[digitalradio] Digital FM versus Digital SSB on VHF
Rick, I have change the topic to more appropriately describe what is being discussed. Judy and I did further testing of 1/4 wave and 5/8 wave antennas for 2 meters on her vehicle using the ICOM IC-7000 at 50 watts out. The base station continued to be the 30 foot high homebrew J-pole and now has 100 watts out from the ICOM 746 Pro. The mobile antennas were only mag mounts, but then again, that is what most of us use. The furthest point out was 40 miles and we could still communicate on 2 meter SSB, but signals were quite weak. When she was mobile, there were locations that were so weak as to be unreadable at times. Some of those areas are difficult to even work the local FM repeater which is about 200 feet higher than our home QTH antenna and about 6 miles closer than our QTH! First, thanks for making the tests! The question is whether or not the shadow of hills resulted in the reduced range on SSB, since in flat country, we can get over 70 miles on FM with DominoEx or over 100 miles on SSB with DominoEx. I am somewhat familiar with the Wisconsin countryside as I used to visit Monroe, Madison, Blue Mounds, and the Dells several times a year - beautiful, rolling, hills. My ancestry is Norwegian and I especially enjoyed visiting during the Pier Gynt festival every year. There were slight differences between the 5/8 wave and 1/4 wave. Sometimes the quarter wave would out perform the 5/8, but in general, the 5/8 did slightly better, especially farther out. Because of the convenience of the quarter wave (entering the garage), it is hard to beat, but I would like to try a half wave Larsen some time. People use the 5/8 wave antenna for increased gain, but mainly because it lowers the takeoff angle from 45 degrees for the ground plane to about 25 degrees for the 5/8 wave. Note that a horizontally-polarized low antenna has a takeoff angle of around 9 degrees in comparison. If I had been using even my modest 4 element Arrow beam, signals would have been quite good at all times, based upon the nearly unity gain verticals. I still need to come up with even rudimentary horizontal dipoles at each end and see how well they compare. Just flip the Arrow beam 90 degrees, but use it on the higher fixed station end, and compare it to a small quad, which can be built in about an hour. http://home.comcast.net/~hteller/OptimizedQuad.zip Now on the KU4AB squalo antennas, this is one of the only halo types that does not seem to have water ingress detuning issues. Even the M Squared products got low ratings on eham because of this problem. The KU4AB design is the one that got the good numbers on the Central States VHF Society test. They did not mention that there were any anomalies in the omnidirectional pattern, but your experience sounds unacceptable! According to the M Squared advertising on the 144HO loop, they claim as you do that only horizontal type antennas can give you the ground reflection gain. Their numbers and shape of the antenna look very much like the KU4AB. I wonder why so many are going with the squalo shape over what would seem to be a stronger shape when in a circle? Even the halo is not perfectly omnidirectional. To get that, you need to turnstile dipoles (or rectangles, or skeleton-slots). I never noticed that on the M Squared site, but it is significant that the company considered to be the premium supplier of yagi's by the weak signal community also finds that horizontal polarization has more gain than using vertical polarization, especially at low heights (and so does the modeling). Can you recommend any current manufacturer for circular halos? The other well known manufacturer has been SK for some time and no one was interested in taking over the business. I think all the halo manufacturers are gone since horizontally polarized mobile antennas generally went the way of the dinosaur with the spread of repeaters. Maybe build my own? A single halo may not be too bad, but I don't know if I can do a good job with phasing lines. And those gamma matches are a challenge. What are stretched quad loops? Can't seem to find anything on them. Or is that the optimized quad, but not intended for mobile operation, more for portable? Avoid matching problems by using turnstiled loops. Here is my prime reference on stretched loops: http://personal.ee.surrey.ac.uk/Personal/D.Jefferies/antennexarticles/behave.htm There is really no good new commerical omnidirectional antenna for 2m, but right after the Shelby, NC, hamfest, I worked K4LY on SSB phone in his driveway, 200 miles away, to a squalo mounted on his Prius. I had him drive in a circle so I could see the pattern, and there were the expected nulls. Signals were marginal, but he lives on a 200 feet hill next to a cell phone tower, and my 13B2 is in my attic at only 25 feet. Did not have a chance to try it using DominoEx, though, but I suspect print would have been very good. We will
[digitalradio] Re: KIJT WSPR BEACON - 503KHZ (CARRIER) NOW TILL LATE
--- In digitalradio@yahoogroups.com, Andrew O'Brien [EMAIL PROTECTED] wrote: Will give a listen for any trans-Atlantic propagation. On Sat, Nov 29, 2008 at 1:29 PM, Graham [EMAIL PROTECTED] wrote: KIJT WSPR BEACON - 503KHZ (CARRIER) NOW (1800 HRS GMT 29/11) TILL LATE Running K1JT WSPR beacon Carrier frequency 503 KHz Dial set 501.5 Khz usb , audio tone 1500 Hz Running approx 100 watts to 35 ft top loaded vertical , (If the pa trips beacon will continue at -14 db level) Reports welcome Tnx - Graham G0NBD / IO83LK -- Andy K3UK Thanks Andy, Looks like only one decode last night from the usa , ran the beacon till 0430 gmt ... G ..
