Yeasu FSM-400DXR Wiring

[kcjaz]

The spec for my Yeasu FSM-400DXR says the max amp draw is 12 amps. I want to run a dedicated circuit from the battery and need to know the correct wire size. When I Google that I found a table that says 8 awg for 15 amps for 25 ft of wire. Seems heavy to me. I have some 10 awg marine wire. What say ye electrical gurus?

 

[kcjaz]

Found this. I think my 10 awg wire will be ok for the 12 amps and length I’ll have.

http://assets.bluesea.com/files/resources/newsletter/images/DC_wire_selection_chartlg.jpg

 

[prharper]

I am running 10 gauge to my Yaesu, no problems.

 

[manofthewoods]

The spec for my Yeasu FSM-400DXR says the max amp draw is 12 amps. I want to run a dedicated circuit from the battery and need to know the correct wire size. When I Google that I found a table that says 8 awg for 15 amps for 25 ft of wire. Seems heavy to me. I have some 10 awg marine wire. What say ye electrical gurus?

YIKES! That be some thick wire. I have a FT8900, I don't recall the manual mentioning any gauge at all. Maybe they're being really conservative?
73s

 

[kcjaz]

YIKES! That be some thick wire. I have a FT8900, I don't recall the manual mentioning any gauge at all. Maybe they're being really conservative?
73s

I think 12 amps is a peak value. I doubt it draws 12 amps all the time.

 

[manofthewoods]

I think 12 amps is a peak value. I doubt it draws 12 amps all the time.

Exactly, peak is TX @ full power, 50 watts. I have mine set to time out @2 minutes of TX. Generally, TX/RX ratios are really low.
For my rig I had to extend the length, I simply matched the gauge.

 

[linuxgod]

The spec for my Yeasu FSM-400DXR says the max amp draw is 12 amps. I want to run a dedicated circuit from the battery and need to know the correct wire size. When I Google that I found a table that says 8 awg for 15 amps for 25 ft of wire. Seems heavy to me. I have some 10 awg marine wire. What say ye electrical gurus?

The BlueSea chart is the best reference, IMO

You can likely use the "non-critical" column as a 10% voltage drop from ~13.5A will still be above 12V nominal and I'm pretty sure your radio will work fine. This says use 12ga for up to 30' @ 15A. Note that's 30' round trip and 15A peak but you should never plan to run more than 80% of peak for continuous load (which would in this case be 12A anyway).

FYI for round trip if you can ground to the body it's like running a smaller gauge for "+" and getting a huge gauge wire for the return "-" almost for free.

 

[manofthewoods]

The BlueSea chart is the best reference, IMO

You can likely use the "non-critical" column as a 10% voltage drop from ~13.5A will still be above 12V nominal and I'm pretty sure your radio will work fine. This says use 12ga for up to 30' @ 15A. Note that's 30' round trip and 15A peak but you should never plan to run more than 80% of peak for continuous load (which would in this case be 12A anyway).

FYI for round trip if you can ground to the body it's like running a smaller gauge for "+" and getting a huge gauge wire for the return "-" almost for free.

View attachment 3033072

I thought about, and wanted to ground to the frame too. But the Yaesu manual says to run + and - directly from the battery. Perhaps to obviate noise issues???

 

[kcjaz]

The BlueSea chart is the best reference, IMO

You can likely use the "non-critical" column as a 10% voltage drop from ~13.5A will still be above 12V nominal and I'm pretty sure your radio will work fine. This says use 12ga for up to 30' @ 15A. Note that's 30' round trip and 15A peak but you should never plan to run more than 80% of peak for continuous load (which would in this case be 12A anyway).

FYI for round trip if you can ground to the body it's like running a smaller gauge for "+" and getting a huge gauge wire for the return "-" almost for free.

View attachment 3033072

I didn’t realize you had to consider “round trip” in these charts. I would have thought the voltage drop of consent would be just to the radio.

 

[Markuson]

I thought about, and wanted to ground to the frame too. But the Yaesu manual says to run + and - directly from the battery. Perhaps to obviate noise issues???

I ran my same HAM unit off of already-shared power running to the rear area… which runs both pos and neg to my 2nd battery via the firewall bib on passenger. No issues with noise (and an excellent radio). I used a 10 and its been excellent. I also added an in-line fuse to be safe. Super easy to add up nearer the battery in the engine bay. Never blown one.

That high power draw is only when transmitting at the highest power setting…and that’s usually only for brief moments here and there anyway. While listening/monitoring, it consumes far less.

**Random tip on that particular Yaesu:

**If you use an external speaker (and you really will be glad if you do)…make sure the speaker’s plug is a three-contact plug. If only two…you’ll only hear audio from one of your two bands you can monitor. -It uses the left/right of the 3-connector to play audio from each. So…With just two, you’ll end up thinking somethibg is broken…but its not. It just needs all three.

 

[kcjaz]

I ran my same HAM unit off of already-shared power running to the rear area… which runs both pos and neg to my 2nd battery via the firewall bib on passenger. No issues with noise (and an excellent radio). I used a 10 and its been excellent. I also added an in-line fuse to be safe. Super easy to add up nearer the battery in the engine bay. Never blown one.

That high power draw is only when transmitting at the highest power setting…and that’s usually only for brief moments here and there anyway. While listening/monitoring, it consumes far less.

**Random tip on that particular Yaesu:

**If you use an external speaker (and you really will be glad if you do)…make sure the speaker’s plug is a three-contact plug. If only two…you’ll only hear audio from one of your two bands you can monitor. -It uses the left/right of the 3-connector to play audio from each. So…With just two, you’ll end up thinking somethibg is broken…but its not. It just needs all three.

