Re: [Repeater-Builder] Repeaters vs RC
Seems rather insane to feel the need to operate an RC Airplane at frequencies that are known for ducting/skipping and actually being somewhat functional in NLOS conditions - it screams I want to be interfered with!. 2390-2400 MHz seems about the right place to run an RC airplane thats not actually a drone - and the spectrum is practically worthless for anything else except linking LOS repeaters and data work and even then its fairly rare. JS Chris Curtis wrote: It's hard sometimes to work out differences between hams when neither ham is fully versed in the other's chosen activity. My first exposure to real RC was my brother back in the 70s. he had an FCC license just for RC. He saved up to be able to carry rocks in his pocket. Any time he went to a gathering of other RC guys, they would have to coordinate their colors. The little colored streamers hanging off their transmitters to let each other know what frequency they were on. So having multiple tx frequency crystals was and is common. Also, a LOT of rx units in the RC craft are synthesized and broad as a barn door. Only the TX is fairly tight and stable. This causes the interference problem but keeps the cost of swapping out frequencies down. So the cost of changing the operational freq is minimal. The RC guy could call up bomar and get 4 new frequencies for his TX for about the minimum order requirement. Only 1 at a time is needed of course but would give some latitude. Now, as for changing bands altogether. I certainly don't discredit the benefits of moving to a newer technology. However, I can see the RC guy give you a funny look and say: how about YOU move up above 2gHz and see how you like it! 6m RC is the coolest and can certainly play well in the shadow of a 6m repeater. 53.45/51.75 is my machine. Good luck on elmering each other, could be a fun learning experience. Chris Kb0wlf -Original Message- From: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com [mailto:Repeater- buil...@yahoogroups.com mailto:Builder%40yahoogroups.com] On Behalf Of m...@nb.net mailto:mch%40nb.net Sent: Sunday, October 11, 2009 7:09 AM To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Subject: RE: [Repeater-Builder] Repeaters vs RC So he is looking at $1000, as he has 5 channels/aircraft. Does that include the TX and RX units? Joe M. On Sun 11/10/09 8:04 AM , k7...@skybeam.com mailto:k7pfj%40skybeam.com sent: A nice system you can pick up for under $300 and even under $200 if you want basic. Mike Mullarkey K7PFJ 6886 Sage Ave Firestone, Co 80504 303-954-9695 Home 303-954-9693 Home Office Fax 303-718-8052 Cellular - FROM: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com [mailto:Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com] ON BEHALF OF MCH SENT: Sunday, October 11, 2009 5:55 AM TO: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com SUBJECT: Re: [Repeater-Builder] Repeaters vs RC Can you define very cheap? Joe M. Jim Brown wrote: If the complainant is trying to control a model, there are lots of options now that do not include a six meter frequency, with the new 2.5 gig systems very cheap. No more frequency interference between models, since they can all operate at the same time with the spread spectrum control system. 73 - Jim W5ZIT No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.5.421 / Virus Database: 270.14.9/2427 - Release Date: 10/10/09 06:39:00 Links: -- [1] http://groups.yahoo.com/group/Repeater- http://groups.yahoo.com/group/Repeater- Builder/join;_ylc=X3oDMTJlMWZubnZ1BF 9TAzk3NDc2NTkwBGdycElkAzEwNDE2OARncnBzcElkAzE3MDUwNjMxMDgEc2VjA2Z0cgRzb GsDc 3RuZ3MEc3RpbWUDMTI1NTI2MjY0Ng--[3] http://groups.yahoo.com/group/Repeater- http://groups.yahoo.com/group/Repeater- Builder;_ylc=X3oDMTJjYWlrdWpwBF9TAzk 3NDc2NTkwBGdycElkAzEwNDE2OARncnBzcElkAzE3MDUwNjMxMDgEc2VjA2Z0cgRzbGsDaH BmBH N0aW1lAzEyNTUyNjI2NDY-[4] http://docs.yahoo.com/info/terms/ http://docs.yahoo.com/info/terms/ Yahoo! Groups Links No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.5.421 / Virus Database: 270.14.1/2407 - Release Date: 10/10/09 06:39:00
Re: [Repeater-Builder] Antenna question
Kris Kirby wrote: On Sun, 11 Oct 2009, Thomas Oliver wrote: Buy a commercial one and cry once. What he said. Give until it hurts, but a DB-224 or a Super Stationmaster with upper brace are a necessity in environments where ice damage is a possible. Do it once, do it right. Or do it every week/month/year. Are you paying for a tower climber? Failing to have the funds you may want to build a colinear out of coax sections. It don't get much cheaper than that. http://www.repeater-builder.com/antenna/wa6svt.html http://www.repeater-builder.com/antenna/wa6svt.html Wait until that develops a crackle... -- Kris Kirby, KE4AHR Disinformation Analyst I thought the prefered poor-man's repeater antenna was a J-pole? Out of curiosity - are the 'square dipole' (or 'gapped loop' or whatever they want to call them) antennas usable for repeater use? Example: http://www.hamuniverse.com/loop.htm I've seen a 'hamsexy' Explorer around these parts (East Texas) with a stack of these on the roof at various frequencies. I personally dislike vertical antennas on cars (at best they generate wind noise, at worst they hit things and get bent/broken) these look like a decent option for truck/SUV use, assuming the other side is hpol too or you're willing to put up with the x-pol losses. JS
Re: [Repeater-Builder] Question on portable repeaters
Perhaps you need two Ford Explorers? :) Theres a lot of them to be found dead for scrap prices. Delete the driveshaft(s) and add a tow bar. Nice inconspicuous repeater platform! 2m RX - 900/1.2 link to other SUV - 2M TX If the link radio TX was very low (few hundred mW?) a smallish deep cycle (SLA) battery should run the RX and link TX for quite a while, and all you'd need then is a notch of some sort to keep the across-the-parking-lot-or-whatever signal from slipping into the 2M RX. Of course, a backpack, ammo box, ice chest or even a small trailer may be an easier solution to work with. I suggest the second Explorer to possibly increase the value of my own dead Ford Exploder. Maybe you could start a trend! JS Peter Dakota Summerhawk wrote: Morning, We are looking at building a portable repeater for special even use. This will be mobile mounted and 2M. My questions is this: If we are using two radios (one for TX one for RX) then what does the antenna separation have to be for all of this to work? Planning on mounting this in a SUV so roof space can be adjusted if need be. Thanks Peter Dakota Summerhawk Laramie County ARES
Re: [Repeater-Builder] OT: Tape
3M Mastic tape? Just remember, it'll end up sticking to anything else you stick it to *eventually*, often in ways that are quite amazing and not reasonably removed. I suggest a layer of standard electrical tape between anything you care about and the mastic tape layer (and another layer of electrical tape outside that to keep the UV away)... JS Mike Besemer (WM4B) wrote: H… wonder when it became ‘Queer Tape’? For the 24 years I was in, it was F-4 tape. (Anybody who ever worked F-4’s knows why!) I still work for the Air Force… I’ll have to ask some of the Spark Chaser and Pointy Heads! 73, Mike WM4B *From:* Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] *On Behalf Of *Kris Kirby *Sent:* Thursday, September 10, 2009 6:37 AM *To:* Repeater-Builder@yahoogroups.com *Subject:* Re: [Repeater-Builder] OT: Tape On Wed, 9 Sep 2009, Majdi S. Abbas wrote: Self-vulcanizing rubber tape is GREAT for splices. However, you need something to wrap it with to protect the rubber...and there's where the friction tape comes in. Traditional splices were self-vulcanizing rubber underneath friction tape for this reason (and it's the reason they are all still available.) There is a type of tape used by the Air Force which is based on silicone which has a unique property of not sticking to hands or anything else except itself. I believe you stretch it a little when you're applying it, but once it's been applied, it is a completely single unit and cannot be unwrapped. (I tried.) The unofficial Air Force term for it is Queer Tape, Times Microwave sells it in their kits for connector sealing. -- Kris Kirby, KE4AHR Disinformation Analyst Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * Your email settings: Individual Email | Traditional * To change settings online go to: http://groups.yahoo.com/group/Repeater-Builder/join (Yahoo! ID required) * To change settings via email: mailto:repeater-builder-dig...@yahoogroups.com mailto:repeater-builder-fullfeatu...@yahoogroups.com * To unsubscribe from this group, send an email to: repeater-builder-unsubscr...@yahoogroups.com * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] Re: Diversity FM reception
I think the larger problem is a lack of standardization in receive antenna systems for broadcast FM. The late 60s/70s brought along ignorant antenna designs, like the windshield-integrated dipole and the 45-degree swept-back dipole. Now we've got even more ignorant designs like the 45 degree stubby on the roof of cars (06 or newer Hyundai Santa Fe is a good example of this mistake), or oddball angled foil designs in/on window glass (01-05 Hyundai Santa Fe is a good example of this). Absolutely worthless for any linear polarization. Amusingly, on the 01-05 Santa Fe, Hyundai decided to integrate a 10 db-ish RX amplifier in the back near the antenna. It also doesn't have any input filtering. Transmitting on VHF anywhere near the vehicle with any bit of power at all absolutely slaughters any FM RX you might have, even when listening to 50kW + LOS transmitter. AM Broadcast is the worst, where all you get to hear is fuel pumps, alternators and ignition... JS Al Wolfe wrote: Back in the late 60's or early 70's we tried this on one of the stations I was involved with. CP can work with separate antennas but only if the vertical and horizontal elements are in the same vertical axis and fed in quadrature or 90 degrees out of phase. And the SWR needed to be absolutely flat, as in 0 reactance or the circular polarization and its benefits were negated.. The results at the time showed some improvement in our mobile coverage but there was a three db hit in general using the same transmitter set up as before the CP experiment. The project was eventually abandoned. Later the roto-tillers, cycloid dipoles, and vees were developed where the circularity was supposedly inherent to the antenna design. I personally like the roto-tiller type as they seem to actually generate a circular pattern with the vertical and horizontal radiation and circularity being fairly predictable. A lot of broadcasters consider circular polarization as a legal back-door method of doubling your ERP. It's pretty much the standard for most FM broadcasters anymore. 73, Al, k9si, retired, mostly Years ago before CP antennas were commonly available, FM stations would feed two separate antennas on the tower. One was H, the other V. Was that then 45 degree polarization??
