Ham College 115


Ham College episode 115 is now available for download.

Ham College 115
Technician Exam Questions Part 2.
T1B – Frequency allocations, Emission modes, Spectrum sharing, Transmissions near band edges, Contacting the International Space Station, Power output.

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George Thomas, W5JDX, is co-host of AmateurLogic.TV, an original amateur radio video program hosted by George Thomas (W5JDX), Tommy Martin (N5ZNO), Peter Berrett (VK3PB), and Emile Diodene (KE5QKR). Contact him at [email protected].

Amateur Radio Weekly – Issue 341

Amateur Radio Weekly

First M17 based radios begin shipping
Connect Systems has begun shipping the first radios that operate M17 out of the box.
Amateur Radio Daily

The rich history of Ham Radio culture
To really belong, you’re going to have to go along with the standard operating procedures universally accepted by Radio Amateurs.
MIT Press

Successful AREDN link
If you pick up something just to learn the thing, you likely won’t go far with it.
N3VEM

VHF/UHF handheld performance comparison
Comparing performance in sensitivity, dynamic range, and adjacent channel rejection.
QRPer

What is the difference between a counterpoise and a radial in a vertical antenna?
In the context of vertical antennas, both counterpoises and radials are used to improve the efficiency and radiation pattern of the antenna by providing a ground system.
VE3IPS

The baked potato radial
Would a Mylar blanket work the same way as the Faraday cloth?
K3FNB

The best reasons to build a go-box
It saves time in the field and helps to ensure nothing is left behind in the shack.
Ham Radio Outside the Box

TD-H3 VHF/UHF radio
You can think of this as an improved Baofeng UV-5R.
K0NR

A one-of-a-kind shortwave radio station
WBCQ is probably the only shortwave, AM, and FM combination radio station in the United States.
RadioWorld

DLARC adds over 1,300 items to new college radio collection
Materials in the collection include ‘zines, radio station program guides, flyers, playlists, correspondence, books, academic theses, magazines, and more.
Internet Archive

Is shortwave on life support?
Today, the shortwave landscape is a mere shadow of itself.
Hackaday

Video

Hustler 6BTV antenna on a dock
Unleashing the power of my 6BTV vertical antenna mounted on a dock over salt water.
W2PAK

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Amateur Radio Weekly is curated by Cale Mooth K4HCK. Sign up free to receive ham radio's most relevant news, projects, technology and events by e-mail each week at http://www.hamweekly.com.

ICQ Podcast Episode 435 – Behind the Scenes of Running a Special Event Station

In this episode, we join Martin Butler M1MRB, Chris Howard (M0TCH), Martin Rothwell (M0SGL), Frank Howell (K4FMH), Bill Barnes (WC3B) and Leslie Butterfields (G0CIB) to discuss the latest Amateur / Ham Radio news. Colin Butler (M6BOY) rounds up the news in brief and the episode's feature a discussion on Behind the Scenes of an Amateur / Ham Radio Special Event Station.

We would like to thank D Renton, Roy Jones, Frank Westphal (k6fw1), Simon Wilton (VA3SII and G7HCD), Denny Morrison (GM1BAN), Stephen Leeman (sm5yra), John R Stengel (W8UC) and our monthly and annual subscription donors for keeping the podcast advert free. To donate, please visit - http://www.icqpodcast.com/donate

  • ARRL on The Weather Channel
  • Band Use by Canadian Hams: Results from the national RAC Survey 2021
  • ARRL Board Completes 2024 Second Meeting, Approves Report to Advance a 3-Year Strategy
  • First M17 Based Radios Begin Shipping
  • From Hackers to Hams? Sure!
  • Broadcasters Grapple With Global IT Outage
  • RSGB Convention Update 2024
  • International Dog Day Special Event Highlights Need for Rescue Efforts
  • Telford Hamfest

Colin Butler, M6BOY, is the host of the ICQ Podcast, a weekly radio show about Amateur Radio. Contact him at [email protected].

TD-H3 VHF/UHF Radio

News Flash: I found a cheap economical VHF/UHF handheld that I really like. The TIDRADIO TD-H3 is getting a lot of attention from YouTube reviewers. You can think of this as an improved Baofeng UV-5R, with a few key features that grabbed my attention:

Improved Look and Feel: This radio looks like a quality product, much improved over the plastic Lego-style industrial design of the Baofeng radios. It feels and looks solid in my hand. The rubber duck antenna seems higher quality although I haven’t tested its performance.

