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Could the iPhone become an Ultralight ?
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Graeme Zimmer <gzimmer@...>
I need some clarity on this.It's explained very clearly on the web site. specifically: "iSDR does not require Internet connectivity, a cellular network, Bluetooth, or WiFi. What you will need in order to receive live signals is an external device (known as an "RF front-end") that converts radio signals into audio signals that can be fed into the iPhone's microphone input" ............ Zim |
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Graeme Zimmer <gzimmer@...>
ferrite61 wrote:
OK, thanks Graeme. Seems to be nothing more than an audioprocessor/amp. Or does it actually have IF filtering? The next step in the evolution of radio technology involves "Direct Conversion" (or "Phasing") type receivers and transmitters. Single Signal Direct Conversion rigs have been around forever, but until recently have not been entirely practical due to the difficulty of constructing accurate Quadrature Oscillators and 90 deg audio phase shifters. DDS oscillators and Digital Audio processors has completely changed all that and so we are seeing a revolution in radio design under the name "Software Radio". The first step was to use a PC to do the audio processing, but increasingly we are seeing small stand-alone processors which can do the work. Using an iPhone is a brilliant step in that direction. Most of the modern cellular phones use this "Direct Conversion" technology, as does the little Si4734 "SDR-on-a-chip" IC which makes your UltraLight class possible. The Superhet is now dead and buried. So the question "does it actually have IF filtering?" is pretty much meaningless, as the technology avoids the use of IF filtering entirely. It does all the bandpass processing at Audio frequencies. ......... Zim |
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tonyzl@...
iSDR is a software defined radio application compatible with the Apple iPhone®, iPod touch® and iPad™.
iSDR is designed for experimenters, shortwave listeners, and amateur radio enthusiasts who would like a truly portable software-defined radio receiver. See what you think at: http://digitalconfections.com/index.php?option=com_content&view=article&id=46&Itemid=54 Regards, Tony King |
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Kevin Schanilec
Hi Tony:
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I hope the SDR app is a good one, as it may get more people listening to the radio. It seems to also require an RF front end, which will make it rather more difficult to catch on, methinks. Alas, no chance of it being an "approved" ULR in that, among other things, the whole set-up will cost more than $100, and the primary function of the iPod/Ipad/iTouch is not primarily for radio reception. MW reception may be pretty poor anyway, having the computer in immediate proximity, but I would imagine that FM and perhaps shortwave reception might be serviceable? Thanks - Kevin S --- In ultralightdx@..., tonyzl@... wrote:
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Graeme Zimmer <gzimmer@...>
ferrite61 wrote:
OK, thanks Graeme. Seems to be nothing more than an audio processor/amp. Or does it actually have IF filtering?The next step in the evolution of radio technology involves "Direct Conversion" (or "Phasing") type receivers and transmitters. Single Signal Direct Conversion rigs have been around forever, but until recently have not been entirely practical due to the difficulty of constructing accurate Quadrature Oscillators and 90 deg audio phase shifters. DDS oscillators and Digital Audio processors has completely changed all that and so we are seeing a revolution in radio design under the name "Software Radio". The first step was to use a PC to do the audio processing, but increasingly we are seeing small stand-alone processors which can do the work. Using an iPhone is a brilliant step in that direction. Most of the modern cellular phones use this "Direct Conversion" technology, as does the little Si4734 "SDR-on-a-chip" IC which makes your UltraLight class possible. The Superhet is now dead and buried. So the question "does it actually have IF filtering?" is pretty much meaningless, as the technology avoids the use of IF filtering entirely. It does all the bandpass processing at Audio frequencies. ......... Zim |
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ferrite61 <dxrx@...>
Does the app use a WiFi connection to an Internet site?
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Does the content come from the AM-band broadcast antenna of such a Radio Station? If it does both, where is the location of the Internet site with respect to the AM-radio-station antenna? In station? X miles away? Reception distance is important here. Only the transmitter to original receiver counts, re-transmission over TCP/IP and/or WiFi does not. I need some clarity on this. Paul S. in CT --- In ultralightdx@..., tonyzl@... wrote:
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Michael <michael.setaazul@...>
From the wording, it appears it doesnt need an internet connection.
