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Messages - Token

Pages: 1 ... 130 131 132 133 134 135 136 137 [138] 139 140 141 142 143 144
2056
Sorry, I have been meaning to update the V24 and M94 pages for some time now, both here and my own pages.  I also have a good and current schedule worked out.

The only freqs still in use by either V24 or M94 are 5715, 6215, 6330, and 6730.  V24 uses all four of those freqs but M94 only uses two of them, 5715 and 6330.  The 6330 freq was added to both the V24 and M94 line-up in either January or early February of 2010.

This mornings M94 you heard used ID 815.  Also, did you notice the audio drop outs that plagued the transmission?  The later V24 transmissions had even bigger audio drops.  Both of these stations do this occasiaonally, eventually the ops will fix the loose connection and all will be back to normal.

Tomorrow morning M94 will transmit again in the same time slot and frequency.

EDIT:  M94 page here updated to include 6330 and the fact that only 5715 and 6330 are currently in use by M94.

2057
HF Beacons / A quick spin around the beacons, October 8, 2010
« on: October 08, 2010, 1212 UTC »
Morning all,

Took a quick spin around the beacons this morning, actually the first time I have sat down in front of a radio in a while.  October 8, 2010.

3449.81 kHz, 1131 UTC, "OK", very weak, but in there
4062.51 kHz, 1136 UTC, "TR", strong and drifty as ever
4079.60 kHz, 1138 UTC, "TMP" sending a temp of 38 degrees
4088.86 kHz, 1140 UTC, Dasher, peaking at over S7
4096.26 kHz, 1142 UTC, Hexie, peaking at over S9
4096.61 kHz, 1143 UTC, Kelsie, peaking at 10 over S9
4097.77 kHz, 1145 UTC, lower half of Mohave Desert Dual Dasher, S9
4102.30 kHz, 1147 UTC, "W" wind beacon, many dits, and slight sag on dashes
4102.77 kHz, 1148 UTC, upper half of Mohave Desert Dual Dasher, S8

I checked for a bunch others, but this was all I heard at the time.  CHecked for "O" on 4103.8, hammered by multiple comm stations in Chinese on 4104 AM.  Checked for Blinky on 5156, hammered by Chinese OTHR.  Checked for Sally on 5205, hammered by Chinese OTHR. Checked for OR on 8211, hammered by Chinese OTHR.  See a trend here?

Everything else I checked for were clear freqs, but did not hear the beacons.  Was before sunrise for several beacons though, so did not expect a few of the daytime only ones.

T!

2058
HF Beacons / Periodic beacon TR on 4061 on October 8, 2010, 0220 UTC
« on: October 08, 2010, 0235 UTC »
The occasional beacon TR is up right now (0220 UTC, October 8, 2010) on 4061.07 kHz.

2059

I put two and two together and deduced from his location ('Yukon wilderness') and his inclination towards a beverage that he might be desiring some directionality and gain back into the states ... the original suggestion towards a loop was made before Beam revealed he had 'nice big property'  :) :) so ... he could build something with some nice gain *and* directionality too, sounds like a prescription written for a Rhombic!

Token, Beam's original query was about construction details, poles/suppots (peg legs  :) :) ) and such - what did you use to hoist/hold your Rhombics up?


Yep, I missed the post he made about location and did not see a need for directionality, I do see it now and agree.

My Rhombics are pretty simple, and light duty.  Around here we have high winds, but nothing like ice loading to worry about.  Because of the high winds I keep my antennas a bit lower than is optimal and accept the performance hit for the ease of maintenance and lower install cost.

Each of my three Rhombics are built slightly differently from the others, but the basics are all the same.

Each are supported by 4 metal poles, one at each of the four points of the “diamond”, feedpoint end, termination end, and across the middle.  If I was going higher or was building a bit more heavy duty I would use telephone poles.  Each antenna is about 30 feet above the ground.  As I said before two are 450 feet along the long axis and 190 feet across the width, one is 300 feet along the long axis and about 130 feet in width (I don’t have the exact width handy).

