Not good reception in specific frqs excellent in others, why?

[spanky15805]

I might be way off base but doesn't Greece use 8.33khz channel spacing? Might be a very small part of the problem. Didn't see any of the 8.33khz offsets in any of the videos.

 

[ATCTech]

I wondered that initially but what I read from the UK CAA shows

25 kHz frequencies end with: 00, 25, 50 or 75.
An 8.33 kHz channel will have a 6 digit channel ending: 05, 10, 15, 30, 35, 40, 55, 60, 65, 80, 85 or 90.

so I'm assuming his 118.625 and 118.675 labels are indeed properly centered frequencies for his 25 kHz step radio. The charts I've looked at show the frequencies published as 118.62 and 118.67, which is technically correct given the the aircraft's radio will select the trailing '5' by default. If someone from the EU or UK can chime in and confirm that please do!

 

[spanky15805]

Trying to find the info for EuroControl that is current isn't easy. Everything 6-8 years old. I know it was mandated for everything above FL195 in 2009. Plus he has some big hills between him and 2 of the 3 airports he wants to listen to.

 

[kbantikos]

Trying to find the info for EuroControl that is current isn't easy. Everything 6-8 years old. I know it was mandated for everything above FL195 in 2009. Plus he has some big hills between him and 2 of the 3 airports he wants to listen to.

https://www.eurocontrol.int/sites/d...n/files/201707-8.33-vcs-user-handbook 1.1.pdf
page 16
and my icom does not have 8.33 tuning step
Yes indeed I have big hills but I listen even to the ground services and the other frq of the tower the problem lies in some very particular frqs and I will not rest until I will find out dead or alive

 

[ATCTech]

Page 30 of that EuroControl document is also very important for understanding the over-the-air phraseology of relaying frequencies, directly connected to what I mentioned from the UK CAA. I didn't see anything specific about "right to the ground" use of 8.33 but I did read 19500ft and below was being added to the radio requirement 3 or 4 years ago. It'll be spelled out deep in ICAO Annex 10, which is the bible of all things telecommunications in aviation not just as a guild, it's the rule book to which any and all deviations must be justified.

 

[Ubbe]

You can set wide or narrow filter for both FM and AM mode. Try to change that setting.

I looked in the service manual, available here: https://www.radioamatore.info/attachments/601_IC-2200H_Service Manual.pdf and the transmitter sends full power straight into the receiver and then there are diodes that conducts and tries to shortcircuit the power to ground. A terrible solution as any of the diodes can go bad and then also partly shortcircuit some of the RX signal or work as a diode mixer creating interferencies.

That guy on Eham that bought two 2200h had one being worse than the other. Icoms specification says that it only guarantees the specifications beteeen 144-147MHz. That 118-136MHz range can be very different in some transceivers.

There's a service mode, hold in two buttons at power up, and do the same to exit it, where you can step thru the settings and adjust the filters for best reception. But that sets the receiver to some fixed frequencies, 118.020 and 136.020 that will require a signal generator with adjustable output signal level.

/Ubbe

 

[kbantikos]

You can set wide or narrow filter for both FM and AM mode. Try to change that setting.

Yes I have done this nothing changes really only the way you hear the signals, it changes only the modulation.

There's a service mode, hold in two buttons at power-up,

Yes there is but it needs the adjust rig which it does not come with the purchase of the machine and of course i don't have it

h
oh man this is painful almost hurts physically where ever I turn around there are only obstacles
if I change this transceiver have you got any better to suggest me mostly for airband? this is just a thought, first I wanna spot the nature of the problem and if all goes to hell maybe I'll start thinking about changing it.

 

[ATCTech]

I'm still using a pair of 30+ year old Icom ICR-7000s, excellent old(er) beasts.

 

[krokus]

If by the mean of hot spot you mean this

then yes it's most probably tv or radio.

I think there is an FM radio station in that interference, which I think is 97.1 to 97.3 MHz. (I presumed that the radio's IF is 10.7 MHz, so I subtracted double that from the shown frequency: 118.625-21.4=97.225 )

 

[ATCTech]

From the Icom 2200H manual:

1st IF - 21.7 MHz
2nd IF - 450 kHz

Spurious and image rejection - More than 60dB

However, that doesn't rule out intermodulation, or the mixing of 2 or more external frequencies resulting in a 3rd (or 4th of whatever...) That can occur externally or within the radio, depending on the circumstances.

 

[kbantikos]

Found it, it is a radio station 90.4 fm

Κανάλι Ένα 90,4 FM | Piraeus

Κανάλι Ένα 90,4 FM, Piraeus, Greece. 9,562 likes · 546 talking about this. Δημοτικό Ραδιόφωνο Πειραιά www.kanaliena.gr www.youtube.com/user/kanalienagr

www.facebook.com

 

[ATCTech]

So an FM band-stop filter may be in order to at least see if part of the problem can be eliminated?