Do you have a picture or maybe a link for the speaker you used? I’m not quite sure what you mean by three connector speaker.

 

[prharper]

Do you have a picture or maybe a link for the speaker you used? I’m not quite sure what you mean by three connector speaker.

He is talking about the external speaker cable that plugs into the receiver.
I ordered a Yaesu external speaker with my FSM-400DXR w/ mod from Gigaparts but they sent me wrong speaker.

This is the replacement they sent that works.

Search results for ZYS-MLS-200-M10 GigaParts.com

GigaParts is the premier destination for the latest in technology products and hobby gear, catering to a wide range of interests: Amateur Radio: A variety of amateur radio equipment and accessories. Computers: Custom PC builds, gaming computers, and ready-to-go PCs. Astronomy: Telescopes...

www.gigaparts.com

WATERPROOF EXTERNAL SPEAKER -
ZYS-MLS-200-M10
$38.95

BTW - After using for over a year, I lost audio on the 70 centimeter band. 2m band worked fine. I did a factory reset of the unit and 70 cm band audio started working again - didn't touch the cable into the receiver. Reloaded my Yaesu config and memories using ADMS-M400 programming software from RT Systems and all good.

If you are coming back to LCDC, some of us can use APRS for vehicle location which is cool.

 

[kcjaz]

He is talking about the external speaker cable that plugs into the receiver.
I ordered a Yaesu external speaker with my FSM-400DXR w/ mod from Gigaparts but they sent me wrong speaker.

This is the replacement they sent that works.

Search results for ZYS-MLS-200-M10 GigaParts.com

GigaParts is the premier destination for the latest in technology products and hobby gear, catering to a wide range of interests: Amateur Radio: A variety of amateur radio equipment and accessories. Computers: Custom PC builds, gaming computers, and ready-to-go PCs. Astronomy: Telescopes...

www.gigaparts.com

WATERPROOF EXTERNAL SPEAKER -
ZYS-MLS-200-M10
$38.95

BTW - After using for over a year, I lost audio on the 70 centimeter band. 2m band worked fine. I did a factory reset of the unit and 70 cm band audio started working again - didn't touch the cable into the receiver. Reloaded my Yaesu config and memories using ADMS-M400 programming software from RT Systems and all good.

If you are coming back to LCDC, some of us can use APRS for vehicle location which is cool.

Thanks. My confusion is the “three contact plug” statement. I only see a single mini plug on this speaker.

 

[prharper]

Thanks. My confusion is the “three contact plug” statement. I only see a single mini plug on this speaker.

See photo of my external speaker cable. This is what @Markuson was referring to, 3 contacts each separated by small black rings on plug.

 

[kcjaz]

See photo of my external speaker cable. This is what @Markuson was referring to, 3 contacts each separated by small black rings on plug.

View attachment 3035698

Ahh. I’m waaaay to literal. Thanks.

 

[Markuson]

Ahh. I’m waaaay to literal. Thanks.

Yes. Many after-market speakers have only 2 contacts here…since, after all, its one soeaker & not stereo. BUT…Yaesu just happens to use all three…and feeds to two frequency monitors to the one speaker that way.

So if your speaker only has two…you’ll only hear one frequency correctly.

Cool Option though…
One cool option this quirk does enable though…is that you COULD run a stereo cable directly into your AUX jack (my 2008 has one)….and dedicate AUX to monitoring on your truck’s stereo.

**This would put one frequency’s comms on the right…and one on the left…which moght actually be cool since it would help your brain know which group’s comms you’re hearing without having to look at which of the two frequencies its coming from.

Would be great when communi ating separately with a tail gunner or leader privately on one…while keeping group comms on the other.

 

[linuxgod]

Yes. Many after-market speakers have only 2 contacts here…since, after all, its one soeaker & not stereo. BUT…Yaesu just happens to use all three…and feeds to two frequency monitors to the one speaker that way.

View attachment 3036065

So if your speaker only has two…you’ll only hear one frequency correctly.

Cool Option though…
One cool option this quirk does enable though…is that you COULD run a stereo cable directly into your AUX jack (my 2008 has one)….and dedicate AUX to monitoring on your truck’s stereo.

**This would put one frequency’s comms on the right…and one on the left…which moght actually be cool since it would help your brain know which group’s comms you’re hearing without having to look at which of the two frequencies its coming from.

Would be great when communi ating separately with a tail gunner or leader privately on one…while keeping group comms on the other.

You're correct, in a mono cable only has 2 (tip and sleeve) where as a stereo has 3 (tip, ring, and sleeve).

If your speaker is only wired for mono, why not just get a mono-to-stereo TRS adapter to mate with the radio?

Amazon product ASIN B0919C5D93
No special wiring required. I'm surprised you need this though because normally a stereo source into a mono speaker plays through both sides, but a mono source into a stereo speaker only plays out one side.

 

[Markuson]

You're correct, in a mono cable only has 2 (tip and sleeve) where as a stereo has 3 (tip, ring, and sleeve).

If your speaker is only wired for mono, why not just get a mono-to-stereo TRS adapter to mate with the radio?

Amazon product ASIN B0919C5D93
No special wiring required. I'm surprised you need this though because normally a stereo source into a mono speaker plays through both sides, but a mono source into a stereo speaker only plays out one side.

Ya, thats a workaround for sure.

The main reason I mention it at all is because this quirk isn’t always obvious, & people can end up wrongly assuming something is wrong with their radio.

 

[kcjaz]

So it seems I need to buy the male part of this plug for power?

I would expected the male part and short pig tail in the box.

 

[prharper]

So it seems I need to buy the male part of this plug for power?
View attachment 3036913
I would expected the male part and short pig tail in the box.

Should have been in the box.