[digitalradio] HAMFEST INDIA 2009
Dr Friends All are invited for the HAMFEST INDIA 2009 in BANGALORE CITY.During the month November 2009. Venue and Date wiill be announced in this group. The Tariff charges in Hotel are affordable. Expecting more DX hams .Bangalore has got international Airport now. It Is a good tourist location. Please plan it well and come to Bangalore. Please contact on : vu3iti_varadan @yahoo.co.in Regards vu3iti(VARADAN) Connect with friends all over the world. Get Yahoo! India Messenger at http://in.messenger.yahoo.com/?wm=n/
[digitalradio] You Have Mail Re: How Can We Push HF Emcomm Messages to the Field?
Well, let me see. 2m/70cm D-star radios can communicate with each other without a repeater. These radios can send audio and slow speed data simultaneously. The slow speed data can be displayed on the radio's screen or on a laptop connected to the radio. The call-sign squelch should work without a repeater. When call-sign squelch is enabled, no voice transmissions or data transmissions will be received unless it is address to that radio's call-sign. Of course the radio must be constantly turned on. The power consumption will be very low because o it is not transmitting while waiting for a message with its callsign o The speaker is off/squelched until a message arrives with its callsign Disadvantages of d-star are: o It is overpriced compared to similar FM only non-Dstar radios. Compared to digital P25 radios that government bodies buy, it is low cost. But most Amateurs are not going to spend their own money on D- star until the prices drop and it becomes only $100 more than a similar FM only dual bander. ICOM's IC91AD handheld was reasonably priced without the d-star board, and not too much extra for d-star. But the other dual band d-star radios have been priced much higher than Icom's FM only radios. o When the signal is not strong enough voice gets very squeally sounding. Most would rather listen to weak FM signals than the D- star squeal. o You simply can not assume your volunteer workforce will have these radios unless your organization purchases them. As I mentioned earlier, one can get similar functionality - a radio that is quiet unless VOICE is received with that radio's squelch code. You can divy out a dozen or so squelch codes for your teams to use in their FM radios. The prevailing radio-email systems require receivers to routinely check into a radio email server to check for mail. This can be automated to be every X minutes (for example every 10 minutes) with Paclink software. So you keep an email server up - like RMS Packet with RMS Relay software, and the field units use Paclink software. If your email server has its internet down, the email capabilities will be limited to sending and receiving email messages among your email server and Paclink stations that directly connect to it via radio. Error-free delivery of the emails is guaranteed with retransmissions if necessary. Another option is 1200 baud packet. I have not played with this very much, but on HF there are several programs where one Amateur radio connects to another Amateur's radio using his callsign, then typed messages are delivered and acknowledged. Automatic retransmissions are performed if necessary to guarantee error-free delivery. The receiving radio transmits - telling the other radio it has received the message without errors. This would require every radio to also have a laptop with the appropriate software. On HF I have used programs such as XPWare and WinPTC. There is also Alpha, but it is not free. I bet the free WINPACK software has similar functionality. It would also be nice if the software will automatically accept a connection call and save the message to a file, so the operator does not need to be intently watching his screen ready to click to accept a connection. Some HF digital modes work under conditions where voice would be unrecognizable. Keep in mind there exists the capability for radios to listen in on digital communications not addressed to them. I am thinking Email server is the best way for you to get your functionality - though the field stations will be polling the email server every 10 minutes or so. Or FM packet digital radio would not require the 10 minute polling intervals - (or some other VHF digital mode) might be what you want. Radio and laptop on all the time. NO need to sit there listening or watching intently IF some kind of auto-accept-connections feature exists. Your message is saved on his laptop for him to read after he returns to his vehicle, or wakes up if sleeping. I am not sure this auto-accept-connection and save the message to a file features exist in existing software. Since I am not very experienced on VHF digital modes, someone else would need to guide you to hardware and software choices. If VHF does not give the range/distance you require, then a digipeater with generator, solar power, or other backup power would expand that range. And then there is also the HF digital option. Howard
