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Author Topic: Which radio...  (Read 1208 times)

ALPARD

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Re: Which radio...
« Reply #30 on: March 31, 2020, 04:28:48 AM »

Another problem with SDRs is that, they will get outdated with time very soon.

I have paid about 3K USD for my Apple Mac desktop about 10 year ago, and it was the best and state of art professional desktop computer system.

After 10 years later, now it is useless chunk of metal just taking up space in my room. Because all the software in it are no longer supported by Apple company, and also in the internet. I cannot even open emails with the computer which weighs about 20kg. It cannot browse internet sites, because its internet browsers are all outdated.

I cannot even upgrade the OS due to the processor itself is outdated.  It all happened in 6-7 years after its purchase. The hardware is too good to throw out, as it is built like a tank. It has been sitting in the room for last 3-4 years doing very little.

Because of this trend, I don't trust any Software based system for long term use. They will be outdated very soon, and users must keep upgrade and upgrade ....

I would rather stick to simple vintage tube radios for SWL which will last life time and more by keep servicing it and changing the parts. At least I know what parts to change and when.

The quality of reception is much of muchness.  The propagation and antenna is more impacting than the radio itself from my experience.

I am now using a 1960s Lafayette HE-40 receiver, which I got  for 10 box non working, and DIY repaired for 10 box replacing some old caps and resistors for SWLing.

It is a great fun catching all the stations on the SW spectrum especially with this 4 tube vintage radio from 1960s.  I feel the stations are coming back on the air.  There are so many stations to listen to every evening.
« Last Edit: March 31, 2020, 04:41:33 AM by ALPARD »
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ALPARD

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Re: Which radio...
« Reply #31 on: March 31, 2020, 05:40:08 AM »

I am now using an iMac for doing general computing and internet.  Bought a brand new about 3-4 year ago, even when my old MacPro is still powering on, and works fine on Hardware level.  None of the software in the MacPro is usable now.
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RENTON481

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Re: Which radio...
« Reply #32 on: April 06, 2020, 08:44:08 PM »

You make some good points about computer tech being outdated so rapidly, Alpard.
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N8FNR

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Re: Which radio...
« Reply #33 on: April 07, 2020, 07:40:25 AM »

You make some good points about computer tech being outdated so rapidly, Alpard.

I bought a FLexradio Flex-5000 SDR in September, 2007 and it went OOP in May 2013. At that point Flex stopped developing the SW, PowerSDR for it. KE9NS is still updating the SW for it and does not charge for this https://ke9ns.com/flexpage.html. Also you can still get the rig repaired.

So even though the rig is 13 years old one is in no danger of the radio going obsolete anytime soon.

Even though the SW for the Flex-5000 runs on a PC or Mac it does not matter if the PC goes obsolete. Just load a copy on a new PC. And it will still run on a Mac or Win system.

I did sell my Flex-5000 and bought a Flex-6400 in February 2018 as I wanted to go with their newer software, SSDR.  So I used the Flex-5000 for almost 11 years which is not a bad track record at all to me. If I buy something I tend to keep it for a long time. But If I am no longer using something I sell it as I am a user and not a collector.

Some of the the newer Flex-6xxx rigs do not require a PC to operate BTW. https://www.flexradio.com/flex-6400/

Zack N8FNR
« Last Edit: April 07, 2020, 07:55:24 AM by N8FNR »
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N4OI

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Re: Which radio...
« Reply #34 on: April 07, 2020, 10:08:09 AM »

I have a lot of options for HF general coverage, but I will really miss my Drake R8 if it ever becomes unrepairable...  (had a scare a while back when the audio cap blew -- easy to diagnose and fix) 

The sound of AM HF broadcast (and even SSB) is just superb...  Open the filter, turn down the tone, plug in the Radiosport RS20s and enjoy...  Just sayin'

73   8)
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VA2DV

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Re: Which radio...
« Reply #35 on: April 09, 2020, 02:04:57 PM »

Icom R-70 by far. Mine was coming from a shore listening station. I sold it to acquire my first hf transceiver.
I also have a nostalgic preference for a cheap Sears « all band receiver » sold in the 80’s. Can’t remember the model. It was drifting like crazy and no BFO.
Not even an antenna connector. I had to twist a speaker wire around the whip.
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ALPARD

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Re: Which radio...
« Reply #36 on: April 20, 2020, 03:02:30 AM »

You make some good points about computer tech being outdated so rapidly, Alpard.

Thanks Renton.  Yeah, maybe it is just my personal experience and I am a bit paranoid from it.
But now even my iMac which had been bought NEW about 3-4 year ago is already getting outdated.

The standard internet browser shipped with the iMac is not able to work with many sites such as Youtube and eBay and even Amazon. I mean it does work up to a point, but when I try to for example, leave feedbacks or cancel Prime Membership in Amazon, then it crashes or displays garbage on the screen.

I cannot upgrade the Safari browser because it says the processor cannot work with the new browsers.

I am not wanting to pay out a few hundred to over a thousand dollars for new computers in every 3-4 years.
But I am not wanting to use iPads or mobile phones for doing my internet shoppings and financial stuff, when I have a good shiny sleek looking iMac sitting on my desk.

I will drop the Apple products for good this time, and go back to the WINDOWS pc.  I used to hate the MS WINDOWS for daily updates which freezes the PC, slowdown and too much problems with virus attacks. That's why I went for the Apple PCs.

