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tpreitzel 21-03-2013 02:54

De-Hamifying DRM (Digital Radio Mondiale)
 
This thread's purpose is primarily about simplifying reception of DRM30 on the shortwave bands as much as possible to encourage listeners without a background in radio. Reception of DRM30 on the medium wave band (AM) and DRM+ on the frequency modulation band (FM) aren't nearly as problematic due to relatively local sources compared to distant sources for DRM30 on the shortwave bands. Effective solutions will largely apply to all bands utilizing DRM30 and DRM+. Before posting, please evaluate your biases (indoctrination) to keep any recommendations as simple as possible for the aforementioned group. Assume other international alternatives, both broadcast and non-broadcast, to DRM30 do NOT exist. Please avoid esoteric language such a Q code, etc.

I have some questions for this group:

1. Where do you reside while listening to broadcasts? Include city, country, and type of residence, e.g. home, car, etc.
2. Do you know if the materials used in building your residence greatly hinder reception of local broadcasts such as TV?
3. How much time can you allocate to receiving broadcasts?
4. Can you accept the possibility of not receiving a scheduled broadcast or part of one?
5. Can you spare at least a couple hundred dollars to buy necessary equipment?
6. Are you familiar with installing and running software on a computer beyond browsing the InterNet?
7. Do you have space and permission to erect an external antenna outdoors if needed?
8. Do you understand the meaning of UTC as applied to time?
9. What factor motivates you to receive broadcasts in one of the DRM standards, e.g. cleaner audio, text, graphics, video?
10. Who can you ask for local help if needed?

I have a question for broadcasters:

Can a creative and thorough application of the DRM standards help a listener to de-hamify the experience of receiving such a broadcast? A few of a vast number of examples include periodic transmission of sufficiently detailed maps so listeners can pinpoint their location within the coverage area of the transmitter, optimal configurations based on season, advisories and rebroadcasts where appropriate due to future and past interruptions in schedule (intense solar and geomagnetic activity), etc.? Ideally, a listener shouldn't have to switch mediums for additional information on a particular broadcast as another medium may not be available.

I have a question for manufacturers of gear enabling reception of DRM broadcasts which includes antennas:

How can you continually improve your product's quality, availability, functionality, and performance to help a listener to de-hamify the experience of receiving a DRM broadcast? Quality, availability, functionality, and performance imply reliability, cost, distribution, form (interface), size, capability, etc.

I'll add more to this thread as opportunity arises.

Aetheradio 21-03-2013 08:41

Well thats a surprisingly interesting set of questions, so heres my perspective:

1. Where do you reside?>> In a wooden house in a town in New Zealand, there is a lot of radio noise coming off the power lines and telephone lines (internet ADSL, VDSL) here, making conventional radio reception increasingly difficult.

2. Do you know if the materials used in building your residence greatly hinder reception of local broadcasts such as TV?>> A minority of houses are now being built using steel framing. But this wont affect TV in NZ because its all digital now, carried on either UHF or direct to home satellite. In both cases, external aerials are used for reception. Apartments are prewired with community antenna distribution.
3. How much time can you allocate to receiving broadcasts?>>Most of the time, if its radio and portable such as built into cellphone, car radio, home stereo tuner or AV receiver.
4. Can you accept the possibility of not receiving a particular broadcast or part of one?>> No, I find a better channel fairly quickly. Of course, a DRM radio will do this automatically, and remain delivering the exact same program to me via a better frequency. I suspect the public do not know this.
5. Can you spare at least a couple hundred dollars to buy necessary equipment?>> Well thats much less money than most youth spend on cellphones and laptops, and yes i could spend that money but nothing is available. Nothing.
6. Are you familiar with installing and running software on a computer beyond browsing the InterNet?>> Yes but I dont recommend that method for someone who wants to get a better radio.
7. Do you have space and permission to erect an external antenna outdoors if needed?>> Yes but its not necessary for shortwave reception, a piece of wire thrown out the window, or buy or make an indoor loop, or use the active antenna that comes with a real shortwave ("world band radio")set.
8. Do you understand the meaning of UTC as applied to time?>> Yes, it means I have to get up at 4am to listen to "The Disco Palace" LOL
9. What factor motivates you to receive broadcasts in one of the DRM standards, e.g. cleaner audio, text, graphics, video?>> because I can. - And I believe its the best system available to do those things.
10. Who can you ask for local help if needed?>> There are a couple of other Shortwave Listeners in NZ who run similar websites

I have a question for broadcasters:

Can your shrewd use of the DRM standards help a listener to de-hamify the experience of receiving such a broadcast?>> I dont think broadcasters understand this question. Although our Radio Broadcasters Association do support the provision for DRM as a standard for future, none have started domestic transmission.

