Re: HiFER capture using a website
I love the fact that sites are HTML5 compat, so Java isn't needed.
Navtex poor
Posted by John Bruce McCreath on March 03, 2015 at 14:41:44.
The number of decodes and the range of stations heard was dismal overnight making me think my equipment had problems, but then I checked the Space Weather site and saw why! Things could be interesting in the coming days.
73, J.B., VE3EAR
P.S. - I've posted some pix and the schematic of my latest build at TheRadioBoard site. Solar eclipse radio experiments, Friday March 20th 2015
Posted by Mike Terry on March 10, 2015 at 10:01:48.
Opera transmissions on 477kHz
See http://www.southgatearc.org/news/2015/march/solar_eclipse_radio_experiments.htm#.VP6_M402ZKY
Comparison of L-400B vs Z1501F Active Antennas?
Posted by Tom Clifton on March 11, 2015 at 15:13:52.
I looked through the archives to see if I could find such a comparison and came up blank. Both appear to be outstanding antennas, and each has its own strengths. I would love to have one of each, but finances dictate otherwise. In the 100khz to 500khz range are they similar in performance? I live in St. Louis which is "rich" in AM Broadcast stations and other urban noise sources and the L-400B handily fixes that problem by not 'listening' there. The Z1501 has outstanding resistance to intermod, and is convenient as I can listen up to 30mhz. The L-400 gets me down to 3khz... Torn between two worlds - any words of wisdom?
13555 JT65 Mode?
Posted by Geek on March 12, 2015 at 09:55:29.
I'm hearing what sounds like very faint JT65 at the watering hole, followed by a CW identifier, then more JT65. Via the Blerp2 WebSDR at 0945 UTC.
Re: 13555 JT65 Mode?
Posted by John Davis on March 12, 2015 at 19:39:00.
In reply to 13555 JT65 Mode? posted by Geek on March 12, 2015
Can you pin down the frequency any closer? Does it appear to be plain JT65, or does the start and end timing (the CW ID) perhaps fit WSPR2? There are a couple of ops who have that capability, although it's been a while since anyone has announced intentions to use the mode.
Re: 13555 JT65 Mode?
Posted by Geek on March 12, 2015 at 21:03:45.
In reply to Re: 13555 JT65 Mode? posted by John Davis on March 12, 2015
Wish I could. Even on weak signal, it was in the background noise. I had to concentrate on the audio in CW-Wide to hear it.
Re: 13555 JT65 Mode?
Posted by John Davis on March 13, 2015 at 04:15:38.
In reply to Re: 13555 JT65 Mode? posted by Geek on March 12, 2015
Interesting. I went out to the field to listen this afternoon, but if it was still on when I got there, it must have been coming from a direction in which the ionosphere was not cooperating.
Conditions at 22 m were fluctuaing pretty wildly. I had WM pretty decently for a while at first, then it faded away entirely for the rest of the afternoon. MP was at the ragged edge of visibility most of the time, but finally came up long enough for one clear "P." Somebody sending slow FSK right on 13555.4 became visible for a fraction of a minute, but faded long before I got an ID.
On the other hand, QRSS6 SIW was mostly OK, and slant SIW was solid the whole afternoon, as were EH and NC. Farther up the dial, MTI and PBJ were OK but with deep fading on a 2 to 3 minute cycle. (They were more consistent in level Sunday afternoon, but were right on top of each other frequency-wise that time. Today they were back to their normal locations.) GNK was good at times today but with deep, rapid fades every couple of seconds.
Will check again in the near future.
John
Re: 13555 JT65 Mode?
Posted by Geek on March 13, 2015 at 05:34:53.
In reply to Re: 13555 JT65 Mode? posted by John Davis on March 13, 2015
Been checking off and on all afternoon and evening myself. Odd conditions, totally blank then explodes with 5 or 6 HiFER's and in 5 minutes they're gone again. Re: Comparison of L-400B vs Z1501F Active Antennas?
I'm wondering now, given the time I heard it, if the signal may have possibly taken a hop from outside North America and if it was a HiFER at all?
Posted by John Davis on March 14, 2015 at 20:09:56.
In reply to Comparison of L-400B vs Z1501F Active Antennas? posted by Tom Clifton on March 11, 2015
Hi Tom. After a week, it's beginning to look as if not very many people have tested both units. I did a search myself recently (and repeated it this week, in fact) to see if I could find any direct comparisons of the two antennas elsewhere on the Web, to no avail.
All I can offer are a couple thoughts based on what people have said about the products individually, but maybe that'll give you a starting point. As you correctly pointed out, the L-400B doesn't have as high OIP numbers as the Z1501F, but it effectively sidesteps AM BCB problems by rejecting medium wave frequencies.