Re: [Repeater-Builder] Re: Repeaters and Water Towers
From what I've gathered from on-site reports and the press, they'd much rather the ham guys get out of the way so they can pull in their kickback-paying overpriced corporate suppliers in ASAP to collect as much DHS/FEMA money as they can get (and kick back...) Ham guys are useful for local/small events/disasters. Soon as the feds and their corporate comm-clowns move in you can, as they've been quoted to say, hand out coffee. Plus, who wants to stand around with a bunch of Blackwater goons? Trailer Park based mercenary forces don't tend to have the best hygiene. JS de W5DK wrote: Some of the sites are not as secure as they look from the street. If you get pressured to leave just point out Homeland Security expects Hams to help them when it gets bad. http://www.arrl.org/news/stories/2006/10/04/100/?nc=1 http://www.arrl.org/news/stories/2006/10/04/100/?nc=1 http://www.nationalterroralert.com/communications/ http://www.nationalterroralert.com/communications/ http://www.fcc.gov/pshs/techtopics/techtopics13.html http://www.fcc.gov/pshs/techtopics/techtopics13.html 73 Don Kirchner W5DK
Re: [Repeater-Builder] Repeaters and Water Towers
Around here, it raised the cost of tower rental which caused all the local PD/FD/etc traffic to move to the water towers! JS kc8fwd wrote: Hello, Has anyone had experience with repeaters at water tower sites now that homeland security is involved? I would like to hear your experience. Thanks Mike KC8FWD
Re: [Repeater-Builder] Re: Closed Repeaters
My views on this: #1 - If you want a closed repeater then you should get a private repeater pair coordinated in an appropriate private-communication pool. will happily assign you a private repeater pair for a reasonable price. Plain and simple. Amateur radio is not a replacement for a cell phone, nor should it be treated like one. If you legitimately NEED private communications this isn't even a significant expense. Make your 'radio club' worthwhile with a *real* private repeater (that your non-radio-geek wife can use, too!) Just because you hold an amateur license doesn't mean your communications/equipment/use are always in the interest of amateur radio and quite often are in the exact opposite interest of the overall community. This also includes situations where all the rest of the users of your closed repeater happen to be licensed amateurs, too. If nothing else, GMRS licenses are cheap (not ham cheap, but cheaper than a 'real' repeater pair) and get you UHF and plenty of power for most communications. #2 - digital does not mean 'closed system' - it means you gotta pay (for hardware) to play. Its also not the end of the 'home made repeater' - if anything its just the beginning... Just my 2 cents as a semi-interested party. JS Maire-Radios wrote: * yes I know what you mean but the good Doctor on the voice message need to have an open mind and not expect everyone to give it all away. If he wants an open repeater maybe he need to get one and pay for it. Let everyone use it any time and see how it goes. The days when you built a repeater from parts is almost over now with all the digital systems out there. * * * * John *
Re: [Repeater-Builder] Re: IMPORTANT - large amount of stolen equipment recovered - is some yours?
The FCC sucked up *all* his gear vs just the gear he was using to break the law, which I believe is allowed since the defendant was a licensed operator of some sort. While my radio geek side likes this, my US citizen side kinda freaks out at the idea... The problem with the $24k FCC fine is that $24k only went to the FCC. The affected mall could file a civil case, but thats not really worth the effort unless the guy has easily accessed money after the FCC gets done taking their chunk. The real question is - what do laptop/desktop computers have to do with some moron screwing with mall cops? You could get *really* outside and say he looked up the frequencies with said computers, but thats about it. Something about this story doesn't quite make sense... JS Jeff Kincaid wrote: This is really rather frightening. Many of us have similar collections of gear, and I'm wondering on what basis it was seized. I don't remember anything in the Constitution about seizure of potentially stolen property. I hope the stuff is his and he gets a really huge settlement (and that the folks he was jamming get the same from him). The idea that a government minion can simply decide that you have too much radio gear and take it seems rather onerous. 'JK --- In Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com, Mike Morris WA6ILQ wa6...@... wrote: Recently the FCC busted a local jammer and when his residence was searched they found a treasure trove. There are over 200 pieces of equipment involved including laptops, desktops, over 120 handhelds and several repeaters. And broadcast equipment including a commercial grade FM transmitter. If anybody has serial numbers on file that matches anything on the lists mentioned below I think that the Ventura County Sheriff's Department would like to hear from you - contact Detective Jon Smith at (805) 494-8216 or via e-mail at jon.smith (at) ventura (dot) org The snippet below is from the CGC Communicator, a broadcast industry weekly newsletter published by Robert F. Gonsett, W6VR, cgc (at) cgc333 (dot) connectnet (dot) com, Copyright 2009, Communications General® Corporation (CGC). Reprinted with permission, and the newsletter has given permission for others to do likewise. No additional permission is needed. ** LIST OF POTENTIALLY STOLEN EQUIPMENT IN THE BONDY CASE The Ventura County Sheriff's Department has prepared its list of potentially stolen radio equipment in the Kevin Bondy case. Mr. Bondy is accused of jamming some southern California radio frequencies as discussed in recent CGC Communicator newsletters. A police search of his residence turned up an extraordinary amount of potentially stolen radio gear. Your help is needed. Is any of this equipment yours? Would you copy this story to others in the land-mobile and broadcast industries, particularly to equipment dealers and publications? If some or all of this equipment is stolen, the owners need to contact the Ventura County Sheriff pronto. Items #120 - 123 involve FM broadcast equipment; the rest is land-mobile gear (including repeaters) with a few miscellaneous items mixed in (e.g. computers, CB amateur radio gear). The first URL takes you to the list. The second URL shows pictures of the FM broadcast equipment and gives contact information for the Ventura County Sheriff. Communications General Corp. has been in touch with Broadcast Electronics concerning Item #120, the solid state 1,000 watt FM broadcast transmitter. Unfortunately, the serial number is a bit outdated for their records, but perhaps you or an equipment dealer would have a record of the sales transaction. Thanks for helping by looking over the equipment list and forwarding this story to others. Equipment list: http://earthsignals.com/add_CGC/Oaks_Mall_09-5771.pdf http://earthsignals.com/add_CGC/Oaks_Mall_09-5771.pdf Photographs of the FM broadcast equipment: http://earthsignals.com/add_CGC/Letters/Stolen%20Equipment.htm http://earthsignals.com/add_CGC/Letters/Stolen%20Equipment.htm Background information on Mr. Bondy: http://www.fcc.gov/eb/FieldNotices/2003/DOC-290813A1.html http://www.fcc.gov/eb/FieldNotices/2003/DOC-290813A1.html **
Re: [Repeater-Builder] IMPORTANT - large amount of stolen equipment recovered - is some yours?