I have a question for manufacturers of gear enabling reception of DRM broadcasts which includes antennas:

How can you continually improve your product's quality, availability, functionality, and performance to help a listener to de-hamify the experience of receiving a DRM broadcast? Quality, availability, functionality, and performance imply reliability, cost, quantity, form (interface), size, capability, etc.>> In my opinion only 2 manufacturers got close to a good product, Sarapulsky and MSway. Unfortunately we didnt get the opportunity to buy them. NewStar is also highly commended for achieving what they have, however none of these radios meet the current DRM minimum performance standards - ie. they dont have DRM+ capability, let alone a high end model with Diveemo.
we have a saying here "dead in the water" - like the DAB radio I have in the office, must have cost a lot, and doesnt even pick up AM or FM stations, and cannot tune into the DAB+ station up the road, that went on air about 2005.
I think consumers dont like getting burned twice in the same decade. If you want to sell a radio, make sure it can pick up the basic worldwide standards. It doesnt cost much. The digital process chipsets available for radios are already there and have digital demodulation and Shortwave tuner, the Pioneer car radios sold here have this in them but the retailers dont know it, so the buyers dont ask for it. In theory when they add the decoding chipset required for the IBOC market it will allow the inclusion of DRM at essentially no extra cost.

tpreitzel 21-03-2013 09:13

Aetheradio,

Maybe just contemplating and then communicating answers to these and other questions can serve as a bridge of communication between broadcasters, manufacturers, and listeners.

More later ...

tpreitzel 06-04-2013 22:20

Add periodic transmission of accurate and comprehensive schedules of ALL DRM broadcasts from a particular broadcaster. Broadcasters, STOP viewing DRM as merely a higher quality version of analog and START using DRM's digital capability to inform the listener. The current situation of forcing the listener to search through reams of data from inaccurate (including outdated) and incomplete schedules is ABSURD and UNNECESSARY.

F1BJB 08-04-2013 14:55

Hi
In short my opinion is that to dé-hamify radio reception it must be computerified.
For ages I used my computer to watch and record TV.
Set top boxes are a very poor and costly alternative only justified by payTV.
The ideal radio receiver for me is a black box connected to aerials on one side
and to a local network on the other.
Self contained receivers should be network compatible for updating,recording
and printing.
Able to deliver and listen to a network stream too.
As far as my receiving conditions are concerned I can say that I am lucky.
This and the use of a low cost SDR receiver are the reasons for my late
come back to short and medium wave listening.

tpreitzel 08-04-2013 20:52

Broadcasters could even transmit periodic surveys digitally which could then be sent to a printer on a local area network (LAN) for mailing. Personally, I have no problem with networking a receiver to a LAN. However, I, personally, wouldn't want my receiver connected to a wide area network (WAN) such as the InterNet, e.g. RadioDNS, which might possibly identify the location of the listener. * Risk of identification of location rises with transmission. The WAN should exclusively be a connection by radio with the broadcaster bearing the sole responsibility and risk for informing the listener. Until the technological and legal aspects of radio allow for unlicensed full duplex communication (greater risk and impossible over longer distances?), a listener can always use postal mail, telephone, radiograms, InterNet, etc. for feedback to a broadcaster when needed. Notice the listed feedback mechanisms involve a third party, the owner of infrastructure, which can allow or disallow communication between two parties. Automating radio functionality as much as possible is logical as systems become increasingly capable and complex.

* See the thread, "Why Shortwave is 'Hear' to Stay"

F1BJB 09-04-2013 08:47

Yes I am aware of the risks of connecting anything to the Internet.
I was more thinking of the possibility to access the receiver with various
WIFI devices and also of locating it in a quiet place.
The main risk with broadcasting is jamming not confiscating receivers.
Here the Net comes to the rescue :-)
It's hard to jam all the recordings that appears instantly here.
Have you tried ?:
http://websdr.ewi.utwente.nl:8901/
IMHO a nice example of modern age radio although it doesn't do DRM yet :-)

tpreitzel 09-04-2013 10:29

Quote:

Originally Posted by F1BJB
The main risk with broadcasting is jamming not confiscating receivers.
Here the Net comes to the rescue :-)


True, as long as receivers aren't using a hybrid technology like RadioDNS.

