTS Ebay Item number: 140143649238 enjoy... s. Yahoo! Groups Links
Re: [Repeater-Builder] Your old work bench - shop pictures are on ebay!
i have talked on radios that had a vibrater in tham butt i'm 53 years old At 11:37 PM 7/31/2007, Mike Morris wrote: You know you are getting old when you recognize that stuff as past project radios... At 04:11 PM 07/31/07, you wrote: Your old work-bench and/or shop pictures on ebay! In case you didn't take any pictures of your bench or shop in years past... some of your equipment found its way onto ebay. :-) LOT OF TUBE GENERAL ELECTRIC MOTOROLA PARTS Ebay Item number: 140143649238 enjoy... s. Yahoo! Groups Links
Re: [Repeater-Builder] Your old work bench - shop pictures are on ebay!
i have talked on radios that had a vibrater in tham butt i'm 53 years old At 11:37 PM 7/31/2007, Mike Morris wrote: You know you are getting old when you recognize that stuff as past project radios... At 04:11 PM 07/31/07, you wrote: Your old work-bench and/or shop pictures on ebay! In case you didn't take any pictures of your bench or shop in years past... some of your equipment found its way onto ebay. :-) LOT OF TUBE GENERAL ELECTRIC MOTOROLA PARTS Ebay Item number: 140143649238 enjoy... s. Yahoo! Groups Links
RE: [Repeater-Builder] Your old work bench - shop pictures are on ebay!
The First time I got Shocked at about 16 yrs Old now 60, I had a Regency Tunable scanner/Receiver had a Vibrator Sometimes it would not work. But if you would bang on it would. So I got a Hacksaw and cut the Cover off thinking I could fix it, I put power on it and Heck it was only 12 Volts, I could hold that in my hand and never got shocked So the Old vibrator was not working I just put my Finger in it and pushed a little well it started working and I got knocked on my Butt Hurt like heck, I will never forget that and I learned at a young age to respect Electricity. Yes we know we are getting old when we recall seeing Equipment like this I recall many Yrs ago giving a Guy who was a Ham a jump Start Because he had a old Motorola in the Trunk on 6 Meters it had a Dynamotor Power Supply. Happy Repeater Building Don KA9QJG