Not that impressive really. Whats all this crap worth, maybe $20k? Not really that much money. FM broadcast parts pop up in rather strange places these days for cheap since theres really not much legitimate commercial market for a boat-anchor transmitter. You'd think someone smart/slick enough to get away with stealing that much gear would likely be smart enough to not get busted by the FCC for screwing with mall cops. Did this guy sell LM radio/programming for a living? JS Mike Morris WA6ILQ wrote: Recently the FCC busted a local jammer and when his residence was searched they found a treasure trove. There are over 200 pieces of equipment involved including laptops, desktops, over 120 handhelds and several repeaters. And broadcast equipment including a commercial grade FM transmitter. If anybody has serial numbers on file that matches anything on the lists mentioned below I think that the Ventura County Sheriff's Department would like to hear from you - contact Detective Jon Smith at (805) 494-8216 or via e-mail at jon.smith (at) ventura (dot) org The snippet below is from the CGC Communicator, a broadcast industry weekly newsletter published by Robert F. Gonsett, W6VR, cgc (at) cgc333 (dot) connectnet (dot) com, Copyright 2009, Communications General® Corporation (CGC). Reprinted with permission, and the newsletter has given permission for others to do likewise. No additional permission is needed. ** LIST OF POTENTIALLY STOLEN EQUIPMENT IN THE BONDY CASE The Ventura County Sheriff's Department has prepared its list of potentially stolen radio equipment in the Kevin Bondy case. Mr. Bondy is accused of jamming some southern California radio frequencies as discussed in recent CGC Communicator newsletters. A police search of his residence turned up an extraordinary amount of potentially stolen radio gear. Your help is needed. Is any of this equipment yours? Would you copy this story to others in the land-mobile and broadcast industries, particularly to equipment dealers and publications? If some or all of this equipment is stolen, the owners need to contact the Ventura County Sheriff pronto. Items #120 - 123 involve FM broadcast equipment; the rest is land-mobile gear (including repeaters) with a few miscellaneous items mixed in (e.g. computers, CB amateur radio gear). The first URL takes you to the list. The second URL shows pictures of the FM broadcast equipment and gives contact information for the Ventura County Sheriff. Communications General Corp. has been in touch with Broadcast Electronics concerning Item #120, the solid state 1,000 watt FM broadcast transmitter. Unfortunately, the serial number is a bit outdated for their records, but perhaps you or an equipment dealer would have a record of the sales transaction. Thanks for helping by looking over the equipment list and forwarding this story to others. Equipment list: http://earthsignals.com/add_CGC/Oaks_Mall_09-5771.pdf http://earthsignals.com/add_CGC/Oaks_Mall_09-5771.pdf Photographs of the FM broadcast equipment: http://earthsignals.com/add_CGC/Letters/Stolen%20Equipment.htm http://earthsignals.com/add_CGC/Letters/Stolen%20Equipment.htm Background information on Mr. Bondy: http://www.fcc.gov/eb/FieldNotices/2003/DOC-290813A1.html http://www.fcc.gov/eb/FieldNotices/2003/DOC-290813A1.html **
Re: [Repeater-Builder] DB-224 patterns on side of tower.
Theres a lot to account for in this: A side-mounting on self-standing towers with significant amounts of leg angle will reduce the 'total blockage' of the antenna in any direction at one time. As long as one dipole is visable on your antenna you can still calculate for that one dipole's gain alone. B not all towers are equal. You're going to see a lot more random reflection/attenuation from a tower thats 'coated' with coax or internal structure vs one thats practically bare. C offset mounting length can make all the difference in the world. a 4 ft offset at 927 mhz is significantly more wavelengths than a 4 ft offset at 2M/220/440. D most towers tend to have less cable hanging on them the farther you go up (or even switch to a smaller structure...) Just a few more things to consider... JS Roger White wrote: Our 145.43 MHz repeater has been on a self supporting tower 450 ft. high, at the 250 ft. level ( a Stationmaster at first and a dB224 later) and now at the 350 ft. level (dB224). The tower face at both heights was considerable (well over 20 to 25 ft. wide). The antenna was offset from the tower leg a considerable distance in both instances and the dipole elements were orientated for a omni pattern. My guess is that the tower face is so big where we have had the antennas at that the effect off offsetting the dipoles in one direction is minor compared to the effect that the large tower face would have on the pattern. As you would expect, the pattern nulls off the backside are considerable, but not severe enough to limit communications. The higher frequency you go, the less the effect is. We have a 224 MHz repeater (dB224JJ set for an omni pattern) at the 300 ft. level and it seems to do quite well hearing off the backside. Our 927 MHz repeater at 400 feet (using an unused paging antenna) seems to hear off the backside almost as well as it does off the front side. Since beggars can't be choosers, we have over the last 25 years on the tower accepted the pattern deficiencies. I can take a few pics if you would like to see how they are mounted. Roger W5RDW Murphy, Texas DFW area - Original Message - *From:* tahrens301 mailto:tahr...@swtexas.net *To:* Repeater-Builder@yahoogroups.com mailto:Repeater-Builder@yahoogroups.com *Sent:* Tuesday, June 30, 2009 2:35 PM *Subject:* [Repeater-Builder] DB-224 patterns on side of tower. Hi Folks, We are putting up the DB-224 on the side of the tower, which is one of those large 3 legged towers. (like you see at microwave telephone sites). I have the DB-products data sheet on the 224, and it has some plots for side mounting on the tower. The plot in question is the 224E (all in line, pointed away from the tower). According to DBprod, it would give the appropriate pattern for our desired area. However, one of the old salts here (who has final say-so) says that you really have to put some left and right angulation on the elements to get that pattern. I guess the real question is how positioning on the side of the large tower affects the pattern - if the elements are directly perpendicular to the tower leg, versus having some rotation on the leg. I'm thinking that we will probably just have to experiment with what we get per old-salt's method see how it works. Anybody have any other ideas? Thanks, Tim W5FN
RE: [Repeater-Builder] Taxes On Antennas Feedlines? What Next?
Now if they could tax for unused/held spectrum. JS From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Paul Plack Sent: Thursday, April 30, 2009 7:19 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Taxes On Antennas Feedlines? What Next? Sounds like an opportunity. There have to be thousands of abandoned antennas and feedlines on towers around the US. Till now, there's been no incentive for companies to let them go until they decayed to the point they fell off on their own. There are antennas you'd never get access to before. Put together a not-for-profit, or work through an existing ham club set up as a 501(c)(3), and provide commercial enterprises an alternative to the costs of having them torn down, with a donation tax credit to boot! Call me passive-aggressive, but figuring out strategies like this is way more fun than carrying picket signs! 73, Paul, AE4KR - Original Message - From: ran...@farmtel.net To: Repeater-Builder@yahoogroups.com Sent: Thursday, April 30, 2009 5:46 PM Subject: [Repeater-Builder] Taxes On Antennas Feedlines? What Next? Maybe this is not new in other states but it appears to be gaining momentum here in Iowa. The county real estate assessors are charging taxes on all cables and antennas on commercial towers. This is whether there is any radio equipment connected or not. Currently I have a couple ham repeaters running on unused antennas on these towers owned by my employer. Nice tall towers too! Now my employer wants these antennas and feed lines removed so taxes won't have to be paid on non-revenue generating antennas. My current plans are to form a non-profit corporation and file for an exemption for the antennas and feed lines. I would like to hear how others have tackled another attempt by government to tax the things we enjoy. Randy WB0VHB image001.jpgimage002.jpg
RE: [Repeater-Builder] Computer noise in 2M Repeater
As a wireless installer with a little RF knowledge, I can tell you *nothing*
is a bigger piece of crap than anything Netgear sells. I'd also guess this
WISP also loses a lot of gear based on what you've mentioned so far. I'd
have to suggest to them the following:
ACisco makes nice switches on the cheap (most WISP POPs don't use more
than a 100mbit switch anyways, you can get a Cisco Catalyst 2924 for under
$50 off ebay, and it's a much higher quality switch with a good power supply
that won't spew RF noise)
BShielded cat5/5e/6 bonded to Mot R56 standards. This will further
eliminate RF spew while greatly reducing lightning failures.
Personally, I'm a big fan of running DC over coax (I use super-cheap RG59,
bonded to R56 standards) and *FIBER* for the data. DC is easy to protect
(MOVs and poly-fuses are your friends), Ethernet is much harder. Fiber is
awesome, easy and cheap. Lightning doesn't affect it, which is a huge
bonus. Ethernet-Fiber transceivers can be had for pennies on the dollar
these days, especially if you only need 10 or 100mbit.
Their noise source may also be the power supply feeding the system.
Assuming they're not using a PoE-capable switch, they most likely have a
'power injector' inline, connected to some sort of power supply. I've
discovered most cheap-o ('Mean Well' is a personal favorite) 'project' brick
power supplies have somewhat dirty output. The long Ethernet run either
increase the noise or work as a much better antenna. 0.1uF capacitors and
ferrites in the correct places can greatly reduce this (or using better
quality power supplies).