At the feed end the antenna the balun is mounted directly to the pole and the pole is hinged at the base so that I can lay it over to work on the feed point.  Each of the other three support points use a pulley mounted to the top of the pole, and nylon rope through the pulley so that I can lower the antenna to the ground for work.  The apex points across the middle are simple antenna insulators and the wire is allowed to float in the insulator.  I have even used ¾ inch sched 40 PVC pipe to make these insulators in the past.  At the termination end is a plexiglass plate with eye bolts to accept the antenna wire, and (on 2 antennas) an 600 Watt 800 Ohm non-inductive load, that is slight overkill, mounted on the plate.  A 600 Watt termination means I can key down 1200 Watts CW indefinitely, and legal limit for extended periods.  In reality a 300 Watt termination should be able to handle legal limit transmissions on SSB with reasonable duty cycles.  The third antenna has only a 200 Watt term resistor, it has handled legal limit power, but I try to remember to not push that antenna as hard.  Included on the plate is a relay so that I can select the termination or deselect it.  With the termination selected the antenna is monodirectional, lower noise, and broader banded.  With the termination deselected the antenna is biderectional, but much more peaky in performance as it becomes more resonance limited.

The feedline is 50 Ohm coax, either LMR400 or RG-214, depending on which antenna.  I have tried both 9:1 and 16:1 baluns, I saw little receive performance difference between them and I think all three are currently using 9:1.  For transmit use I use a tuner at all times, but the raw SWR is not too bad in several bands.

The wire used is not all that important, unless you are running high power, and for receive or lower power (say 400 W or less) transmit applications I have run #18 stranded copper ground wire that can be gotten at places like Home Depot for about $30 for 500 feet.

If you have the land and can orient a Rhombic in a “good” reception direction for you then a Rhombic is a decent choice.  But, if you are unsure of your primary reception directions, or want omni performance, than a large sky loop would be my selection.

2060

On the funny bands it works just like Tube Shortwave said, in fact I have not been able
to hear anything above 5 megs on it aside from local CW :-\.



So ... numerical result data wasn't convincing?

  (copied from the first response - data from chart on W8JI website at the link found in the first post)

  http://www.w8ji.com/receiving.htm  )

Antenna Type        RDF  (dB)      20-degree forward gain (dBi)   
---------------    -----------     ----------------------------     
1/2wl Beverage           4.52                 -20.28           

Vertical Omni, 60
   1/4wl radials           5.05                     1.9


Gee, willya look at the "forward gain" at the 20 degree incoming angle ... much signal at 20 dB down *?  :) :) :)

Prior to seeing W8JI's chart I had not realized such a big difference existed (btw a beverage and 'sensitivity' related to elevation angle), and tend to be 'skeptical' of off-handed claims unless I can see some numerical data since there are so many old-wives -er- ham tales out there ...


Nice to see some confirmation of what W8JI saw too  :) :)


* Relative to a 0 or 1 degree elevation angle



A couple of issues here.

The W8JI data quoted does not really explain why Beam Tetrode is not getting better performance, and, a pet peeve of mine, when is a Beverage a Beverage?

First, the W8JI data does not explain why Beam Tetrode is not getting the performance he should from the Beverage.  The quoted numbers, for a half wave Beverage, are not applicable to the areas he is having problems with.

Beam Tetrode has a Beverage that is 80 meters long.  He specifically states it works with better signal to noise than his G5RV on 160 and 80 meters but is not working well above 5 MHz.  At 5 MHz the antenna is near 2 wavelengths and the 20 degree gain performance from the W8JI chart should be within 6 dB of the vertical.  6 dB is 1 or 2 S units, depending on how your radio is calibrated.  1 or 2 S units are important, don’t get me wrong, but should not equal “I have not been able to hear anything above 5 megs on it aside from local CW”.