One Radio, Three Modes: The firmware can be set to operate in three distinct configurations: Ham (transmit on 2m and 70cm ham bands only), GMRS (standard FCC Part 95 GMRS channels) and Normal (which is basically unlocked). You can easily switch between these modes but the memory information does get reset. So in most cases, you will need to reprogram the radio with your favorite frequencies after you change modes. The exception might be GMRS mode which will reset to standard GMRS channels. The flexibility of these three configurations is quite nice: The Ham configuration is great for normal ham operating with no risk of going “out of band.” I can loan out the radio in the GMRS configuration knowing that the user won’t inadvertently transmit on the ham bands. And, of course, the Normal mode provides access to a wide range of frequencies, to be used carefully, abiding by the relevant regulations.

USB-C Connectors: The radio battery has a USB-C connector for charging and a USB-C connector for programming (with Chirp or the TIDRADIO app). This may seem minor, but using a common industry-standard connector is a huge convenience factor. For example, I recently packed my gear for a trip and found that the USB cables I normally carry for my smartphone and tablet will handle the TD-H3 just fine. So there is no need for a drop-in cradle, extra charger or special programming cable.

Video Reviews

Apparently, TIDRADIO gave away a gazzillion radios to ham radio Youtubers and asked them to review the radio, so you’ll find many reviews out there. This one gives a good overview of the radio’s capabilities:

This radio is not quite the One Radio To Rule Them All, primarily because it won’t be convenient to switch between configurations. However, the radio is legal for GMRS and ham use, so that is definitely a plus. Will the FCC object to this kind of flexibility? Who knows, but they haven’t so far.

This video from KS6DAY shows how to switch between the three radio configurations:

Some Problems

Early on, several Youtube reviewers reported high spurious emissions coming from the radio. They fed this information back to TIDRADIO, who responded with a design change and some updated radios to test. They appear to have corrected this problem…the three radios in my possession tested out fine. There have also been some complaints about how a few features work and TIDRADIO has responded with a firmware upgrade to address those issues. So we can give TIDRADIO a good grade for responsiveness but poor marks for releasing a product that was not completely baked. Unfortunately, there are many videos in the etherwebz claiming the radio has problems and it is a challenge to sort through the actual situation today.

To become familiar with the radio, KS6DAY has a series of videos that explain how to use the radio. Lots of good information here:

Summary

As I mentioned, I have three of these radios and may be going back for more. For me, they fit the role of that “spare radio” that is kept in my vehicle, loaned out to other people, or just stored away for When All Else Fails.

73 Bob K0NR

The post TD-H3 VHF/UHF Radio appeared first on The KØNR Radio Site.


Bob Witte, KØNR, is a regular contributor to AmateurRadio.com and writes from Colorado, USA. Contact him at [email protected].

Mode Use by Band Allocation in Canada

Results from the RAC 2021 Survey

What modes of transmission are used in various amateur radio bands? We are aware of the stalwarts of SSB or CW on HF, FM on two meters, and so forth. But some still use AM and there’s the various digital modes, like the venerable RTTY. The weak signal modes implemented under the WSJT-X software (FT8 etc.) have seemed to exploded on the bands. But where? And in what share of reported use by amateur operators?

In this article, I present some of the reported modulation modes used in specific groups of bands for Canadian amateur operators. The mode distribution by band is shown in a pie chart with the percent usage for each band. (Click on the graphic for a larger image.) This allows the reader to quickly identify where a specific mode is used and how diverse modes are for a given band allocation. This depiction does not show how much a mode is used in terms of time, only how the mode’s reported use is distributed across bands.

As a convenience to readers, I have reproduced the bar graph illustrating the percent of Canadian hams reporting the use of each band in an appendix below for quick reference.