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If it did, it would be a 3G radio - and very expensive listening. From the description given, it looks like an overkill frontend plug-on for a high-end smartphone. It needs an external antenna. Longwire for AM??? How very portable! Interesting gizmo, but no competition for a proven uldx DSP rx! Michael UK ----- Original Message -----
From: "ferrite61" <dxrx@...> To: <ultralightdx@...> Sent: 29 July 2011 06:48 Subject: [ultralightdx] Re: Could the iPhone become an Ultralight ? Does the app use a WiFi connection to an Internet site? Does the content come from the AM-band broadcast antenna of such a Radio Station? If it does both, where is the location of the Internet site with respect to the AM-radio-station antenna? In station? X miles away? Reception distance is important here. Only the transmitter to original receiver counts, re-transmission over TCP/IP and/or WiFi does not. I need some clarity on this. Paul S. in CT --- In ultralightdx@..., tonyzl@... wrote: and iPad. iSDR is designed for experimenters, shortwave listeners, and amateur radio enthusiasts who wouldlike a truly portable software-defined radio receiver.
------------------------------------ Yahoo! Groups Links |
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Graeme Zimmer <gzimmer@...>
I need some clarity on this.It's all explained very clearly on their web site. specifically: "iSDR does not require Internet connectivity, a cellular network, Bluetooth, or WiFi. What you will need in order to receive live signals is an external device (known as an "RF front-end") that converts radio signals into audio signals that can be fed into the iPhone's microphone input" ............ Zim |
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Graeme Zimmer <gzimmer@...>
Michael,
Interesting gizmo, but no competition for a proven uldx DSP rx!I suggest you read up on SDR radios if you think this is just an interesting gimzo! .......... Zim |
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Michael <michael.setaazul@...>
I would maintain that this particular application is a gizmo
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- of interest to an informed and well-resourced aficionado. Without an effective external aerial, which would rather defeat the ideal of portability of a smartphone, it is unlikely to be impressive on MF. With a short wire antenna, it might well perform on HF and above. It will certainly be interesting to read empirical reports from users already owning a high-end smartphone. For MF applications, a uldx rx with DSP would be preferable, especially when budget is an issue. SDR radio implementations with more appropriate hardware are indisputably now well established and proven. Unfortunately, my resources do not allow me to participate, although I would be interested in a diy application with free software that would work on an ancient system :-) Michael UK ex 9Q5TS ----- Original Message -----
From: "Graeme Zimmer" <gzimmer@...> To: <ultralightdx@...> Sent: 29 July 2011 07:51 Subject: Re: [ultralightdx] Re: Could the iPhone become an Ultralight ? Michael, Interesting gizmo, but no competition for a proven uldx DSP rx!I suggest you read up on SDR radios if you think this is just an interesting gimzo! .......... Zim |
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Graeme Zimmer <gzimmer@...>
Michael
Without an effective external aerial, which would ratherWhere do you get this idea from? There is no reason why it can't use a ferrite rod or loop or whatever you wish. ........ Zim |
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Michael <michael.setaazul@...>
Without an effective external aerial, which would rather------------------------------------ Where do you get this idea from? There is no reason why it can't use a ferrite rod or loop or whatever you wish. Zim ------------------------------------ Precisely : the convenience and size of a smartphone is somewhat compromised by the addition of a QSD and a ferrite or loop. Not all would be able to assemble a QSD kit and matching ferrite or loop. Until both items become available commercially for the informed user, perhaps as a single unit (price?) which plugs into a higher-spec smartphone, this application remains experimental. I will certainly follow its development, and especially look forward to reading other opinion and comments of users who try it. Michael UK |
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Graeme Zimmer <gzimmer@...>
Not all wouldYou do realise that many of the newer communications receivers already have an I/Q output? And that commercial SDR frontends have been available for some years now? ......... Zim |
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Marc Coevoet
Op 29-07-11 09:45, Michael schreef:
In fact, the iPhone is like a computer, but a small one. If a SDR software works on the iPhone, made in open source, it will work on other linux platforms, like android... For a project that works as well on Android, Nokia, WinCe phones, and the way it can be accomplished (open source cross compiler), look here: http://wiki.navit-project.org/index.php/Main_Page Has nothing to do with radio, but is a very good example. I don't think a phone is an ultralight, but if you want to discus ultralight SDR .... we're heading for a new class ... Marc -- The "Penguin" has arrived - and he's not going away - ever. What's on Shortwave guide: choose an hour, go! http://shortwave.tk 700+ Radio Stations on SW http://swstations.tk 300+ languages on SW http://radiolanguages.tk |
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ferrite61 <dxrx@...>
OK, thanks Graeme. Seems to be nothing more than an audio processor/amp. Or does it actually have IF filtering?
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Paul S. in CT --- In ultralightdx@..., Graeme Zimmer <gzimmer@...> wrote:
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ferrite61 <dxrx@...>
Thanks for that. WE've noticed around here that there is a "low freq. local osc." of about 45-48kHz. I thought that might be some form of 2nd IF-on-a-chip or mixer-osc.
