[Repeater-Builder] Re: antenna plan
I think you would be much better off getting a folded dipole antenna like a DB224 for VHF or a DB411 for UHF. You can set the dipoles to favor the town by putting 3 facing the town with one left facing the opposite direction so the back door isn't too badly affected. Dan N8DJP Re: antenna plan Posted by: Paul Holm p...@chargertech.com kc0hst Date: Thu Aug 19, 2010 7:47 pm ((PDT)) Hopefully it is not uncool to be the first to respond to one's own post. I'll take the fact that there was no flood of flames, or naysayers, to indicate that my plan is worth attempting. So as a follow-up question, I would ask, could anyone offer recommendations for a yagi, corner reflector, or other directional antenna, suitable for duplex use, with a beamwidth of no less than 30deg and a gain of no less than say 7dB? 73 Paul - Original Message - From: Paul Holm I'm looking for input on an antenna plan. I'd like to change to an ellliptical pattern that favors the bigger town in the county which is roughly at 270 deg west and about 6 miles away. I'd like to take a yagi or corner reflector and mount it lower, at the railing or a short distance up the mast, and point it at the town I'd like to focus on
[Repeater-Builder] Re: What have I got?
Sound like a PURC unit. You have exciter at 450 mw out that goes into a tripler/low level amp that gives 2W out, that goes into the 75 watt amp which in turn drives the last stage. Not bing familiar with the model number, I would guesstimate the final out is around 350 watts. Dan N8DJP
[Repeater-Builder] Re: Dual receivers on one antenna for RX only site
One thing was missed regarding cable lengths. The loops in the cans are part of the equation for figuring the 1/4 wave length. I've seen that discussed here many times in postings related to inter-cable lengths on duplexers. But the 1/4 wave length issue only applies to the inter-cabling between the cans. It is my understanding that the antenna to duplexer lengths are irrelevant since the T connector and the rest of the feedline are all part of the equation. It's not like the T is some magical device that makes the rest of the feedline disappear electrically. The only time length might be a problem is if the entire feedline happens to be a resonant length. If by some chance that happens, then changing the jumper a couple of inches will clear that. Dan N8DJP Posted by: n...@no6b.com n...@no6b.com no6b Date: Tue Mar 9, 2010 8:29 pm ((PST)) At 3/9/2010 20:12, you wrote: OK, question... If you put a cable which is 1/4-wavelength at VHF between the T and the UHF cavity, it's 3/4-wavelength at UHF. Since any odd multiple of a quarter wavelength will invert the impedance, what will this really accomplish on the UHF cavity side? Doesn't matter at UHF, since the cavity looks like (hopefully something close to) 50 + j0 ohms @ UHF, so the cable length has no effect (other than plain ol' cable loss) @ UHF. At VHF, the short at the UHF cavity connector (I'll take Gary's word that it looks like a short off-resonance, though to be sure you'd want to put the can on a VNA to get the actual phase angle at the connector) needs to be transformed to an open at the T so it has no effect VHF. The short-to-open transformation @ VHF is accomplished with a 1/4 wavelength of coax @ VHF. The dual-band diplexers are usually high-pass/low-pass arrangements, and lose something like 0.2 dB while providing 40 dB or more isolation. Assuming you get a real one, and not something made with PIM-prne materials, would this not be a safer bet? It's true you wouldn't need to mess with cable lengths if a cross-band diplexer were used, but OTOH it would be another piece of hardware in the system that really isn't necessary, since the cavities are already there. Plus if you're really worried about PIM, you'd probably have to move up to something like a cross-band coupler from TX-RX, which IIRC runs over $300. Bob NO6B
[Repeater-Builder] Re: Dual receivers on one antenna for RX only site
Actually, Gary, you are 180 degrees out. On a pass cavity, off frequency signals see a very high impedence path, an open not a short. If your version were true you could never use pass cans as a duplexer since both sets of cans together would show a short to EVERYTHING. The T connector is just an impedence bump to the radio equipment, nothing more. It is not an active device, like a preamp would be, that makes the rest of the feedline disappear. He can use the T connector and any random length of cable to connect, as long as the whole feedline doesn't show up as a resonant length. Dan N8DJP Posted by: Gary Schafer gascha...