In Figure 1, AM and SSB modulation find their traditional bands. One half of the AM use resides in the 80- to 10-meter bands. It is used to a lesser extent in 160-meters, 2-meters and 6-meters with sparse usage in the remaining band allocations. There are contests organized around two meters which may well create some of that use as well as SOTA and related operations. The Magic Band of six meters is open for distance seasonally and sporadically within and outside that season. The use there is likely predicated on the propagation eccentricities of six meters. The microwave bands have small use of AM. Recalling the smaller segment of hams operating in these bands (see appendix), this use may be ardently deployed by a smaller number of active amateurs there.

The use of single sideband usage is unsurprisingly dominated by the 80-10 meter HF bands with six meters coming in a distant second. The six meter and 160 meter bands come in next at 19 and 14 percent, respectively. This is followed closely by two meters (13%). These figures tend to decline sequentially as the frequency band increases. SSB is a frequently used mode, largely in frequency bands that are fairly known to active ham operators.

Turning to the use of CW, it is an original mode for the radio amateur. There are many, many debates as to the status of how much Morse Code is used on the ham bands today. For the first time, this national survey documents both how many hams say they use CW (32%) and where they use it as shown here in this article. As displayed in Figure 2, CW is used in several bands, dominated by HF (80-10 meters) at just over one-third (35%). Two bands bookending HF finds CW a common mode: 160- and 6-meters. This mode’s usage drops off precipitously in the 70cm band, 900 MHz, and 10 GHz bands. These are followed by the 1.2 GHz band with the rest having nominal CW activity reported in this survey.

These national survey results should serve as a benchmark—along with the share of hams reporting the use of CW in the appendix—for future discussions of the status of CW operations, at least in Canada.

The rise of digital data modes (especially the wildly popular FT8) is confirmed in this national survey of hams. Some inferences can be made using signal spots (like PSKreporter) of specific transmissions and reception circuits but they do not represent the broad population of all ham operators, only signals over a transient period. The HF bands, from 80 to 10-meters, are used with digital data modes by over one-third (35%). This is followed by 6 meters (15%) and 160-meters (12%) as well as 2-meters (12%). There is nominal to significant digital data mode use on the rest of these band allocations as well. The 70cm band has, for instance, 6 percent of these amateurs using digital data modes there. Thus, digital data modes are a significant means of communicating in most all of the amateur band allocations for Canada. While HF and nearby frequencies are the prominent areas, it is only 24 GHz that show no reported digital data mode activity as of 2021.

The uses of a modern digital voice mode as well as a traditional data mode, RTTY, are summarized in Figure 3. It is no surprise to the reader who is active on 2 meter and 70cm repeaters that some 85 percent of the relative digital voice usage across bands is concentrated here. The 2-meter band has 44% while the 70cm band has 41% of digital voice use in Canada. The rest reflect nominal patterns, such as the 4 percent with digital voice operations in the 6-meter segment. These specific digital modes (DStar, etc.) are not broken out separately in this survey. The picture of where digital voice modes are used is rather clear in these results.

The traditional data mode of RTTY remains largely an HF-centered transmission style. The 80- to 10-meter bands garner almost three-fourths (71%) with the 160-meter band trailing far behind in second place at 15 percent. The remainder trail off as the frequency goes up the spectrum. RTTY is still used, perhaps during RTTY-allowed contests, but it is used almost wholly on HF and 160 meters.

The final transmission mode presented in this article is slow-scan television (SSTV). Figure 4 contains these results. Like RTTY, it’s largely an HF use pattern (52%). However, for SSTV, two meters has almost a third (31%) of the traffic in this mode. The 70cm band follows (8%) with six-meters right behind (6%). The 1.2 GHz band, gaining in popularity due to more commercial equipment being available, is used by 1 percent. The other slivers in this pie chart round down to zero percent but it does reflect small numbers of microwave-oriented ham operators making use of the spectrum. Will that grow? It will take another replication of this survey a few years in the future to determine if that prospective growth is measurable in such a broad survey like this.

