I had a guy email me via my Dad's Radio web site, saying he had problems receiving 2CH Sydney, does anyone live in Sydney and can you receive 2CH ??
The email reads............
wondering if you can help with a problem I have with my hmv radio..its recently been restored and unfortunately doesnt like my favourite am station,2ch,1170..it does pick it up ,strongly in fact but the audio is riddled with whistles,whines,and howling type noises,volume is fine. the radio picks up plenty of other stations but none are music ones ..is there anything that can be done to fine tune 2ch ?? also just to test I tried a refurbished stromberg carlson bakelite mantle,this is worse, wont pick up 2ch..not a whisker..other stations are fine..any ideas ??

I am in pretty much the opposite situation. I work in North Sydney and have a radio in my office which is in service between 07:30 and 16:00. It picks up 2CH and 2SM (I only listen to 2CH) clearly but they gradually decline in performance from there going back to the start of the dial. 2UE and 2GB are audible but not exacly loud. 2KY and 2BL can barely be heard and 2PB and 2RN are so weak that it is painful to try and hear what is being said.

I think it is more to do with the radio itself rather than transmission issues and the same may apply to your contact's receiver. I don't have the necessary equipment to perform detailed alignment procedures on a radio so I do it by ear and if it gets the stations I want to hear then I usually leave it at that.

In my experience, 2CH is able to be received strongly in most parts of Sydney and beyond, so my guess is the problem is the receiver and/or it needs a better aerial.

I'd suggest that he try tuning 2CH on a modern receiver, say in his car, for comparison.

Also suggest asking what part of Sydney your correspondent is in, and when the problem is worst: daytime or nighttime.

If it is just the one station, then I would guess the receiver may be located very close to the transmitter and perhaps picking up some artifacts of transmission reflected from structures nearby (even a tin shed might affect received signal), or spurious emissions that don't travel far from the transmitter. The interference could be a product of the specific location plus the specific modulation frequency.

2CH used to transmit from Homebush Bay along with some of the other commercial AM broadcasters in Sydney - is the receiver close to there?.

Another wild thought - could there be some grimy dust in the tuning condenser that is shorting some of the capacitance just at the point where, or near, 2CH should be tuned? Cleaning the condenser vanes is not hard.

Maven

It could be RFI from a computer, or a switching power supply, or a computer modem. See if another radio in the same location gets the same RFI.

If it is just the one station, then I would guess the receiver may be located very close to the transmitter...

There are parts of Gore Hill and Artarmon (North Shore suburbs of Sydney) which have black spots for all transmissions including the digital television signals the towers located here transmit. This is hard to fathom for most people though residents in the blocks of flats on the Pacific Highway in this area have better luck tuning into the signals from regional networks transmitting from Knight's Hill near Wollongong. Even in North Sydney where I work we get a strong signal from Prime, WIN and Southern Cross.

Driving past the ABN2 transmitter tower blacks out every radio signal I try to tune, AM or FM. It's a case of when a 5kW signal from Homebush Bay comes up against several 1.2MW signals from close by it's a case of Goliath defeating David in the biggest way possible.

It is odd that only one station is affected 2CH is a nightime station here but normally only has the normal fading in and out. That can be a product of location as 2AY (Albury) works OK here during the day but as the day moves to evening, then it starts the fading in and out.

Interesting, as that one is not far from me. The higher the frequency, the more is the tendency for those type of stations to send signal upwards.

HMV distincly tells you that if you change components within the RF section then it needs to be re-aligned and they rarely use 455kHz.

If the alignment is wrong, there is the chance of it impinging on the AGC, which derives it's voltage from the signal strength.

Valves like 6U7 are virtually uncontrolable if their shields are missing, if there are superhetrodyne whistles, then something is not right.

An oscillation from within the set is quite feasably, strong enough to shut down the set via the AGC.

Moving parts around when refurbishing, can help cause instability, via induction.

I think that set needs more work: It is not right. HMV's don't normally by design, have bad habits.

What model is it? Eg the last HMV I fixed / restored was an 880


Marc

It has been many years since I was in Sydney and listening to 2CH whilst in the metropolitan area.
Was always under the impression 2CH was always strongly received throughout the city area without any problems.

Keeping in mind many nowadays have computers, all sorts of battery chargers or other gadgets with switchmode power supplies they would be the first target.

Sitting here in my workshop if I have any sort of valve AM radio running have to switch off the computer monitor and 3G modem as well as unplug various plugpacks etc before I can do any real on air testing.

There may well be a spurii being emitted dead on 1170kHz from any of these devices.