eHam
eHam Forums => Software Defined Radio => Topic started by: K4BDA on November 22, 2022, 03:59:31 PM
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Just wondering how the performance of a SDRplay RSP1A or equivalent compare to...
high end older properly tuned up radios like the Hammarlund HQ-180A... or equivalent...
or any of the Hammarlund receivers.
Other older receivers may be Collins, Drake, National, Hallicrafters, etc.
Thanks,
Will, K4BDA
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A 14 bit SDR receiver should have an adjacent channel selectivity of at least 95 dB, 2 kHz away.
I had a HQ-180 back in the late 60's and it was not very selective and suffered front end overload. the RF gain control was your friend.
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Subjective opinion....
I have restored several HQ boatanchors. Fun to play with, easy to work on. Nice to see one come to life, and wonder who last used it.
Performance is abysmal by today's standards. Even a HQ-180, top of the line then, pales compared to a low end receiver now for Shortwave. Selectivity was marginal. Receiving above 20 meters really fell off a cliff. I have heard Collins were great, but never owned one.
But, the audio was great on AM, like shortwave broadcasts. Enjoyed many hours listening to the world on an HQ.
Sold mine when International Broadcasters started shutting down or moving to digital modes. Sad to see.
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Only one of those systems will make your heart glow-
and smell like hot dust when you turn it on.
Only one will even enter the picture when you're in need of some ham radio romance or nostalgia...
Only one will let you sit at your shack chair and get lost in time....
And both can sit proudly side-by-side in your shack.
Happy Turkey Lurkey day guys. Gobble till ya wobble!
Chuck and Blitzy
I Remain-
Blowzo the Humble Ham of YouTube
dit dit
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No tube type receiver/transceiver can compete with currently offered SDR/solid state radios. Great in their time, but that time has long gone.
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Well, just to add a little perspective to this guys...
In 1957 I got my ticket when I was a teenage boy interested in electronics.
I worked the world using a $49 Hallicrafters S-38D receiver...
(for which I paid $38 brand new from the PX at Fort Jackson, SC... via a friend of the family.)
and a 50 watt Heathkit DX-20 transmitter which I built myself.
Started out with CW then later built a screen grid modulator for the DX-20 and worked AM on 80 thru 10 meters.
All using dipole antenna's hung in the trees in our yard.
I know modern equipment is much much better... but back then I thought I was doing great... and I was :-)
73's
Will, K4BDA
PS - Later, from scratch, I built a linear for the DX-20 with a pair of 813's in the final and a couple of 866 mercury vapor rectifiers.
I used my electric train transformer to power the 813 filaments through a handmade filament choke.
And continued with the S-38D receiver for several years.
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I enjoy restoring old rigs as well but I have no illusions about their performance compared to modern SDR's.
Have a look a this Sherwood list,
http://sherweng.com/table.html
Even the Collins R390 only has a dynamic range at 2 kHz of 79 dB. Modern SDR's are around 30 dB better. In terms of frequency accuracy, stability, bandwidths available, there is no comparison. The first time I heard SSB on an SDR, it was a bit of a revelation. Being about to select a 3 kHz bandwidth made SSB sound much better than I had ever heard before.
But the enjoyment of these rigs is not solely based on technical performance. It's really admirable what these old rigs could achieve back so long ago.
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....... It's really admirable what these old rigs could achieve back so long ago.
And it's admirable what hams could achieve back so long ago with these old rigs, when the CW, AM, and SSB subbands were a lot more congested than they are these days.
73, Ed
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We can meet or exceed the "sensitivity".
We can meet or exceed the "selectivity".
We just can't find a place to mount all the "knobs"!
-Mike.
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No comparison? Really? Look again at the Sherwood and see where the Drake 2B stands. They are listed according to one characteristics, but a radio can be better represented by a vector rather than a scalar. Also pay attention to the sensitivity values and the Blocking. And the fact that you can also process the IF to have any sort of filtering by means of a simple converter and you can reach the stability you want using external DDS or other low noise oscillators.
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No comparison? Really? Look again at the Sherwood and see where the Drake 2B stands. They are listed according to one characteristics, but a radio can be better represented by a vector rather than a scalar. Also pay attention to the sensitivity values and the Blocking. And the fact that you can also process the IF to have any sort of filtering by means of a simple converter and you can reach the stability you want using external DDS or other low noise oscillators.
All true perhaps but why go to all that trouble with hacking a 2B unless just for the nostalgia? Fire up an RSPdx SDR or an Elad or most any other mid-to-high-end SDR and away you go with those benefits and more.
But with that said, I do use several vintage receivers here regularly in addition to my SDRPlay RSPdx receivers. I use an Elmac PMR-8 for casual hamband listening and sometimes a KnightKit R-100A for shortwave.
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A contact and a qsl card is just as thrilling no matter the equipment.
I wonder where my RAL-5 regenerative rx would be on Sherwood's list... Gadz, it was built in the 1930's and my main rx in 1957, I invested $6 in it if memory serves...
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Working CW in crowded band conditions: SDR / modern receivers are superior...
Listening to SW broadcasts with ethnic music: Hammarlund, Collins and especially the Drake R8 are the best, Jerry, the best!
Just sayin' 8)
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In my listening experience, I would say that noise reduction is the very best thing modern radios have brought to the table, and it's the thing that matters most to everyone except intense contesting and DX pileups, where extreme selectivity and dynamic range matter too. (That, and waterfall displays, but that's not a performance metric per se.)
However, there are some really excellent outboard DSP units on the market today for use with any receiver, including those beautiful vintage receivers (for example, the DSP noise reduction units made by BHI, West Mtn, SOTA, etc).
73, Ed