Quote:

Originally Posted by F1BJB
It's hard to jam all the recordings that appears instantly here.
Have you tried ?:
http://websdr.ewi.utwente.nl:8901/
IMHO a nice example of modern age radio although it doesn't do DRM yet :-)


Firefox 18 just hangs on the aforementioned website's script. My version of Firefox uses Gnash instead of Adobe's plug-in for flash content and java is a buggy mess since Oracle gained control of Sun Microsystems ... I'm unsure of the actual cause of Firefox's freeze since the script doesn't complete.

Anyway, I'm rapidly tiring of buffering and banned proxy servers on the InterNet. Give me ole' time radio with a new twist, DRM30 and Diveemo (low frame rate video on DRM30) since I can't have DRM+ evidently. Will Diveemo ever be standardized, I wonder?

tpreitzel 19-06-2013 07:09

With the persistent problem of inaccurate schedules in DReaM, I recommend the developers of DReaM remove the code dealing with retrieving schedules altogether. FORCE broadcasters to assume their responsibility of periodically transmitting their complete seasonal schedules digitally. This responsibility of scheduling lies ideally with the broadcasters, not ANYONE else. Broadcasters think hybrid solutions, e.g. forcing listeners onto the InterNet for information, are satisfactory. The latter approach is NOT satisfactory. The latter approach is simple laziness on the part of the broadcaster. Maybe, the listener doesn't have personal access to the InterNet. Instead of broadcasters FORCING listeners to switch mediums to vainly search for accurate schedules, why not FORCE broadcasters to do their damn job of informing their listeners?

See my previous comments, broadcasters, as you're failing miserably to inform your listeners!

F1BJB 23-06-2013 08:06

Hi
I agree .
AFAIK the data capabilities of DRM are not very useful.
Using them for schedules and frequencies would be a good idea
Another thing missing is the possibility to record the full transport stream.
This would allow later computer processing of it like printing of time tables or QSL cards.
One could even imagine merging several recordings of the same transmission
from various places in order to correct errors.

tpreitzel 17-09-2013 04:44

xHE-AAC
 
The new extended HE-AAC v2 codec is a major development in simplifying the decoding of quality DRM broadcasts for the average listener. Until DRM broadcasts are much more plentiful, the majority of broadcasters should adopt 16 QAM for the MSC, lower their bit-rates to ~ 14 kbps and use xHE-AAC. Do it, broadcasters!

tpreitzel 15-10-2013 06:22

A nice article outlining the need for appropriate ergonomics.

http://www.drm.org/?p=2529

tpreitzel 15-11-2013 06:25

Reception at my location over the past two weeks has been poor due to the vast number of solar flares and their concomitant effects on the geomagnetic poles of the earth. Do broadcasters honestly expect their listeners to tolerate the inability to receive their broadcasts for two weeks? Clearly, nearly ALL digital broadcasts are demonstrably underpowered in less than ideal conditions. Furthermore, more broadcasters along with the HFCC need to allocate more spectrum of the 60, 49, and 41 meter bands to digital broadcasts as well. Either broadcast digital in the 60, 49, and 41 meter bands or be exiled to the 13 meter band! ;)

Since beginning to listen to shortwave a couple of years ago, this stretch is the worst that I've encountered thus far.

Linux-DRM 15-11-2013 07:27

Prop
 
Yes, propagation has taken a battering recently (I blame the sun :) ).
'Low powered' DRM transmitters are borderline for me right now unless they are within a 1500km radius, more than likely due to my high latitude and high occurrences of solar flares.

I work on the premise that if you can't receive a shortwave broadcast with basic equipment it defeats the purpose (for me at least).

Cap

DRM-OM 16-11-2013 08:03

Quote:

Originally Posted by tpreitzel
ALL digital broadcasts are demonstrably underpowered in less than ideal conditions.

Note that total DRM power is limited to max. 40% of analog CARRIER only power for technical reasons. So don't expect more power - the operator would have to upgrade the equipment completely, not just buy an exciter.
This is a feature.
DRM is "sold" to transmitter operators with the arguement to save energy = money!

b.t.w.
Quote:

Originally Posted by http://www.drm.org/?page_id=105
In France, where the regulatory authorities have already approved DRM as the digital successor to Medium Wave, two transmitters will cover the entire country.

sorry, but this is ridiculous

tpreitzel 16-11-2013 09:07

Quote:

Originally Posted by DRM-OM
Note that total DRM power is limited to max. 40% if analog CARRIER only power for technical reasons. So don't expect more power.
This is a feature.
DRM is "sold" to transmitter operators with the arguement to save energy = money!


