Shookdown! VHF transmitting but not receiving...?

[KeithH]

As Vic S says "Channel 80 is a two frequency channel on the International set used in the Uk but a single frequency channel on the American set". The international frequencies for the duplex Ch80 are vessel transmit = 157.025. vessel receive = 161.625. However, the US channel 80A is a simplex channel operating at 157.025.

So... if your radio has accidentally been switched to the US frequencies, you will be able to transmit on the same frequency as the marina receives, but not hear their reply.

It turns out that many international VHF radios can be switched to the US frequencies- often by doing something like holding one or two of the buttons down - guess why I know that! Worth looking in the instruction brooklet.

My radio shows the word "INT" on the display when in international mode, and adds an A when in US mode.

One way of checking is if you leave the radio on CH80, you might hear others calling the marina, when of course normally that is not possible do do that if on "proper" international Ch 80.

 

[MagicalArmchair]

Thank you for all your help. As suggested, I posted the VHF off to ICOM and, even though the unit is as old as the hills, they repaired it free of charge as it was the DSC filters with the known fault. It’s all fitted back to the boat now and works a treat.

If only you could get that service from other companies!! Our AEG microwave (£400 of it!) failed after four years, do you think they would help in any way?? No chance, even when I waved the consumer goods act at them.

Great service from ICOM, I will be buying their gear again.

 

[Amani]

Apologies for resurrecting an old thread, but this seem quite relevant to the problem we're experiencing:

As another person has mentioned, ICOM radios are susceptible to IF Filters failing. I have replaced literally dozens of them in the last 5 years or so. If it is a DSC radio then ensure the DSC IF Filter is replaced at the same time!
Takes about an hour to strip the radio, remove old filters and replace with new ones.
Getting the solder out of the ground PTH is sometimes a sod.
If you are only 'average' with a soldering iron then best to bite the bullet and have someone more proficient repair it for you.
Cost of parts and labour shouldn't be more than £50. The filters are about £5 each or less at trade.

Regards,
Stephen

Our Icom M411 marine VHF does not receive DSC messages. Everything else works fine - sending DSC, voice ops both send & receive. Antenna has recently been measured good, MMSI is programmed correctly. We can send a DSC message to a buddy boat but never receive their acknowledgment (which is being sent, tested with a third radio). What makes this a safety issue is that we're not receiving our own PLBs' MOB alerts over DSC either.

This issue had me baffled since I assumed that voice & DSC use the same analog circuitry... until I read the above discussion about bad IF filters... so
- is the M411 is one of the models affected?
- does the M411 have a separate IF filter for DSC?
Then I would guess our DSC IF filter is shot.
- are there any other plausible causes of what we're seeing?

Since we're in Luperon (Dominican Republic) we'll probably have to organize a repair ourselves.
- does anyone have a service manual and/or circuit schematics for the M411?
- what are these IF filters called as components? is there a model number, a specific value to get?

Any help appreciated! Cheers, Nic on S/V Amani

 

[Ian_Rob]

Thank you for all your help. As suggested, I posted the VHF off to ICOM and, even though the unit is as old as the hills, they repaired it free of charge as it was the DSC filters with the known fault. It’s all fitted back to the boat now and works a treat.

If only you could get that service from other companies!! Our AEG microwave (£400 of it!) failed after four years, do you think they would help in any way?? No chance, even when I waved the consumer goods act at them.

Great service from ICOM, I will be buying their gear again.

Same here. ICOM fitted new filters on my 16 year old IC505 free of charge the week before last. I posted it on the Friday and it was back with me 9.00am the following Thursday. Excellent service.

 

[Bilgediver]

Deleted

 

[Amani]

Well, Icom Germany did not offer to have our radio repaired free of charge. A friendly service technician did however tell me the exact IF filters to get: LTM 450 EW (Icom part number 2020002490). He also advised to exchange both IF filters simultaneously. There seem to be no major hurdles to doing this for someone who knows how to solder, the biggest challenge being to desolder the old 5-pin filters.

Thanks for putting me on this track!

 

[Refueler]

Not saying its in this case ... but most company's if the fault has been known and subject of recall in past - even if years ago - they will repair free of charge later.

This has happened with a few items of mine .. one that stands clear in mmy memory is my Sony Handycam .... even though such item had been surpassed by digital - I took it into a Sony dealer who took one look - said - ARRRR yes the main switch ... come back in couple of hours. Went back and all fixed ... charge ? Guy just answered - it was a recall years ago - doesn't matter how long later - recall still applies.

 

[Amani]

Not saying its in this case ... but most company's if the fault has been known and subject of recall in past - even if years ago - they will repair free of charge later.

This has happened with a few items of mine .. one that stands clear in mmy memory is my Sony Handycam .... even though such item had been surpassed by digital - I took it into a Sony dealer who took one look - said - ARRRR yes the main switch ... come back in couple of hours. Went back and all fixed ... charge ? Guy just answered - it was a recall years ago - doesn't matter how long later - recall still applies.

Generally speaking, sure. But in our case Icom Germany explicitly told me to turn the radio in to one of their dealers for repair at my own expense. There was also an undertone of "don't bother us with this ancient model, buy a new radio" to the entire conversation with customer service (as opposed to that technician - he was great).

Just reporting this as a counterpoint to all the positive experiences posted above with (I presume) Icom UK. Your mileage may vary.

 

[Refueler]

Generally speaking, sure. But in our case Icom Germany explicitly told me to turn the radio in to one of their dealers for repair at my own expense. There was also an undertone of "don't bother us with this ancient model, buy a new radio" to the entire conversation with customer service (as opposed to that technician - he was great).

Just reporting this as a counterpoint to all the positive experiences posted above with (I presume) Icom UK. Your mileage may vary.

Not arguing your point .. I've had some really shitty response to repair requests ... for boat stuff - worst I had was Raymarine ...

Called them - you would think I just called them all back from holiday or something ... the conversation on the phone was literally - go away - cannot be bothered.

I was just posting that some of these repairs people quote as 'gold stars' for a brand - could as I found a number of times and when I've told the story to others - had similar response from them .. they are 'recall' items.