@comcast.net k4fmx Date: Wed Mar 10, 2010 10:47 am ((PST)) Well yes the T is sort of a magical device that makes the OTHER SIDE of the T disappear electrically. Actually it is not the T itself that does the job (that is just where IT happens) but it is the quarter wave length cables that perform the magic! Without the quarter wave length cables between the T and each set of cavities the duplexer would not work! That is what provides the 50 ohm isolation between tx and rx cans so the feed line still sees 50 ohms. The quarter wave cable effectively disconnects the transmitter from the feed line at the T (at the receive frequency). The quarter wave cable on the receive side of the T effectively disconnects the receive side from the feed line (at the transmit frequency). Without doing this each would load the other down and there would not be 50 ohms at the antenna port of the T. Once you are on the other side of the T (the antenna port) the feed line length has no effect on the duplexer operation. All that the quarter wave lines do on the duplexer side of the T are to give isolation to the opposite side (tx-rx) so each does not short out the feed line. A similar thing happens between can cables in a duplexer but rather than using them for isolation they are used to enhance the notch of each can by presenting a high impedance at each cans T from the previous cavity. Working with a high impedance is easier to notch out than a low impedance. The notch in the first cavity presents a short (low impedance) at the unwanted frequency and 50 ohms at the wanted frequency. By coupling the next cavity with a quarter wave length cable (at the unwanted frequency) that short is transformed to a quite high impedance at the next cavity while at the same time the wanted signal being at 50 ohms is passed to the next cavity where it sees 50 ohms and goes on its way unatenuated. But we are left with the high impedance at the unwanted frequency that was transformed by the quarter wave cable. The second cavity notch is also tuned to the unwanted frequency which it pulls down to a short (low impedance) to give further attenuation. When I say the notch presents a short it is not really a short but a very low impedance of say a few ohms. But by having the unwanted source impedance high rather than at 50 ohms it is much easier to pull the high impedance down with the few ohms short circuit than it would be if we were working at 50 ohms for the unwanted. It works like a voltage divider between the two impedances. The higher the source is (from previous cavity) to the short the more loss there will be which is just what we are looking for. In the case of the quarter wave cable to the T on the output of the duplexer we want to transform the low impedance up to a very high impedance at the T so that it does not load the circuit at that point on that frequency. 73 Gary K4FMX
[Repeater-Builder] Re: Motorola cabinet key
If it is the double sided key then its a 2553. If the cabinet has an external handle that the lock is in its a CH751. For some reason Motherola used a different key on the 6' cabinets than on the shorter (Compa) cabinets. Unfortunately I don't have a spare, but they are made by Chicago Lock Co. and they should be able to sell you what you need. Dan N8DJP
[Repeater-Builder] Re: Unlawful in Il to Rebroadcast Public Safety Communications
What seems to be getting overlooked by everyone including the Illinois legislature is that they have NO authority to pass any law governing how the airwaves are used. The communications act gives SOLE jurisdiction over the airwaves to the FCC, period. If they pass this law and then try to prosecute someone they could be in for a world of hurt from a federal lawsuit filed by the victim, a suit that the state could not possibly win. Just one man's thoughts. Dan N8DJP Re: Unlawful in Il to Rebroadcast Public Safety Communications Posted by: Walter H walter.howard...@gmail.com ka1jfy Date: Fri Feb 19, 2010 1:33 pm ((PST)) What /I/ can add, is that the FCC has said that if you want privacy for your communications, then encrypt them. Clear voice is available to anyone with the appropriate receiver. No, I can't find my source for this, I've read all the Daily Digests for the last 5+ years, and I believe it was in a letter ruling. BTW, if you go to the url listed, you'll see that it's still in committee. Not passed by the House nor Senate, nor signed by the Governor. WalterH
[Repeater-Builder] Re: Antenna Pattern Question
Bill, thanks for the tip, however the repeater is a UHF. I don't see anything on Comprod's site showing a UHF with a reflector screen. I guess I will just have to improvise! I was looking to see if any other members had done such a thing before so I didn't have to re-invent the wheel so to speak. 73, Dan N8DJP Re: Antenna Pattern Question Posted by: William Becks wbe...