Now. the strobe problem you're describing sounds like a potential horrible
electrical problem at the site. In my experience an FM rig shouldn't be
greatly affected by a strobe. It also shouldn't be causing a
problem/reaction with the WISP gear (it may be causing damage to it!) so I'd
definitely find out what is going is going on with the strobe.
Good luck!
Jacob Suter
From: Repeater-Builder@yahoogroups.com
[mailto:repeater-buil...@yahoogroups.com] On Behalf Of Jim Russell
Sent: Saturday, April 25, 2009 8:53 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Computer noise in 2M Repeater
Thanks for the input from all of you. I went to the tower site this
afternoon to give another look at the problem. The noise has gotten worst.
Our receiver is greatly desensed. The only equipment on site is the site
owner's UHF repeater, our two meter repeater and the Internet equipment. The
site owners equipment doesn't seem to be affected. The strobe lamp puts a
buzz in our receiver each time it fires. I noticed one of the green lamps
on the Netgear switch get brighter when the strobe fires. I'm sure the
Internet equipment is affected by that. The two meter is our primary
machine used in our storm watch activities. I tried to contact the Internet
company today with no answer. Will try again Monday. Again thanks for the
information.
Jim WK5Y
- Original Message -
From: Eric Lemmon mailto:wb6...@verizon.net
To: Repeater-Builder@yahoogroups.com
Sent: Saturday, April 25, 2009 9:15 AM
Subject: RE: [Repeater-Builder] Computer noise in 2M Repeater
Jim,
This situation happens all too often, and it usually occurs because cheap
equipment is used (plastic boxes to contain the amplifier, unshielded cable,
no ferrites, ineffective grounding. etc.) to keep the installation costs
down. This is a misguided approach, because repeated visits to fix a
leakage problem will always cost a lot more than a first-class system would
have cost. Sound familiar?
Another possible factor is that *some* wireless installers are primarily IT
(Information Technology) folks who have relatively little experience with
the RF environment at a repeater site. I have met a few of these clueless
guys, whose eye glaze over when I talk about an interfering carrier from a
CPU crystal or intermodulation. They're used to installing APs and bridges
in office buildings, and don't see anything different about tie-wrapping a
more powerful box to a tower that supports many other services, except
perhaps using some electrical tape and silicone goop to waterproof the
connectors. Don't laugh- it happens!
So, to answer your question, immediately contact the wireless system owner
and advise him that his system is interfering with yours, and it must be
fixed promptly. Don't quote the FCC rules quite yet. If the polite
approach does not get results, contact the site owner. Above all, do not
just sit and wring your hands. The wireless owner must comply with Part 15
rules, but he must be told if there is a problem.
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 Jim Russell
Sent: Friday, April 24, 2009 7:20 PM
RE: [Repeater-Builder] Ridiculus
The serious question is does the county have the legal right to prohibit such operations? Radio transmissions are federal jurisdiction only, at least from every document I can quickly Google up. How many ham radio operators actually transmit more than 3 hours/day on shortwave? JS From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Lee Pennington Sent: Wednesday, April 08, 2009 3:38 PM To: undisclosed-recipients: Subject: [Repeater-Builder] Ridiculus === THIS IS ABSOLUTLY REDICULOUS! Subject: California County Taking Actions To Silence ALL Ham Activity From: www radiobanter com San Luis Obispocounty supervisors took drastic and unprecedented action yesterday by passing an ordinance that would prohibit amateur radio operators, known as hams, from operating their transmitting stations. The measure was put in place to eliminate what officials said were health risks associated with transmitters located close to children. A legal struggle is expected. By a vote of 4 to 1 with one abstention, the governing board of SLO county took action aimed at addressing a recent Stanford University study that showed a correlation between ham radios and attention de ficit disorder and hyperactivity in children, as well as nagging reports of interference caused by radio hams operating their high-powered transmitters in residential neighborhoods. Our primary responsibility is to provide a safe environment for children to live without the dangerous effects of radio waves constantly bombarding them and causing proven neurological and psychological problems, said E. Duane Nyborg, an attorney who represented the county in several court cases in the past year. Hams are not the only culprits, but they are usually in very close proximity to children and are no doubt a major contributor to the health problems we've been seeing. The interference is just the last straw that convinced the county that something had to be done about it. Atascadero city manager Laura Lopez said that she has seen a tenfold increase in the number of complaints of interference from ham radio operators in the last six months. New housing developments which have dramatically increased the population there and placed homes unusually close to each other are the predominant contributing factor. Similar conditions exist in most of the county. We have radio hams getting into toasters, electric pianos, light bulbs, everything, from their powerful transmitters that cause all this static. Many of our citizens can't use basic appliances or watch television because of all the junk that the hams are broadcasting, she tol d the Press-Telegram by telephone. Hams can't say they didn't see this coming. They were warned by the county last year that if they did not submit to a check of their stations by officials, they would have limits imposed on their operation. Few consented to the searches, which most decried as invasive. But nobody expected a total ban on transmissions. This is outrageous. You'd better believe we're going to fight back and win. This is a totalitarian seizure of our rights that is totally illegal and can't stand up, said Frank Wilson, a local ham club president. He said there were no formal plans for an appeal yet but preparations were underway. Wilson claims that a federal preemption of local zoning ordinances, called PRB-1, delineates three rules for local municipalities to follow in accomodating antenna structures such as are used by hams. But Nyborg says that PRB-1 applies to antenna structures only, and not the transmitters used to feed the antennas with a radio signal. We know all about PRB-1. That's why we said nothing about antennas. This law is not about antennas. It goes after the root of the problem, which is the transmitters that put out huge signals that get into the brains of our children and short-circuit them out. Those are the facts, that's what the scientific evidence points to, he said at a news conference called shortly after the county's action. In 2008, a grou p of researchers in the school of Environmental Health and Safety at Stanford published their findings that exposure to ham radio signals for three hours per day increased the risk of hyperactivity and related disorders by 10% in children aged 12 and under. This effect was seen when a typical ham radio was turned on up to ¼ mile away. The San Luis Obispo city office says that up to 11,000 children in that city live that close to a ham radio station. The Stanford study showed that frequencies around 3.5, 7, and 14 Megahertz were the most harmful, but that the danger existed all the way up to 450 Megahertz and above. We know where the hams are, that information is easy to get on the Internet, said former mayor of Paso Robles and current
RE: [Repeater-Builder] (OT) APCO P25 horror stories anyone?
I agree entirely on the RF part of your article. But. Digital modes somehow eliminate feedback? Echo cancelation exists but a great deal of the time it fails miserably. You end up with voice-frequency delayed retransmission in the audio which IMHO is harder to understand 'through' than reasonable (ie - public safety person using lapel mic/HT to talk while inside the car with the car's radio's volume reasonably low) feedback. I personally don't understand the actual need (other than paying the FCC/Congress's bills) for all this nonsense of tightening up tx bandwidth. My scanner says theres a lot less on vhf/uhf than there ever was before as the business users all migrated to cellular. Is the 'real world' trick to just apply for 2 side-by-side 12.5k slots and run your big fat 25khz carrier down the center? ;) JS From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Nate Duehr Sent: Wednesday, April 08, 2009 2:25 PM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] (OT) APCO P25 horror stories anyone? If it's either there or its not is supposedly a problem, you'll never see that go away in digital comms. You can bit-stuff FEC codes by the metric truckload into a signal all day long, but at some point, it just falls out. That's digital. Period. Anyone surprised by this must not be paying much attention to how these technologies work. MORE IMPORTANTLY: You can't LOWER channel bandwidth and retain audio quality and still have room for tons of FEC. Good old Nyquist and his mathematical friends... Hint: THE REAL ACHILLES HEEL OF P25 AND OTHER DIGITAL SYSTEMS... is that we're trying to implement them in LESS RF BANDWIDTH than the traditional FM analog signals. The natural progression should have been to convert to digital in the SAME channel spacing (expensive, and no economic gain, perhaps), and then start cranking up the compression over the years. The speed at which BOTH requirements were driven in, is painful for all. You mention that hams detect things using digital techniques, far down into well below the human ear noise floor on analog receivers. What you fail to mention is that those systems REPEAT the message over and over and over again. (WSJT, for example.) This isn't possible in a real-time voice system without using MORE bandwidth. It could have been done. Making a digital system that accurately reproduces telephone quality audio or better, and has multiple transmissions of the same bits (error correction) is certainly a no-brainer. (The entire telephone network runs on such technology these days... try finding an analog stepper switch at your local CO! Since they're not using RF paths that fade, and have other problems, their error correction needed is miniscule compared to an RF system.) Other's have also complained that the VOCODERs chipsets from DVSI introduce too much audio delay. I personally feel that complaint is a red-herring, since prior to audio delay on digital systems, there was always the feedback loop howl... same problem, just different timing and our ears aren't used to it. Once you get used to either one, you learn to move away from the loudspeaker... it's informal training, in most user's heads. Never seen any public safety radio folks go out to a parking lot and show anyone how to avoid feedback howl, but the users figured it out from seeing PA systems and people giving speeches, etc. But many probably don't easily make the mental leap that digital echo on-scene is the same thing. And I doubt anyone's got time to show them how to avoid the audio loop-back noise either, but if they give the users a hint that it's CAUSED by the same thing, they can apply their old head-knowledge to the new systems. (Don't stand next to the truck that has the big loudspeaker turned all the way up!) The engineering needed to deal with background noise is that it's going to take some super-duper DSP heavy hitter math to get RID of it prior to feeding the VOCODER. That's going to cost some serious bux... It's already common in the telco central office and audio/videoconferencing world, especially as packetization delays have been added by the move to VoIP on the long-haul circuits. Conferencing/wireline engineers have much easier challenges though, and can do things like ping the room for acoustics at the start of a call... or slowly slide in an adjustment for removal of echo as the bitstream passes by in the most advanced echo cancellers in the world. (Ever notice how most conference room speakerphones ding or play little snippets of music or similar at the beginning of a call? You think it's just another techno-noise, but the DSP is actually sampling the echos off the room walls, glass windows, etc... and adjusting the digital filters accordingly.) Unfortunately, the typical mobile radio user's environment is continually changing, they're not willing to pay $3000 a radio (well, some did...
