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An interesting Pam radio...

 
Katie Bush
(@katie-bush)
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Hi all,

Just being curious, but I have in mind a Pam table radio, but no model name or number.. The only clue being "703" stamped into the chassis just above the serial number.

My curious was roused by the available bands on the scale - the legend reads "S - T - M - L - G".. Short, Medium, Long, and Gram are all self explanatory, but what does "T" stand for?.. The scale reads from 80 to 190, but doesn't indicate kHz or MHz. :aaq

It seems unlikely to me that it would be MHz, but yet is tempting to believe that "T" means "Television" (sound).. Then again, what, in the late fifties or early sixties, would reside at 80 to 190 kHz?

Curiosity was fuelled even further when I came across yet another set of the same period, also showing a "T" band and covering the same scale.

Go on someone, tell me what's it all about? :aab

Marion

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Topic starter Posted : 05/12/2015 11:05 pm
Mikeymushradio
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Possibly Trawler band many sets of yore had a seperate band for the seafarers but largely unused now.

30s radio and round tube tv fan collector of lost causes and poor old things that need some tlc.

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Posted : 05/12/2015 11:32 pm
Cathovisor
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Trawler, or "Top Band" as the amateurs like to call it. 80 to 190m.

Pye were big on providing the "Trawler Band" on their sets: allegedly it came about from their acquisition of Orr Radio Ltd., who previously did such a thing on their sets.

The ubiquitous Pye P75 has a special model called the P75T, which dispenses with the usual short wave band and replaces it with the aforementioned Trawler Band.

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Posted : 05/12/2015 11:32 pm
Katie Bush
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Hi guys, and thanks! :aad

That would explain it, and somehow, I couldn't see it being MHz :ccg but what a clown I must be - I wasn't thinking in metres, as an alternative meaning. :ccb Moreover I think, thinking metres, but talking kHz.

Marion

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Topic starter Posted : 05/12/2015 11:43 pm
Marc
 Marc
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That was a good question posed Marion,
I've learned something new there. :aad

Marc.

Marc
BVWS member
RSGB call sign 2E0VTN

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Posted : 05/12/2015 11:52 pm
Katie Bush
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Hi Marc,

That's you and me both who've learned something!

Everyone else......

Now then.... 'Top Band' - Is that where all the "Spitfire" guys hang out? Not the Supermarine Johnnies, but the AM modulator bods, with the Top Band modifications.

Likewise, is that where the AM pirates have gone? And then technically, what actually should be there nowadays - if anything?

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Topic starter Posted : 06/12/2015 12:10 am
sideband
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Top band is 1.8 - 2.0 Mhz and was a favourite of amateur radio operators on AM (I don't think there was ever any SSB on top band), Not sure if it's still used or maybe it's used differently by amateurs now. I believe there is (or was) a beacon somewhere around 1.9.

When I first started building radio's back in the 60's, top band was a favourite of mine because it was relatively easy to re-tune a MW receiver to receive it. It was popular on Sunday mornings and I remember one particular amateur, Bill, (G3EFS) who was fairly local and had a very strong signal. Very knowledgeable and willing to advise others.

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Posted : 06/12/2015 12:27 am
Hartley118
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Yes, Trawler band. Look in a museum in any fishing town, and if there's a radio there, it'll likely feature trawler band. Used by wives and mothers ashore to listen to communications from their family members out at sea. Pretty evocative of the hazards of a past era in UK fishing.

I have a couple of Pye radios with Trawler Band, but there's very little to be heard on it today. Right at the top, just below 200m, you may catch classic pops on Gold.

Both Pam and Orr were Pye companies - they seem to have responded well to this market.

Martin

BVWS Member

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Posted : 06/12/2015 12:42 am
Nuvistor
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Trawler band, yes had sets in the late 50's with trawler band on them and listened to them as well, very often called 'Fish phone'. Was there an emergency frequency around 2.1/2.2 Mhz?

Top band contest http://cq160.com/rules.htm both SSB and CW. Not active anymore on Amateur radio, not sure myself how the hobby is fairing.

Frank

Frank

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Posted : 06/12/2015 1:36 am
Terry
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The 1.9MHz "beacon" was the Decca HiFix navigation system, with a somewhat musical sound.

We used to have a top band receiver running in the workshop so that we could listen to the local net with all of the retired hams all over Essex and part of Kent every morning.

It could be quite entertaining at times!

When all else fails, read the instructions

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Posted : 06/12/2015 9:13 am
turretslug
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Was there an emergency frequency around 2.1/2.2 Mhz?

2.182MHz, frequently highlighted on marine receiver tuning scales- once frequency synthesis came along, a "Normal/2.182" quick selection switch became commonplace.

Near my parent's house in Calas de Mallorca, there's a slightly ghostly and fly-blown little museum with a couple of '50's Spanish table radios featuring this maritime band (somewhat ornate, but not to the "Marmite" baroque excess of some of their French contemporaries!. Each time I go, I think it's a shame to see them just fading away, would be absorbing to fettle them and get them back in voice. Then, the sun and the beach beckon....)