Conclusions

Transmission modes in Canada largely conform to what many readers would expect for the traditional modes of SSB and AM. CW use may be somewhat surprising but should be compared to the prevalence of CW usage by Canadian operators (see appendix). The use of digital voice and data modes is much more diverse in some ways. Digital voice has taken flight on both repeaters but particularly the small, inexpensive “hotspots” that operate via the Internet to connect local operators to other repeater systems worldwide. Digital data modes have exploded through the proliferation of the WSJT-X software and it’s variants. Many hams in the public sphere decry the use of, for instance, FT8, over using voice or CW modes. However, it has made many bands more active as can be seen by others analyzing the online databases of observations such as WSPR, PSKReporter, and the RBN sites. Such is how behavioral change occurs in large, moderately organized groups like amateur radio. It is the collective behavior that shapes the usage of a technological innovation like weak-signal modes and such.

My overall assessment of these results is that the Canadian ham bands are both stable, in the main, and innovating in some frequency bands. I say this partly because the microwave regions have a pluralistic set of modes in use today. This is undoubtedly the result of experimentation as well as competitive contesting or DXing activities. The combination of modes plays well into the future growth of both the operational efficiency as well as the market development for commercial products. The recent release by Icom of their IC-905 transceiver is a case in point.

I hasten to note this. Some readers will invariably say, “But I don’t see that [result]…” Sure, an individual ham operator’s observations either on the bands or elsewhere are a relatively unique way of gathering observations. They are not consistent across observations as people look at the world in differing ways. And, they do not garner insight into a collective national view of what is consistently obtained in a large-scale survey such as that for the RAC Survey 2021. Please bear that in mind with regard to these results as you read them.


Appendix: Band Usage Bar Chart from Full Report


Frank Howell, K4FMH, is a regular contributor to AmateurRadio.com and writes from Mississippi, USA. Contact him at [email protected].

LHS Episode #549: Ham Exam Prep Deep Dive

Hello and welcome to the 549th installment of Linux in the Ham Shack. In this deep dive episode, the hosts go over their own personal histories with studying for the various amateur radio exams. Also discussed are open source software and other online resources for learning information and techniques for passing your ham radio tests. Then we try to pass the exams again as licensed hams. Hilarity ensues. We hope to hear you on the air soon and we also hope you have a great week.

73 de The LHS Crew


Russ Woodman, K5TUX, co-hosts the Linux in the Ham Shack podcast which is available for download in both MP3 and OGG audio format. Contact him at [email protected].

Finding Your Best Crystal Radio ‘DX Diode’


Over the past few weeks I’ve had time to examine many dozens of diodes, mostly germanium, in my crystal radio diode collection. Many of them were removed from equipment built in the '50s and '60s (old diode matrix boards), some are vintage NIB 1N34As while others are modern SMD Schottky style diodes.

 
There are numerous excellent websites such as this one by Dick Kleijer or  SV3ORA's site  ... all describing elaborate ways to determine which diode is ‘the best one’ (the holy grail diode!) for crystal radio work. Most methods use a vigorous, somewhat complex test procedure plus a lot of math, most of which is well beyond my old brain, in attempts to flesh out each diode’s inherent characteristics ... as the sites referenced above illustrate, the simple appearance of a crystal diode belies its complexity and determining  diode behaviours can be more challenging than one might suspect.

My testing procedures were much more basic, and in the end, may hopefully reveal the best diode in my collection. I think one needs to undertake this with the understanding that there really is no overall ‘best' crystal radio diode but rather, only a diode that is best for your particular system and what works best in my system may not necessarily be the best one in yours.
 
My plan was to measure a few diode behaviors, shrink the list of candidates and then compare them against each other in my system's high-Q tank circuit.
 



My first step was to measure Vf or the forward voltage needed to ‘turn the diode on’. This can usually be determined to reasonable accuracy by using the diode test function on most digital multimeters. I’ve always supposed that the diode with the lowest Vf  turn-on threshold would probably be the most sensitive, but is it the only factor? Hopefully my tests would indicate if anything else is in play.
 
The next task was to determine the minimum signal level of a 1000 Hz modulated carrier on 1400 kHz that could be detected by each candidate diode. An RF probe was used to measure the level of signal capacitively coupled into my crystal radio’s antenna tuning stage which was then lightly coupled  into the detector stage, using the diode under test. No importance was given to the actual base level of this signal other than to note the level at which it could first be detected by ear (using sound powered phones) and making sure the coupling distance between stages remained the same for all diodes under test. This allowed me to compare weak-signal diode ‘sensitivity’ to the diode’s previously measured turn-on point or Vf value. Would the diode with the lowest Vf also be the most sensitive when used in a detector circuit composed of complex impedance, resistance, reactance and capacitance values that the test diode would be looking into?
 