The next section is a minor rant from me, feel free to ignore it, but I am agonna say it ;)  A half wave Beverage just is not a Beverage, I tell ya!  By the way, it is presented here for discussions sake, not arguments sake, if it comes off confrontational that is accidental.

What makes a Beverage a Beverage?  The original patent (1381089, filed June 7 1921) claims that the operational affects of the Beverage start at “over” 1/2 wavelength and increases in performance from that point.  More recent definitions of the length of a Beverage (and all known real-world applications of the Beverage by it’s inventor, Harold Beverage) are “more than one wavelength”.  While this does not mean a Beverage or Beverage like antenna cannot be only half a wavelength it would be a strong indicator that if you want one to work, as a Beverage instead of as a random low wire, they should be “long” in relationship to the wavelength, ie, a full wave or longer.

With this in mind it becomes pretty clear why the W8JI data shows such a high main lobe for a 1/2 WL “Beverage”.  A 1/2 wave antenna that is unterminated will display a main lobe somewhat perpendicular to the wire axis in free space.  In close proximity to the ground the primary lobe energy towards the ground will be reflected up, adding to and remaining in plane with the perpendicular to wire axis lobe, OK, it can become somewhat more pronouncedly double lobed at this point.  Terminating the wire at the far end will “bend” the lobe towards the termination.  The velocity of the signal in the conductor is slower than the velocity of the signal in free space, so the longer the wire, the more the lobe will be “bent” towards the termination end.

So, a halfwave Beverage will have a high angle cone in the direction of the termination.  The longer the length of the Beverage the lower the included angle of this cone, and the greater the gain in the primary lobe.  At a half wave the main beam is pointed up so the gain towards the horizon, relative to a “no gain” (some verticals do have gain, lets assume none for this) omni directional vertical, is down significantly, just over 20 dB if the W8JI data is correct (and there is no reason to believe it is not).  The main lobe itself of the Beverage may have more gain than the vertical (probably around 3 dB if the vertical is 1/4 wave), but it is pointed more up in relationship to the vertical.

As I said above, the longer the Beverage the more this main lobe comes down towards the horizon and, at the same time, the more gain the main lobe has.  And thus the gain delta at 20 degrees between the vertical and Beverage is down to about –6 dB by the time the Beverage is 2 wavelengths long.  However, the gain in the main lobe is now up around +4 dBi or more.  So, the longer the better, but also the more directional.

But all of this is plotted along the wire axis.  The main lobe at the horizon and some angle (angle depends on antenna length and other factors) off the axis of the wire in the horizontal plane will be many dB up from the vertical omni performance.  These main lobes on the horizon still will not have as much gain as the main lobe up does, but it is closer to the theoretical.

Placement of a Beverage, or any other fixed directional antenna, is important because once placed they are going to work well in a specific direction and, by design, not so well in others.  With a Beverage think about where you are placing the lobes, not just the wire axis, a long enough Beverage (say over 3 Lambda) should start to blur the lobes with the wire axis.  With a Rhombic the central axis is the lobe axis.

2061
Rhombic - I'm surprised no one mentioned the Rhombic (including me  :) :) ). I thought of it about a weak after my first response ...

If you have the room (real estate), the Rhombic can do what I think you want the Beverage to do: directionality.

The Rhombic will give you directionality, but also doesn't have the limitation of a  'low angle of reception'.

I did not mention the Rhombic because I was not aware he was looking for directionality.  In fact that was why I mentioned beware the directionality of the Beverage, or plan for it.

I have three Rhombics myself, and absolutely love them.  One is a 450 footer pointed 270 deg true (South Pacific, Malaysia area, and Australia for me), another 450 footer pointed 035 deg true (Europe, Middle East, and N Africa for me), and the last is a 300 footer pointed 310 deg true (China).