I'm aware of that artificial limitation, but it's precisely that technicality that needs review in scenarios consisting of less than favorable atmospheric conditions. Is it possible with modern detection systems to dynamically allow transmitters to adjust output power along their targeted path under adverse conditions? I don't know, but the current situation certainly is far from optimum as the sun doesn't allocate power statically.

Linux-DRM 16-11-2013 11:04

DRM Power
 
Yes, this is true, it is a selling point of DRM to operators, saying that you can run less power with the same listener impact (in theory) and I understand the technical reasons (interference etc).
In reality it does not translate to that unless good receivers/antennas are used with an excellent signal to noise ratio but this unfortunately is only afforded by enthusiasts...like us...consumers struggle to receive low power DRM transmissions which has been proved on a number of occasions (by me and others). When I had the DR111 (and currently test using the MR 27024) I can/could only receive AIR, REE and RRI consistently using the whip under stable propagation conditions, all these stations use power >50kW.
Sure, run lower power but not so low that the signal can't be received by the listener. DRM is either there or it isn't, people are not going to sit and listen for 10% audio (where 90% is silent).

Cap

Quote:

Originally Posted by DRM-OM
Note that total DRM power is limited to max. 40% if analog CARRIER only power for technical reasons. So don't expect more power.
This is a feature.
DRM is "sold" to transmitter operators with the arguement to save energy = money!


DRM-OM 16-11-2013 11:23

Quote:

Originally Posted by Linux-DRM
Sure, run lower power but not so low that the signal can't be received by the listener. DRM is either there or it isn't, people are not going to sit and listen for 10% audio (where 90% is silent).

A former staff member of the frequency management of a big broadcaster once told me that if there is a minimum field strength for undesturbed conditions you have to add an overhead of >20dB (which translates to a factor of 100 in power) to cope with atmospheric conditions like flares and fading etc. to ensure a reliability of 98% or above - "that's a minimum, otherwise people will switch off"
If these days 50kW is not enough for satisfactory reception - noone will ever run up to 5MW DRM on shortwave!!!

Linux-DRM 16-11-2013 16:34

I never said 50kW was not enough power to satisfactorily receive DRM, it was a value based on the reception of a very limited number of DRM stations in a consumer environment using a whip antenna (not the best antenna in the world, but one used on nearly every portable radio and probably the only antenna used by a non-enthusiast consumer).
Maybe living in the northern latitudes is not the best place to be, I am sure tests further south would be more fruitful :)

Cap

Quote:

Originally Posted by DRM-OM
A former staff member of the frequency management of a big broadcaster once told me that if there is a minimum field strength for undesturbed conditions you have to add an overhead of >20dB (which translates to a factor of 100 in power) to cope with atmospheric conditions like flares and fading etc. to ensure a reliability of 98% or above - "that's a minimum, otherwise people will switch off"
If these days 50kW is not enough for satisfactory reception - noone will ever run up to 5MW DRM on shortwave!!!


DRM-OM 16-11-2013 17:59

Quote:

Originally Posted by Linux-DRM
Maybe living in the northern latitudes is not the best place to be, I am sure tests further south would be more fruitful :)

If "UK" means "United Kingdom" - is that such far north?

But in any case these facts from the BBC Devon MW report apply to any DRM transmission:
Quote:

Second, whilst the night‐time coverage of DRM is greater than the equivalent ‘clean’
AM coverage, it is apparent that the technical limit of AM coverage is not the same
as the limit at which listeners will stop listening to it. Thus, listeners will tolerate
much more cross‐talk from interfering sources than is catered for in international
planning standards, even more so if it is content that they especially wish to hear.
Similarly, listeners will listen to field‐strengths well below the international limits
even if the result is audio which is covered in static and noise.(...)

Third, the failure mode of DRM is – as with all digital systems – dramatic. The
transition from working perfectly to not working at all is fairly sudden, even
considering that DRM is designed to provide a measure of graceful degradation for
longer than some other digital systems. Thus, listeners who previously received a
degraded, interfered‐with AM service at night now received nothing. At other times,
given the dramatic fluctuation in interfering signal strength, listeners found the radio
services dropping out – or burbling, or becoming ‘metallic’ in sound3 – and taking
some while to restore, despite any actions they took.

Linux-DRM 16-11-2013 19:08

Yes, it is, far north of the UK.
I am very familiar with Project Mayflower.

