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Old 24th Apr 2019, 6:45 am   #81
Radio Wrangler
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Default Re: ISB Receivers

The term ISB best fits the case where the transmitter applies different information to the two sidebands, or there may even be two separate SSB transmitters sharing a carrier source.

If the transmitter applies the same information to both sidebands, and a receiver chooses which sideband to reproduced based on, say, interference or fading, then 'sideband diversity' is a good description. The difference lies in the intent of the system, the TX may be a plain old DSB AM job with full, reduced or suppressed carrier and the receiver may be one capable of fully independent sideband reception.

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Old 24th Apr 2019, 2:58 pm   #82
John KC0G
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Default Re: ISB Receivers

The GE YRS-1 was the commercial adapation of the single-sideband adapter which was published by Don Norgaard in QST, July 1948. See pages V-35 to V-40 of the GE Sideband Handbook at http://the-eye.eu/public/Books/Elect..._1961_text.pdf

While on the subject of sideband convertors. there were a number made here in the USA in the 1950's. See http://www.navy-radio.com/rcvr-ssb.htm Perhaps some of these convertors were commercial designs which were adopted by the US military. Some, probably not all, offered ISB capability. Several were made by TMC (Technical Materiel Corporation). You may find further information at http://www.tmchistory.org/

See also the HF Diversity Receiving Systems page at the same site. Some systems effectively had ISB capability. See also the the HF & MF receiver page, and the link to the R-1051 page. My understanding is that the R-1051 was built for the US Navy. It had ISB capability. It was also incredibly expensive. The early General Dynamics versions reportedly cost over the $20,000, and the last Stewart-Warner version around $50,000.

73 John

Last edited by John KC0G; 24th Apr 2019 at 3:13 pm. Reason: correction
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Old 21st May 2019, 2:39 am   #83
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Default Re: ISB Receivers

John, thanks for the links – plenty to consider there.

Quote:
Originally Posted by Radio Wrangler View Post
If the transmitter applies the same information to both sidebands, and a receiver chooses which sideband to reproduced based on, say, interference or fading, then 'sideband diversity' is a good description. The difference lies in the intent of the system, the TX may be a plain old DSB AM job with full, reduced or suppressed carrier and the receiver may be one capable of fully independent sideband reception.
A good summary of sideband diversity reception of DSB transmissions was given in the POEEJ 1952 October article on SSB/ISB, as follows:

“Single-sideband Reception of Double-sideband Telephony Transmissions.

“When a d.s.b, transmission is received in the normal d.s.b. type of receiver, severe degradation of the quality due to non-linear distortion often occurs if selective fading is present, as already discussed. The distortion due to selective fading can be overcome by receiving the d.s.b. transmission in a single-sideband receiver, in which one sideband only is selected and is demodulated against a stable high-level carrier, either the original carrier after filtering, amplification and limiting to remove fading and noise, or a local carrier.

“Another advantage of this method of receiving a d.s.b. transmission is evident when an interfering signal falls in one of the sidebands of the transmission. Such an interfering signal appears in the audio-frequency output of the receiver if d.s.b. reception is employed, but with an independent-sideband receiver it is possible to eliminate the interfering signal by selecting the sideband which is clear of interference.

“In the absence of interference an independent-sideband receiver can be used to receive the two sidebands of a d.s.b. transmission separately. The two audio-frequency outputs, each carrying nominally the same intelligence, will have undergone attenuation of some frequency components relative to others, but the attenuated components are not necessarily of the same frequency in both cases. Thus, by suitably combining the two audio outputs, a frequency-diversity system is obtained which results in a steadier audio output with less frequency-selective fading than is possible with normal d.s.b. reception."

One could say that the Crosby exalted carrier DSB demodulation system (which was included on at least the early Crosby ISB assemblies) and the GE YRS-1 (in DSB mode) automatically provided the frequency-diversity system mentioned in the GPO article, without the need for any sideband recombination circuitry On the other hand, adding a simple recombination circuit to a regular ISB receiver was probably the simplest route. As far as I know, Radio New Zealand (or NZBC as it then was) simply used a fader between the two sideband outputs of its Marconi HR21 ISB receivers at its Quartz Hill facility. I understand though that the Costas loop is even better for demodulating DSB under selective fading conditions than say a PLL. This is attributed to the fact that the Costas Loop, in using the sidebands to recreate the carrier, follows the short-term phase variations of the latter whereas the PLL provides a flywheel effect.