The RF signal coupling was adjusted so the injected carrier could be varied between 0 and 10mV as measured on the RF probe. For each diode, the signal level was slowly increased from ‘0’ until the 1400kHz tone-modulated AM signal could first be detected.
 
The lowest 'first detected' signal level was .6mV while the highest level required 3.4mV, representing a pretty good range of diode behaviours. There were 49 different diodes in the test pool.
 
Four of the 49 diodes detected the .6mV signal, six detected the signal at .7mV, and nine first detected the signal at .8mV. The remainder required a still higher level of injected signal. The average level of first detection was 1.2 mV.
 
Of the four .6mV ‘best detectors’, their turn-on Vf values ranged from .15V to .38V while the .7mV and .8mV detectors had a Vf between .181V and .40V!
 
It seemed, not surprisingly, that generally the higher the Vf turn-on threshold, the greater was the level of signal injection needed for first detection … but evidently using the Vf value alone to determine the ‘best diode’ was not the hard axiom I had always assumed it to be!
 
Since a low Vf was not necessarily needed for good sensitivity, would there by any other tests that might indicate best performance?
 
The next trial was to measure actual diode currents in my hi-Q detector while receiving a lightly-coupled constant level input signal (1400kHz) to see how this value related to Vf. Measured diode currents (Id) varied from 9uA to 14uA for the same level of input signal, with the diode having the lowest Vf also producing the lowest current level ... hhhm! There was more to this than I expected, but generally, the lower valued Vf diodes tended to produce the most current and consequently the louder headphone signal … but not always! Some diodes with a Vf as high as .46V yielded high currents!
 
This now begged the question, “Does the higher current diode with a higher turn on (Vf) prove to be a better overall performer than the diode that turns-on early but produces a weaker signal?” What is the relationship between diode current and weak signal detection?
 
The next step was to express the relationship mathematically by calculating the ratio between the diode’s Vf and the level of diode current  (Id) measured in the previous test (Id / Vf). Each diode could then be assigned a number (Vdx) that might possibly indicate it’s true performance potential in my own system.

The diodes with the highest Vdx values would then be A-B tested under real receive conditions to see if any (or just one!) particular winner(s) might emerge … and if Vf was as critical as initially believed.
 

The Vdx values proved most interesting and seemed to account for some of the anomalies noted in earlier measurements with some of the higher Vdx values coming from diodes not necessarily with a low Vf. I’m hoping that this sorting concept properly takes into account both turn-on level (Vf) and current level (Id), since a higher level in either number will compensate for a lower level in the other. Vdx values ranged from 23 to 66, with seven diodes in the higher 53-66 range.



Click Image For Larger View


All of the 49 diode's test parameters were put onto a spreadsheet and listed in order of their Vdx value.


Click Image For Diode Spreadsheet Data


The highest Vdx assignment of 66 went to my 40-year junkbox resident, a JHS Sylvania 1N3655A microwave mixer diode. It will be interesting to see if it really is the best of the lot! Although it did not produce the loudest signal (Id) compared with others, its Vf turn-on was an impressive .181V and its weak-signal detection level was good although not the lowest. A couple of the UHF diodes exhibited the interesting behaviour of picking up the UHF data stream 'clicks' from my nearby wifi booster. The 1N3655A was one of them.
 
1N3655A Vf = .181V Id = 12uA Vdx = 66
   

Diode #2, with a Vdx of 62, is a mystery diode with a very low Vf of .197V. It was slightly louder and oddly enough, dug down slightly further than the 1N3655A, which had a slightly lower Vf. Although I don’t recall specifically, I suspect the diode may have been removed from a VCR front end many years ago.
 

Mystery diode  Vf =.197V  Id = 12.2uA Vdx = 62
 

Diode #3 with a Vdx of 61 is a modern SMS7630 Schottky microwave detector diode in an SMD package. Although it did not produce a competitive level of loudness (Id) in the diode current test, its shockingly low Vf turn-on of .147V and weak-signal detection threshold were the best of all diodes tested. Before testing, all SMD diodes were mounted on small PC boards in order to attach leads.
 