Quote:

Conclusions

The Plymouth trial tested a particular situation: a one‐for‐one conversion of an
existing service on an existing assignment from AM to DRM, subject to the required
international parameters. As a result, it turned up a number of issues for DRM’s use
in the UK if deployed in this manner. It is clear, though, that all of the problems
experienced from a technical perspective can be overcome if there was a willingness
to increase the power of the transmissions, add more medium‐wave transmitting
stations to the network, and re‐plan the use of frequencies.



tpreitzel 14-02-2014 15:26

To simplify receiving DRM broadcasts for listeners new to digital shortwave, install equipment for a location which allows one to meet these basic requirements for decoding audio:

A broadcast with a Main Service Channel (MSC) of 64 QAM:
1. With some minor variance, receiving equipment must maintain a Signal-To-Noise Ratio (SNR) of at least 16 dB for consistent decoding.

A broadcast with a Main Service Channel (MSC) of 16 QAM:
1. With some minor variance, receiving equipment must maintain a SNR of at least 10 dB for consistent decoding.

Unfortunately, most current broadcasters use 64 QAM with the AAC+ codec for the MSC. Some potential broadcasters of DRM then have the gall to complain about the ineffectiveness of DRM. Why not employ a configuration, i.e. 16 QAM for the MSC, suitable for noisier conditions since most digital broadcasts on the shortwave bands are underpowered? Naturally, these SNR's depend on usage of Mode B. With Mode A, add 6 dB to the minimum SNR.

tpreitzel 17-03-2014 04:46

Cost
 
As an aid in de-hamifying DRM, let's specify the overall cost to the SWL for listening to digital broadcasts. Most potential listeners won't object to paying ~ $200 (current value and exchange) total for the necessary equipment to receive digital broadcasts on the shortwave bands. Erecting artificially high standards for reception will continue to relegate DRM to a limited group of people, e.g. licensed "hams". Although we're not quite to the point of reducing the total financial outlay to $200 for listening to digital broadcasts on the shortwave bands, it's a reasonable and attainable goal in my opinion. When the total financial outlay to the SWL is ~ $200 for the necessary equipment and broadcasters start using robust configurations employing a MSC of 16 QAM or the power levels are increased to 60% of analog for digital broadcasts on the shortwave bands, then and only then will the potential of digital broadcasts be realized on the shortwave bands. Thankfully, DRM now has a sufficient codec in xHE-AAC and a few broadcasters like VOR, Vatican, and VON are employing sane configurations to fully realize the potential of DRM on shortwave. Given the current limitations on power, I'm convinced that more digital broadcasters on the shortwave bands will soon follow the leads of the aforementioned broadcasters.

tpreitzel 09-04-2014 04:25

Another barrier to popularizing the use of the shortwave bands is KNOWLEDGE. Frankly, if potential listeners have to first learn vast amounts of technical information to use a technology, it will NOT be used by the average person. Shortwave NEEDS the average person with non-technical skills, not another licensed "ham" spouting esoteric and largely irrelevant information. Shortwave NEEDS diverse content produced by a diverse audience. Confine the SWL's technical knowledge to primarily learning a radio's interface. The rest of the burden should primarily fall into the laps of the manufacturers and broadcasters.

tpreitzel 28-03-2015 02:33

While testing coverage of my LPDRM broadcast today, I meet a lady along the route. She was genuinely interested in my project. As I was walking along the fringe area, my DR111 wasn't decoding audio at the point of our initial meeting. We decided to walk together for a few blocks as I discussed DRM in relation to my DR111. Eventually, my DR111 started to decode audio from my broadcast shortly before we departed. She appreciated the experience. This lady is a typical consumer with little technical skill beyond operating a radio. Our discussion focused on the capability of digital radio and she left impressed, but somewhat overwhelmed by the apparent complexity. Digital radio, including DRM, should strive to reach such a potential customer, but the interface of the radio must be radically simplified and robustness of broadcasts improved. The DRM standards are sufficient, but deployment for the typical consumer still requires much work.

Aetheradio 28-03-2015 21:28

Quote:

Originally Posted by tpreitzel
.... she left impressed, but somewhat overwhelmed by the apparent complexity. Digital radio, including DRM, should strive to reach such a potential customer, but the interface of the radio must be radically simplified and robustness of broadcasts improved. The DRM standards are sufficient, but deployment for the typical consumer still requires much work.


