Archive for the ‘antennas’ Category
New Antenna: The Following Footprints Are of My CW Signals (2021-March-14 @ 04:00 to 04:20 UTC).
March 15th, 2021 | 
Author: The following footprints are of my CW signals on 2021-March-14 at about 04:00 to 04:20 UTC.
Click on this image to see a larger version of this image:
Location: EM89ad – Ohio
Antenna: OCD (Off-center Dipole)
Description of Antenna:
This is an off-center dipole, with the two legs running East-East-South (approximately 125 degrees of North), and West-West-North (about 306 degrees on the compass). The westward wire (leg) is approximately 107 feet in length, while the eastward leg is about 95 feet in length.
These legs (an off-center-fed dipole) is directly connected to about 90 feet of 450-ohm ladder line, which is hanging directly below, vertically, the feed point. The feed point is 50 feet above the ground.
The ladder line terminates (at the 12-feet-above-ground point) to a 4:1 current balun. This current balun then connects to a 100-foot LMR 50-ohm coax, which is running into the radio shack. It is connected via an antenna switch to my Icom IC-7610 transceiver. I am transmitting a 100-watt CW signal using an Icom IC-7610, in the following format:
TEST TEST TEST DE NW7US NW7US NW7US
The Reverse Beacon Network reports any spotting of this test transmission. The beta mapping interface, at http://beta.reversebeacon.net/main.php, then maps the resulting spots. To learn more about the RBN, visit http://beta.reversebeacon.net/index.php, or, http://reversebeacon.net/index.php.
I show the 20-, 30-, 40-, 60-, 80-, and 160-Meter band footprints.
I’ve been capturing these CW transmission spots, at different times of the day, today. I’ll get data from several days, at regular intervals, and create a overview of how the antenna appears to be working during this month and under these propagation conditions.
73 de NW7US dit dit
..
BCB DX + A (Possibly) Quieter Receive Antenna
The earlier very quiet geomagnetic field has produced some amazing propagation on the AM Broadcast Band for west coast DXers. Where local blowtorches don't splatter the band, the past few nights have produced audible signals from several European countries while the mornings are filled with Asians and signals from Alaska ... yes, on the AM Broadcast Band!
The morning of October 11th was particularly good here, with 9 different stations in Alaska heard. Listen and see if you can hear the identification at the top of the hour (7 AM my time):
780 KNOM Nome https://qsl.net/ve7sl/knom.mp3
670 KDLG Dillingham https://qsl.net/ve7sl/kdlg.mp3
700 KBYR Anchorage https://qsl.net/ve7sl/kbyr.mp3
680 KBRW Barrow https://qsl.net/ve7sl/kbrw.mp3
890 KBBI Homer https://qsl.net/ve7sl/kbbi.mp3
This is a short clip from HLAZ, Far East Broadcasting Company, with their 'Radio Liangyou' program in Japanese. HLAZ is located in Jeju, South Korea. They will also respond to reception reports with a nice card ... sadly a growing rarity with AM broadcasters nowadays.
These were received using my Perseus SDR and 10' x 20' active loop pointed to the NW.
Hopefully these nice conditions will continue for some time but on the other hand, I'd like to see the Sun ramp-up its sunspot production as fast as it can, which would likely put a damper on these quiet conditions. (post edit: and that's exactly what happened!)
An interesting antenna that may help overcome their noise issues is described by KK5JY on his website here.
It looks simple enough to deploy and try to see if it overcomes your local noise issues. Those with underground utilities however, may find that it makes the noise worse.
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| courtesy: kk5jy.net |
Just Get On The Air! (A Makeshift Temporary Dipole Shortwave Antenna)
It might not take as much antenna as you may think would be necessary to make two-way contacts on shortwave radio (as an amateur radio operator putting an HF transceiver on the air). However, often, makeshift antennae are effective enough to be viable–just look at all the contacts many amateur radio operators make with their low-power (QRP) rigs (transceivers) using short, helically-wound, mobile antenna sticks. If they can work magic with such inefficient antenna setups, surely your effort at an antenna would pay off to some degree. Right?
Of course, I want to make a proper dipole out of this example antenna. But, while I wait for the rest of the parts I need to complete this antenna project (pulleys and a ladder, and maybe a potato launcher), I’ve put this makeshift antenna on the air, with it just high enough so that I can enjoy some time on the shortwave bands.
With this antenna, I’ve made successful two-way voice and Morse code contacts (QSOs) with stations in Europe and across North America. I am able to tune it on the 60-, 40-, 30-, 20-, 15-, 17-, 12-, and 10-Meter bands. Reverse beacon detection picks up my Morse-code CW signals, especially on 40 meters (the band on which it is tuned physically).