On the other hand, whether or not the Z1501F can avoid intermod problems by virtue of its greater linearity depends on just how RF-rich your neighborhood is. If you live too close to a couple of those 10 and 50 kilowatters, or if you try to use it with a whip that's too long or mounted too high for the ambient field intensities, you might still end up with overload issues (unless perhaps you trap one or more of the offending signals).
The only specs I can find on the Web for the Clifton Laboratories product are for the Z1501D, which are no longer entirely applicable. I corresponded with Jack Smith a couple of weeks ago, and he told me that the F model has a couple of significant differences over its predecessor. For one thing, the input device is now a dual-gate FET instead of the classic J310, and the unit works on 18 V rather than the former 13.6 V supply. I'm not sure how much impact the dual gate transistor has on linearity, but the increased supply voltage ought to at least enhance the amplifier's strong-signal capabilities. I wish there were published results we could consult to confirm the degree of improvement.
It sounds as if one of your deciding factors may be how much you really want to listen up to 30 MHz versus how much listening you actually do down to 3 kHz. The Z1501F has improved coverage down to 10 kHz these days, which is also the L-400B published spec, so the difference between them at the low end is not as large as it used to be.
As for sensitivity, the published spec for the L-400B is approximately -6 dB, implying that a signal with a field intensity of, say, 1 mV/m would yield an antenna output of 0.5 mV. That can be affected by how it is mounted, of course, but since the whip and amplifier section are basically unitized, there won't be a lot else you can do to alter the gain. The sensitivity of the Z1501F can be made greater (or lesser) by choice of whip length, provided overload doesn't become an issue.
And of course, there's also the difference in price to consider. The L-400B lists for $179, while the Z1501F and its matching supply run about $310.
John
Re: Comparison of L-400B vs Z1501F Active Antennas?
Posted by Tom Clifton on March 15, 2015 at 21:33:12.
In reply to Re: Comparison of L-400B vs Z1501F Active Antennas? posted by John Davis on March 14, 2015
Well, this started out as a fairly simple question, with a yes/no reply. As with all things, it gets more interesting when you start digging into the details.
Initially I had 'decided' that Clifton Labs was the winner - being able to use the same antenna for monitoring HiFer's being the turning point. The price slowed me down some, but sometimes waiting while you scratch up the bucks is a good thing.
Since then, three things have happened. First was reading about the Wellbrook ALA100m small active loop. Second was rereading the March 2015 QST article on the DK6ED double loop. Third was digging through Jack Smith's most excellent web page seeing what I could do with a pair of his Z10042A Norton Amplifiers to build the DK6ED double loop. (I figured that by the time I bought all the parts I would have spent $50 - half the cost of a pair of Z10042A's)
It was then that I saw the Z10130A FET Bufffer Amplifier for Langford's Antennas, and that lead me to a VE1ZAC dual loop design. Bingo...
The web page at www.ve1zac.com lead me to his article "A New Homebrew Magnetic Receive Loop at VE1ZAC" and it had a link to http://active-antenna.eu/ where for the low, low price of 82 Eu you can buy a set of boards that appear to work in the manner I desire.
Besides that, I have an old Radio Shack tv antenna rotor in the basement (assuming I can find it in the junk box) that will let me rotate it so that I can null out the local AM power houses. KSDK at 550kzh and KMOX at 1120khz. A pair of 50kw behemoths that pretty much get into everything...
By the way - Search your favorite on-line auction site for "hd tv motorized antenna" It appears that for under $30 you can buy a device suitable for rotating small loop antennas from a number of sellers. Only thing wrong with it is you have no idea what direction the thing is actually pointing, but for nulling out local guys it might be fine.
SJ going QRT for the season
Posted by Sal,K1RGO on March 18, 2015 at 15:17:28.
Well it's that time of year and the wind has altered my LF antenna as well so it's time. SJ on 185.303 kHz will be QRT and when the wx gets ok I will fix the hanging wire. Until next year......... MLS Beacon
later......Sal, K1RGO
Posted by Mark on March 18, 2015 at 18:05:11.
Re: Comparison of L-400B vs Z1501F Active Antennas?
Hi all,
I plan on keeping Beacon MLS at 186.204 on till the end of March. It will continue to operate on QRSS30 till April 1st. Thanks for all the signal reports! I changed my mind about switching to a new loop antenna next season and will simply rebuild the cap hat assembly to make it stronger for the ice and snow. Thanks again for your support...... Mark AC8CL
Posted by Doug Williams on March 18, 2015 at 23:40:12.
In reply to Comparison of L-400B vs Z1501F Active Antennas? posted by Tom Clifton on March 11, 2015
Hi Tom. I have both, and have actually owned three L-400Bs over the past couple of decades.
Both antennas, IMO, are sufficient for anyone looking to break into LF listening. Either antenna should net you many NDBs, or be sufficient for weak signal QRSS work.