RE: [Repeater-Builder] Re: LMR-400 and Belden 9914 DuoBond
Even Times Microwave disagrees with you. JS From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Patrick Patterson Sent: Friday, March 20, 2009 3:07 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Re: LMR-400 and Belden 9914 DuoBond Why would you say I know better than to use these in duplex service? I have used LMR400 for duplex cables for years and have never had one single problem. If you do your calcalations correct for figuring the length of your cables then there should not be any problems. LMR400 is the best and then there is Heliax. --- In Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com , James Delancy ctra...@... wrote: Does anybody know any actual differences between these two cables (other than manufacturer, the obvious and the fact that the Belden actually seems to have a solid copper center conductor whereas the LMR-400 seems to be possibly steel core)? Thanks! Please don't flame me ... I know better than to use these in duplex service ... I just want to know more about them! James WJ1D image001.jpgimage002.jpg
RE: [Repeater-Builder] Split site link via IP
I suspect you could use this for your needs: http://app-rpt.qrvc.com/ and a USB-equipped Linux capable system - doesn't need much horsepower since you're not forced to additionally compress the audio. I suggest using a small 'embedded' type Linux-running system, like the Ubiquiti Routerboard/Routerboard Pro. They're inexpensive and rock solid. OpenWRT has packages for what you need to run Asterisk. Non-obvious awesomeness of this: 1) You can also use it as the controller for your backhaul IP link (just add Atheros chipset MiniPCI card). You can add the minipci cards, prebuilt pigtails/coax, and 25+ dBi gain 5ghz antennas (assuming perfectly clear LOS between the repeater sites) for about $100/endpoint. 2) You're basically using a full blown phone switch/pbx controller to run your radio. Autopatch? Got it. Linking? Got it. Voice (cooler than dtmf!) control? Got it. Basically its only limited by your ability to configure Asterisk. 3) add another USB device and you're controlling another radio, with the same or a completely different configuration/usage of the first... Calculatons: Ubiquiti Routerstation: $69 USB header connector: $5 USB audio device: $10 CM9 802.11a/b/g adapter:$35 UFL to N-F pigtail: $10 26 dBi 5.8 GHz parabolic: $55 --- Total (per end):$184 Just add LMR-400, audio cables, and have a blast JS -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:Repeater- buil...@yahoogroups.com] On Behalf Of Ethercrash Sent: Monday, March 09, 2009 9:43 AM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Split site link via IP My repeater group is considering building split-site 6m machine. As an inter-site link, I was thinking of using some sort of VOIP arrangement via the internet. I'm curious if anyone has tried something like this: My idea is to use a point-to-point, private link (i.e. not IRLP or Echo) to pump audio and maybe even some signaling between sites. The receive site would consist of the receive radio, controller (most likely an Arcom), and a PC to do the encoding/streaming. The transmit site would consist of a PC to decode the audio stream, a PL decoder for TX logic, and the TX radio. The basic premise would be to take audio from the RX (PL filtered), fed thru the controller, mixed with link PL, and fed to the PC's audio input. The PC then streams the audio over the internet to the RX site PC, where it is decoded and fed to the TX radio, which will be keyed by a PL decoder (provided the IP encode/decode process hasn't mangled the PL). Whew... Now, question is: will it work? Or more properly, has anyone made this work? I'm going to try it on a small scale just to prove concept, but I'm curious if anyone has tried this already. My intention is to use something along the lines of Winamp with Shoutcast or Windows Media Encoder to stream the audio. I'd rather find a Linux- based CLI encoder if such an animal exists. I had thought about using IRLP nodes as endpoints, but IRLP policy would preclude that. Thoughts? Encouragement? FTW is he THINKING?!?! ;) I'd be interested in the group's thoughts, and I'll report the results of my experiments. Thanks 73, Brian, N4BWP Yahoo! Groups Links
RE: [Repeater-Builder] Somewhat OT - How to make HDTV *really* work
It matters a lot when you're looking to purchase an antenna. All UHF/VHF antennas are a compromise. Get what you need or get both and run multiple feed-lines or an RF switch. JS -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:Repeater- buil...@yahoogroups.com] On Behalf Of Thomas Oliver Sent: Friday, March 06, 2009 9:51 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Somewhat OT - How to make HDTV *really* work It really does not matter what channel they are on as the tv's or converter boxes scan for all possible channels when you install them. plug and play. tom [Original Message] From: MCH m...@nb.net To: Repeater-Builder@yahoogroups.com Date: 3/6/2009 10:33:52 PM Subject: Re: [Repeater-Builder] Somewhat OT - How to make HDTV *really* work You know, I was doubting the arguments posed by the government, but I'm starting to think they were right. It's just too much for the consumer to grasp DTV as it currently sits. I mean, if a *technical* bunch like this can't understand how a channel 2 station can be on RF channel 25, what hope is there for the consumer? Maybe it should be postponed indefinitely until the stations all get their original channels back or they simply change they logo from Channel 2 to Channel 25 and forget this alias XX-Y channel format. Joe M. Ken Decker wrote: Good grief folks, how difficult is this? Checkout the website site below. For example: in San Diego it shows KPBS as channel 15-1. Click on the call letters. It shows channel 15, the former analog channel and what it still is identified as.. Then it shows (RF 30), that's the channel it's on in the digital transition, but it identifies as Channel 15-1. The nice map also shows where the transmitter is located and a engineering SWAG as to the signal level to expect. The Digital TV Transition: DTV Reception Maps http://www.fcc.gov/mb/engineering/maps/ Ken - Original Message - *From:* JOHN MACKEY mailto:jmac...@usa.net *To:* Repeater-Builder@yahoogroups.com mailto:Repeater-Builder@yahoogroups.com *Sent:* Friday, March 06, 2009 12:41 PM *Subject:* Re: [Repeater-Builder] Somewhat OT - How to make HDTV *really* work What is the callsign of the (ch. 7) station we are talking about? -- Original Message -- Received: Fri, 06 Mar 2009 12:35:36 PM PST From: Chuck Kelsey wb2...@roadrunner.com mailto:wb2...@roadrunner.com To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Somewhat OT - How to make HDTV *really* work The same. - Original Message - From: JOHN MACKEY jmac...@usa.net mailto:jmackey%40usa.net To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Sent: Friday, March 06, 2009 3:28 PM Subject: Re: [Repeater-Builder] Somewhat OT - How to make HDTV *really* work What frequency was channel 7 digital and frequency channel 7 analog? -- Original Message -- Received: Fri, 06 Mar 2009 08:12:39 AM PST From: wd8chl wd8...@gmail.com mailto:wd8chl%40gmail.com To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Subject: Re: [Repeater-Builder] Somewhat OT - How to make HDTV *really* work Paul Plack wrote: Jim, You might want to READ IT AGAIN yourself. Here's where the misunderstanding started. John wrote that if the digital is on a very different frequency, reception may be different. Your response was that if your antenna worked on one, it should work on the other, Period. You appeared to have a misunderstanding. Don't get mad at people who try to help. That's kinda why this place exists. No, that's not what I said. I said that if an antenna works on CH7 analog, it should work on CH7 digital, and if it doesn't, the problem is the source. Yahoo! Groups Links --- - No virus found in this incoming message. Checked by AVG. Version: 7.5.557 / Virus Database: 270.11.8 - Release Date: 3/4/2009 12:00 AM Yahoo! Groups Links
RE: [Repeater-Builder] Coax Cable - Question
Sounds mechanically similar to Times Microwave LMR-400 to me. I agree with the other poster on using silver crimp-type connectors. I don't like the cheaper chrome/nickel plated crimp connectors. The threaded portions tend to flake when being screwed/unscrewed, which leads to odd results. I highly suggest attaching the cable to your mast/tower/whatever so it does not move in the wind. I also use automotive gasket maker under the crimp ring to help seal out the elements. Doing this, I've had short N/N jumpers in the air otherwise unsealed with no sign of weather issues after 2.5 years (obviously nothing in radio years, but.) JS From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Gmail - Kevin, Natalia, Stacey Rochelle Sent: Sunday, March 01, 2009 10:29 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Coax Cable - Question Hi Guys, Sorry about addressing this question here, but I know it has been talked about before and I know there is a lot of knowledge from experence hooking up repeaters. Okay, my question. At my work they have been installing and upgrading our wireless Lan systems. In the process of the install they have had a number of shortest lengths of coax cable left over. Knowing I was a ham they offered some of these to me. Being a ham I did not turn it down, well it's 50ohm. Now at home I checked and see it's marked Beldon 7810A RF400, 50 ohm. It's solid core, foam di-electric foil + a tight braid. Don't believe this is what they call double-shielded.? I am sure I can get a connector over it. I do not intend using it in our repeater, but was thinking of using it at home as leads for my HF to UHF radios to antennas (I made a junction box on the outside of the house). If anyone can help with some advice, I'd be grateful. Please do not turn this into a debate, don't want to upset the moderators - Thanks. Just want to use it, if suitable. Kevin, ZL1KFM.
