Quote:
Originally Posted by fairbank56
The Icom M-604 has a pigtail microphone jack on the back of the unit that is electrically in parallel with the microphone jack on the front of the unit so all you need to do is connect this to the DVR assuming the MIC level is enough to drive the DVR for recording of the transmit audio. Do you have a link for the marine DVR?
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That's what I was leaning towards right now. (I made a typo in my previous post and said IC-M60 instead.) There don't seem to be many VHF's with removable microphones, and that one has the best receive capabilities I can find for under $2000. If the microphone level is not high enough, is there a way to amplify it from the radio side? Also, I don't see any pinouts in the manual. Do these radios usually have a
service manual available?
The marine DVR can be found at
this url. I was told that the VHF interface would only work with their DVR and wouldn't be compatible with our PC-based recording system. From a technical standpoint, I don't understand how that would work - audio is audio, right? The only thing I can think of is that maybe they have figured out a way to crack into the command mic interface, and it requires some processing with their proprietary computer
software to convert into an audio stream.
Quote:
Originally Posted by Healer52
I don't understand your comment about the scanner....just put it on the simplex/output freq and record on a DVR or whatever. If it's recording the output of the repeater it doesn't matter that your antenna is lower - unless you're outside the antenna aperture. Thats why repeater outputs are on high antennas: For big coverage.
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We don't have a repeater. As much as I'd like for us to have one, we just use standard VHF marine radios for all of our communications. There is only one high antenna for us to use, and it would be difficult and cost prohibitive to add another antenna to our shared tower.
Quote:
Originally Posted by Healer52
If you want to record local simplex chatter on handhelds, a similar receive-only device will work, at the scene. You can put it in an otterbox or something for waterproofing. There are very inexpensive VOX (voice activated switching) switches available as well, to save tape/space.
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If two boats are out of range of each other, the one radio that can hear both of them is at our communications center. It would be possible to record audio at the scene, but it would ideal to keep recording centralized in our communications center. The existing system also runs in the background with no human input required. If the
equipment were carried on the boats, it might get turned off accidentally, or the files might not be transferred back to the communications center.
Quote:
Originally Posted by daddle
Given your requirements re antenna, channel tracking, recording it looks like your only option is to swap in a VHF with a recording option built in (probably some expensive police basestation), OR have an engineer modify your existing radio. The modification would seem to be straightforeward and $2000 sounds about right.
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A regular land mobile base station like most public
safety agencies use would not be type accepted to operate on the VHF marine band. I have had trouble getting this clarified, but the consensus from the radio shops that I have contact is that even with our FCC
license, we still need to use type accepted VHF radios - they can't just program a land mobile radio to work on VHF marine frequencies. As much as I'd love to get a Spectra or a shiny new XTL-5000, they just can't be legally programmed.
If it costs $2,000 to modify an existing VHF radio, I'm better off
buying a class A
DSC radio with a dedicated output to a VDR and a superior receiver. I'm hoping that there is a way to just tap the microphone cable and mix it with the receive audio, since we don't have that kind of
budget.