The bottom line: just get something up in the air and start communicating. Improve things over time. You’ll have much fun that way.
73 de NW7US dit dit
Software-Defined Radio: Try Before You Buy? You Might Like It!
Sure! You don’t need to have a software-defined radio (SDR) before you start learning how to use the technology; there are a few different paths you can take, exploring and learning about SDR.
One way to gain some experience with SDR without spending a dime is to install a free software package for the very popular, non-Linux, operating system (that starts with ‘W’), and give SDR a test drive. If you like it, you might consider getting your own hardware (like the SDRplay RSPdx, for instance), and connecting it up to your computer and running this software, too.
Why I Dived Into SDR
I have always loved radio, ever since the early 1970s, when I discovered shortwave radio. In the last couple of years, I’ve had an increasing interest in the world of SDR. When I am working, but away from home (remember those days, before Covid?), I want to sample news and programming from around the world, but through shortwave. The way to do that, I found, is by using the various SDR options which allow a person to tune a remote receiver, and listen.
I also find working with the waterfall of a typical SDR-software user interface rewarding because, instead of blindly searching for signals in a subband, I can see all of the received signals on the scrolling time representation of a slice of frequency. Simply select that signal on the waterfall, and the radio tunes right to it.
I often connect to different SDR radios around the world, to catch all manner of shortwave signals, from maritime, military air, trans-oceanic air, or coast guard radio traffic, or other interesting HF communications including amateur radio CW and SSB signals. Occasionally, I also check out VHF and UHF signals from around the world. All of that, while instead an office building that is not suited for shortwave radio reception.
I’ve now decided to give back to the community; I’ve added my SDR receiver to the collection of receivers located around the world on the SDRSpace network of SDR radios.
My new SDRplay RSPdx software-defined radio receiver is live, via http://www.sdrspace.com/Version-3, using the SDR Console software (Version 3).
The receivers are online whenever I am not transmitting and when there are no local thunderstorms.
Antenna Port A is connected to a wire antenna (a horizontal 100-foot wire that runs out from my house’s chimney to a tall tree; about 10 feet of that wire is oriented vertically, where the wire passes through a pulley and then is weighted down so it can move with wind-driven tree movement), while Antenna Port B is connected up to a VHF/UHF discone.
Both antenna systems have an AM Broadcast band notch (reject) filter reducing local AM Broadcast-Band radio station signals by about 30 to 40 dB. I need to use these because the very close KLIN transmitting tower is just miles away and those signals overwhelm the receiver. When I use the signal filters, the local AM Broadcasting signals no longer overwhelm the receiver.
In the following video, I first explain my SDR setup, and in the second half of the video, I tune around the radio spectrum, using the software to control my SDR receiver.
A Couple of Questions
After watching this video, WO9B wrote an email to me. Michael asked of me two questions, summed up as:
1. Your SDR window has the IF screen on top. How is that accomplished?
2. Your AM Broadcast filters; more info, please. I live in the area of mucho broadcast stations and that looks like something I could use.
In the following video, I demonstrate how I changed my layout of the SDR Console software. And, I mention the AM Broadcast Filter for SDR Receivers (the hardware filter is found here: https://g.nw7us.us/3kU5SJN).
To Use My Receiver
Download the latest version of SDR-Console from https://www.sdr-radio.com/download – there is a 32-bit and a 64-bit Windows installation package.
The 64-bit installation package may be downloaded from one of these three sources:
1. Google: https://g.nw7us.us/3auBq44
2. DropBox: https://g.nw7us.us/310ooIG
3. Microsoft: https://1drv.ms/u/s!AovWaZDu7Hrd3U-yqK1bs3wuaFw2?e=o4nKeh
The 32-bit installation package can be downloaded from one of these three sources:
1. Google: https://g.nw7us.us/3iLasrZ
2. DropBox: https://g.nw7us.us/3g4VcVc
3. Microsoft: https://1drv.ms/u/s!AovWaZDu7Hrd3U4mJiiRtI9lm70s?e=HDG4ZX
Install the SDR Console package according to the directions given. Once you have the software installed, you will want to add my server. It takes some work to get familiar with the software, but there are online FAQs on how to begin.
One guide on how to add a server to the list from which you can pick may be found, here:
https://www.sdrplay.com/wp-content/uploads/2018/02/SDRConsoleV3-ServerGuide1-1.pdf
I worked on getting all of the bugs worked out of my installation before making the video. It did take some work, and reading up on things. But, the software is solid and a good contender against SDRuno, and HDSDR, and, this way I can share it online with you.
My server is known as, ‘0 NW7US‘ — it will be online when I am not using my antenna systems for transmitting. It will be offline during thunderstorms, or during times when I must use the systems for transmitting.