Each of mine has a switched 800 Ohm termination (600 Watt non-inductive, but for receive only use a 1 Watt carbon resistor would be fine) that can be controlled from the listening desk.  This means with the termination selected the antenna is directional along its primary axis, but when I switch the termination out the antenna becomes bi-directional, along the axis and reciprocal.  This gives me directions of 270 and 090 on one, 310 and 130 on another, and 035 and 215 on the other.

When terminated the Rhombics are also fairly low noise antennas.

The 450 footers are about 240 feet per leg length, which means at 20 MHz the gain is roughly 12 dBd, at 10 MHz the gain is roughly 9 dBd, and at 6 MHz it is roughly 7 dBd.  The 300 footer has legs about 168 feet long, meaning about 10 dBd at 20 MHz, 7 dBd at 10 MHz, and 5 dBd at 6 MHz.  Those are calculations, not measurements.  In the bi-directional mode subtract 3 dB from each of those numbers.

My Rhombics are not really optimized, I built them more to my property constraints than anything else.  So, the enclosed angles are not quiet as good as they should be, but pretty close.  For example, the 270 deg antenna is 450 feet long and 190 feet across the wide part, it really should be more like 220.  Also, they really should be higher.  Here I have them at about 30 feet, they would work better if I had them more like 50 feet.  But, as we clock winds of 100 MPH about once a year in the region (although I have not seen that at the house) I keep them fairly low and survivable.

I also have a couple of wire V-beams that work well and are again directional.  The nice thing about a V-beam is that you only need one tall support (at the apex), but the supports at the far ends can be low, say 8 feet.

I still say that if I for some reason I could only have one antenna, and I need it to be for general use and omni directional, it would be a horizontal sky loop, made as large as I could get away with.  I would want at least 60 feet per side, and a height of 25 feet or more.  I am, however, very glad I am not limited to one antenna.

2062
Shortwave Broadcast / Re: Running Log From Tonight
« on: September 21, 2010, 1337 UTC »
Thanks for the reply, Token. Guess I just got a bit lazy. I didn't intend to cause any confusion to anyone and apologize for any difficulty in understanding my post. I kinda made the assumption that people on the board went to the settings menu and selected their time and date for forum usage, posting, etc.

People probably do set the time and date for forum postings, but that is not the same as reception reporting.  For receptions the convention is UTC time and date.

Date differences are always confusing even for me! I get your nitpick on signal reports. Just a habit for me to note signal strength on my radio's meter since years ago. But, you do have a good point about meter calibration!

I also note the signal strength on the S meter, and I try to keep my meters correctly calibrated, at least as correctly as I can.  The meters on SDRs are simply fantastic for keeping in cal.  However, S meter readings and RST are two different things, just as SINPO is another signal rating system.  It is not unheard of in my log to find all three listed, S meter, RST, and SINPO, although my default is simple S meter unless the signal is other than perfectly readable.

2063
Shortwave Broadcast / Re: Running Log From Tonight
« on: September 21, 2010, 0004 UTC »
A couple of observations for you.

Number one, times are best expressed in UTC and 24 hour format, this is a near universal radio convention.  Broadcast schedules are pretty much always published in UTC.  If you say Central Time you assume everyone knows what that is and is willing to convert it to something useful to them…say the UTC that printed schedules will be in.  In most cases people will just ignore such a post rather than convert back and forth.  In some cases people in other countries will not understand what you mean by Central Time.  UTC is the same for everyone, and does not change through the year.  And IF you use UTC, don’t forget to also express the date in UTC, for example 1100 PM for you might be 0500 UTC, but it will be 0500 the next day on the calendar, and some broadcast schedules are day specific.

