AM and FM DX


#2151

FM yagi

try this

https://zcg.com.au/d/Y204BSS/

http://www.radioparts.com.au/product/00442056/y3fma-fm-radio-antenna-aerial-hills#.W-zDe8JoSUk


#2152

Thanks -but I was looking for an antenna that covers Band II FM and Band III metro TV all in one.


#2153

Yeah, I guess they would be harder to find now that metro areas don’t need wide band VHF antennas anymore now that all VHF is CH 6-12 only.


#2154

This isn’t really a long-distance catch, but I thought I would go into detail about it anyway as it’s somewhat related to the topic. I decided to go for a drive up to Oran Park yesterday afternoon. I can remember there being discussion on MS not too long ago about how Power FM’s signal is not as strong in Sydney as it used to be, so while I was driving around the area, I decided to switch over to Power FM and see what the signal was like for myself.

Thanks to my dashcam, I was able to record the moments where Rhema FM interfered with Power FM’s signal. Here is a snippet from when I drove eastbound towards the Oran Park Town Centre:

As you can see, the reception of the two signals in the Macarthur area is very fickle. Power FM’s signal was patchy in Narellan, but I was able to receive it quite strongly driving northbound on The Northern Road around Cobbity. It wasn’t until I drove into Oran Park that Rhema FM’s signal had completely wiped out Power FM. Just as a side note, i’m glad that I was able to listen to “Shine” in it’s entirety. :wink:


#2155

Coincidentally I was out Liverpool way. I quite enjoyed 89.3 FM 2GLF. Its only 80 W, I think SWR is like 200 W. Wonder how well 2GLF go towards Macarthur?


#2156

That sums up my experience with Power Fm in that area too.

Since moving to the new Win TV Tower with more directional antennas, and Rhema’s increase in strength now they are on the Sea Fm tower. Power fm now only just makes it to their licence boundry at Hill Top interference free.

I cannot receive it at all at my location in NW Sydney. When I have ducting from the south there is some slight co-Chanel interference to Rhema at best. Eagle fm is much easier to receive at my location then Power Fm.

In contrast since Wave and i98 moved tower with Power Fm, and installed their new antennas, their signal is now much stronger into Sydney. I98 does not suffer from co-Chanel interference from News Radio anymore at my location.


#2157

Based on my coverage maps from their site at Mt Pritchard, 2GLF gets out quite well towards Denham Court and Ingleburn, but patchy further south as you go into the Macarthur. They are better on the Holsworthy side out towards Campbelltown.

What let’s down 2GLF is their broadcast site is quite low compared to 2SWR which is about 100m ASL higher.
2SWR is restricted to 50W towards Liverpool and Macarthur but with their height advantage gives them overspill into these areas.


#2158

I do notice SWR reception , does start to slide faster south of the transmitter, think it is also related to the topography too. HHH really gets wiped out around the Horsley Park area. Up my way, SWR is still able to be received in the Hornsby area although does suffer cochanneling at Waitara but you can listen to it.


#2159

Don’t know if that NEWFM spur on 107.7 issue has been fixed?

I discussed this with another tech at work, & did a number of calculations, turns out it seems, that this particular event, is a third level intermodulation problem, caused by (most likely) 102.9 KOFM interfering & mixing with 105.3 NEWFM.

Exactly where & why it’s happening I can’t answer not being the tech on site, but NEWFM techs need to check all filters, & shielding of the TX’s & associated program input gear, & try & find where & why KOFM is getting into the NEWFM TX.

I also can’t answer why it’s not permanent, & predominately happens around summer time, but I still feel the old NBNTV VHF Ch.3 antenna array has something to do with it?

You asked before why KOFM never seems to have this issue only NEWFM, well KOFM it seems is a major cause, & also doing other calculations, when some of the other stations mix with NEWFM, the Inter-mod spur falls on 102.9, so you’d likely not hear it over the main 102.9 signal, the 102.9 signal to noise should be noticeably different though.