Sort of covered in earlier posts on this thread, robustness of broadcasts is entirely controlled by power levels and frequency planning. It can be done, but broadcasters dont see any money in it and the reality is the transmitters need to be provisioned at 10x existing capabilities of analog levels. Its all in the fine print of the DRM trials and papers hosted on the consortium website. one doesnt get that impression reading the 'public' sections, though.

I think you are right, its deployment for the typical consumer that needed the work. Probably too late now. Consumers expect that the radio in their new car or cellphone / tablet / DroidTV stick will get the signals they want to hear. Despite best efforts and encouragement (by the Consortium) nothing has become available for a consumer to happen upon that capability. The only manufacturers that were capable of crafting a consumer - useable product have abandoned their plans, although still listed as DRM members.

That leaves the Avion as possibly the only consumer radio to be sold now.
http://drmnainfo.blogspot.co.nz/2015...nstration.html

But this one is never going get consumer traction. doesnt look simple to use. If AIR ever accept it for their tender, it will be because of the AM stereo requirement. They have that capability in their new transmitters - NX series.

tpreitzel 12-05-2015 20:20

A significant number of broadcasters suggest that most media will eventually be streamed on demand from users. Personally, I think the future of broadcasting isn't nearly so clear. Ubiquitous, illegal spying will play a significant role in limiting the appeal of duplex communication. Notice how governments promote projects such as "Big Whoop" which smacks of former fascist tactics that employed Brownshirts to snoop for the regime in power. Simplex communication will continue to provide users some privacy amidst such technological abuse. Media viewed on demand will affect video more than audio anyway.

In the frenzied pace of today's world, the influence of websites like the Drudge Report demonstrate the power of brief and current sources of information. A broadcast via radio which utilizes DRM can effectively duplicate the format of the Drudge Report. Global24 should take notes. Although broadcasts via radio in the future will eventually become more specific and briefer than historical broadcasts, simplex radio is just too robust and private to succumb to sources of media delivered on demand and therefore susceptible to ubiquitous spying. The future for simplex digital radio as delivered both domestically and internationally is bright indeed. As I've stated previously, the main problem with the adoption of DRM lies squarely with the unimaginative thinking and poor configuration of broadcasts by broadcasters, not the standards.

tpreitzel 02-06-2015 20:44

I was listening to a fairly strong, analog shortwave broadcast with minor fading on my SDR-4+ last evening. In quieter environments, e.g. sleeping, loudness plays a significant role in the clarity of reception. Even with a strong signal, the minor fading of an analog shortwave signal is problematic. Digital Radio Mondiale (DRM) has no such problem. If a listener values retention of his hearing, I don't recommend headphones on analog shortwave broadcasts at all. Shortwave broadcasters need to adopt DRM now!

As for shortwave broadcasters insisting on the availability of dedicated DRM receivers before starting regular DRM broadcasts, such insistence is basically a poor excuse for not doing so. True, dedicated receivers would help widen the potential audience, but nearly everyone has a personal computer or access to one with freely available software such as DReaM for decoding of the digital signal. Except for some remote villages, probably most African listeners even have access to a computer where a digital broadcast could be received, decoded, and disseminated locally. Again, shortwave broadcasters need to adopt DRM now!

F1BJB 03-06-2015 09:15

Quote:

Originally Posted by tpreitzel
I don't recommend headphones on analog shortwave broadcasts at all.

I made the same observation.
I think 2 factors are involved:
SDR are totally flat between 10Hz and 300 Hz it is not the case of a classic BCL
Broadcasters try to compensate for the BCL case.
Some HIFI SSB signals even try to compensate for the roll off of the crystal
filter by concentrating 90% of the power below 300 Hz :mad:
A tip I use is that I listen on a TV set fed by HDMI and there is an equaliser
in the TV set .
And no headphone connector :)

tpreitzel 04-06-2015 21:49

Quote:

Originally Posted by F1BJB
A tip I use is that I listen on a TV set fed by HDMI and there is an equaliser
in the TV set .
And no headphone connector :)


Although not as flexible, your method is much operationally simpler than my current method involving several pieces of software. Your method is in keeping with the spirit of this thread and I recommend it. Few potential listeners to broadcasts on shortwave will adopt a method as complex as mine. If only broadcasters would use robust configurations of DRM on shortwave and thereby remove such temptation. DRM solves very important problems with analog shortwave.

Good suggestion!