Number two, frequencies for short wave broadcast stations are most often in even 5 kHz steps (there are exceptions, but they are a small percentage).  It is best with SW BC stations to assume the nearest 5 kHz step until you can confirm otherwise.  Your 1134 PM 7273 kHz Arabic posting would be 0534 UTC, and that most likely means you had the 7275 kHz broadcast of RTV Tunisia, in Arabic.  Your 6174 kHz listing is harder to resolve, unless you heard an announcement of "China Radio International" I suspect it was not that.  Regardless, confirm the freq, and do NOT just peak the sound by ear for an AM station, that will not always give you the honest center frequency.  If you have a radio that is USB/LSB capable you can select either of them and "zero beat" the carrier.  If you have a radio with a BFO knob that technique might not be accurate.

Number three (OK, this one is a nit pick ;) ), what is "5 by 9 exactly"?  The RST scale is not related to the S meter on your radio, so S9 on the meter is not necessarily the "9" in 5 x 9, 59, or 5 and 9, regardless of how you express the term.  The second digit in the RST usage is a relative number, from 1 to 9, with the 1 being the weakest and the 9 being the strongest.  Yes I know it is very common these days to say something like "59 +20 dB", and places like Wikipedia say this is normal (but not the amateur radio specific wiki), however this was not the intent of the RST scale.  In the intended usage this would mean the stations was “perfectly readable” and a “very strong signal, plus 20 dB”.  Not everyone’s S meter is calibrated to the same scale, and on some radios the very strongest station might only push an S7 on the meter, that station would still be "5 and 9".  Remember that not all radios even have an “S meter”, and not all signal strength meters are calibrated in S units, some are simple 0 to 10 scales or something similar.  This was particularly true when the RST system was developed.


2064
Howdy all,

I did a few vid captures of some of the beacons that can easily be heard from my location pretty much daily and or 24/7.  Later I may add some of the harder to get beacons, but they may be a little noisy, not sure how they are going to turn out.  I chose the SDR-IQ and SDR-14 with SpectraView to record as I think the more simple display shows up better in small video than any of the other SDR GUI's.  Besides that I simply like the waterfall of SV better than the others here, even if the SDR-IQ is not as good a receiver, on paper, as my Excalibur, my Perseus, or my Flex-5000.


4079.64 kHz, TMP in AZ: http://www.youtube.com/watch?v=9JleXTmQnJA
4089 kHz, I think in Death Valley: http://www.youtube.com/watch?v=AcM8YaQRXRQ
4096.26 kHz, Hexie: http://www.youtube.com/watch?v=Laj1gR6MrB4
4096.6 kHz, Kelsie: http://www.youtube.com/watch?v=A9GCJ-OxoLM
4097.26 kHz, Inyo Whooper: http://www.youtube.com/watch?v=LKrQYG38KjA
4097.8 kHz, un-named dasher near Death Valley: http://www.youtube.com/watch?v=TlIN1VEr2JE
4102.33 kHz, W, Windy: http://www.youtube.com/watch?v=VhuPcNZ-EIk
4102.8 kHz, un-named dasher near Death Valley: http://www.youtube.com/watch?v=zA2SmVY1chQ
5205.36 kHz, Sally: http://www.youtube.com/watch?v=ZZuaTlHb-YQ
6626.4 kHz, Rainy and Rocky together: http://www.youtube.com/watch?v=1Mkh6Nf2Sbs
6626.65 kHz, Rainy alone: http://www.youtube.com/watch?v=2SQlI3--HBU
6700.5 kHz, Hexie 2: http://www.youtube.com/watch?v=Jq9_UqqJMu4
8000.5 kHz, S: http://www.youtube.com/watch?v=rE49nzA8Y6k
11003.45 kHz, I think this is Echo: http://www.youtube.com/watch?v=VwYWX37qTMc

4097.8 and 4102.8 kHz un-named dashers, and their synchronization: http://www.youtube.com/watch?v=D14rXmHgNvU

2065
Shortwave Broadcast / Re: 6.164.00 AM
« on: September 10, 2010, 1735 UTC »
And you are sure it was German, not Dutch?  Also, what kind of radio are you using and could you have the freq off by 1 kHz?  Depending on the radio it can sometimes be difficult to find the exact center freq of an AM signal, peaking the signal by ear will not always result in the true center freq.