Software-defined radio is a great way to hear all sorts of communications, from local AM broadcast stations, FM stations, VHF Air Traffic, to shortwave radio stations including amateur radio HF communications.
Thank you for watching, commenting, and most of all, for subscribing; please subscribe to my YouTube Channel: https://YouTube.com/NW7US Also, please click on the bell, to enable alerts so that when I post a new video, you will be notified. By subscribing, you will be kept in the loop for new videos and more.
73 de NW7US
.. (yes, this is an expansion of an earlier post… forgive the redundancy… thank you) ..
Check Out My New SDRplay RSPdx Software-Defined Radio Receiver – Live!
My new SDRplay RSPdx software-defined radio receiver is live, via http://www.sdrspace.com/Version-3, using the SDR Console software (Version 3).
The receivers are online whenever I am not transmitting and when there are no local thunderstorms.
Antenna Port A is a wire antenna (100′), while Antenna Port B is a VHF/UHF discone. Both have an AM Broadcast band reject filter, reducing local AM Broadcast signals by about 30 to 40 dB. I need to use these because the very close KLIN transmitting tower is just miles away and those signals overwhelm the receiver. When I use the signal filters, the local AM Broadcasting signals no longer overwhelm the receiver.
Let me know what you think. Enjoy!
To use my receiver:
Install the latest version of SDR-Console which can be downloaded from https://www.sdr-radio.com/download
Install SDR Console according to the directions given. Once you have the software installed, you will want to add my server.
It takes a little to get familiar with the software, but there are online FAQs on how to begin.
My server is known as, ‘0 NW7US‘ — it will be online when I am not using my antenna systems for transmitting. It will be offline during thunderstorms, or during times when I must use the systems for transmitting.
Software-defined radio is a great way to hear all sorts of communications, from local AM broadcast stations, FM stations, VHF Air Traffic, to shortwave radio stations including amateur radio HF communications.
Thank you for watching, commenting, and most of all, for subscribing; please subscribe to my YouTube Channel: https://YouTube.com/NW7US Also, please click on the bell, to enable alerts so that when I post a new video, you will be notified. By subscribing, you will be kept in the loop for new videos and more.
Video:
73!
PAØRDT Miniwhip Shakedown
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A recent posting to the 'ndblist group' by Mike, an ardent NDB DXer in the UK (Sussex), announced the recent completion of his four-part video series describing the installation and testing of a new PAØRDT active antenna.
If you may be contemplating the installation of an active antenna such as this, or perhaps making a start at DXing the NDB band or listening on 630m, then you might enjoy following Mike's journey as he demonstrates that living in the noisy suburbs need not keep you from enjoying the LF/MF bands. Mike includes some interesting tests involving his grounding system versus noise ingress and the results of keeping the electrical main's ground isolated (or not) from the antenna cable's ground. The PAØRDT active whip is available from PAØRDT himself or if you are handy with a soldering iron, you might choose to build the same antenna in your workshop. These simple yet highly effective receiving antennas are being used successfully by hundreds of listeners all over the world and for their size provide some pretty amazing performance.
Much more information on the PAØRDT e-probe antenna may be found here in a previous blog posting. To see more of Mike's videos, you can visit his interesting Youtube Channel here.
My 10’ x 20’ Active Loop
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| courtesy: americanradiohistory.com |
After recently installing a new coax run out to the loop and after five years of summer sunlight, the plastic food-storage container used to house the loop’s preamp (Wellbrook ALA100LN ... LF-30MHz) finally bit the dust ... literally.
Last week I replaced the housing with a slightly larger plastic box but I’ll still be faced with the UV bombardment and eventual deterioration of the clear plastic and lid unless I do something different.
I’ve a couple of thoughts but am hoping for some other suggestions from blog readers.
I have thought about spray painting the container, which may (or may not) prevent UV damage, but wonder if paint will stick to the smooth plastic surface? Maybe if scuffed-up a bit it would stick ... if so, the coating could be annually renewed.
Another idea is to cover it with duct tape ... not pretty, but possibly doing the job. Any other thoughts out there?
Part 2 and Part 3 of this blog were originally published when the loop was first built (2014) and describe the antenna details as well as showing the loop in action ... listening on the NDB and broadcast band as well as showing its nulling capability. It’s been a great performer and I can highly recommend the ALA100LN for a large aperture receiving loop. I’m looking forward to what will hopefully be a good winter of exciting loop DXing.
Part 2 - New LF / MF Loop
Some may recall my blog back in July (Wellbrook Loop Plans) describing a new loop that I had been thinking about as a possible replacement for my 10' shielded loop. I had been doodling various construction ideas using PVC tubing in an effort to keep it as light as possible, without introducing any metal near the loop. On Monday of this week, I dismantled the 10' loop in preparation for my new experimental rectangular loop.