In the following link, none of the software is calibrated as I was merely demonstrating the complexity of listening to analog shortwave with sufficient fidelity. If you look closely, you'll notice that I should have swapped the I/Q in DReaM. I used DReaM for the noise reduction. I used Jamin' for the equalization. I used Quisk for the tuning. The developers of Quisk need to remove the requirement to install Pulseaudio. I literally stripped the Pulseaudio code from the source so it would compile on Slackware. In DReaM, I selected the cleanest sideband to increase clarity since the 10 kHz signal was weak and low in volume. The results were very good, but complicated. In all honesty, I wouldn't listen to analog shortwave for any length of time if DReaM hadn't included the Speex noise reduction.

http://tinypic.com/view.php?pic=2d7y7pj&s=8

Can the maximum file size for attached images be slightly increased please? 100 kB is too low for modern displays. A maximum of 150 kB would be much better.

tpreitzel 20-06-2015 19:31

I received my analog AM stereo transmitter, ASMAX-1, recently from ASPiSYS in Greece. DRM on the MW band will be pressed hard to achieve such quality. On a high quality receiver, e.g. Meduci MW-2, the sound from the ASMAX-1 is awesome, except for one thing, hum. ;) I'm sure that I can solve the problem with hum eventually. I'm continuing testing.

However, except for the quality of the sound (mainly useful for musical sources), the overall experience for a listener is significantly better with the DRMAX-1 transmitter or DRM on the MW band. DRM is just too flexible, solves significant problems with receiving analog broadcasts, and is potentially much simpler to deploy for the listener even on the MW band. On shortwave, the disparity between DRM and analog is even greater. I write from experience. I do confess, however, that AM stereo can blow one's mind with quality WHEN interference is eliminated and a quality receiver is used.

Aetheradio 20-06-2015 22:06

good results. Do you have any comparison recordings of RNZI when they broadcast DRM and AM simultaneously using their same power (PEP capability wise ) transmitters? I can always get a fair AM signal but rarely get any audio from the DRM - being located too close. Its worse on the car radio so I use Radio Australia there. But they dont seem to do DRM to compare.

I've updated the Blog with my last AM stereo vs. DRM tests, also plagued by some intermittent transmitted noise - which turned out to be a faulty 24v switchmode plugpack I was using for the carrier generator.

http://radioalchem.blogspot.co.nz/20...g-pattern.html

tpreitzel 22-06-2015 19:29

Quote:

Originally Posted by Aetheradio
good results. Do you have any comparison recordings of RNZI when they broadcast DRM and AM simultaneously using their same power (PEP capability wise ) transmitters? I can always get a fair AM signal but rarely get any audio from the DRM - being located too close. Its worse on the car radio so I use Radio Australia there. But they dont seem to do DRM to compare.


Not at the moment since I'm living in a basement apartment. Other members of this forum might, though.

Quote:

Originally Posted by Aetheradio

I've updated the Blog with my last AM stereo vs. DRM tests, also plagued by some intermittent transmitted noise - which turned out to be a faulty 24v switchmode plugpack I was using for the carrier generator.

http://radioalchem.blogspot.co.nz/20...g-pattern.html


Thanks.

I've ordered a hum eliminator in an attempt to kill the hum on my AM stereo broadcasts. When I do, I'll post some files comparing reception of AM stereo and DRM at very low power levels. I'm pretty sure that AM stereo will only work acceptably at very short distances with such low power. As it is, I had to increase the RF output from the ASMAX-1 transmitter significantly in an attempt to match the range of the DRMAX-1 transmitter. AM stereo sounds great at short range with my Meduci MW-2. Since the Meduci MW-2 isn't a very sensitive receiver, I lose the AM stereo signal beyond ~ 50 feet from the antenna. I'm currently looking for a more sensitive AM stereo receiver for testing my ASMAX-1 transmitter, but I suspect a robust DRM transmission will be superior in nearly every way at such low power levels.

tpreitzel 27-08-2015 20:48

If the current geomagnetic storms in the northern hemisphere are an example, only the Vatican's robust transmissions to the HFCC 2015 conference will prove remotely reliable over the week. Hopefully, attendees at the HFCC conference will finally get the same memo that the Vatican received years ago, i.e. use a MSC of 16 QAM on shortwave.

PhilipOneL 28-08-2015 12:12

Quote:

Originally Posted by tpreitzel
If the current geomagnetic storms in the northern hemisphere are an example, only the Vatican's robust transmissions to the HFCC 2015 conference will prove remotely reliable over the week.