@centurytel.net wgbecks Date: Fri Nov 20, 2009 7:18 pm ((PST)) Dan, The VHF fiberglass Omni's within 6 feet of your building-top antenna can cause pattern distortion just as is the case with side mounted tower installations. However, I recall from your original posting that your application requirement is to produce a deep null +/- 45 degrees with as much gain as possible elsewhere around the compass. The best candidate for this application would be a corner reflector array such as the Comprod 470-70 (Assuming VHF) that develops 30 dB Front to Back with a main horizontal beam width of 67 degrees. Check URL: http://www.comprodcom.com/en/antennas/base/pdf/471-70.pdf If the 67 degree horizontal beam width is too narrow for your intended coverage area and you can live a little less front to back ratio, then a better choice would be the Comprod F-3713 that has a flat reflector screen mounted behind the folded dipole radiator elements. Check URL: http://www.comprodcom.com/en/ecatalogs/BaseStation2005-Full.pdf You should expect to obtain nearly the same published pattern shape and gain with either of these antennas for your building-top installation provided that you are able to mount your antenna such that the fiberglass Omni's are behind the reflector and not out in front of the main beam of the array. This gives you the advantage of a large reduction in radiation (excitation) toward the Omni's that significantly reduce overall parasitic radiation from these sources with little or no net change from published pattern shape and gain. A secondary benefit is an increase in isolation from the other VHF systems that may prevent or reduce the possibility of receiver desense or transmitter IM among the three systems sharing the rooftop. Good luck with your project! Bill, WA8WG
[Repeater-Builder] Re: Antenna Pattern Question
Bill, The antenna will be a building-top installation. The only thing near field is a couple of VHF fiberglas omni sticks that are over 6' away. Interaction with anything else will be insignificant. Thanks Dan N8DJP Re: Antenna Pattern Question Posted by: William Becks wbe...@centurytel.net wgbecks Date: Thu Nov 19, 2009 4:13 pm ((PST)) Dan, Before you make any decisions about selecting any specific antenna for your application, you need to know or specify top or side mounting. Then you'll need to consider any and all metallic objects present in the near environment of the antenna because they constitute reflective or parasitic sources that can have a profound impact on the actual far field radiation pattern obtained. I have done a lot of NEC modeling in order to make a more informed scientific estimations of how these factors modify the final radiation pattern before attempting to choose any specific antenna for a given application vs. placement and orientation about the tower. NEC modeling is only and good as the modelers ability to accurately construct a model that truly depict the real world electrical environment of the antenna. It's doubtful that you would ever get an antenna manufacturer to model, or to guarantee a particular pattern outside of those field patterns derived from their antenna test range due to the complexity of modeling and of offering such service. Cellular and other similar providers largely employ directional panel arrays are virtually free of any significant radiation in the direction of the tower, supporting structure, or other antennas in the near environment. Therefore, their engineers don't need to consider the unwanted effects of parasitic radiation sources external to the array. Unfortunately, those of us relegated to VHF and UHF systems end up illuminating a rather large area of the tower resulting in a complex number of parasitic radiation sources that change the resultant pattern that otherwise might radiate per the text books if located in free space. Bill, WA8WG
[Repeater-Builder] Antenna Pattern Question
I have a repeater that I need to have as tight a cardiod pattern as possible. I have looked at the dipole antennas such as the DB-411 and they don't really shut down the back door quite enough. Does anyone have any antenna modeling software that would show the result of adding an 18 wide screen to the back side of the mast on the DB-411? Does anyone have any experience in home-brewing a modification like this? Dan Hancock N8DJP
[Repeater-Builder] Re: Antenna question
Since no one else has mentioned them I'll say take a look at the Hustler Spirit series antennas. Built similar to Stationmasters without the charging you for the name price. http://www.new-tronics.com/main/html/base_spirit.html Dan N8DJP --- In Repeater-Builder@yahoogroups.com, W3ML w...@... wrote: Now I realize that the DB type antenna is the best, but we do not have 800 bucks to buy one. You can do FAR better than that price. Primus Electronics, Joliet, IL. 800.435.1636. I have no connection with them other than being a very satisfied customer. Laryn K8TVZ
[Repeater-Builder] Re: Tram 1481 Dual Band UHF/VHF Antenna
One other thing to check for if you take it apart. If Tram is like Diamond, it uses capacitors for RF coupling/matching along the length of the antenna. These are power limited. Two transmitters TXing at the same time can make them go and they also can pop easily if there is a surge like a nearby lightning strike. Losing these caps seems to effect the UHF far more than the VHF. Rotsa ruck. Dan N8DJP
[Repeater-Builder] Re: Antenna suggestion question?