#2160

I did notice that too in relation to SWR reception to the south. To the north it starts to slide north of Blacktown City. At my location at Stanhope Gardens it is at moderate strength. Alive 90.5 from Baulkham Hill comes in much stronger for me.


#2161

When I walk my district, I enjoy walking a lot, I take this radio these days rather than my dab one. This locks in fm radio stations better than any other pocket radio I had. In my area Pennant Hills for local community radio, HHH number one, Northside radio 99.3 number two, then Alive 90.5, maybe 88.5 then SWR 99.9. but it depends where I walk.


#2162

Is there any plan to remove the Ch3 VHF antennas off the tower since they are now no longer in use?


#2163

No not to my knowledge, unless there’s big tower works planned, or they need extra tower loading capacity or space, generally the cost to remove, outweighs the risk of leaving it there.

Broadcast Australia have hundreds of unused antennas on towers around Australia, & even hundreds of unused transmitters in the TX huts, because the cost to remove & dispose of, outweighs no cost to leave as is, unless tower or building space is needed.

BA gifted TXA the UHF antenna on the Artarmon tower in Sydney, & I’m sure they’ve done the same/similar to other tower owners elsewhere, as the cost to remove was greater than the cost of loss.


#2164

Would they reconsider this if your hunch is correct and the mixing problems are associated with the VHF Ch3 antennas.

I guess it is only the dxers who are noticing this. If 2GO was getting wiped out by the spur in their coverage area SCA would be making a big deal about it!!

Down in the Gong they went to the effort to completely remove the old Win Analouge tower!!!


#2165

I definitely notice that The Edge 96.1 has much reduced strength these days. Have they reduced RF power? I98 is also much weaker than it used to be & Wave FM unaffected. - I noticed the post about these two up in the chat.

It also seems that Way-FM 91.9 Canberra has moved to the Jerrabomberra TX site? (Judging by the reception on a portable radio)


#2166

Probably not, but if it’s confirmed & NEWFM can’t do anything else to stop it, ACMA can force it to be done, under interference rules.

Yeah, but kinda funny considering it’s SCA causing the issue.


#2167

Its very hard to tell here at Charlestown, 2GO is very strong here, just as strong as NEW FM really, that spur is only detectable where 2GO is a bit weaker. I won’t really know until I get in my car on the weekend and go down into Newcastle.

Thanks for your replies on the other Qs too.

Its the NEW FM audio that can be heard on 107.7, so isn’t it more of a NEW FM issue?

Otherwise, wouldn’t the spur be on 100.5 (2.4 mhz down from 2KKO) and not 107.7? (2.4 mhz up from NEW))


#2168

C91.3 in my view has improved.


#2169

Enhanced reception from the north tonight with Rockhampton commercial (RDS) and community stations (stronger than ABC) plus Gladstone and Yeppoon. Also Mackay ABCs and MMM 98.7


#2170

Actually it depends where the inter-modulation is happening?

If it’s somewhere in the NEWFM chain, then yes it’s their problem.

Unlikely as NEW has had similar issues multiple times over the past few years, but it could be in the KO chain, then it’d be their problem.

If it’s the old NBN Ch.3 antenna (like I think is a good possibility), or even coming from a rusty joint on the tower structure itself, that’s generating the inter-modulation spur, then it’s ultimately NBN TV’s problem.

If it’s definitely NEW & KO mixing (which I’m convinced it is, having done multiple calculations), then there will also be a spur on 100.5, but with the strength of 2RPH around Newcastle, you won’t hear it underneath.

There will also be a 5th order inter-modulation spur on 98.1 (which will be even weaker than the 100.5 & 107.7 spurs), so if you can get a complete null of 98.1 Gosford & Muswellbrook close to Mt Sugarloaf, you may hear that one too?

Yes this Spur on 107.7 is still active, I was at Edgeworth again today in a different car & it’s still a problem.