I had a Perdio "Town and Country" battery portable at one point- an unexceptional set, with a sprog-laden trawler band. Should have hung onto it as an example of the genre, though.

A bit more Pye musing here;

http://www.vintage-radio.net/forum/show ... hp?t=57691

and a mention of a Rees-Mace set (and its nostalgic association with a much-diminished industry), subsequently the company was associated with Pye;

http://www.vintage-radio.net/forum/show ... hp?t=92983

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Posted : 06/12/2015 12:13 pm
Niall
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2182 kHz is still the MF marine band distress and calling channel, equivalent of Ch. 16 VHF (156.800 Mhz) although a lot quieter. All activity now is on Upper Side Band SSB. For a long time after ssb was introduced marine MF sets would still transmit on AM on 2182 for compatibility with older kit.

This means that you won't hear anything intelligible on "trawler band" other than amateur AM if the receiver doesn't have a BFO. If you have another set with the same frequency coverage you can place them next to one another and use one as an injection oscillator at signal frequency to resolve SSB. I used to have a wonderful lashup for 10 meter band listening using this method; two old pushbutton car radios stacked vertically, one with the top cover removed the other with the bottom removed. The "receiver" radio was connected to one of those CB converter boxes with the mix crystal changed for a model control one.

In many cases the Normal / 2182 switch meant that 2182 was crystal controlled, other frequencies were tuned with a free running VFO.

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Posted : 06/12/2015 6:29 pm
Synchrodyne
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The descriptor “trawler band” (TB), less commonly “marine band” (MB) was also found on some New Zealand receivers for the band that typically covered from high MF into low HF. It seems to have had some legitimacy within the UK industry, insofar as it was used in for example the 1955 edition of the Radio Servicing Pocket Book”, pertinent page attached.

Whilst the TB/MB usually covered the 2 MHz and often the 4 MHz marine bands, it also typically covered the 120 metre and 90 metre tropical shortwave broadcasting bands, and often the 75 metre international shortwave broadcasting band. Sometimes TB/MB coverage extended upwards enough to cover the 60 metre tropical shortwave broadcasting band.

An oddity though is that whilst a four-band receiver with say MW, TB, SW1 and SW2, might well have the 49 through say 13 metre international shortwave bands marked at appropriate dial positions on places on SW1 and SW2, TB did not including markings for 120 through 60 metres. For reasons unknown, the latter group were often ignored for the setmakers.

A UK export example like that was the Bush EU24. It had six bands, MF plus five HF, right up to 30 MHz. The upper four HF bands each had two of the shortwave broadcasting bands well market with their corresponding Teleflic optical bandspread positions, this covering 49 through 11 metres. But the 1.75 MHz to 5.9 MHz band, whilst it had some station names, had no references to the 120 through 60 metre bands.

Cheers,

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Posted : 07/12/2015 8:31 am
turretslug
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It does seem odd that manufacturers of receivers covering this frequency range didn't publicise their coverage of the 60, 90 and 120m bands more- after all, advertising generally will famously trumpet anything that might add to customer appeal and "specmanship"- whether strictly relevant and useful or not. Perhaps it was their status as a replacement for the MW (and LW) allocations in regions of high thunderstorm activity that meant that they were generally of relatively low power, short range and provincial outlook that meant that they were perceived of as little interest outside their target area. That "target area" consideration would still have been a significant part of the intended export market, anyway, and "provinciality" can itself be of appeal, whether to ex-pats or just those with an interest outside their own regional sphere. The 75m band was always a good place to find one of the European stalwarts such as Deutsche Welle but it was never much more than a "region" band.

It's curious that the Bush set mentioned bothered to cover as far as 30MHz- 26MHz (11m) seems a sensible place to stop, even in a high-end domestic set and it's arguable that even 22MHz (13m) was as high as most listeners would realistically have been after. Tuning rate and resolution suffer enough in "traditional" topology receivers at high HF without reaching for large and low-utility spans of several MHz, not to mention oscillator stability. Certainly, "root 10" frequency span per band, dictated by the gang capacitor swing required for coverage of the MW broadcast allocation meant that a great many sets offered 2.3-23MHz coverage in two bands.

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Posted : 07/12/2015 1:59 pm
Synchrodyne
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Whilst the tropical bands may have lived in the shadows way back when, around the 1980s or thereabouts tropical band DX’ing apparently became a “sport” and reviews of current HF receivers often included comments as to how well they handled reception of the typically low-power transmitters that were used, often with NVIS aerials as well. By then though how good such receivers were for relaxed programme listening was not given much house room. (Many would not have passed my ad hoc BBC WS Play-of-the-Week test though.)

I suppose too that one could impute the meaning “tropical band” to the TB label, as an alternative to “trawler band”.

As to the Bush EU24 and its coverage, the 30 MHz upper limit – the top of the HF range - might be attributed to “specmanship”. Or possibly coverage of the 10-metre amateur band was desired.