Try this one T.J. I've used one of their UHF antennas and they are very good quality. Specs seem to fit exactly what you are looking for. http://www.kathrein-scala.com/catalog/K5516231.pdf Dan N8DJP Antenna suggestion question? Posted by: T.J. kc8...@yahoo.com kc8lts Date: Sat Feb 14, 2009 10:52 am ((PST)) Here is my dilemma. One of my current work radio sites is being decommissioned and torn down. My new replacement site has some antenna restrictions and I'm having trouble finding an antenna to fit the bill. The old site is 110 ft. tall and I have a DB-264 antenna set for omni pattern at 6 dbd on the top now. The new site is 225 ft. tall but will not allow dipole antennas only fiberglass collinear antennas. I normally use the Sinclair SC229 in this situation, but the site management says that is too tall and doesn't want that either. They will only allow something up to 16 feet in hieght, give or take a little. So I'm looking for something of high quality commercial grade and about maybe 3 to 4 dbd gain, around 16 ft. tall or so. I thought that there were these type antennas available as I've seen and used them before, but now I can't seem to find anyone that sells new ones. All I can find are unity gain or the big ones like I already have. Did the main antenna manufacturers stop making the in between size VHF collineer antennas? If I'm just missing it for some reason, or losing my mind, can someone point me in the right direction. Thanks
[Repeater-Builder] 900 Duplexer
I am trying to decide on a duplexer for a 900Mhz portable repeater made from a pair of Maxtracs. I have found several on eBay that seem suitable, but if any of the guru's on here have input I would appreciate hearing your thoughts since I'm not usre which to choose. These are the ones I'm looking at http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItemrd=1item=250327529615ssPageName=STRK:MEWA:ITih=015 http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItemrd=1item=310101567541ssPageName=STRK:MEWA:ITih=021 http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItemrd=1item=250315811678ssPageName=STRK:MEWA:ITih=015 Thanks and 73, Dan N8DJP
[Repeater-Builder] Re: UHF LINK ANTENNA QUESTION HELP NEEDED!
Is the tower yours or are you on donated space? Can you re-mount your antenna and make other changes on the tower? If so, I assume the beam is end-mounted since it's only 5 elements. Try mounting the beam through the tower instead of on the leg nearest the target repeater. Then take some sheet metal and attach it to the side of the tower the offending signal is coming from. This should sufficiently block the offending signal. Dan N8DJP 8a. UHF LINK ANTENNA QUESTION HELP NEEDED! Posted by: n2len [EMAIL PROTECTED] n2len Date: Sat Sep 27, 2008 10:00 pm ((PDT)) Can anyone please offer me some assistance. I am trying to link my VHF repeater to a club machine on 440 MHZ. For now I received permission to link directly on their input until the club installs a remote base and yagi next spring. There repeater is about 20 air miles away. I am using a 5 element UHF Yagi about 45 feet up a 170 Rohn 65 at my hub site! The Yagi is facing due West. The link works fantastic with 5 watts however I am receiving a 440 MHZ repeater on the same input over 100 air miles away to the South. 90 degrees off the side of the Yagi. So my question is. Any input to solve this antenna related problem to Buffer that weak signal from the south? Any move of the antenna lowering, different antenna etc... Any ideas would be greatly appreciated
[Repeater-Builder] Repair/Modify DB Antennas
For those of you who did not receive the attachments I sent earlier, I have posted them to the Files section. Dan N8DJP
[Repeater-Builder] Re: P25 (mis)Information?