RE: [Repeater-Builder] Just a comment about recent Ebay Auctions
Narrow-banding is making Japan and China rich (they don't make many radios in the USA anymore) and giving hams a whole lot of equipment to pick through. JS -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:Repeater- buil...@yahoogroups.com] On Behalf Of skipp025 Sent: Wednesday, February 25, 2009 10:12 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Just a comment about recent Ebay Auctions Re: Just a comment about recent Ebay Auctions Just my 50 cent comment about recent Ebay repeater and related two-way radio equipment auctions Wow! I'm not sure if it's related to the economy, a lot of change in the radio industry or a combination of both, but I'm seeing a lot of high quality repeater, radio and tower site parts going for dirt cheap prices. A lot of the above mentioned auctions are for New Old Stock (NOS, never used) equipment and parts. A number of people - agencies appear to be cycling out UHF Pyramid SVR repeaters. Man there are a lot of them for sale cheap. [Be advised they are an older version, quite usable but different than the current SVR Repeater Model]. And enough people making and selling various repeater controllers to choke a horse... cough, cough... cheers, s Yahoo! Groups Links
RE: [Repeater-Builder] Somewhat OT - How to make HDTV *really* work
Is this the reason for the move to UHF? Back when I lived in the city I never really saw much/any 'ghosting' on UHF stations, but horrible ghosting on some VHF (all the transmitters were within a couple miles of each other, so it wasn't an issue of transmitter/receiver site). Seems like if the signal is significantly more Fresnel sensitive, UHF would be a logical choice. I still don't understand the 'upgrade' for terrestrial HD. What should have happened was a push to satellite. There's plenty of spectrum and space in the Clark belt, and its easier to get a solid signal waving around a 18 Directv dish than it is to try to 'dx' in some HDTV in most circumstances (most RVers and truckers I know can peak-aim a single feed directv/dishnet dish in under 2 minutes) JS -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:Repeater- buil...@yahoogroups.com] On Behalf Of Chuck Kelsey Sent: Monday, February 23, 2009 9:38 AM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Somewhat OT - How to make HDTV *really* work Dynamic multipath interference, in which the delay and magnitude of reflections are rapidly changing, is particularly problematic for digital reception. While this just produces moving and changing ghost images for analog TV, it can render a digital signal impossible to decode. The 8VSB-based standards in use in North American ATSC broadcasts are particularly vulnerable to problems from dynamic multipath; this has the potential to severely limit mobile or portable use of digital television receivers. Solving the problem might require that different standards be adopted for mobile use. Chuck - Original Message - From: wd8chl wd8...@gmail.com To: Repeater-Builder@yahoogroups.com Sent: Monday, February 23, 2009 9:10 AM Subject: Re: [Repeater-Builder] Somewhat OT - How to make HDTV *really* work JOHN MACKEY wrote: If the digital is on a very different frequency, then the frequency change is a reason why digital reception may be problematic. For example, if you are using a VHF antenna to try to receive a UHF digital signal, that will be problematic. I should be able to use any normal TV antenna. If it works on analog Ch 7, for instance, it should work on digital ch 7. Period. If it doesn't, there is something inherently wrong with the medium. Again, RF is RF. The antenna doesn't care how it's modulated. Yahoo! Groups Links Yahoo! Groups Links
RE: [Repeater-Builder] OT DTV
I find it horribly inaccurate since it doesn’t take into account receiving height. What height are they calculating for? Set-top first-story height? Rooftop? Tower top? At the dirt? I know they didn’t compensate for the 20 ft altitude change between the end of my driveway and the front door of my house. The exact position of the receiving antenna dictates a LOT. A couple years ago, with my scanner and a telescoping antenna, I could hear 1 UHF station’s audio at my mailbox (low, at the road) Near my house, 4 ft AGL - 3 Inside my house, 4 ft AGL – 1 (I watched 9/11 news off this station using set-attached rabbit ears, go figure). Oddly enough, not the same station that I can hear at my mailbox (this station would be very non-LOS at my mailbox) At the ‘tree line’ on my tower – 7 150’ up my tower – a whole hell of a lot more (all high power stations from Tyler/Lufkin/Houston/Dallas-Ft Worth/Austin/Shreveport/Beaumont [within 250 miles or so]). Some were very faint, but definitely there (and this is with an Omni antenna and a half-deaf Uniden scanner…), some were stomped on by local low-power stations. The issue at that height is the antenna being directional enough to isolate on-channel noise. Now, the real question is, how bad does Fresnel affect DTV vs analog. I betcha you’ll have horrible problems with DTV signal in areas that tend to ‘ghost’, where analog TV was perfectly watchable/listenable, just somewhat annoying. 9901 Sweetwater, Houston, TX 77037 (house where I grew up) had this problem. As downtown Houston “swole” in the late 70s/early 80s ghosting became more and more of a problem. All we could do is kick our antenna farther west and add a variable signal attenuator (ie ‘ ghost filter’) - didn’t help a whole lot. JS From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Ralph S. Turk Sent: Friday, February 20, 2009 8:19 AM To: Repeater-Builder Subject: [Repeater-Builder] OT DTV Good morning All The following is a new FCC web site for DTV Follow instructions carefully. Wait for the program to calculate info. Seems to be one of the best. Confirms what I know from working in the TV business for 30+ years. Last several installing DTV. http://www.fcc.gov/mb/engineering/maps/ Ralph,W7HSG
RE: [Repeater-Builder] Somewhat OT - How to make HDTV *really* work
How much RF does it take to get a clear NTSC picture? Usable? I know the local cable tower tried to get at least a -20 dBm signal (!!!) on analog TV inputs. Most DTV converter units with published spec's need between -82 dBm and -86 dBm at the antenna jack on the back of the unit to capture a complete bit stream. I do *not* know how much SNR is required to get a complete bit stream. Personally, I'm not in the TV business but I crawl around on a lot of rooftops and 'nice' home-use TV towers. Most people's OTA setups contain at least one range-eating screw-up. These things will do a lot worse nasties to a digital signal than an analog: A improperly assembled antenna. So many times I see the UHF 'bowtie' on store bought all-band antennas positioned incorrectly. The instruction sheet knows best. B Unsealed coax connections. F connectors ain't waterproof, not even the 'snap-n-seal' ones. C Most preamps I run into are at least 10 years old. Sure they might still work, but RF transistor technology has sure improved in the last few years. These amps are *not* going to pass DTV acceptably. In my rf/data experience otherwise, if the bitrate/frequency ratio is very high (DTV is doing 20 mbit out of 6 mhz of spectrum, that's a pretty damned high ratio) D Height. If you want your antenna close to the ground, might I suggest getting a little round grey one that points to the Clark Belt, with a box attached that requires you to shove dollar bills in an envelope every month to continue working. You will be happier. Personally, I've always heard rural TV requires one foot of height per one mile of distance in flatland conditions... I think this holds true once you're 25 miles from the transmitter site (maybe less if the site isn't a typical 1950 ft tall tier-1 market TV tower). Check your location against topo maps. Just one small hill can screw up all your calculations (or a big river valley can pull signals in from ridiculous distances at low heights) E Bad coax choices: Either incorrectly crimped, incorrectly handled, improperly spec'd (white indoor coax won't stay 'good' outdoors for more than a few months, maybe a year) etc coax used, then badly installed (not secured). There are very good 75 ohm coaxes available. RG-11 is pretty nice stuff. F off-channel noise slaughtering your amplifier. Most TV amps are unfiltered (or contain a simple 88-108 FM trap), if you've got a big pager transmitter, repeater, etc (cellphone stuff doesn't tend to count since its fairly low power) nearby you could easily be 'hosing' the entire setup. Filters are your friends. I plan to do some experimentation with marketed-for-cable-company inline filters. Normally used to keep Basic Cable customers from seeing other channels, or cable-modem-only customers from watching TV, they sell these in all sorts of specialty frequencies for cheap. Can't beat cheap + published specifications. Here's how I'd get HDTV today, assuming I really wanted to watch OTA TV: Info: I'm about 175 miles from Houston's tower farm, 140 miles from DFW's tower farm, and there's a sprinkling of stations around Tyler and Lufkin... I have a 150' rohn 25 in my yard, about 185 ft from my house. There's currently 2 strands of multimode fiber going from my house to the tower, speaking Ethernet (100mbit, full duplex). I'd buy one of these: http://www.silicondust.com/products/hdhomerun ($180), place it in an outdoor-friendly metal enclosure with an Ethernet-fiber converter/transceiver. I have isolated 120VAC running up my tower already, powering the gear isn't a problem. Add antennas. I'd most likely go with dedicated VHF and UHF antennas and tuned/filtered amplifiers on each, and use a nice 'ham radio' type rotator. Keep the coax short, use RG11, and seal it well. I'd buy a nice HTPC (Home Theater PC... nothing fancy, just a basic PC with TV-friendly outputs. If you've got a decent TV it'll take HDMI or DVI, which is even better). Microsoft's set-top/media center edition software is good enough to test with, at least. ($400-500ish total here) Dedicated duplex (2 strand) fiber run from the top of the tower to the top of my TV set... Of course, having the tools, fiber, ends and knowledge helps. And, after all this, I'd get to watch horrible reality shows, get my daily dose of propaganda (news), watch late-night TV guys make asses out of themselves, and the 3 decent shows PBS shows when they're begging for more money to run transmitters that they don't need (pbs.org should offer streaming...) Doesn't really seem worth the effort/wind load/money... :) JS -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Chuck Kelsey Sent: Friday, February 20, 2009 6:42 AM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Somewhat OT - an interesting antenna design This is going to be a bigger problem than many stations may have anticipated. A friend of
RE: [Repeater-Builder] Somewhat OT - How to make HDTV *really* work
Outlook needs a 'trigger lock' on the send button... Also, I have no idea why outlook decided to add a bunch of crap to my email. Guess I should be using a decent mail program! edits below: C Most preamps I run into are at least 10 years old. Sure they might still work, but RF transistor technology has sure improved in the last few years. These amps are *not* going to pass DTV acceptably. In my rf/data experience otherwise, if the bitrate/frequency ratio is very high (DTV is doing 20 mbit out of 6 mhz of spectrum, that's a pretty damned high ratio) Continued: If the bit density is very high, you really do not want to use amplifiers. Amplifiers *always* add distortion. You also can't magically 'find' signal that's below the noise floor with an amplifier. All you can *really* do with an amplifier in most digital systems is make up for coax losses (as long as the amp is mounted at the antenna, and no the far end of the loss), which one would be better off making as small as possible and eliminating the amplifier. With DTV this is easy since you're dealing with 1's and 0's, capture and process the data as close to the antenna as possible, and move to a less 'lossy' medium to move the data into your house. If you insist on using coax and decoding at your TV set, you're going to have to buy good coax. 'good coax' satellite use isn't always good for OTA TV use. All *real* pro setups I've seen here use RG11 or larger *75 ohm* coax. --- JS
Pagers in 2009 - why? (was: [Repeater-Builder] A desense issue)
Seriously... What is today's market for pagers? I can't imagine there's any real reason for them to continue to exist. If the FCC can force you to quit using your perfectly good 25 khz rig, force the multi-billion-dollar-a-year OTA TV industry onto HD, or the zillion other examples of the FCC's absolute power, why hasn't someone asked the FCC why the paging industry is continuing to camp on a pile of spectrum with insane EIRPs that regularly cause co-site and near-site crosstalk problems. Playing with my rather deaf scanner, in a rather low-population area, I hear almost no pager traffic - enough that it could easily all be placed onto a single channel or thrown onto a cellular network. Unluckily, there is just enough traffic on practically everywhere from 145 to 960 mhz that it causes problems on any high mounted site. Come on, who's for a Paging Sunset? JS -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Jed Barton Sent: Sunday, February 08, 2009 4:26 PM To: repeater-builder@yahoogroups.com Subject: [Repeater-Builder] A desense issue Hey guys, Alright, perhaps some of you have some ideas, cause this one has driven a bunch of us absolutely crazy. At one of my repeater sights, I have a 220 repeater, a 440, and a 900. Also, there is a paging transmitter about 3 feet away from all of this. Here's the issue. The paging transmitter is desensing both the 440 and the 900. The 440 repeater is a kenwood tkr850, and the 900 is an msf5000. I'm running a set of 4 cavity wacom cans on UHF, same for 900. The paging transmitter is transmitting on 152.6. We've watched it, and there is no doubt that the paging transmitter is the problem. The transmitter is a Glen Air. We can shoot a weak signal in to the UHF repeateror the 900 with the service monitor. That weak signal will get very strong as soon as the paging transmitter unkeys. We even went to the extreme of getting a filter from par electronics to knotch out the 152.6, but na, didn't work. As if this isn't bad enough, the antennas for the 900 and the 440 are only about 25 feet apart horizontally, it's as far apart as they can go. Any thoughts guys, anyone ever run in to this situation? Thanks, Jed Yahoo! Groups Links
RE: [Repeater-Builder] Amateur Radio Repeater Usage
Here in East Texas (near Crockett to be exact) I have to use APRS to see if my 2m antenna/rig still works. I'm RX only (no license) so I can't see if the area's listed repeaters actually still work. My old Kenwood TR7400A doesn't have PL anyways :) One of these days I'll get around to taking the test. It's depressing when the only local ham radio group in the county's weekly net only has 4 check-ins. I personally don't see much future in amateur radio in its current path. I personally don't think d-star is going to magically adjust the path. What we need is something that's socially acceptable in 2008. Squawkbox HTs don't cut it. You need trunking, smart roaming, full duplex with echo canceling, and a proper control system that includes not having to verbally repeat your callsign like a kid with Tourettes syndrome. Basically, what I'm suggesting here is an (inter)national trunking system, similar to a cellular system with a local conference method, and using (logically) the internet (or at least IP) as its backbone. No more dinking around with echolink, no more begging to use an autopatch, no coordination problems since this would logically include AFS and TPC. Imagine *just* the public safety/emergency uses? No more sorry bill, didn't mean to key up on top of you issues. Look at your cell phone. It's cute, it's stupid, but it sure is damned useful and easy to use. Also, they're attractive enough to draw almost 50% of the world population. Why haven't hams taken the *next* step in this direction? IDEN without the IDUH? Come on, who's with me? [ducking shots from cellcos and cellco vendors] JS -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:Repeater- buil...@yahoogroups.com] On Behalf Of Kris Kirby Sent: Tuesday, December 16, 2008 3:01 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Amateur Radio Repeater Usage On Tue, 16 Dec 2008, Tony L. wrote: We're continuing to experience a significant drop off in usage of ham repeaters (all bands) in the Northern NJ area. It is not uncommon to find a repeater that has been dormant for months. What's it like in your part of the country? In central Alabama, entirely too quiet. Two meters is normally only used during drive time, and despite eight 440 machines that cover the city, none are irregularly or regularly used. Seems like we're in the doldrums of ham radio. -- Kris Kirby, KE4AHR k...@catonic.us But remember, with no superpowers comes no responsibility. --rly Yahoo! Groups Links
RE: [Repeater-Builder] VoIP Phone Service
I suggest a Linksys PAP2-NA (an unlocked ethernet-based ATA) I personally use vitelity.net for my business's voip service. I tested Teliax with good results also. If all you need is termination (outgoing calls) you're only billed per minute (and it's not like the average autopatch is THAT busy). For my business, we're almost all incoming so we order unlimited incoming DIDs and pay the 1.4c/minute or whatever for domestic outgoing. I can't suggest the PAP2 enough. It's a solid little unit with lots of adjustability. Don't try to save $5-10 by getting a 'lesser unit' - just not worth it. JS From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Mike Mullarkey Sent: Saturday, November 22, 2008 10:58 AM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] VoIP Phone Service I am wanting to install a cheep, very cheep phone service VoIP at the repeater site using the second IP I have available to me. I would like to have a service that uses an ATA that can be configured to work with the service I end up going with. I have herd that the Magic Jack will not work since it times out after 24hrs of no use. Any Suggestions. Thanks, Mike K7PFJ
RE: [Repeater-Builder] 2.4 Ghz wireless radio and 145.410 repeater
