AM and FM DX


#2131

Thanks mate, here’s the video so you can send it to them & see what we mean, I had another video from years ago when it was doing similar but can’t find that one now.

At this location 2GO should be clear & in stereo, even though it’s close to Mt Sugarloaf.

You might have to turn the video volume up to hear it clearly?

NEWFM Spur over 2GOFM

Bit of a background & insight to the issue, I’ve been thinking about it all night, & am going back to my original theory about the old VHF Band 2 NBN TV antenna, being the cause?

This wide bandwidth spurious issue with NEWFM has been going on for a number of years, it’s not permanent & does happen at any time of the year, but mostly seems to show itself around summer time, thus annoys the local DX fans as it blocks a number of out of area frequencies.

This issue never happened until more or less straight after NBN TV turned off their Analogue transmitter on VHF Channel 3 & has been happening ever since. I don’t think they’ve done it (& probably won’t due to making it a lightning attractor), but I’d like NBN to ground their old VHF Band 2 antenna stack, or remove it completely from the tower & see if it solves this issue?

I think it may be picking up, mixing & re-radiating various FM stations? I have heard 102.9 KOFM lower down the band as a spurious transmission before, but unfortunately NEWFM is the worst, being quite strong at times & seems to be more often & for longer periods of time than any of the other local stations.

If you look at this latest occurrence, it’s the sum of the difference between NEWFM on 105.3 & KIISFM Sydney on 106.5 with the resultant audio falling on a generated frequency of 107.7 which happens to be 2GOFM Gosford, & it’s strong enough to wipe it out completely in an area where 2GOFM is normally easily & clearly receivable.


#2132

If that’s the case, I wonder why it’s only really NEW FM that’s affected and why it’s not permanent?

The spurs on various frequencies from 104.5 to 105.9 haven’t been there for some time now, and could be heard as far away as Singleton and Bulahdelah, even during the cooler months.


#2133

What I find interesting is that despite the “spurs” from New FM, it’s actually the most difficult Newcastle commercial FM station (with KOFM Triple M Newcastle usually being the best) to receive in my home location of Sydney during tropo! :confused:


#2134

It’s not permanent as it would depend on the strength of the other frequencies the antenna’s picking up & how strongly the frequencies mix, hence it’s always been worst around the summer months.

As I mentioned this time it would be 105.3 & 106.5 (Sydney) mixing/adding, with NEWFM being the predominant audio.

I never checked, but there’d likely be another spur on 104.1, which could actually have KIIS as the predominant audio?

As I also mentioned I have heard 102.9 lower down the dial in the past, but the ultimate reason it’s mostly NEWFM is the nearby used frequencies, & where in the band the added & subtracted mixed frequencies fall.

Most 106.9 issues would fall outside the top of the FM band & 102.9 would be lower down the band or possibly even fall on 105.3, but around most parts of Newy that wouldn’t be noticeable.


#2135

For me in the Campbelltown area, that’s not the case, as 2ST from Bowral, which also broadcasts on 102.9, comes in strong, hence why 102.9 Triple M (formerly KOFM) would be the most difficult Newcastle commercial FM station to receive in my home location during tropo, whilst New FM & Hit 106.9 are more easier to receive.


#2136

Thanks, that makes sense, in a way, I hope you are wrong on the VHF 3 antenna being the cause, as that sounds like it could be problematic in getting someone at NBN to fix it!


#2137

Something similar could have been going on with Mount Canobolas a few years back. Maybe it’s still going on for all I know. I picked up Smooth FM audio on 89.5 at Millthorpe in 2015, and a one-time MS member did the same with 106.5 (Mix, as it was then) a few years before that.

(I actually nabbed the ID in that clip at 0:52).


#2138

What a catch! I saw your Gulgong video not that long ago and thought how??? They are really some good pick ups, I mean all the sydney commercial fms from over 300kms away!!!


#2139

There was some tropo about at Gulgong that morning as luck would have it (even though it was late June). Not regular reception on a car radio.


#2140

What does tropo actually mean?


#2141

Tropospheric ducting. This page provides an excellent summary. Basically, in certain weather conditions (usually high pressure), FM signals get trapped in an inversion layer and can refract back to earth well beyond the horizon.

Sporadic E (or E-skip- ‘Es’) is another type of propagation and involves reception between 800- 2500 km. It occurs when dense groups of solar charged particles enter the ionosphere (100 km above the surface), mainly between late November and late January in the Southern Hemisphere. The signals refract off this area of ionisation. There are a couple of events per year where double hop E-skip occurs; signals either refract twice off the ionosphere or ‘bounce’ between patches of ionisation. Distances for double hop E-skip average around 3500 km.


#2142

Ok thanks, so does that mean fm signals could travel an extra 200-300 kms this summer or every summer for that matter? Is 200-300 kms normal during tropo? Or how far is it normally?


#2143

It really depends on what sort of weather is present- generally, hotter and drier summers are better for tropo, though. Tropo levels are always better in summer than winter.


#2144

Skip on FM can’t be too far away. Receiving activity on 6m (50Mhz) today from SA, QLD & NZ


#2145

Did a quick band scan on the car radio at my location, no eskip but there is currently enhancements of Newcastle, Port Stephens, and Middle Bro. Have not checked on the home hifi with omni fm antenna as that gives best dx reception for northern signals.


#2146

Yes, it’s been quiet in the last week or so with the cooler weather around.

Today is a bit more humid and overcast, I will have a check tonight!


#2147

For lack of a better place.

I am replacing TV antenna in Brisbane. The problem is lack of antennas available that cover Band II and III to allow simultaneous DTV and FM reception.

The old antenna covers 0-69 and I could position it to receive some out of area FM like Breeze, Rebel, Mix, River, Hot, Sea FM etc. and have this amplified and split (about 8 times) and piped into A/V amps, bedroom DAB/FM system, computers etc. Not a DX- quality installation but it gave much better reception and more choice than a piece of wire out the back of a tuner.

Same problem must arise for MATV systems on buildings that want to provide an FM and TV socket in apartments.


#2148

Why do you need to replace it?

Also, the wider the coverage is, the less effective it’s likely to be on any frequency (which you probably already know).

Best bet is Jaycar or Hills maybe?


#2149

The plastic has perished from the UV rays.

I’ve asked around and haven’t found anything to suit.


#2150

Please… not Jaycar!!! Hills are properly manufactured. Most of the Jaycar stuff is junk.