Yesterday, Thurs 28/8/15, I caught the Vatican's DRM b/c on 11890kHz 2230 -2300 UTC. I don't know whether they were aiming towards me (in eastern Newfoundland, Canada), but their power (250 kW) probably sent it in all directions. I'm listening right now to the recording I made on the MR27024 (with an outdoor eight-metre wire aligned W-E). The signal was best around 2240 with very close to 100% audio decoding for five or six minutes. But by 2252 it had deteriorated substantially with only about 15% audio decoding, and by 2250 there was no apparent signal at all.

tpreitzel 28-08-2015 21:22

Quote:

Originally Posted by PhilipOneL
Yesterday, Thurs 28/8/15, I caught the Vatican's DRM b/c on 11890kHz 2230 -2300 UTC. I don't know whether they were aiming towards me (in eastern Newfoundland, Canada), but their power (250 kW) probably sent it in all directions. I'm listening right now to the recording I made on the MR27024 (with an outdoor eight-metre wire aligned W-E). The signal was best around 2240 with very close to 100% audio decoding for five or six minutes. But by 2252 it had deteriorated substantially with only about 15% audio decoding, and by 2250 there was no apparent signal at all.


You were listening off the reverse lobe of the beam. The stated power is likely the analog equivalent. The Vatican is probably using ~ 125 kW in the digital mode. Furthermore, the ionosphere has been very unstable (auroral effects at higher latitudes as well) over the past few days so your reception off the reverse lobe is proof of the Vatican's wise and robust configuration.

tpreitzel 15-06-2016 20:51

I've included a picture of my antenna system. It's a product of some imagination and experience. Personally, I don't like clutter, but I need to do certain things. I constantly strive to balance time, money, and space. We can literally move our entire household with a bicycle and a trailer if needed.

I only wish manufacturers were as considerate in their designs of equipment. Although the wideband magnetic loop is an excellent concept, it's currently a bit too expensive. The RF PRO-1B is built like a tank and performs extremely well. The outdoor UHF/VHF antenna is made by 1byOne and can be purchased from Amazon. It's fairly well made for its low price and surprisingly performs above average. but don't expect great performance. The 1byOne will pull in ATSC stations indoor from about 10 miles away. Before attaching the 1ByOne, I received about 6 listenable FM stations at night. After attaching the 1ByOne, the number jumped to more than 40 listenable stations. In this picture, the VHF/UHF antenna is obviously not connected.

You'll have to decide where your priorities lie, but radio is a tool for me, not an end in itself. Hopefully, the picture will give new listeners some help in planning their systems. One doesn't need wires and equipment everywhere. Good luck.


Palm Springs commercial photography
http://www.webfilehost.com/?mode=viewupload&id=3149639

tpreitzel 06-07-2016 18:35

Now the real "fun" begins ...

After listening to the constant commercial breaks in some shortwave broadcasts, I've decided to rant a bit about the subject. For example, the Powerhour on the Genesis Communication Network (GCN) has nearly constant commercial breaks which is aggravating over an extended period, e.g. 30 minutes. Although the host announces the upcoming breaks, it's still annoying to mute or retune every 5 minutes or so.

Here's a suggestion for these broadcasters. Limit commercial breaks to a MAXIMUM of 15 minutes per hour, e.g. five 3-minute breaks per hour. If a broadcaster can't fund their production by limiting commercials to 15 minutes per hour, then seek additional funding mechanisms or stop broadcasting altogether. You're currently annoying listeners to death. Here's another suggestion... Use some of your resources (are you listening, Alex Jones?), to fund the manufacture of multimedia DRM radios and encourage GCN or WWCR to install DRM transmitters for their capability of transmitting advertising data concomitantly with the audio which should mitigate the aforementioned problem.

tpreitzel 24-02-2017 19:15

Thanks to Thomas over at SWLing Post, here's a potentially viable alternative to more expensive magnetic loops. If the AM band, bands if you prefer, is to remain viable, magnetic loops will probably play a major role so this development is important. Competition breeds quality while reducing cost, major factors in increasing acceptance by the masses.

http://swling.com/blog/2017/02/the-w...-loop-antenna/

tpreitzel 27-05-2017 20:50

While listening to a comment by Ray Robinson of KVOH that he wasn't necessary wedded to shortwave, a flash of inspiration appeared in my mind. ;)

Although I haven't read about this idea elsewhere, I'm fairly sure that this possibility has been discussed previously by other people.

Can the Creative Commons license be extended to include distribution of content solely via shortwave? In other words, create a license for content that is only legally distributed via shortwave frequencies. Maybe, restricting distribution for open content via shortwave will help sustain shortwave's viability.

PS I haven't checked the Creative Commons licenses for quite awhile.


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