SMS7630 Schottky  Vf = .147V  Id = 9uA Vdx = 61


Diode #4 (Vdx of 60) is an ISS98, another modern Schottky microwave detector. I recall seeing this diode recommended for good performance in an FM crystal radio detector. Its sensitivity level was excellent.
 

ISS98 Schottky Vf = .211V  Id = 12.5uA Vdx = 60


Diode #5 (also with a Vdx of 60) appears to be a normal germanium of unknown type. I suspect it was used as an RF mixer since it was found on a small printed circuit board with three others, connected in a diode ring configuration typically seen in balanced RF mixers. It produced high current as well as good weak signal capability. 
 

Mystery diode Vf = .22  Id = 13.2uA Vdx = 60


Diode #6 (Vdx of 55) also looks like a germanium of unknown type with a body striping of gray-white-green-gray. If the last band is ignored, this could be a 1N895, a UHF germanium diode. It shows the typical internal cat-whisker type of junction often seen on the 1N34 germaniums.
 

Mystery diode Vf = .238V  Id = 13uA Vdx = 55


Diode #7 with a Vdx of 53 is marked as a ‘95481’ on a green body. It had excellent sensitivity and produced a strong signal (Id), elevating it to the top tier to be looked at more closely.


'95481'  Vf = .246V  Id = 13uA Vdx = 53


Diode #8, another germanium mystery, earned a Vdx of 49 due to its fairly high Id level.



Black 'T'. Vf = .258V  Id = 12.5uA  Vdx = 49


The rather beat-up looking Diode #9 is marked with what appear to be house numbers, '1846' and '6628'. I believe this was pulled from an old portable radio's FM section many years ago. Interestingly, like some of the UHF mixer diodes, '1846 / 6628' detects my high speed modem data stream clicks. Additionally, this tortured specimen produced the highest level of signal among all 49 diodes, with an Id of 14uA.


Vf = .294V  Vdx = 48 Vdx = 14 (Schottky?)


Diode #10 appears to be the brother of Diode #8 with a Vdx of 48. Although it has a lower turn-on point and was a better weak signal detector, it did not produce as much Id as its sibling, dropping it one notch lower on the list. Like its brother, it also has the mystery 'T' marking. Both are most likely unmarked 1N34As.

Vf = .252V  Id = 12 Vdx = 48


As well, three other diodes garnered my interest. Although they ranked lower than I expected, all had previously been found to be good detectors in my system. Their lower ranking may be a hint that my system of grading is not a valid method of determining best performance. All three will be given a harder look in the upcoming elimination tests.

The first is the germanium FO-215. Often touted as 'the holy grail' crystal radio diode but I have never found it to be particularly outstanding. Maybe my system has a lower Q than it really needs in order to show its stuff. This diode is shown on the bar graph above as #11. During testing, it appeared much less capable of weak signal detection than most others but its low Vf and high Id elevated its overall ranking.

Vf = .272V  Id = 13uA  Vdx = 48


The second diode is the Soviet-era D18, a military-grade germanium in a glass '50s-style package. I have previously found it to be a very good detector but its high turn-on level lowered its ranking. The D18 appears on the bar graph as #12.



Vf = .366V  Id = 12.2uA Vdx = 33


The third diode is a vintage Sylvania 1N34 from the 50s and likely one of the first 1N34s to be manufactured. Although it produces a loud signal, its Vf was higher than expected. As I recall, it was salvaged from an old parted-out Heathkit.  It appears on the bar graph as #13.


Vf = .335V  Id = 13uA  Vdx = 39


As mentioned earlier, one can measure and calculate a large amount of data for crystal diodes while they sit passively on the bench but they really need to be mounted, tested and compared in the actual system in which they will be used. Comparing diodes 'A-B' style in real time with weak signals may be better than any measurements made on a diode being bench-tested. 

Will a new ‘holy-grail’ emerge from the pile? This type of testing requires a lot of careful listening so time will tell. 

Testing will be ongoing over the summer / fall months ... stay tuned for the final results, hopefully in time for the fall DX season!

Steve McDonald, VE7SL, is a regular contributor to AmateurRadio.com and writes from British Columbia, Canada. Contact him at [email protected].

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