Sensitive Marine Radio Recommendation for Monitoring

MDScanFan

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I have a separate thread in the antenna forum on trying to improve my fringe vhf marine reception at home - the focus is on the coax and antenna. I figured this is a better location for discussion of a radio specific question. I notice more variation than I was expecting in reception quality among a few analog RS scanners. Some of the radios either don’t catch a transmission or if they do it is more noisy than the others.

For my setup I plan to dedicate an antenna and a radio to marine receptionI am wondering if a dedicated marine radio would work better than a scanner in this situation?

I am looking for feedback on that question and possible recommendations for radios I should consider. I see a bunch of new and used handheld and mobile marine radios on eBay but I have no idea how well they work on receive. I would be willing to spend $50-$100 to give one a try but don’t know where to start and whether it is worthwhile.
 

RFI-EMI-GUY

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Since you are focusing on the marine band. I woukd suggest that the receiver having best selectivity will be required in order to filter out NOAA weather broadcasts which are powerful. A notch filter, if you can find a very good one may help. To answer your question a dedicated marine radio, or a decent VHF commercial radio may be best because you can actually compare specifications
 

N5XPM

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Good thought here. The marine band radios are already programmed and tuned for the 156-162 Mhz band and ready to go. Marine radio jargon includes dual and triple watch, etc. to follow more than one channel. Scanning may not be particularly fast, which may not matter if there are not too many channels involved. A VHF commercial radio covers a larger band but not be programmable for the Wideband like the marine band radios are. Commercial radios also introduce a learning curve and hardware / software to program them. I have some good experience for ICOM, but there are some good Unidens and others as well. Most marine radios also include weather alert functions as well. I would recommend the ICOM 300, 400 or 500 installed series if I was going to try this approach. For receive only, you would only need a 2 -4 amp power supply. Like to hear how this goes.
 

RFI-EMI-GUY

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Yup N5XPM. I programmed up a VHF Motorola Systems Saber with VHF marine and it was a bear to do so. A decent fixed mounted marine radio with published RX specs is where I would start. If nearby a NOAA WX TX, the receiver IM spurious and adjacent channel specs woukd be where I would focus.
 

jcop225

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Should be able to find a Motorola CDM1250 for around $100 and I'd hazard a guess it has better selectivity than you'll find in an off the shelf marine radio. They can be programmed for wide FM and most sellers will probably program the marine channels you're interested in and set up a scan list for you.
 

mmckenna

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I agree, there are some nice marine VHF radios out there. Hook them up to 12 volts, connect your antenna and you're good to go.

I'd be interested to see how sensitive they really are. The low price on some of them concerns me.Would be interesting to put some on a service monitor and see how they do.

There are a lot of good VHF commercial radios out there that will work, but keep in mind that marine VHF is not narrowband, so some of the newer radios will need to have the wide band access capability to work. As jcop said, CDM's are cheap on the used market and perform pretty well. Programming software/cable can be expensive, depending on how you choose to approach that challenge.
A number of the newer Kenwood radios will perform well, also, most of the newer ones are Part 80 certified, not that you'd be transmitting.

For overall price, I think getting one of the existing VHF marine radios would be a good approach. Should be more sensitive and selective than your scanner. If you want to expand later on, look for a used CDM-1250, CDM-1550, Kenwood TK-7180, NX-700, etc. They'll all do what you want if you have wide band access.
 

MDScanFan

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The Motorola 1250 has some nice specs but i am inclined to stick with a radio that does not need to be programmed.

I took a look at the specs for some icom and standard horizon radios. Sensitivity is 0.22 to 0.4 uV, selectivity of 70-80 dB, spurious and intermods of 70-80 dB. The sensitivity is on par with my scanners but the selectivity, spurious, and intermods are much lower.

For reference I also looked at a 2m mobile (icom 2100h) and it is 0.18 uV, 60 dB, and 65 dB, respectively. This seems on par with some of the marine radios I found.

I don’t have a good feel for what spec levels I should target or a first trial with a marine radio. I suspect any of them will be better than my scanner so maybe I am splitting hairs among them. What do you think?
 

Ubbe

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It's difficult to judge a radio by its specs. When you see sensitivity figures they are measured in a lab enviroment with no interferencies. That's not how its gonna operate in the real world.

I heard from users of marine radios that they are not particulary good receivers compared to land mobile radios. On the sea you have few interferencies and are far away from any big powered transmitters. Land mobile radios made to be used in a city have to cope with a lot of interferencies and have to withstand close by transmitters that could overload a receiver. Any Motorola type of radio are usually good. Try and contact a local HAM club and listen with them if they can program a Motorola radio for you and then choose to buy a radio that they have the software and cables for. You would look for a radio with several scan lists that can be programmed with different scenarios and that will include the current selected channel in the list and have the option to manually exclude channels from the list, nuisance delete.

I know that Motorola Mc-Micro that are a german model have an excellent receiver that makes them good in basestation applications. It has a squelch that automaticly gets to a more open state with a long squelch tail when the signal are weak, just the thing you want when you listen to fringe signals, but when the signal strenght goes up it has very thight squelch with almost no squelch tail. I haven't seen any other radio having that type of dual squelch action.

I cannot fault TYTs MD380 radios, they are solid as a brick and are unaffected by any interference and they also have DMR. It's the most sensitive receiver I have for fring signals that are very weak and have a steady reception while adjacent channels are being keyed. You probably will see the same with most radios that use narrow varicap tuned filters that follows the frequency you are monitoring. Try to avoid direct conversion receivers, most dual band radios are that, and cheap radios like Baofeng doesn't work.

/Ubbe
 

PACNWDude

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Icom IC-M602 radios have a very sensitive receiver. Just do not try to use two of them on the same vessel, that can become a problem. They are also usually $300-400 each. However, the most selective Marine VHF radios I have ever maintained where the older Motorola Triton, Triton II, and Tritin II+ marine VHF radios. These can still be found on auction sites and at some marina's that have older commercial vessels. These radios are old enough that they came out long before digital Selective Calling (the red "panic" button) and are housed in a mostly metal case to keep out unwanted noise from other electronics nearby.
 

MDScanFan

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I researched options on the used market. My preference is to stick with a marine radio instead of a land mobile radio that needs to be programmed. And I don’t want to invest too much in this initial trial, <$100.

From my searching the Icom M3xx and possibly M4xx line of radios seem like potential candidates. Such as the M312, M322, M402, etc. Do you have any feedback on these radios for what I am trying to do? Anything else to consider?

Also, for what is is worth, I ran some more radio comparisons. The best so far is my ol’ HTX212 2m mobile. Signal quality is better than the three scanners I tried. Perhaps that points to a dedicated marine band radio helping with reception over a broadband scanner.
 
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N5XPM

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The positive results on the 2m mobile make sense, as it is designed to only work in the VHF hi band, which is where you want to be.
 

cbehr91

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Lots of options that will do better than a scanner. Any number of 2m rigs or CCRs will receive the marine band better than any scanner. I and many others have used 2m rigs for rail monitoring (the rail band is slotted in the 160-161 mHz range, so right near the marine band). The Yaesu VX150/170/FT-250/270 are all good. I have a Kenwood K20 that hears really well, but is a bit prone to intermod. I also have an AnyTone 518UV that does a good job. Its selectivity seems better than the Kenwood. The Kenwood TM-281 is what I use for a mobile. Another excellent radio.

As far as scanners, the one I've used that heard the best were the Regency HX1000/1200/1500 series made in the 1980s. Also prone to intermod though.
 
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