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 Mystery station on 1377
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 Return to top of page · Post #: 1 · Written at 6:52:51 PM on 12 October 2017.
Robbbert's avatar
 Location: Sydney, NSW
 Member since 18 September 2015
 Member #: 1801
 Postcount: 671

At night I like to listen to a certain Melbourne station on 1377. This is usually received without problem, however during a fade-out, an American station becomes audible. The station seems to mostly broadcast sport (or at least these 2 guys talk a lot), and I once heard an ad for the American Heart Foundation. However, I haven't been able to get a station identification, and most of the time it is swamped by the Melbourne station.

I don't know where the station is located (I doubt it's actually in America), it's there all night, strongest just after sunset until midnight. After that the Melbourne station is just too overwhelming.

A search of the net failed to find anything useful. Any ideas?


 
 Return to top of page · Post #: 2 · Written at 7:05:37 PM on 12 October 2017.
GTC's avatar
 GTC
 Location: Sydney, NSW
 Member since 28 January 2011
 Member #: 823
 Postcount: 3972

A case of image frequency interference?

Does it happen on other receivers?

BTW: If you're into DXing AM, I once had use of a Crane CCRadio-EP set and it would pull in stuff from all over the place outdoors with nothing but its internal ferrite rod.


 
 Return to top of page · Post #: 3 · Written at 8:09:53 PM on 12 October 2017.
Brad's avatar
 Administrator
 Location: Greenwich, NSW
 Member since 15 November 2005
 Member #: 1
 Postcount: 4375

Don't forget that US channel spacings are 10kHz. Have you tried fine-tuning the station in question when Melbourne fades out? It could be on Hawaii or Midway or Guam.


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Brad.

A valve a day keeps the transistor away...

 
 Return to top of page · Post #: 4 · Written at 8:57:25 PM on 12 October 2017.
Robbbert's avatar
 Location: Sydney, NSW
 Member since 18 September 2015
 Member #: 1801
 Postcount: 671

Does it happen on other receivers

Yes, all the ones I tried.

Brad, when the American station starts to interfere, there's a see-sawing effect indicating the stations are separated by only a few hertz.


 
 Return to top of page · Post #: 5 · Written at 9:09:22 PM on 12 October 2017.
Brad's avatar
 Administrator
 Location: Greenwich, NSW
 Member since 15 November 2005
 Member #: 1
 Postcount: 4375

My guess is that the US station is on 1380kHz. I don't have a radio strong enough to try for myself unfortunately. The only valve radio I have at hand is a Plum Pudding.


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Brad.

A valve a day keeps the transistor away...

 
 Return to top of page · Post #: 6 · Written at 11:40:03 AM on 13 October 2017.
Tinkera123's Gravatar
 Location: Melbourne, VIC
 Member since 5 October 2009
 Member #: 555
 Postcount: 308

Robbert,

Cannot help with ID of second radio station .... but 1377 (3MP) Classic Rock .... transmitter in Frankston ..... one of my strongest AM stations ... good music to listen to whilst working in my garage.

I would be interested to know what radio and aerial/antenna system are you using?


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Cheers, Ian

 
 Return to top of page · Post #: 7 · Written at 1:49:25 PM on 13 October 2017.
Robbbert's avatar
 Location: Sydney, NSW
 Member since 18 September 2015
 Member #: 1801
 Postcount: 671

I have a few radios tuned to 3MP throughout the house. In the roof is unused wiring originally for distribution of TV signals, so now used by some radios as an antenna. Also, some rooms have telephone wall sockets, but the phone line in that house is disconnected. This gives me an antenna all the way back to the exchange, several km away. Some rooms don't have access to either of those, so just use a wire to the metal curtain rod. In the garage, the metal roll-a-door does the job.

If I needed more antennas, the gutter could be used, or the metal shed.

As far as I can see, any decent superhet valve radio should be able to pick up the signal. In the back room is a tiny beat-up 4-valve Philips connected to the curtain rail, and it does a great job. Of course, being 4-valve, there's not a huge amount of volume. No idea what model it is as the sticker is missing, but it has 6M5, 6N8, 6AN7 + rectifier.

In the garage I have a choice of another Philips in a blue plastic case, or my Kenwood TS-930S. Each of these is connected to a roll-a-door.

In my bedroom is a 4-valve Airzone with miniature valves and it uses the antenna in the ceiling. It is as sensitive as the 4-valve Philips, but has a lot less volume.

The other day I connected a Kriesler 11-7 to the telephone line, works well as you'd expect.

So, lots of choices, and I'd expect many other radios would work perfectly well too, given a good aerial.


 
 Return to top of page · Post #: 8 · Written at 4:11:45 PM on 13 October 2017.
Ian Robertson's Gravatar
 Location: Belrose, NSW
 Member since 31 December 2015
 Member #: 1844
 Postcount: 608

Oh I wish it was that easy for me!

I live in a line of 8 townhouses. I have a huge amount of electrical noise that emanates from the power switchroom where the cables come in from underground. Wipes out the AM broadcast band almost totally.

I found I can get noise-free reception at the back of the block, so last weekend I ran some RG59 through the basement and up the fence, breaking out to some hookup wire running along the back fence.

This works much better (I can actually listen to 702 if I ignore the bias lol) but there is some roll-off at the top of the band. So I need to do it properly with a matching transformer and a local ground.

When I get the right ferrite to make the transformer I'll report back.