[digitalradio] Re: Odd noise in receiver
Hi Dave, I have a similar type noise in our neighborhood. By doing some DF'ing, we've pinned it down to a neighbor's house, but haven't been successful yet in gaining their confidence to let us explore beyond their front door. Can here it on VHF when we're at their front porch. Is it time synced, i.e. is the accuracy such that it's being derived from a 60Hz/Xtal time base. In my case, it's not. It comes on for APPROX 12 seconds and goes off for APPROX 3 seconds, but if I listen to it over a few minutes, it will drift up or down. Also, I noticed I can hear it at ~ 16.7KHz offsets, which makes me think it could be PC video related. Not sure if it could be switching power supply related, I thought most of them were 100's Khz. Actually, It had been across the full 20M band last year when we were DF'ing, but now it's discrete. I have a wav file I can send you if that would help. Fortunately, it's been down to S2-3 as of late. It also seems to be tied to colder weather (thermostat control??). BTW, the neighbor is 300-400 feet away in a suburban area (70' x 120' lots) . W5AHC is another ham in the neighborhood and he's ~100 fett closer and hears it as well. Hope this helps. Let me know what it ends up being. tnx es 73 Bruce - W3NJ --- In digitalradio@yahoogroups.com, Dave 'Doc' Corio [EMAIL PROTECTED] wrote: Wonder if anyone has encountered this type of noise. It's a raspy, pulsating sound. It lasts 10 seconds, is silent for 5, then starts again The pulses are about 5 per second. It's showing up on a lot of bands. Right now I have it at about 21.048, but have heard it on several ham frequencies. We haven't added any new electronics in the house at all. We are in a rural setting, with the nearest neighbor several hundred feet away. We do have cable TV and cable internet, and I wonder if this might be a test birdie I've heard mentioned in the past. It seems to run 24/7, and just started up within the last few days. Any ideas? Thanks in advance 73 Dave KB3MOW
Re: [digitalradio] Re: Odd noise in receiver
Thanks for the info, Bruce. I didn't have a chance to record it or measure it accurately before it disappeared Friday evening some time. As to if it's time synced, I would have to guess that it is. It was extremely close to 10 seconds on and 5 seconds off, and the number of pulses was 55 during the on period. Granted, timing it with a stopwatch is not exactly precise, but it was close enough that I'm reasonably certain it's timed somehow. The simple fact that it stopped Friday night leads me to believe it's some type of commercial activity. I've had the rig on a lot this weekend, and haven't heard it once. It also stopped before I could log exactly where it was. If I'm lucky, it's gone, never to return. I doubt it, however. If it comes back, I'll get a recording of it and post it. If you have a recording of yours, please send it to me! May not help, but it sure couldn't hurt! Tnx es 73 Dave KB3MOW Bruce Sawtelle wrote: Hi Dave, I have a similar type noise in our neighborhood. By doing some DF'ing, we've pinned it down to a neighbor's house, but haven't been successful yet in gaining their confidence to let us explore beyond their front door. Can here it on VHF when we're at their front porch. Is it time synced, i.e. is the accuracy such that it's being derived from a 60Hz/Xtal time base. In my case, it's not. It comes on for APPROX 12 seconds and goes off for APPROX 3 seconds, but if I listen to it over a few minutes, it will drift up or down. Also, I noticed I can hear it at ~ 16.7KHz offsets, which makes me think it could be PC video related. Not sure if it could be switching power supply related, I thought most of them were 100's Khz. Actually, It had been across the full 20M band last year when we were DF'ing, but now it's discrete. I have a wav file I can send you if that would help. Fortunately, it's been down to S2-3 as of late. It also seems to be tied to colder weather (thermostat control??). BTW, the neighbor is 300-400 feet away in a suburban area (70' x 120' lots) . W5AHC is another ham in the neighborhood and he's ~100 fett closer and hears it as well. Hope this helps. Let me know what it ends up being. tnx es 73 Bruce - W3NJ -