The strength of the L-400B is the cost. It is considerably cheaper than the Clifton Labs antenna + coupler.
The weakness of the L-400B is the construction. The antenna whip and amp are sealed in a piece of PVC tubing. This means breaking out a hack saw if repairs ever need to be made, and also there is no provision for grounding at the antenna site.
The DC coupler for the L-400B is housed in a cheap plastic box. Also I have dissected an L-400B and found the construction/soldering quality to be something like I used to see from MFJ in the 1980s.......serviceable, but not pretty.
Also keep in mind that LF Engineering provides no schematic for the antenna amp that is housed inside the PVC tube. I assume the reasoning is that, since it is sealed, it is not user serviceable.
Nonetheless, the L400B is actually a good performer for LF listening and I have logged many NDBs and a good deal of Lowfers using the L400B.
The Clifton Labs antenna is a very sturdy, professional unit, well constructed using many surface mount components and housed in solid metal enclosures with plenty of provisions for grounding. The Clifton Labs power coupler also includes an isolation transformer that helps prevent unwanted interfering signals from traveling down the coax shield between the coupler and the antenna.
I have logged most of my Lowfer reception reports in the past several years using the Clifton Labs antenna, including transatlantic amateur LF signals on QRSS and WSPR, most every USA Lowfer Part 15 station, and even several 8 kHz amateur experimental signals.
The Clifton Labs antenna, IMO, is top shelf, and I say this with no reservations. Be sure to also use the Clifton Labs DC coupler if you decide to go that route.
If you go with the L400B, I strongly recommend you get the BNC option, which means you have to supply your own coaxial cable between the antenna and the DC coupler. To me, this is far preferable to the tiny RG-174 that is supplied with the standard L-400B.
Re: Beacon JAM 187.015khz status
Posted by Lee on March 19, 2015 at 08:47:09.
In reply to Beacon JAM 187.015khz status posted by Lee on February 25, 2015
Thanks to all who have listened. I will be turning off JAM 187.015khz Monday 3/23/15. This coming weekend is your last chance till next season. Now next season is iffy. The Santa Ana winds of this season have stripped the antenna of almost all UV protected tie wraps. Major maint is required. My global master plan is to, lower the antenna, replace tie wraps, and add two more radials. That would give JAM 8 radials with a scirt wire. Good for cap to ground. See ya next season, the lord willing and the creeks don't rise! National RBL-5 LF Receiver Value?
KE6PCT
Lee
Posted by Kevin Carey on March 22, 2015 at 03:36:43.
Can anyone give me a rough idea of what one of these sets is worth in good-to-very good condition? Tnx. --Kevin
RTE 252 Off air this week
Posted by Alan Gale on March 22, 2015 at 12:54:23.
Hi All,
Just saw this posting by Mike Barraclough on the British DX Club mailing list, this might offer some of you a chance to hear the Algerian BC station in the clear for a change.
Date: 22 Mar 2015 04:38:49 -0700
RTE website
The service on Longwave 252 will be unavailable from 10 am on Monday 23rd March until 5.30pm on Wednesday 25th March.
This is due to essential maintenance of the transmitter.
Mike
Re: National RBL-5 LF Receiver Value?
Posted by Tom Clifton on March 22, 2015 at 16:00:37.
In reply to National RBL-5 LF Receiver Value? posted by Kevin Carey on March 22, 2015
Secondhand Radio.com has one listed for $150. Don't know if this is a valid offer, or condition, but it is the only one I have found (so far)
http://www.secondhandradio.com/ShowAd.aspx?id=4816
Re: National RBL-5 LF Receiver Value?
Posted by Kevin Carey on March 23, 2015 at 13:00:57.
In reply to Re: National RBL-5 LF Receiver Value? posted by Tom Clifton on March 22, 2015
Thanks Tom, That gives me a start! Many thanks & 73.
Observed phenomenon
Posted by The other Lee on March 26, 2015 at 15:32:03.
I've been living up on the Maine/New Brunswick border for three years now. To my West and South are paper lands mostly (land owned by a paper company - heavy woods) to my East and North/Northwest are the Canadian Maritime provinces.
I've been listening and do very nicely with Canadians but very poorly with US NDBs. I get *no* US NDBs and only a few DGPS stations from the US.
Integrating everything I've heard over time and plugging it into WWSU I plotted out a radar-like display of what I'm hearing. Would you believe that I see a plot that roughly follows the line of the woods - NW, N, NE, E, SE I get NDBs, all from Canada. Other directions I get nothing.
The area has one geological distinction, a LOT of limestone under the soil to the W, SW and S. And trees, lots of them. And low hills along those lines, too. (But there are low hills in the good directions too.) I'm wondering if the limestone and the trees are making an exceptionally LW RF absorbtive shield.