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Old 10th Sep 2019, 9:50 am   #84
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Default Re: ISB Receivers

First Post!

Synchrodyne, I have an ex ZLC Marconi Hydrus down here in CHCH if you ever want to see one in the flesh. :^)

It's next to the stack of Racal RA17L's (my favourite valve receiver).
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Old 10th Sep 2019, 5:40 pm   #85
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Default Re: ISB Receivers

A stack of RA17s? Trying to re-create the famous scene in 'Goldfinger'? Almost everyone in the cinema was looking where the laser beam was going to go. I was the kid ogling all the Racals instead.

Oh, hello and welcome!

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Old 12th Sep 2019, 9:24 am   #86
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Default Re: ISB Receivers

Thanks for the welcome David. Excited to meet someone from HP Scotland. I believe my 8970b's came from there.

I love that scene in Goldfinger.

I used to portable DX with a RA17L would you believe, in a Mini. I built a collapsible G S Maynard "Q Multiplier and Spiral Loop Antenna" (Practical Wireless March 1981) and that folded up and sat across the back seat, then the RA17L went in the passenger seat (strapped in to a 4 point harness) and off I went! A great radio and a great antenna!

Day to day use of the RA17L stopped once I could afford a Drake R8B.
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Old 12th Sep 2019, 11:25 am   #87
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Default Re: ISB Receivers

I bought a new, unopened RA117 from a surplus dealer in Yorkshire and drove it north to Scotland on the back seat of the Cooper S I'd 'restored' == built up from a new shell.

8970b....

Ah, I got asked to look into production difficulties with those in the mid 90's and I found the IF gain steps were not perfectly additive due to some leakage in the 20MHz IF. A fix was easy and all of a sudden units on the line started being in the middle of their accuracy tolerances. While doing this, I noticed it used an MC6809 chipset... ooo -err rather obsolete, and life-bought. Stocks were dwindling, and the 8970 was going to be needed by customers long-term.

I used to have all the design notes from the original 8970 team sitting on my desk. Fascinating readiing. I think they're landfill somewhere outside Edinburgh now.

So I cooked up an idea for a replacement noise figure box. Built a breadboard that covered a couple of benches and did some marketing figures. Management bought the idea and we staffed up a project which turned into the 8970 replacement. As the company split, it went out as the Agilent Noise Figure Analyser family. The receiver was partially DSP and did true RMS noise level measurement (better than diodes if the noise PDF is uncertain) built in graphics and coverage to 26GHz. I did the matching smart noise sources as a 1-man project. I understand sales have been over a quarter of a billion bucks. My share was nothing beyond the salary.

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Old 12th Sep 2019, 11:00 pm   #88
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Default Re: ISB Receivers

I want my old 8970B back!
Happy memories of the later stuff too.
But this is not helping about ISB receivers, drifting to RA117s and Mini Coopers.
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Old 13th Sep 2019, 5:48 am   #89
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Default Re: ISB Receivers

Quote:
Originally Posted by hpcollector View Post
First Post!

Synchrodyne, I have an ex ZLC Marconi Hydrus down here in CHCH if you ever want to see one in the flesh. :^).
Welcome to the forum and thanks for the offer – you might hear from me next time I plan to be in Christchurch!

Do you have to get it back from ZLC yourself, or was it brought back for disposal by the NZPO when ZLC was decommissioned?


Cheers,
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Old 14th Sep 2019, 8:20 am   #90
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Quote:
8970b....

Ah, I got asked to look into production difficulties with those in the mid 90's and I found the IF gain steps were not perfectly additive due to some leakage in the 20MHz IF. A fix was easy and all of a sudden units on the line started being in the middle of their accuracy tolerances. While doing this, I noticed it used an MC6809 chipset... ooo -err rather obsolete, and life-bought. Stocks were dwindling, and the 8970 was going to be needed by customers long-term.