I never cease to be amazed at how the simple answer to problems like this get overlooked. Give the FD noise cancelling microphones. The less background the mic picks up the less distortion problem there is. I've been on an 800 digital sytem for about 13 years now. Our earlier purchased radios came with noise cancelling mics, that later ones didn't. OMG what a difference. Some radios are so low in TX audio that even with the console volume at full you have trouble hearing the troopers. Then you get someone who's used to the noise cancelling mics using the non cancellers and they blow you out of the console. I guess the Motherola engineers never heard of ALC or the concept of using it on the console to keep audio levels even. Dan Hancock N8DJP Re: P25 (mis)Information? Posted by: Steve S. Bosshard (NU5D) [EMAIL PROTECTED] bosshardss Date: Thu May 29, 2008 9:10 am ((PDT)) On re-re-reading the post, I suspect the MA/COM salesman proposes just adding an analog trunked group to the system and calling that group talk-around. Just another group in the trunked system. Any group can be either Provoice (EDACS only) or P25 digital or Analog FM. To many folks in the land mobile business talk-around refers to simplex operation on the output frequency of a repeater station and operation independent of the repeater station. (hence my earlier post about collisions with trunked and simplex operations). From what I understand the problem with high noise environments and intelligibility is due to the characteristics of the DVSI IMBE vocoder and how this noise is treated in quantizing. Another talk group will not help in building coverage issues because the trunked system treats all groups alike unless a group by attributes is steered to one particular site in a multisite system. I am most familiar with simulcast. I believe the problems with P25 digital are exactly that and have nothing to do with brand or manufacturer. 73, Steve NU5D
[Repeater-Builder] Re: Off Topic (but with on topic questions): NTIA propaganda
It was my undeerstanding that all digital TV would be on UHF, no VHF and that the VHF spectrum would be re-allocated. Am I in error? Dan N8DJP --- In Repeater-Builder@yahoogroups.com, MCH [EMAIL PROTECTED] wrote: Has anyone else here seen the bull put out by NTIA on https://www.dtv2009.gov/FAQ.aspx = 1. What is the digital television transition? At midnight on February 17, 2009, all full-power television stations in the United States will stop broadcasting in analog and switch to 100% digital broadcasting. Digital broadcasting promises to provide a clearer picture and more programming options and will free up airwaves for use by emergency responders. = will free up airwaves for use by emergency responders.??? The TV spectrum is being freed up by ANALOG stations and the SAME SPECTRUM will be reused by DIGITAL stations. The only spectrum being freed up by TV for PS use is on the 764 MHz + band. (two TV channels, I believe) and has nothing to do with a transition to digital. The same could have been achieved by simply moving those analog stations to other channels. An analog allocation is 6 MHz. A digital allocation is 6 MHz. How is digital saving spectrum? As there are some broadcast types here, maybe someone can explain the technology used where X analog stations using 6 MHz each will be more efficient by the same number of stations using 6 MHz each. Is this that new math they are using? I would like to apply the same to 2M to get more spectrum out of it. If I take my 16 kHz analog signal and make it 16 kHz digital, will we be able to fit more repeaters in the band? (aside from the fact most will have no users) Joe M.
Re: [Repeater-Builder] seperation between 2 440 antenna's
Refer to the charts here for your answer. http://www.repeater-builder.com/antenna/separation.html Dan N8DJP 3. seperation between 2 440 antenna's Posted by: JOHN KIHL [EMAIL PROTECTED] johnkihl Date: Mon Jul 9, 2007 6:58 am ((PDT)) Good Afternoon, We are putting up a 440 repeater antenna with over 100watts and we are looking at putting a yagi directional 440 below it. What is the rule of thumb for seperation required, 15feet of 20? Thanks 73 kb3nqs [EMAIL PROTECTED] 800-741-5152 - Get the Yahoo! toolbar and be alerted to new email wherever you're surfing.
[Repeater-Builder] MSF5000 Manual
Our group just bought an MSF5000 900 Mhz, 75 watt repeater. The thing is immaculate and the unit is even the PC programmable version, not the eprom. New we need a manual. Does anyone have the MSF5K manual for either 800 or 900 band they can part with? Or even one we could borrow long enough to copy? Dan N8DJP n8djp at yahoo dot com - Never miss an email again! Yahoo! Toolbar alerts you the instant new Mail arrives. Check it out.