 
 Return to top of page · Post #: 9 · Written at 8:15:44 PM on 13 October 2017.
BringBackTheValve's Gravatar
 Location: Linton, VIC
 Member since 30 December 2016
 Member #: 2028
 Postcount: 60

Robbert,

Last night I tuned into 1377kHz on my beloved Stromberg Carlson.

At approx. 2040 LST another station began beating in, gradually at first but quickly dominated.

The image station presented two American gentlemen discussing biblical references. My first impression was my beloved (I cannot praise that receiver enough) SC had DX'ed a USA station, but no.

Next morning I checked in my workshop and another receiver (crappy cheap Grundig contemporary copy) hooked up to a 150 metre LW antenna was also getting clobbered, not by U.S. A. dialogue, but Aussie. Bloody horse racing!

Yep. 3UZ. 927kHz belting through.

Tonight, as I type this email, I am back indoors with my gorgeous SC (God I love that receiver) listening to Melbourne's Classic Rock Radio.

On the side I have two other receivers on standby. If and when I get clobbered I will be able to determine for sure if 3UZ are the culprits.

Will report soon.

And, regarding the gentlemen I thought were coming through DX from the U.S.: I believe 3UZ may have a side program later at night which does contain religious content, as well as overseas racing results etc.

Got to go The Doors are playing on 1377kHz.

Cheers,

G


 
 Return to top of page · Post #: 10 · Written at 8:38:04 PM on 13 October 2017.
GTC's avatar
 GTC
 Location: Sydney, NSW
 Member since 28 January 2011
 Member #: 823
 Postcount: 3972

So, image frequency interference as I suggested?


 
 Return to top of page · Post #: 11 · Written at 11:46:18 PM on 13 October 2017.
Robbbert's avatar
 Location: Sydney, NSW
 Member since 18 September 2015
 Member #: 1801
 Postcount: 671

3MP is certainly a good station, that's for sure.

So at that house I listen to 2CH during the day, and 3MP at night. 2CH is good strength at daytime and gets stronger at night. Evening is the worst because the ground wave and sky wave are changing and producing horrible cancellations. 3MP can sometimes be heard just before sunset, then nothing for a while, then slowly comes back and gathers strength through the night.

Most Melbourne stations are difficult to receive here due to only being 9kHz from Sydney stations.

At this house I don't bother with radios, being on the internet means I can simply listen to 3MP or MMM classic radio online.

I can actually listen to 702

702's antenna is visible from out the front of this house. With its red lights, it looks like a giant valve in the distance at night. I'd expect a crystal set could produce a roomfull of sound when tuned to 702 or 2RN.

my beloved Stromberg Carlson

I was at Wynyard station today, and they've replaced the old wooden escalators to York St with nice shiny metal ones, looks really nice. Above them is a giant advert from 1948 featuring Stromberg Carlson radios.


 
 Return to top of page · Post #: 12 · Written at 6:15:22 AM on 14 October 2017.
Brad's avatar
 Administrator
 Location: Greenwich, NSW
 Member since 15 November 2005
 Member #: 1
 Postcount: 4375

I was at Wynyard station today, and they've replaced the old wooden escalators to York St with nice shiny metal ones, looks really nice. Above them is a giant advert from 1948 featuring Stromberg Carlson radios.

I saw that about a week ago and I was too far down the escalator to grab a photo. I think it was a view of a part of the station with an advertising billboard in the background showing a woman using a Stromberg Carlson radio. It was cheeky of Stromberg to place that ad there so close to the head office of AWA.

As for the old escalators, it was a shame they required replacement. I guess that nothing lasts forever and they were quite worn after being in service for a good 80 years and they didn't meet current safety requirements - modern escalators can sense when toes get caught in them and shut down before half your leg ends up dragged between the treads so the writing was on the wall. To the credit of those who did initiate the replacement, the new escalators have kept the original look with timber panelling between each escalator and even the bumps to stop hoodlums sliding down them. I think one of the oldies still remains at Town Hall Station and it'll most likely go soon.


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Brad.

A valve a day keeps the transistor away...

 
 Return to top of page · Post #: 13 · Written at 8:06:47 AM on 14 October 2017.
BringBackTheValve's Gravatar
 Location: Linton, VIC
 Member since 30 December 2016
 Member #: 2028
 Postcount: 60

GTC,

There seems to be a numerical relationship with the two competing stations and the standard 455kHz IF.

If we minus 455kHz from the 1377kHz wanted station, we end up with 922kHz, pretty close to 3UZ's 927kHz.

I never did get a good handle on image frequency in class, but I reckon there is a good chance 927kHz is imaging at 1377kHz.


 
 Return to top of page · Post #: 14 · Written at 9:04:55 AM on 14 October 2017.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 2729

The ultimate objective of the frequency used for IF was to have it such that its heterodynes did not fall on a radio station frequency: Spacing originally 10's, so we changed it to 9, more likely to add more profit than any substantive concrete reason. This is rather why I like HMV's around 457.5KHz

If you have an issue? The accuracy of the Signal Generator can play a part. Calibrating a Signal Generator with the Tone/ Modulation "ON" will in many cases cause it to be wrong.

There may well be benefit in checking the IF calibration. At risk of loosing signal etc, when there is more than one IF Transformer, you can try setting one IF slightly low & the other high & increase the rejection a bit more either side.

Most IF's run on the high side of the incoming signal, so adding IF frequency (& harmonics) to the station frequency should give an indication of where each multiple is going to land. Even 455 + 455 = 910 comes into play 457.5 + 457.5 = 915 which is not a station in the old system

There are stations in Argentina, Canada, Mexico & several in USA that broadcast on 1380KHz & that's close enough to sneak in.


 
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