I used to have all the design notes from the original 8970 team sitting on my desk. Fascinating readiing. I think they're landfill somewhere outside Edinburgh now.
That's not the news I want to hear! Waaaaaaaa!

Quote:

So I cooked up an idea for a replacement noise figure box. Built a breadboard that covered a couple of benches and did some marketing figures. Management bought the idea and we staffed up a project which turned into the 8970 replacement. As the company split, it went out as the Agilent Noise Figure Analyser family. The receiver was partially DSP and did true RMS noise level measurement (better than diodes if the noise PDF is uncertain) built in graphics and coverage to 26GHz. I did the matching smart noise sources as a 1-man project. I understand sales have been over a quarter of a billion bucks. My share was nothing beyond the salary.
I am speechless. Don't get me started on Agilent/Keysight! Especially storing all the historic stuff in a wooden building in California and having it all destroyed in the recent bushfires!

Sorry about the OT stuff, guys.

Quote:
Originally Posted by Synchrodyne View Post
Quote:
Originally Posted by hpcollector View Post
First Post!

Synchrodyne, I have an ex ZLC Marconi Hydrus down here in CHCH if you ever want to see one in the flesh. :^).
Welcome to the forum and thanks for the offer – you might hear from me next time I plan to be in Christchurch!
No worries mate! Time it for the local VRS meeting - first Thursday every odd month IIRC.

Quote:
Do you have to get it back from ZLC yourself, or was it brought back for disposal by the NZPO when ZLC was decommissioned?
It got handed down to me by another enthusiast who was running out of space and wanted it to go somewhere safe.

All the units are stored in one of those glass fronted upright shop chillers, in a 20ft container. No rack unfortunately. Have spares and also, I think, documentation.
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Old 3rd Dec 2019, 8:02 pm   #91
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Default Re: ISB Receivers

Going back to posts #72 and #73 there were a number of books which came out of Collins:

1. Fundamentals of Single Side Band, by the Collins Radio Company, softcover
There were three editions, dated ca. 1957, 1959 and 1961. IIRC the 3rd edition did not have the fold-out schematics of the 2nd edition. I kept the 2nd ed and sold the 3rd.

2. Amateur Single Sideband, by Collins Radio Company, 1962, hardcover
This was reprinted in paperback By Communications Technology in 1977.

3. Single Sideband Principles and Circuits, by E.W. Pappenfus, Warren H. Bruene and E. O. Schoenike, McGraw-Hill, copyright 1964.

All three authors were with the Collins Radio Company, but Ernie Pappenfus (ex-W9SYF, ex-W0SYF, ex-WB6LOH, K6EZ) had left in 1962. At that time he was Head of Development, Department B, with responsibility for the development of amateur equipment, AM Broadcast transmitters and SB HF military equipment. (Source - Electric Radio, Feb. 1990, #10, p. 8)

4. Single-Sideband Systems and Circuits, edited by W.E. Sabin and E.O. Schoenike, McGraw-Hill, 1st ed 1987, 2nd ed 1995.

A revised 2nd ed was published under the title "HF Radio Systems & Circuits" by Noble Publishing in 1998. This edition is still in print, now published by SciTech Publishing which is an imprint of the IET (Institution of Engineering Technology). The later printings do not seem to come with a CD. The original printing in 1998 came with a floppy disk.

Collins really did work things out. I will not part with my copies of #3 and #4.

The Collins KWM-389 was a very high end amateur radio transceiver which was sold from ca. 1979 to 1983. I once saw a service manual for it which extended to two ring binders, the first of which was very thick. I wonder how thick or thin the Japanese ham radio service manuals were at the time. Collins only knew one way to do things, ie as well as they could. There was also a companion general coverage receive, ie the 451S-1, which was very rare and now seriously expensive. It appears that one sold at the well-known auction site in 2014 for $18,100.