[Repeater-Builder] Re: Pre-selector preamps
Actually the famous GLB preamp is still available. After a couple coporate buy-outs the new company is called Simrex and they still sell the original GLB unitand the even offer and amateur radio discount. Here is the web page. http://www.simrex.com/site/products/special.htm Dan Hancock N8DJP 5e. Re: For Sale Midland Base Tech Transmitter Receiver 450 - 470 MHz Posted by: Mike Morris WA6ILQ [EMAIL PROTECTED] web_magician Date: Fri Dec 22, 2006 9:42 pm ((PST)) At 07:40 PM 12/22/06, you wrote: Hey Vincent Thanks I know about ARR for preamps but Im looking for a Preselector Preamp like the old GLB units.. Check out www.anglelinear.com Mike WA6ILQ __ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com
[Repeater-Builder] Re: GMRS UHF Ham Repeaters Sharing an Antenna
Get one of Sinclair's offerings similar to this model. It will take care of the the broad frequency range problem. http://www.sinclairtechnologies.com/catalog/series.aspx?id=280 Sometimes the obvious problem isn't a problem at all. Dan N8DJP 4c. Re: GMRS UHF Ham Repeaters Sharing an Antenna Posted by: Eric Lemmon [EMAIL PROTECTED] wb6fly Date: Mon Nov 13, 2006 7:01 pm ((PST)) Bob, Most of the posted replies seem to ignore the obvious incompatibility issue: GMRS and 70cm Amateur transmitters operate in different bands! Generally, a repeater antenna should be resonant at the transmitter frequency, since the receiver is usually much less picky. So, the issue is really one of finding an antenna that is equally efficient at a GMRS frequency of 462.575 MHz as it is at 444.200 MHz, and THEN finding a way to properly match the antenna for two disparate services. I am not aware of any antenna that will work efficiently on two such widely-spaced frequencies. Even though it may be possible to jury-rig two repeaters so that they can share an antenna that is a poor match to either, is this a good idea? A properly-engineered system would likely use two antennas, one for each system. My concern is that the respective duplexers will not be driving similar or even properly-matched loads. I guess I'm just not used to solving complex design issues with a cheap 'n' dirty solution... But hey, it's worth a try, right? Please report the results. 73, Eric Lemmon WB6FLY - Everyone is raving about the all-new Yahoo! Mail beta.
Re: [Repeater-Builder] OT: FT-8900 help
When I lost the 2M section on mine Yeasu only replaced a diode. Has worked fine ever since. Repair charge was very nominal, actually much less than I expected.Dan N8DJPMessage: 5 Date: Fri, 06 Jan 2006 22:13:40 -0800 From: [EMAIL PROTECTED]Subject: OT: FT-8900 helpThe output power of my Yaesu FT-8900 quad bander has dropped to 0.25 watts, regardless of power setting. 10, 6 2 meter TX output is nominal (5/10/20/50 watts). Current draw on UHF TX is 4.8 amps, again regardless of output power setting.The final device in the radio is a broadband power MOSFET covering all 4 bands, so it's OK. I'm thinking something possibly opened between the MOSFET drain antenna (switching diode, filter etc.), but why would the current be so high even on low power (low power on the working bands is around 1.4 A)?Bob NO6B Yahoo! Photos Showcase holiday pictures in hardcover Photo Books. You design it and well bind it! YAHOO! GROUPS LINKS Visit your group "Repeater-Builder" on the web. To unsubscribe from this group, send an email to:[EMAIL PROTECTED] Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
Re: [Repeater-Builder] UHF Preamplifier
Have you guys tried the Simrex (formerly GLB) helical resonator pre-amp? It's great for repeater applications. Very selective and moderate gain. If you're using Bp-Br type cans you don't need any further filtering. http://www.simrex.com/site/products/preselector/Preselector1.pdfhttp://www.simrex.com/site/products/preselector/preselector_diagram.pdfI haven't bought one in quite a few years, but the last one I got was in the $150 range.Dan N8DJP Date: Sun, 18 Dec 2005 08:26:10 -0800 From: [EMAIL PROTECTED]Subject: Re: UHF PreamplifierAt 12/17/2005 10:15, you wrote:I've got the same setup. I also have a 4-sectionCelwave bandpass filter between the duplexer andpreamp. I found that the 17dB gain was way too muchfor the receiver, and the noise level increaseddramatically, to the point that I had to tighten thesquelch settings. The sig strength metering went from10 to 14uA with no signal.Why is that such a bad thing? If you add a preamp to a RX your measured noise power doesn't increase, it means that the largest source of noise in your system is still your RX that there's still room for improvement.Unless you're really worried about dynamic range, the ideal setup would be one in which the total noise power added by the addition of the preamp equals the noise present at the front end of the RX. This should provide the best balance of system noise figure dynamic range. If a 10 to 14 uA change represents 3 dB, then you'd be all set at that point.I don't know what's up with your carrier squelch. A well-designed squelch circuit shouldn't care how much noise power is present at the front end. Perhaps there's another problem with the RX: low gain in an IF stage, limiter problem, etc. that's causing the discriminator output to change with input noise power.Bob NO6B__Do You Yahoo!?Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com YAHOO! GROUPS LINKS Visit your group "Repeater-Builder" on the web. To unsubscribe from this group, send an email to:[EMAIL PROTECTED] Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