By the way, I forgot to ask you this 3 days ago when we first started talking about noise sources right near you and you said you'd run the radio on a battery with no positive impact on the noise floor. Now that I see very clearly in the larger photo the 12VDC supply you're using is a switching power supply, that's a huge no-no with radio equipment and I truly hope when you did the battery power experiment that the Alinco supply was FULLY turned off, as in unplugged from the mains, not just disconnect from the radios? Whether it's directly affecting the problems we're sorting through or not you really should invest in a good linear supply and put anything and everything switching as far away (like in the garbage!) as possible. If you must continue to use it, please move it a long way from the radios, many feet at least, as even that may help a bit. Any other small wall-wart supplies like that can also be noisy as heck.

 

[kbantikos]

So an FM band-stop filter may be in order to at least see if part of the problem can be eliminated?

That's definitely for sure I've got to start from somewhere, have you got any suggestions for a man living in E.U?
i mean is this filter going to help?

https://www.freebytes.com/catalog/product_info.php?products_id=1746&language=en

Please set in mind in Greece my choices are limited so I am looking rather from abroad. PAR electronics seems great but it's in U.S
Regarding the rest of your post received it loud and clear and i will act accordingly although i have removed as far as possible the icom from Alinco i did not notice any differences and yes i have killed the entire's house electricity so Alinco was not working either basically nothing was working at all.
Also, any suggestions for any airband base scanners or transceivers or even handhelds doing good with an external antenna mostly for Airband listening to, it would be highly appreciated please set in mind that i prefer them in new condition and not used cause as i just said Greece has very limited choices to put in in a nice way.

 

[kbantikos]

After purchasing a connector (to connect my handheld to the exterior antenna and see how it goes) to test if the bandpass filter that I already own works I can say that it works like a charm but it does not have any effect on my icom so we forget about a better perhaps airband filter like the above mentioned and I am heading directly towards an FM band-stop filter as already mentioned by ATCTech the rest of questions remain as it is.

 

[Ubbe]

That's definitely for sure I've got to start from somewhere, have you got any suggestions for a man living in E.U?i mean is this filter going to help?

It attenuates the signal to less than half in the air band and only attenuates 6dB at 104MHz. Get something like this: FM Notch Filter, FM stop band filter, RTL SDR T820 Flightaware ADSB 2m 70cm | eBay or this: RTL-SDR.com Broadcast FM Band-Stop Filter | eBay and get som coax with the correct connector at the ends, or adaptors. 20cm RG58 Kable BNC Male Stecker To SMA Male Gerade Crimp Coax Pigtail 20in FG | eBay

/Ubbe

 

[ATCTech]

Good job Ubbe!!

I can't recommend any particular radio from personal experience but the guys here on RR all seem love the Uniden BC125AT (search this forum to make sure I have that model number correct) and it DOES scan/search/save in 8.33 kHz steps. Be really carefull to check that part in anything you consider. Over here nobody is concerned about those steps.

 

[Ubbe]

Over here nobody is concerned about those steps.

It seems that they only use 8.33 at high altitudes in EU where aircrafts have a huge range with their transmissions. At lower altitudes used for approach departure and local control to a tower they assign a 8.33 label that are 5KHz off from the 25KHz bandplan, but when I checked two of those they where spot on to the 25KHz bandplan and not 5KHz off. So usually no reason to not use standard 25KHz bandplan in VHF air in my area and any old scanner/receiver can be used.

/Ubbe

 

[kbantikos]

Same here i have the impression that under a certain FL (flight level) no one is really bothered since in Greece we don't have really air traffic congestion.
Yes, Atctech i have seen that, I was just wondering if I can achieve something better by purchasing any of the icom -a25c or Yaesu fta550l or 450l and connect them to my external D777 antenna with an air bandpass filter, maybe that makes any difference I don't know I will look into it.
I ordered the filter and now I am waiting and when it comes I will DEFINITELY let you know how it went.
Guys (mostly Atctech and Ubbe but and all the others too) thank you from the bottom of my heart for your endless posts help and time you devoted to me I really really really appreciate it and if you ever come to Greece or plan on visiting it please send me a message via this forum I would like to know that.
So thank you one more time and we will talk again when the filter has been tested (RTL-SDR.com Broadcast FM Band-Stop Filter).

 

[ATCTech]

I would *love* to get to Greece someday, but for now I'd settle to just get across the Canada/US border to my Niagara Falls New York mailbox once in a while. It's quite a world we're existing in, stay safe everybody!

 

[ATCTech]

kbantikos, it's six week later... I'm dying to know if you've made any progress!