73 John
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Old 3rd Dec 2019, 9:01 pm   #92
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Default Re: ISB Receivers

It should of course be the KWM-380
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Old 29th Dec 2019, 10:04 pm   #93
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Thumbs up Re: ISB Receivers

Hi, you experts! New member here.
How very strange I seem to miss the boat so regularly.
After a lifetime (nearly) lusting after a GE YRS-1, finally came across a reference just before Xmas on https://antiqueradios.com/. Knocked off a quick reply, but the thread is probably dead.
Then just now found one on eBay, sold last October for $9.99 (plus crazy postage).
And then you guys, still at it .
What doesn't seem to get a mention (except by Pat Hawker) is what GE's "Lighthouse Larry" (George H Floyd) did with it, as he described in his 1951 G E Ham News: modified the output to feed LSB to Left and USB to Right audio channels... Binaural Sideband reception.
The phasing method quickly went extinct, and so did binaural.
Binaural has hardly received a mention, let alone implementation, in 70 years. It has been an obsession since early teens, and I finally got around to trying it this autumn, using Gnu Radio Companion. It works, it is beautiful, it would surely help LW/MW Dxers, especially with slight carrier offsets.
Happy New Year.
Paul
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Old 3rd Jan 2020, 6:19 am   #94
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It is interesting that the phasing method did not catch on for ISB communications reception. Possibly there was concern about the longer term stability of wideband phase-shift networks. And perhaps a viewpoint that where the two sidebands were radically different, e.g. voice on one and VFT on the other, the “solid” separation provided by sideband filters was more robust.

The history of “connected events” seems to be something like this.

In 1945, Crosby published details of his exalted carrier HF receiver, which was provided with synchronous demodulators (using filtered, reconditioned carrier) for both AM and PM. (IRE Proceedings, 1945 September, with a precis in Electronics 1945 March.)

Later in 1945, Belles (of Harvard) published his system for reduction of heterodyne interference. Like the Crosby receiver, it used similar synchronous demodulators to obtain the AM and PM components, and then added or subtracted the quadrature phase-shifted PM signal to the AM signal. (Electronics 1945 December.)

About a year after that, Dome of GE published his work on wideband phase shift networks, with SSB generation as one suggested application. (Electronics 1946 December, also US Patent 2566876 filed 1946 April 17, granted 1951 September 04.)

Then in 1947, Norgaard of GE put it all together in terms of SSB generation and selective sideband reception. (US Patent 2611036, filed 1947 November 12, granted 1952 September 16.) The GE YRS-1 was one outcome of Norgaard’s work.

Crosby added the Dome phase-shift network to his exalted carrier receiver, which could then receiver AM, PM, USB and LSB. This was covered in US Patent 2575047, filed 1948 July 14, granted 1951 November 13. Whether Crosby actually used this circuitry in his production receivers and adaptors I do not know. Some of these were SSB/ISB as well as exalted carrier, but as best I can determine, the SSB/ISB side was done with filters.

Thereafter it all seemed to go quiet for quite a while.

There seemed to be renewed interest in synchronous demodulation (not necessarily with the selective sideband capability) towards the end of the 1960s, perhaps because solid-state devices made it easier. When the phasing method of sideband separation reappeared in production receivers, it was for selective sideband reception of AM broadcasts rather than for ISB communications. The Sansui TU-X1 hi-fi “supertuner” of 1979 (MW only on AM) was an early example. In the early 1980s there were also some Accuphase hi-fi tuners with the same facility, again MW only.

In 1983 the Phase Track Liniplex F1 HF receiver appeared. This used a tracking PLL demodulator and the phasing method to provide selectable sideband reception of HF broadcasts. There is an interesting history there. The designer (whom I met once in the early 1990s) at one time worked for a major American manufacture of highly regarded professional communications receivers. When he was stationed overseas, he wanted to listen to the BBC World Service, but found his employer’s receivers not well suited for comfortable listening to programme content. So he looked at the problem and then designed what was a suitable receiver for the purpose. I bought the later F2, and used it for listening to the BBC WS for about 14 years or so. It was the only HF receiver I have used that passed what I called the “BBC WS Play of the Week” test. "Play of the Week" arrived on Saturday evenings when I was living in Texas, and the objective was to be able to sit back in the armchair, glass of red liquid in hand, cat on lap, and capture the play (and there were some good ones back then) without any strain. The F2 (feeding the Quad/Celestion, later Quad/KEF hi-fi system) did the job admirably. My backup receiver was a JRC NRD-525 with outboard Sherwood SE3 synchronous demodulator, but it was not a match. (The NRD-525 was more of a DX’ing receiver than one for extended listening to programme content.)