The six bands were: Range 1 - 30 to 20.25 MHz; Range 2 – 20.25 to 13.7 MHz; Range 3 – 13.7 to 9.05 MHz; Range 4 – 9.05 to 5.9 MHz; Range 5 – 5.9 to 1.75 MHz; Range 6 – 1750 to 524 kHz.

Ranges 1 through 5 were referred to as shortwave bands, with no mention of the “trawler band”. It was stated in the manual: “The short waveranges are bandpsread over five ranges to facilitate tuning, the tuning scale being calibrated in megacycles, with the recognised Broadcast Bands marked in metres.”

It would appear that at the time (1951 or thereabouts) Bush recognized the 11 through 49 metre bands, but not the 60 through 120 metre bands, even though they were extant at the time. (I think that they dated at least from the Atlantic City 1947 meeting, if not before.) But oddly enough, there were station names on the Range 5 dial, even though the metre bands were not marked. Actually, when thinking about it, I don’t think that there would have been room for four expanded (for Teleflic correlation) metre band scales on any one range, so maybe that’s why Bush did not include them.

The first time I saw the “TB” waveband designation was on a new Columbus brand radio (locally made) that my folks acquired circa 1959-1960. This had MW, TB and two SW bands going up to around 22 MHz. Unlike the Bush, it lacked an RF amplifier, and one could overload it with a long aerial. In contrast I never succeeded in overloading the Bush, even though at the time we lived around a couple of km from the Auckland regional transmitters. Thus I developed a prejudice against AM receivers that did not have RF amplifiers. The Quad AMII tuner – with an RF stage – was similarly overload resistant in the same location But the AWA AM3 tuner, with an RF stage but using bipolar transistors, definitely was not. Thus formed another prejudice against small-signal bipolars in RF applications, at least the non-portable kind. That was later amplified by the miserably wretched overload performance of the bipolar VHF tuner in the Philips K9 colour TV receiver, when compared with a valved TV receiver with a regular turret front end. And that was in “mild” conditions, with but one Band I and one Band III transmitter. (Pye NZ had the smarts to fit a fet-based VHF tuner in one of its early colour TV offerings, I should guess following American practice as the European OEMs seemed to be a bit clueless in this department at the time.)

Anyway, back to the trawler band, once I was alerted to that nomenclature by the Columbus example, I noticed that it was quite commonly used on NZ-made domestic radios of the period, with “marine band” sometimes also being used instead. Auckland being a major leisure boating centre, the 2 MHz marine band was well-known at the time, probably before VHF RTs were around in any number. AWA for example made a low-cost 2 MHz marine transceiver for small vessel applications. The change to SSB for marine HF, announced late in the 1960s I think, was not at all welcomed by the Auckland boating fraternity. At the time it was said that the lowest cost SSB RT sets were about three or four times the price of the AWA AM unit – quite probably so. Anyway, NZ negotiated some kind of extension – several years – during which AM equipment could still be used on the 2 MHz band. So the trawler band on NZ domestic radios had extended utility for listening to local marine traffic.

Marion, apologies if I have somewhat hijacked your thread, but I did enedavour to swing it back to the “trawler band” in the end.

Cheers,

Steve

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Posted : 09/12/2015 5:22 am
Anonymous
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2182 kHz is still the MF marine band distress and calling channel, equivalent of Ch. 16 VHF (156.800 Mhz) although a lot quieter. All activity now is on Upper Side Band SSB. For a long time after ssb was introduced marine MF sets would still transmit on AM on 2182 for compatibility with older kit.

U.K. Coastguard Stations DO NOT now maintain a watch on 2182 but monitor 2187.5, which I believe is the DSC calling channel.
http://www.coastalradio.org.uk/ukcoastal.html

Mike

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Posted : 09/12/2015 9:16 am
Niall
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U.K. Coastguard Stations DO NOT now maintain a watch on 2182 but monitor 2187.5, which I believe is the DSC calling channel.
http://www.coastalradio.org.uk/ukcoastal.html

Mike

That must be quite a recent change, last time I looked they were saying no headphone watch, only speaker watch, same with 16.

They are determined to get everyone on to DSC, personally I think it's reliance on overcomplicated technology for the sake of it. Also results in everybody having a radio with a "press here for rescue helicopter" button which is no substitute for prudence and seamanship.

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Posted : 09/12/2015 11:50 am
Doz
 Doz
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Top band is 1.8 - 2.0 Mhz and was a favourite of amateur radio operators on AM (I don't think there was ever any SSB on top band), Not sure if it's still used or maybe it's used differently by amateurs now. I believe there is (or was) a beacon somewhere around 1.9.

When I first started building radio's back in the 60's, top band was a favourite of mine because it was relatively easy to re-tune a MW receiver to receive it. It was popular on Sunday mornings and I remember one particular amateur, Bill, (G3EFS) who was fairly local and had a very strong signal. Very knowledgeable and willing to advise others.

Still very much in use. Usually LSB these days, along with CW and various data modes.

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Posted : 09/12/2015 12:21 pm