Are these units plugged into the same circuit? I'm guessing the wireless internet gear installed has a dirty power supply or a large amount of vhf-band noise being pushed back down. A lot of cheap wall-wart power supplies (or cheap Chinese 'project' supplies) are crap. This is getting surprisingly common - even the cigarette lighter charger for my cellphone spews crap all over the VHF and FM broadcast band. I do wireless internet installs for a living, and you'd be surprised the general lack of quality control is used on most gear. I'm curious - what gear was installed? JS -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:Repeater- [EMAIL PROTECTED] On Behalf Of n9lv Sent: Thursday, November 20, 2008 7:16 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] 2.4 Ghz wireless radio and 145.410 repeater I just had a 2.4 Ghz internet wireless antenna mounted at the top of my 120' tower which is where the antenna is for the 145.410 repeater. I am getting intermod into the system that causes it to hang open. Anyone ever had these issues and how did you go about remeding the problem. And I can't shut off the internet as the family would hang me, and would rather not shut off the repeater. There is besides the TXRX duplexers two DB4001 filter duplexers on the system. Funny part is that once it starts the interference, I can remove antenna from the receiver and it continues to intermod until I kill the transmitter. I can hit the remote PTT and it will key the repeater, no noise into the system until I reattach the antenna port to the receiver. Thanks. Mathew
RE: [Repeater-Builder] Broken Rock MT. tower collapse
I'm guessing that'd be the national weather service transmitter at 162 MHz. Close enough to look like FM broadcast, but the ridiculous power requirements aren't there. The NWS site north of me uses antennas that resemble slightly smaller FM transmitter 'loops'. FM commercial stations use very good antennas to save money on transmitters and electricity. The NWS has your tax dollars to spend! Of course, being that the NWS is only generally looking for 1-5kW EIRP, it may be cheaper to lease less tower space and throw on a slightly hotter transmitter. JS -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:Repeater- [EMAIL PROTECTED] On Behalf Of neal Newman Sent: Wednesday, October 29, 2008 7:59 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Broken Rock MT. tower collapse looking at the Pictures YEP an FM went off the air.. Must have been a Non Com based on the Type of antenna I only see 2 bays
RE: [Repeater-Builder] Broken Rock MT. tower collapse
Was this from shearing or vibration? If they're merely vibrating off, I'd have to say this is an application for Loctite, blue grade. The nice part with the blue stuff is you can inspect the torque and/or dismantle the tower later without having to use a torch. Higher grades of Loctite are stronger but much harder to disassemble later. JS -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:Repeater- [EMAIL PROTECTED] On Behalf Of wa5luy Sent: Tuesday, October 28, 2008 8:24 AM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Broken Rock MT. tower collapse Yesterday morning the one of the communications towers on Broken Rock Mt. in western Arkansas collapsed. This self supporting tower was over 200 feet tall and had cell service and the NOAA weather radio for our area. The tower collapsed with a wind of no more than 50 miles per hour and had survived hurricanes Gustov and Ike. Last year I found some large bolts, nuts, washers on the ground at a similar tower where our repeater in Hot Springs is located. We had a tower company inspect our tower and they found loose bolts and one leg connection with all but one bolt missing with no nut. I am mo expert but it appears to me by looking at the leg connection of the collapsed tower the same condition occurred. Both towers were less than 12 years old. Pictures can be seen at http://hsara.org/. Scroll below the map. The moral of this story is check those bolts and check them often. Wayne WA5LUY Yahoo! Groups Links
RE: [Repeater-Builder] UHF Repeater Antenna -- UPDATE
Err, I meant, coax center pin and ground. Oops. JS -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:Repeater- [EMAIL PROTECTED] On Behalf Of Jacob Suter Sent: Monday, October 20, 2008 12:17 PM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] UHF Repeater Antenna -- UPDATE DC Grounded, in my experience, means the center pin and the coax will show a dc short when tested with a DMM. Lightning? Corrosion? Manufacturing defect? JS
RE: [Repeater-Builder] UHF Repeater Antenna -- UPDATE
DC Grounded, in my experience, means the center pin and the coax will show a dc short when tested with a DMM. Lightning? Corrosion? Manufacturing defect? JS -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:Repeater- [EMAIL PROTECTED] On Behalf Of Cort Buffington Sent: Monday, October 20, 2008 11:29 AM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] UHF Repeater Antenna -- UPDATE Folks, *Continuation of Previous Thread: UHF Repeater Antenna Discussion* We climbed the tower on Sunday and checked things with the wattmeter between the Feedline and the antenna. At the bottom, we were making 75 Watts at the duplexer output. At the top, after going through 105' of LDF4.5-50A (just over 1dB of loss), a PolyPhaser, and a 6' jumper of RG400 (from the duplexer to the PolyPhaser) we were seeing 57 Watts. I show that as about 1.2 dB of loss, which seems quite reasonable. The F10, at the top, showed me about 1.5W reflected... or 1.34:1 VSWR. The antenna is a DC grounded colinear, and we showed no measurable (with my DMM) resistance between the center pin and outer conductor of the Hardline/Antenna combination. Right now, we're of the mind that the feedline is good. 73 DE N0MJS -- Cort Buffington H: +1-785-838-3034 M: +1-785-865-7206
RE: [Repeater-Builder] Desense has me pulling my hair out! (Was DB4060 Duplexer Cables
I've never worked with cans or repeaters, but I've witnessed similar issues caused by oxidation/corrosion. Have you tried using a conductive grease on the housing joints and the rods? It appears silver-based grease is suggested for all applications above 50 mhz. Good luck! Jacob Suter (unlicensed newb) From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Mike Besemer (WM4B) Sent: Monday, October 06, 2008 7:39 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Desense has me pulling my hair out! (Was DB4060 Duplexer Cables Okay. I got the cable dilemma sorted out thanks to some photos I'd taken earlier, but I CANNOT get the desense out of these things. Some history: The cans and the repeater were both in storage for several years. We got a 'too good to be true' deal on the site and I pulled everything out of storage. The repeater (Mark 4) and cans were both originally on 146.85. The repeater was brought back to life on 145.11 and I tuned the cans using an HP-8920A. When I was done, I had no detectable desense either into the -8920A or at the site. Fast forward 2 months. The repeater goes deaf. I make a trip to the site (about 40 minutes) and find terrible desense. I blamed the service technician who'd just installed a new repeater for the BoE at the site, tweaked up the cans and everything was fine. for about a day. The repeater sounded great and the sensitivity was fine, but it had a terrible noise on transmit after it had been at rest for a while. About 2 minutes of RF would clean it up and it would work fine until it rested again for about 40 minutes. then it all started over again. The noise was only when the squelch was open. ID's and announcements were fine. (AH-HA!) I finally got a chance to make the trip back to the site and pulled everything home with me. I took a look at the repeater, just to give it a clean bill of health. It all looked good. I made only a few minor tweaks. The cans were noisy. I could turn the bandpass screws and I'd get noise on the receiver. That's what led me to pull the cans apart (below) to inspect and clean. There was some growth on the copper further up the outer tube, but nothing by the fingerstock. I have it a nice vinegar bath and cleaned it with a paint roller stuck inside the outer tube. It cleaned up nicely and I gave it a nice bath with the garden hose and baked the whole thing in the oven until it was good and dry. The entire process was repeated for each can. The enclosure with the notch capacitor was removed for this process, and the tuning rod screws were removed from the top to let the tuning rod drop down so I could get into the outer tube. After I put it all back together, I checked the fingerstock and it all looked good. Initial tuneup with the HP-8920 went fine and I soon had the repeater running through the cans into the -8920, breaking the squelch at about -116 dB with no detectable desense. Then. I went to bed. The next day, the desense was back with a vengeance. Been tuning for 2 days now (I thought I found it last night when I found a connector spinning on one of the cables going to the T-connector) and I CANNOT get rid of it. Sometimes it sounds like an AM radio driving under a power line. sometimes it just crackles. It's got to be microarcing somewhere, but I HATE taking those cavities apart again. (BTW, the cable with the spinning connector was replaced with good, MILSPEC RG-214 and MILSPEC connectors.) Have I missed anything? I'm really starting to think that these things are beyond salvage, but I sure hate to break that news to the club! Help! 73, Mike WM4B