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Paul S. in CT --- In ultralightdx@..., Graeme Zimmer <gzimmer@...> wrote:
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nz0i <charles.scharlau@...>
By purchasing a used or refurbished iPod touch, and building the RF front-end yourself, you MIGHT be able to set yourself up with an SDR receiver using iSDR for under $100. You can also get an iPhone 3Gs for around $50 with a 2-year contract in the USA - but of course the monthly charges would put the total cost WAY over $100.
Since all the Apple iOS devices are designed primarily to serve other functions (phone, music player, etc), and require a special app and hardware to turn them into MW receivers, I guess they will always fail to fully adhere to the strict definition of an ultralight. Still, iSDR can provide a remarkably high level of performance in a very portable package. And if you happen to already own a compatible Apple device, then the cost to you is very low indeed. 73, Charles NZ0I |
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nz0i <charles.scharlau@...>
I meant to mention one more thing: regarding SDR on other devices, like Android, Webos, QNX, Symbian, etc.
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The main thing preventing SDR on those devices is the lack of stereo microphone input. Note: I say mic *input*, not stereo earphone output. In-phase/quadrature detection requires two input signals, each 90-degrees out of phase relative to one another. So stereo input is required -- though for amplitude modulation modes (AM, SSB, CW) the software can do the detection using just a single input signal. But I digress. If you hear of any other portable programmable device, other than an iPhone, iPod touch, or iPad, that accepts external stereo microphone input, please let me know. For now, I'm aware of no Android products or any other programmable handheld devices that can support full I/Q stereo input. 73, Charles NZ0I --- In ultralightdx@..., "nz0i" <charles.scharlau@...> wrote:
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Michael <michael.setaazul@...>
Thanks for your informed input, Charles. Very helpful.
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Can you suggest links to diy RF frontend designs? What aerial and frontend configuration is necessary for the iPhone DSP to equal a DSP uldx with, say, a MW 7" external ferrite as featured on this site? Michael UK ----- Original Message -----
From: "nz0i" <charles.scharlau@...> To: <ultralightdx@...> Sent: 01 August 2011 17:35 Subject: [ultralightdx] Re: Could the iPhone become an Ultralight ? I meant to mention one more thing: regarding SDR on other devices, like Android, Webos, QNX, Symbian, etc. The main thing preventing SDR on those devices is the lack of stereo microphone input. Note: I say mic *input*, not stereo earphone output. In-phase/quadrature detection requires two input signals, each 90-degrees out of phase relative to one another. So stereo input is required -- though for amplitude modulation modes (AM, SSB, CW) the software can do the detection using just a single input signal. But I digress. If you hear of any other portable programmable device, other than an iPhone, iPod touch, or iPad, that accepts external stereo microphone input, please let me know. For now, I'm aware of no Android products or any other programmable handheld devices that can support full I/Q stereo input. 73, Charles NZ0I ---------------------- In ultralightdx@..., "nz0i" <charles.scharlau@...> wrote: be able to set yourself up with an SDR receiver using iSDR for under $100. You can also get an iPhone 3Gs for around $50 with a 2-year contract in the USA - but of course the monthly charges would put the total cost WAY over $100. player, etc), and require a special app and hardware to turn them into MW receivers, I guess they will always fail to fully adhere to the strict definition of an ultralight. you happen to already own a compatible Apple device, then the cost to you is very low indeed. ------------------------------------ |
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nz0i <charles.scharlau@...>
Hello Michael,
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Unfortunately I'm not familiar with the DSP uldx, so I can't provide an informed comparison. I have built resonant ferrite loop antennas for 3.5 MHz band, including the one pictured on the Digital Confections web site. With careful construction and attention paid to tuning the antenna to resonance, and using the SoftRock kit as a front end, I can say that the sensitivity is on par with other handheld direct conversion receivers that I've used for radio direction finding. Not great sensitivity, but adequate. I should mention that the dynamic range and selectivity are quite remarkable. Also, the modes that iSDR supports go well beyond what is found in most handheld units. And the graphic spectrum display is found on no other handheld receiver so far as I know. There are several front end kits and fully-built units available for purchase from a variety of suppliers. You can find a list at the iSDR forum: <http://digitalconfections.com/index.php?option=com_kunena&Itemid=61&func=showcat&catid=4> Other things to note: the iPhone 4 does NOT currently support stereo microphone input. But I have heard from Blue Microphone that they are planning to sell an iPhone 4 stereo microphone adapter later this year - contact Blue Microphone directly if you have questions about their product plans. The iPod touch and iPhone 3Gs will require an external stereo microphone adapter as well, and the adapters are generally available, but do add cost to the setup. More details on how to connect a front end to the various Apple iOS products are available on the forum linked above. Also, feel free to contact me off the list if you have more questions. 73, Charles NZ0I --- In ultralightdx@..., "Michael" <michael.setaazul@...> wrote:
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