Anyone else ever encounter such a phenomenon? I now believe that this is a real phenomenon and not just operator error given WWSU's evidence.
Lee
Re: Observed phenomenon
Posted by John Davis on March 26, 2015 at 19:55:20.
In reply to Observed phenomenon posted by The other Lee on March 26, 2015
Your observation is largely consistent with what is known of ground conductivity in that region. The FCC M3 ground conductivity map shows northern Maine to have no more than 1 mS/m conductivity, which extends a fair ways to the south; while just to your southwest (depending exactly where you are) lies some of the worst conductivity in the entire country, 0.5 mS/m. To the southeast, there are no longer many NDBs on the air, and you have to go some ways directly south (across more of that 1 mS/m soil) to find any as well.
Just across the border, the ITU world conductivity atlas shows conductivity values 2-5 times higher in the St Lawrence River basin, and one small patch of 10 mS/m; plus 2-5 mS/m values in much of New Brunswick, PEI, and Nova Scotia. Farther away in eastern Nova Scotia and over all of Newfoundland, conductivity is down to 1 mS/m again, but the path between them and you crosses over seawater (5000 mS/m) part of the way.
That would account for groundwave propagation being better from Canada and worse in the afflicted directions. But having said that, it still should not be zero reception. How far from the trees to your antenna, I wonder, and what sort of antenna is it?
Also, do you observe that same phenomenon at night? Skywave should not be impacted by ground conductivity.
John
Did these VLF-transmitters really all exist?
Posted by Samuel on March 26, 2015 at 22:07:57.
Did the VLF-stations shown on the list http://www.cbk.waw.pl/~ewa/vlf/praca.pdf really all exist? As the coordinates in this list are for stations, which existed or exist are not correct, it is difficult to verify it, but are or were there really VLF-transmitters at such remote places like Dikson or Matochkin Shar in Russia?
Are or were there really further VLF-stations in former Soviet Union than these mentioned in Wikipedia:
Alpha transmitter Novosibirsk: 55°45′22″N 84°26′52.4″E
Alpha transmitter Krasnodar: 45°24′12″N 38°09′29″E
Alpha transmitter Khabarovsk: 50°04′24″N 136°36′24″E
Alpha transmitter Revda: 68°02′8″N 34°41′00″E
Alpha transmitter Seyda: 67° 3′ 7.92″ N, 63° 4′ 19.2″ E
Vileyka: 54.462356°N 26.769218°E
Arkhangelsk: 64.360491°N 41.568489°E
Nizhny Novgorod: 56.171945°N 43.931667°E
Bishkek: 43.039444°N 73.6125°E
Khabarovsk: 48.48555°N 134.82333°E
Imeretinskaya: 44.773592°N 39.547311°E
If yes, where? Why are there in former Soviet Union VLF-stations far away from the coast?
Re: Observed phenomenon
Posted by Geek on March 27, 2015 at 10:29:28.
In reply to Observed phenomenon posted by The other Lee on March 26, 2015
Back in the 80's, I noticed geologic phenomena as well when putting pins into a map where I logged NDB's. The strongest and most frquent signals to me near Vancouver, BC originated from beacons that dot fault lines, especially along the west coast.
Re: Did these VLF-transmitters really all exist?
Posted by John Davis on March 27, 2015 at 22:31:43.
In reply to Did these VLF-transmitters really all exist? posted by Samuel on March 26, 2015
I do not know if all the transmitters listed in the PDF document were ever built and used, but I can provide some answers for the last question:
<<< Why are there in former Soviet Union VLF-stations far away from the coast?
Those which serve as navigational stations need to be located at numerous places, many of which will be inland. For a time signal station, the chief criterion is to be near the intended users of the service.
Even for submarine communications, there are some advantages to a site that is away from the coast. Salt air increases the maintenance required for any tower, and it is especially expensive to service the large antennas required at VLF. These costs include periodic cleaning and painting of the mast itself, occasionally cleaning and replacing guy wire insulators, greasing guy wires and elevator cables, and repairing any corroded electrical fixtures for tower lights and elevators.
Fortunately, inland locations are not necessarily a detriment to signal propagation at VLF. The effect of ground conductivity on signal attenuation is much less at lower frequencies. If the ground conductivity is at least reasonable, it will make little difference whether a high power VLF transmitter is near a coastal village or a hundred or more km inland.
Before the era of cruise missiles, a station inland would also be considerably easier to defend than one on the coast. There's more chance of shooting down enemy bombers, or of discovering and capturing commando forces attempting to sabotage a transmitter, if it is located well within the homeland. The transmitter at Nizhny Novgorod, for instance, is the old Goliath transmitter of World War II fame. The German submarine command located Goliath not on the coast near Kiel, which might have seemed a logical choice, but well inland, taking advantage of a site with very good soil conductivity to make its ground system work efficiently.
John
potrzebie