Radio Nederland out of Bonaire in the Antilles broadcast on 6165 kHz in Dutch from 0400 to 0427 UTC, and that should have been 2300 to 2327 (1100 PM to 1127 PM) local for you.

The time is right, Dutch is pretty close to German to a person who does not speak the language, and the freq is about right.  So my bet is it was Radio Nederland.

2066
OK, first of all small loops are going to be more quiet than many other types of antennas.  However, keep in mind that part of the reason is that small loops are also very inefficient.

Small loops are great if you can not put up a full sized antenna or if you want a second, directional, antenna that can null noise sources.

In general the physically larger the antenna the more signal you will pull in, it is simply about capture area or aperture.  So a large antenna will get signals that a small loop cannot.  Of course the noise floor will often come up also, but signal to noise is the key, not an absolute lack of noise or not.  And very large antennas, even simple wire antennas, can exhibit directionality that must be taken into account.  If the main lobes of an antenna are in directions you can not use, and nulls are in important directions, then it will seem the antenna is not working well, when the antenna is really just fine, but the installation is less than optimal.

A good, low noise, large antenna is a full wave sky loop.  One cut for 80 meters and about 20 to 30 feet off the ground will work very well for receive applications from AM BCB to about 20 MHz.  It works above that freq, but will be best below 20.  This antenna would be laid out in a square about 64 feet on a side.  Actually, it should be a circle, but a square is a good compromise between support simplicity and performance, it could even be an equilateral triangle, but you would start to get some pretty noticeable nulls in the coverage.

The Beverage is a fine antenna, but if built as a true Beverage it will also have some directionality, so keep this in mind during your planning stage.

2067
HF Beacons / Re: Morse Beacon Keyer
« on: September 02, 2010, 2254 UTC »
Or something like the Parallax Basic Stamp 1 or 2 could be used.  The 1 would draw only 1 mA while working and the 2 would be about 3 mA.  Both can hold a couple thousand lines of code and send whatever CW you want it to, while reading sensors and including that in the CW stream.

Buying them from Parallax can cost a bit (BS 2 is about $45) but I ahve seen them on Epay for less than $20.

2068
General Radio Discussion / Re: Those annoying "sweeping" sounds...
« on: August 10, 2010, 0117 UTC »

Several different sweeps - or several 'returns' from the same Ionosonde transmitter?

It appears one of the sweeps converges with the long one about 17 MHz ... and there is a faint trace of a third starting lower down about 16 MHz and another about 20.5 ...

Usually the Ionosonde transmitters are staggered in time, that is, they have an assigned 'time slot' if you will around the hour so they do not overlap and cause a signal to appear at a receive site that was unplanned is and therefore unknown ...


Several different ionosonde transmitters.  Not all of them sweep at the same rate, thus different slopes on the display, and it is not uncommon for them to cross at times.  Yes, I know they are often quoted as "100 kHz per second" sweep time, but some are intentionally faster or slower, I have seen sounders sweep anything from 50 kHz per second to 250 kHz per second.


2069
Synthesized female voice did all the talking.  Several songs, none that I recognized.  Fairly strong, but synth voice made it hard to understand.

Multiple IDs, but I could not make any out until the sign off at 0254, turned out it was World Wide Radio Redneck, WWRR.  Announced QSL info, but again I could not copy due to the synth voice.

2070
General Radio Discussion / Re: Those annoying "sweeping" sounds...
« on: August 05, 2010, 2347 UTC »
Here s a shot of a couple sweeping from about 6600 to 28000 kHz.  It actually did go to 28000, although it is hard to tell on this image because of the traffic near there, I had to magnify the screen in real time to see where it ended.  Normally I can not see them this wide, typically I only see a given one for 12 MHz or less, what end of the spectrum depends on time of day.


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