OK, there are LINIX, but they are not very user friendly and there were no many application S/W before. But it is another platform I am thinking of migrating from the disappointing Apple products.
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SM0AOM

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Re: Which radio...
« Reply #37 on: April 20, 2020, 09:03:24 AM »

The performance differences between various HF receivers are becoming less and less important, as the spectrum congestion decreases, and the man-made noise floor increases.

There are very few cases today where a "premium-class" receiver makes any greater difference, primarily when co-located operations are contemplated.

The IC-R71E showed a very good price-performance relation at its heyday during the mid-80s. It definitely outperformed the Collins 51S-1 when used for Air/Ground watchkeeping receiver applications, and was on par with other contemporary receivers costing 8-10 times more.

Some of the original batch of ten bougth in 1984 are still in H24 operations some 35 years later, as well as their successor, the Palstar R30A.

I have a "soft spot" for 70/80s solid-state receivers, such as the
ITT-SRT CR302 and CR90/91. Partly because I had old friends and former colleagues in their design teams.

Other very good receivers from this era are the Telefunken-Deutsche Aerospace E1800, Skanti R-8003, Racal RA3791 and Rohde&Schwarz EK085.

SDR has changed the roadmap completely. A modern SDR such as the Perseus or Kiwi provides performance which is only a few dB below very expensive receivers, at a very small fraction of the cost.

The actual performance of various HF receivers has been evaluated in recent times, both by static measurements, side-by-side comparisons and in simulated operating conditions.

The latter was the subject of a recent paper presented at the Nordic HF Conference;
"Performance Limits For HF Communications Systems Using Realisable Hardware Solutions",
in which a large number of HF receivers in widely varying price levels and ages were compared.

It turned out that even very high-priced receivers did not provide a dramatic performance advantage when used in an RF environment made up from transmitters of "average" performance.

Today, it appears that the "point of diminishing returns" has been reached, and that R&D money would be better spent improving the transmitters.

Something very high on my "wish-list" is a "Sherwood list" of transmitter performance.
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ALPARD

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Re: Which radio...
« Reply #38 on: April 20, 2020, 09:35:33 AM »

I agree that most complicated and sophisticated design of HF receivers are not really needed, if one is only listening to AM BC on SW bands.  Most of these commercial BC stations on the SW bands use hundreds and thousands of kilowatts and gigantic antennas which can be heard with simple 2-3 band analogue SW receivers with just telescopic antennas.

I recall when I started out SWLing in my teen times, my first SW receiver was a ten dollar used 3 band MW SW1 SW2 Sanyo portable analogue radio, and it was hearing many DX stations such as BBC, VOA, ABC and Radio Japan and Radio Korea with just the builtin telescopic antenna.

More sensitive and selective receivers are needed , for that extra sensitivity and selectivity in reception when one is into SSB and CW receiving or actual QSOs, as most of the ham radio stations are using 100W or less on their wire dipoles and GP antennas.
But then in this case, it would be better getting the HF transceivers rather than receivers?

For instance, my ICOM IC-751A transceiver is still very nice to listen to, and receives better than most other dedicated high end receivers I have t tried.
« Last Edit: April 20, 2020, 09:38:44 AM by ALPARD »
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W9WQA

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Re: Which radio...
« Reply #39 on: April 20, 2020, 11:05:45 AM »

give me an sdr box, nice 7300 display,a big knob to tune, ez band selection, for $99 !!
i cant imagine any future without a waterfall, waste of time. hope someone makes it...
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SM0AOM

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Re: Which radio...
« Reply #40 on: April 20, 2020, 11:07:51 AM »

More sensitive and selective receivers are needed , for that extra sensitivity and selectivity in reception when one is into SSB and CW receiving or actual QSOs, as most of the ham radio stations are using 100W or less on their wire dipoles and GP antennas.
But then in this case, it would be better getting the HF transceivers rather than receivers?


Sensitivity does not help you when the system is either external noise or interference limited.

Selectivity does help in some extent, if it does suppress strong interfering signals at larger spacings from the centre frequency, but not if the causes of interference come from adjacent channel emissions from the transmitters falling into the wanted signal passband of the receiver.

"Yesteryear", when the arms race between the HF broadcasters was in full vogue, the large-signal properties of receivers were crucial, as the vast amounts of strong signals around especially in Europe created intermodulation noise and other overload effects.

The only remedy was to add RF selectivity in front of the receivers so fewer signals reached the front-ends, and to adapt the input level range to the antenna noise factor so the receivers were not more sensitive than necessary.

This was the "credo" of the "receiver guru" at Marconi, B M Sosin, during the 70s. Some other informed people, like G3PDM, DJ2LR, W7ZOI and W0IYH, also "jumped on the band-wagon". Most others continued to focus on sensitivity.

Today, the focus in amateur radio still is on receiver performance, and there are receivers that claim sub-microvolt sensitivities and 110 dB close spaced dynamic ranges.

Seen in perspective, the common HF user today has an antenna noise figure of 30 to 40 dB on frequencies below 10 MHz, corresponding to an usable sensitivity of around 2-2.5 microvolts.

It takes specially selected and protected receiver sites, far away from man-made interfererers, to get lower.

Further, a receiver adjacent channel suppression of 100 or 110 dB is quite useless when the suppression in typical fielded transmitters is perhaps 40 or 50 dB worse.

Professionals realise this, and adapt the frequency allocation plans for e.g. military and aeronautical HF systems to the expected equipment performance, both receivers and transmitters.

Very few users, amateur or professionals, are going to notice any greater difference today if a "mediocre" receiver is substituted for a "premium".


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