I've had the Wellbrook loop preamp here for a few months, so it was now or never, while the weather was still 'antenna-friendly'. Now I do understand that this goes against one of ham radio's long-standing traditions that dictates all antenna work must wait until the weather can't get any worse. Antennas built in the winter rain always work much better than ones put up in the summer. Hopefully it's not Wouff-Hong or Rettysnitch punishable but the fall DX season is almost upon us and I'm not waiting for the rain!The new 'loop' is not really loop-shaped but is rectangular (10' x 20') and more like a Flag antenna shape. I considered a Flag but really don't need any back-end nulling capability since I'm mainly interested in listening to the east and to the north.
The main boom section is composed of two sections of 1" PVC thick-wall (Schedule 40) pipe joined at the center and reinforced with a 10' section of 2" x 2" Douglas Fir. In addition, the boom has a truss of 1/4" Dacron to take out any end-loading sag. The vertical end sections are 3/4" Schedule 40 PVC pipe, fastened with a T at the boom end. The center mast is made of 2" Schedule 40 ABS pipe with a long section of 1 1/2" ABS nested inside that telescopes upward to anchor the truss ropes and give some additional rigidity to the mast.
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| Main boom and mast construction |
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| Looping E/W |
Although the preamp is completely sealed and weatherproofed, I still decided to mount it inside a container. The container also provided a convenient anchor to terminate the loop end wires (PVC-coated #18 stranded) without putting any tension on the soldered terminals.
Although I have not had much time to listen, and conditions are still in 'recovery' mode from earlier disturbances, initial indications are that everything is performing as well, if not better, than expected. It certainly outperforms my 10' active shielded loop by a large margin. I have yet to do any serious S/N comparisons between it and my primary LF receive antenna, a large inverted L, which must be tuned to resonance for the desired listening range. I believe that the very quiet loop / Wellbrook combination will provide an overall S/N improvement.
I have always believed that smaller loops provide deeper and sharper front-to-side nulls so I was pleasantly surprised to measure (using Perseus) null depths from 25-30db, on various groundwave signals ... more than expected. Skywave signals also deliver sharp deep nulls in the order of 22 - 25db ... again surprising, but I'll take them!
A brief listen while pointing S-E last evening turned up good signals from 1 kW'ers KYHN (1650kHz) in Fort Smith, Arkansas and KKGM (1630kHz) in Fort Worth, Texas. An early morning listen revealed good audio from JOIK (567kHz) Sapporo, Japan and JOAK (595kHz) in Shobu. Down in the ndb band, little 25-watter 'IP' on 210kHz was an all-time new catch from Mobile, Arizona.
There is still much to learn from this new antenna system but the biggest challenge will be keeping it up all winter. I did lose one of my 10' loops after several years, due to wind, when the main (un-reinforced) PVC mast eventually failed from flexing fatigue. I will tie the ends of the new antenna down when the winds get strong to reduce as much mast flexing as possible. I could however, run the risk of violating another long-standing radio adage ..."if your antenna stays up all winter, it's not big enough". I just can't win.
Part 3 - Loop Listen
As Murphy would have it, and in spite of the low amount of solar activity, LF/MF propagation has been very poor since getting my new 10' x 20' loop in place. The few front-to-side nulling checks that I have done, have produced results varying from around 20db to 30db, depending upon the signal. I suspect the depth of null is also affected by the signal's arrival angle but there is still more to learn. The pattern seems to be very close to that of a typical circular loop...the classic figure-8 pattern illustrated below as shown on the Wellbrook data that came with my ALA100LN preamp.
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| Courtesy: http://www.wellbrook.uk.com |
More typically, the null is around 21-22 db as shown on this test while listening to the ground wave carrier of the 'YZA' NDB (236kHz) located in Ashcroft, B.C., about 150 miles to the NE. As expected, the null is fairly sharp and the front / rear lobe, fairly broad.
One short check at dusk produced nice signals from CJBC, the French-language station in Toronto. The past few nights it has been very strong but with a strong echo effect. I wonder if there is more than one CBC outlet here (860kHz), such as a low-power repeater, causing the echo.
At the same time, while still fairly light outside, WCCO in Minneapolis had a nice signal just before sunset.
No matter how poor conditions become, it seems that the Hinchinbrook (Alaska) NDB, 'ALJ' (233kHz), is always strong ... looping north.
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| Courtesy: https://www.google.ca/maps |
(Since originally posting the above, I have been using the Tiny Take free screen capturing software, to produce better quality catures of my Perseus recordings. It's also probable that my new iPhone would produce a high quality video of my computer screen compared to the older iPad used for these ones, but it's something yet to be tried.)
Hopefully conditions will only get better as the season progresses and I am able to give the loop a good workout ... before it gets too windy!