At about the same time (1983), Sony released the ICF-2001D/2010 which had PLL synchronous demodulation and sideband separation by phasing. For its price, it was fine, and it was using one of these (somehow I ended up with two of them) that convinced me that synchronous demodulation with selectable sidebands was the answer for HF broadcast listening. Sony used the same IC set that it had developed for AM stereo decoding, and which had been used for example in the SRF-A100 portable FM-AM stereo receiver. I had one of these before my first ICF2010, and when using the headphone output to feed the stereo system, it have a surprisingly good account of itself on AM, which pointed to PLL demodulation as also being a pathway to lower distortion.

An interesting comment made to me by the Liniplex designer was that where reception conditions allowed the use of both sidebands of an HF broadcast, the Costas loop actually provided slightly better audio quality than the tracking PLL. Apparently this was because, by using both sidebands to guide the loop, it was able to track the short-term phase variations of the carrier. On the other hand, the PLL was better than the Costas loop when it came to selective sideband reception. So ideally you’d want both in an HF broadcast listening receiver.

Regarding binaural listening, back in the later 1980s there was a columnist for the American magazine “Monitoring Times” who was in favour of this approach. I guess that if you used say a Sony SRF-A100 (or one of the Sansui or Sony hi-fi tuners with multi-system AM stereo decoders) set to the Kahn ISB mode, then with a mono AM broadcast you’d have more-or-less LSB on one channel and USB on the other.


Cheers,
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Old 3rd Jan 2020, 7:12 am   #95
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Default Re: ISB Receivers

One of the Lowe HF receivers had synchronous demod available as an option.

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Old 3rd Jan 2020, 7:40 am   #96
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The Lowe HF-125 of c.1987 certainly had a synchronous demodulation option. I looked at that before I bought the Liniplex, and in fact had some correspondence about it with the Lowe folks. The synchronous option was fairly simple, without the selectable sideband facility. One would have to offset the tuning to obtain one sideband over the other. (The same was required of the NRD-525/SE3 combination, making it a lot fiddly to use.) Anyway, I had the impression that the HF-125 was essentially a communications receiver, whereas the Liniplex was designed specifically for HF broadcast listening and that alone. So I opted for it, although it was in noticeably higher price bracket. The Lowe would probably have been fine as a “second” receiver, but when the time came for that I chose for the NRD-525, which was generally regarded as “best-in-class” at the time. The following JRC NRD-535 had a selectable sideband synchronous demodulation option, but I was advised that this was intended primarily to allow sideband selectability for communications purposes rather than better audio for listening purposes.


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Old 21st Jan 2020, 10:43 pm   #97
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Default Re: ISB Receivers

The Plessey PRS 2280 was a general coverage comms rx which offered ISB synchronous reception of either sideband. Just dug out a review in SWM by John Wilson from Oct 1988 in which he compares it to the Racal RA1792. The 2280 uses a 100Hz crystal filter to lock the CIO and Wilson was particularly impressed with its use for broadcast reception.
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Old 21st Jan 2020, 11:47 pm   #98
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Default Re: ISB Receivers

We have previously read in this thread that the PR155 (1967) offered ISB reception. Later variants of the 155 were the PR1551 and PR1553 frpm 1976. These also covered 15kHz to 30.1MHz in 1MHz bands, keeping the modular construction with the turret front end. The 155x use Si devices throughout and DBM mixers. The 1551 had a film scale dial while the 1553 had a Digitron numeric display. I will add some photos another day
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