[Repeater-Builder] Re:OT: NC man charged with 'driving a cop car'
I don't know who you talked to, but no such "manual" exists. There used to be a printed version of "Michigan Compiled Laws", a very thick book that contains all state laws (not local ordinances), but I haven't seen a new printed version since the laws became available on-line. Fines collected from State Police arrests do go to the library fund, but not from arrests by county or local agencies. And your comment about drinking pop while reading makes no sense to me. Dan Hancock N8DJP 13 years with MSP Come to think of it I had a conversation with the Michigan State Police Communications department, they told me that EVERY police, Sheriff, and Post has a copy of the Communications Manual , she stated weather or not anyone took the time to read it is another story. and Section 508 has a House Bill called HB 4544 which will change the scanner law no permit, but a commission of a crime misdemeanor or a felony has 2 fine structures and sentancing guideline .I would not drink a bottle of pop while reading the proposed statute. price is $1,000.00 to $2,000.00 and add 1 to 2 yers jail time, money is fwd. to the libary fund.go figgure. Start your day with Yahoo! - make it your home page YAHOO! GROUPS LINKS Visit your group "Repeater-Builder" on the web. To unsubscribe from this group, send an email to:[EMAIL PROTECTED] Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
[Repeater-Builder] Micor Mobile Repeater - No Audio?
Many years ago, my friend W8ICN told me of a cure for the invisible corrosion on Micor pins that they had developed at Detroit Edison. I couldn't remember what it was, so I dropped him an email about it. Here is his reply. Dan Hancock N8DJP We used a mixture of Squibb mineral oil and isopropol alcohol, about a 1:3 ratio, 1 part mineral oil and 3 parts alcohol. With the boards unplugged, coat the pins and sockets using a small artist brush. The alcohol evaporates quickly leaving a fine coat of oil on the pins which inhibits corrosion. Works well. Do not scrape the pins otherwise you will be removing the plating causing even bigger problems. Of course if the pins are corroded to start with, gently clean off the gunk before applying the oil and alcohol.DanDaniel Hancock wrote: Read the messages below. What was the "magic solution" you guys at Edison used to help with this probelm? It was a mixture of two thingsmineral oil and something maybe??? Message: 18 Date: Sat, 04 Jun 2005 21:42:21 -0700 From: Mike Morris [EMAIL PROTECTED]Subject: Re: Micor mobile repeater - no audio?At 07:00 PM 6/4/05, you wrote:Hey gang,I've got a "Repeater Builder" UHF micor converted mobile repeater running great for several years.. Last week sometime it stopped passing audio.. dtmf, etc... I can key it fine from places like usual, but it doesn't seem to pass any audio.. Would this be more of a controller issue or possibly something awry with my micor? Its running a CAT250 controller. Comments appreciated ofcourse.RodNJFirst clean the inter-board pins.Power it off, remove all the screws that mount the boardsthat plug into the center board, and unplug them halfway,then plug them back in several times i.e. "stroke" themale pins in and out of the female connectors (and getyour mind out of the gutter). I've seen several Micorsdevelop weird problems that were temporarily "fixed"that way. The fix lasts 6 months to a year, and I'veyet to come up with a cure other than soldering themall, which - while the problem is fixed - makes theradio unrepairable in the future. The problem seemsto occur much less often in mobiles, but does occur.Same problem happens to Mitreks, but Moto cameup with a fix for that ... replacement connectors withdifferent metallurgy in the plating of the contact pins.Mike WA6ILQ[This message contained attachments] Discover Yahoo! Get on-the-go sports scores, stock quotes, news & more. Check it out! Yahoo! Groups Links To visit your group on the web, go to:http://groups.yahoo.com/group/Repeater-Builder/ To unsubscribe from this group, send an email to:[EMAIL PROTECTED] Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
[Repeater-Builder] MSR2000 Service manual