[digitalradio] Yahoo radiointerference group - Re: Odd noise in receiver
FYI, although email traffic has been low, there is the Yahoo group radiointerference where various audio/screen captures can be found. Would be good to upload any info on the signature you have for others to comment. I'll be posting my files there. If anyone has inputs, their appreciated! tnx Bruce --- In digitalradio@yahoogroups.com, Dave 'Doc' Corio [EMAIL PROTECTED] wrote: Wonder if anyone has encountered this type of noise. It's a raspy, pulsating sound. It lasts 10 seconds, is silent for 5, then starts again The pulses are about 5 per second. It's showing up on a lot of bands. Right now I have it at about 21.048, but have heard it on several ham frequencies. We haven't added any new electronics in the house at all. We are in a rural setting, with the nearest neighbor several hundred feet away. We do have cable TV and cable internet, and I wonder if this might be a test birdie I've heard mentioned in the past. It seems to run 24/7, and just started up within the last few days. Any ideas? Thanks in advance 73 Dave KB3MOW
Re: [digitalradio] Yahoo radiointerference group - Re: Odd noise in receiver
Thanks! I never thought to look for a forum on interference! 73 Dave KB3MOW Bruce Sawtelle wrote: FYI, although email traffic has been low, there is the Yahoo group radiointerference where various audio/screen captures can be found. Would be good to upload any info on the signature you have for others to comment. I'll be posting my files there. If anyone has inputs, their appreciated! tnx Bruce --- In digitalradio@yahoogroups.com mailto:digitalradio%40yahoogroups.com, Dave 'Doc' Corio [EMAIL PROTECTED] wrote: Wonder if anyone has encountered this type of noise. It's a raspy, pulsating sound. It lasts 10 seconds, is silent for 5, then starts again The pulses are about 5 per second. It's showing up on a lot of bands. Right now I have it at about 21.048, but have heard it on several ham frequencies. We haven't added any new electronics in the house at all. We are in a rural setting, with the nearest neighbor several hundred feet away. We do have cable TV and cable internet, and I wonder if this might be a test birdie I've heard mentioned in the past. It seems to run 24/7, and just started up within the last few days. Any ideas? Thanks in advance 73 Dave KB3MOW
Re: [digitalradio] HAL ST-8000A to Teletype ASR33
--- On Sun, 11/30/08, Steve Ripper [EMAIL PROTECTED] wrote: From: Steve Ripper [EMAIL PROTECTED] Subject: [digitalradio] HAL ST-8000A to Teletype ASR33 To: digitalradio@yahoogroups.com Date: Sunday, November 30, 2008, 12:01 AM I have a HAL ST-8000A and recently purchased a Teletype ASR33 and want to use these for receiving RTTY. I am looking for anyone who may have, or know where I can find, information on how to properly hookup the HAL to the Teletype. Any information or direction would be greatly appreciated. Regards, Steve R. [EMAIL PROTECTED] I can't help on the hook up. I looked at the St-8000 write up and did not see that it had way to convert 5 level to 8 level signals. Most rtty on the ham bands is going to be 60 wpm (45.45 baud) 5 level data. The ASR33 is a 8 level ASCII printer if I remember corectly. I think it is a ASR32 that is the 5 level Baudot printer.
[digitalradio] Signalink FT-840
Anyone have experience with FT-840 Signalink USB?Ray,K4YDI
[digitalradio] Re: identify this mode?
--- In digitalradio@yahoogroups.com, Jose A. Amador [EMAIL PROTECTED] wrote: That's OK for aural reference, but a .wav cilp is required for decoding. Jose, I gave thought to what you said and it makes sense. The 'aural reference' and screenshot is good, but the ability to decode is even better. I was concerned that I wouldn't get that ability, but before I committed to the concern, I decided to test the theory. I recorded several HF digital modes and saved them as MP3 files, set at 128Kbps/48000Hz/Mono. I could have added my own phasing, sine characteristics, modulations, base frequency, etc. But it's untouched audio, straight from the rig. Upon playback, I've been able to decode every MP3 I've made. Is there any specific modes that you were referring to? Maybe I missed it. f, k2ncc