Anyone know where I can buy both the service and the application manuals for a VHF MSR2000? I don't care if new or used as long as they are complete. Thanks Dan N8DJP __ Do you Yahoo!? Meet the all-new My Yahoo! - Try it today! http://my.yahoo.com Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
[Repeater-Builder] Part ID
I have a plug in module that I got with some Spectra-tac receivers. It is similar to the metering module for these units, except that it has no switch on it for the various functions. It has only a meter face, a speaker on/off switch, and a meter +/- switch on the face and a speaker on the board. It has part number ZLN6133A stamped on it. Anyone who can tell me exactly what equipment this is for and what it meters (since there is no selector)? Dan N8DJP __ Do you Yahoo!? Yahoo! Mail is new and improved - Check it out! http://promotions.yahoo.com/new_mail Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
[Repeater-Builder] International Crystal
Anyone know if International still offers an amateur radio discount? I know they had a special procedure to get it, a particular person to talk to etc. Anyone up to date on this? Dan Hancock N8DJP __ Do you Yahoo!? New Yahoo! Photos - easier uploading and sharing. http://photos.yahoo.com/ Yahoo! Groups Links To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ To unsubscribe from this group, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] Transmission line cost performance
Nice comparison chart here. http://www.k1ttt.net/technote/coaxloss.html#tables You'll have to do your own price comparisons since prices change all the time. Dan N8DJP From: Budd Turner [EMAIL PROTECTED] Subject: Transmission line cost performance comparisons Happy Turkey Day All Anyone know of a cost and performance comparison done on transmission lines out there? ie. RG-58, RG-8x, RG-8, RG-213, 9913, LMR-200, LMR-400 etc __ Do you Yahoo!? Free Pop-Up Blocker - Get it now http://companion.yahoo.com/ Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
[Repeater-Builder] Re: Static / desense problems
Why do you believe that double shielded cable is necessary for an antenna run? What are you trying to keep the signal out of? Inter-cabling within the cabinet needs to be double shielded to prevent interaction between the TX and RX portions, but once those signals are merged at the output of the duplexer they are both on the same feedline anyway and double shielding is expensive and unnecessary. For short antenns runs, RG213 is actually an excellent choice. The only exception to this is if there is no duplexer being used and the repeater is operating on split antennas with parallel feedline runs, then 100% shielding is necessary. Under these circumstances LDM400 or 9913 would be a good choice if heliax is not available affordably since the cables are not being used in a duplex setting. Dan N8DJP Date: Tue, 11 Nov 2003 15:38:12 -0500 From: Jim [EMAIL PROTECTED] Subject: Re: Static / desense problems Gene Colson wrote: And I am going to once again proclaim that with proper connectors, LMR 400 is as good as it gets.No more noisy that RG213. I am using it on 900 , 440 and VHF duplexers and assure you , there are no problems, Gene W7UVH Of course not-RG213 is unsuitable for duplex as well, as it is NOT double shielded!!! Or do you mean RG-214, which IS double-shielded? And Andrews LDFwhatever-50 is as good as it gets for feedline for ANY application! (well, maybe a few exceptions, like if you need radiating feedline, or plenum-rated...) -- Jim __ Do you Yahoo!? Protect your identity with Yahoo! Mail AddressGuard http://antispam.yahoo.com/whatsnewfree Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
[Repeater-Builder] Re: Static / desense problems
Date: Wed, 12 Nov 2003 18:47:59 - From: Laryn Lohman [EMAIL PROTECTED] Subject: Re: Static / desense problems H-- what about the case where your single shielded cable runs past a high power paging antenna, Unlikely, since that stuff is normally at the TOP of the tower, but special circumstances require special solutions. or your own repeater tx antenna? Seems that leakage INTO your receive antenna coax could be a consideration here. Um, I covered that... About RG213, I've witnessed desense in a duplex situation when using this cable while it is being flexed. I have never seen this. But I do have an acquaintance who wondered why all the jumpers on his duplexers made noise when he touched them. Of course failing to solder the shield in the PL259's had something to do with that. Bottom line-using solid shield coax is almost never a bad choice. Laryn K8TVZ Never said it was. Sometimes people can't afford it though. If I was doing a building-top installation with a short feed-line run, had a limited budget, and had to choose how to spend my money, I'd put more into the antenna and use RG213 before I would skimp on the antenna just to buy 30' of heliax. Dan N8DJP __ Do you Yahoo!? Protect your identity with Yahoo! Mail AddressGuard http://antispam.yahoo.com/whatsnewfree Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
