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Author Topic: Kenwood MB-430 Bracket Warning. Why?  (Read 2012 times)
WB5JEO
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« on: October 28, 2009, 08:43:55 PM »

Kenwood repeatedly cautions about using the MB-430 bracket to mount the radios it's designed for vertically, with the rather vague warning about adverse effects on operation. Does anyone happen to know just what adverse effects they anticipate, particularly with the 440SAT? And have you actually experienced a problem in near vertical mounting or know of someone who has. I'm looking at an angle of anywhere from 45 to 60 degrees off horizontal, the days of generously overhung dash assemblies with plenty of room underneath being long past.
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N3OX
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« Reply #1 on: October 29, 2009, 04:56:32 AM »

The TS-440S has some fairly microphonic circuits in it.   The hygroscopic rubber potting the  VCO circuits that causes all the problems with  dots was to help mitigate this.

I can imagine that having road vibration forces (which I would guess are going to be more vertical than horizontal) parallel to the circuit board by mounting the radio vertically would be worse in terms of microphonics.  The board has no flex at all, relatively speaking, in the in-plane direction, for example.

I don't know that this is a problem, I'm just speculating.  I did take all the goo out of my TS-440 to fix the dots problem and I remember during the testing process, if you tap it hard it does indeed have some microphonics... you can make a CW carrier frequency go "boinnngggg..." by hitting the radio hard enough :-)

I'm imagining that this would be worse for vibration in the plane of the circuit boards vs. transverse to that plane, but I could be wrong.

73
Dan
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73,
Dan
http://www.n3ox.net

Monkey/silicon cyborg, beeping at rocks since 1995.
AA4PB
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« Reply #2 on: October 29, 2009, 05:34:01 AM »

I would expect it is a heat issue. If the radio has a rear heat sink and its mounted face up then the heat sink doesn't get good air circulation and the generated heat rises up thru the radio to the front panel.
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K0BG
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« Reply #3 on: October 29, 2009, 06:14:23 AM »

Bob nailed it. Not only is it microphonic as Dan indicates, the cooling is sub-standard no matter what you do to circumvent it. The 430, and the 440 share this problem, by the way.

Personally, I wouldn't run one mobile unless you want to sound like a hillbilly with a twang, and I'm not being facetious.

Alan, KØBG
www.k0bg.com
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WB5JEO
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« Reply #4 on: October 29, 2009, 08:49:38 AM »

Thanks for those. I note that some makers of commercial mobile radios also warn against vertical mounting, and I assumed it was worry about heat issues. I find a good number of folks who ran it mobile without complaint, but we know various radios have their own particular known issues that don't always appear but, when there are problems, those are the most common. I would expect a radio with less than well-designed heat handling to be sensitive to anything that tended to work against its heat dispersion, and I suspect vertical mounting would do that. And, of course, the glue issue is mentioned a lot. I'll be alert to those problems with what will likely end up being a mounting at about 45 degrees, maybe a bit less. It's otherwise not a difficult mounting, and a bumpy road test will be done early. (Crown Victoria, so at least it's not in a rough-rider pickup.) Hopefully it won't have to be in mobile service too long before a new compact HF mobile takes its place.
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VE7DQ
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« Reply #5 on: October 29, 2009, 06:35:38 PM »

I'm curious.  Where does Kenwood assert a vertical mounting for the radio?  I'm looking at the document that comes with an MB-430, and it says nothing about vertical mounting; in fact, it illustrates horizontal mounting of the radio in at least three different places.  My '430 manual says nothing about either vertical or horizontal orientation.  The '440 manual has one sparse paragraph and two notes about mobile operation; nowhere does it discuss the orientation of the radio.  The only caution they mention says... "Do not install the TS-440S near the heater outlet".

Am I mis-interpreting your definition of 'vertical' mounting?

In any case, and in my experience, most problems with the final section of the '430 and '440 have more to do with solder connections on the PA circuit board than the cooling capacity of the heat sink; for normal SSB operation the cooling is more than adequate.  

First I've heard of the microphonic issue, though... I'll try one of my '430s in the truck the next time I go mobile.

In the mean time, JEO, go for it.
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WB5JEO
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« Reply #6 on: October 29, 2009, 07:22:06 PM »

Their warnings appear with reference to the mount itself. For example:
http://www.who-sells-it.com/images/catalogs/639/196/ct/TS-2000Brochure_0001.jpg

It always mentions "operation and safety." I understand the "safety" reference as largely lawyer language. Odd that it would consistently appear in advertising and not in the mount manual itself. I just wondered if anyone had actually put the 440 into mobile service mounted vertically or nearly vertical and had a problem they could associate with the orientation. So far as I can find, it's never been described by any user who put their experience anywhere on the Internet. Or if someone had actually asked Kenwood what they were worried about. I begin to suspect it's just a matter of them designing the thing with horizontal mounting in mind and not wanting to be accused of it being inadequate. Mine has certainly not overheated on the bench, which seems to me to impede air flow more than most mobile installations. I actually could get close to horizontal, but I was trying to leave the pull-out cup holder affair functional in the Crown Victoria.

(I know. But gotta have a cup holder. Right?)
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VE7DQ
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« Reply #7 on: October 29, 2009, 08:03:37 PM »

Interesting!  Note, however, that this warning shows up on the TS-2000 brochure.  Perhaps there's something unique about the '2000.  

The warning does not appear on the TS-440S brochure, or in the 430 and 440 instruction manuals.  Draw your own conclusions.  

Incidentally, my TS-120 mount puts the radio at about 60 degrees, and I notice no operational difficulties with it.  I'll use the same mounting angle with my '430, but it'll be a couple of weeks before I get a chance to get mobiling again.
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VE7DQ
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« Reply #8 on: October 29, 2009, 08:09:45 PM »

Yes, cupholders.... ah, yes!  Maybe they don't want coffee or cola slopped into the front panel of the radio, what with all that expensive microprocessor and control circuitry in there.  That's about the only reason I can think of for not mounting it vertically.  Yessss... I've seen it many, many times in vertically mounted commercial service radios...

There ya go!
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K0BG
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« Reply #9 on: October 30, 2009, 06:25:52 AM »

There are actually two problems being discussed here.The microphonics and the heat-related ones.

As Dan pointed out, the microphonic issue has to do with the way the VFO is mounted. As the radio ages, so do the mounts, and the microphonics gets worse. This effects more than just the 430/440.

The vertical mounting is a heat issue. After extended use, the heat sink gets rather warm, as it does in all SS radios. When the radio is vertically mounted (heat rises after all), when you go back to receive, and the fan stops, there is still enough latent heat seeping up through the radio to cause problems. One of those is the aging of the VFO mountings.

With respect to the 430, it has another problem also related to heat. It is not uncommon for the second mixer (as I recall) to drift enough to cause the filter bandpass to shift. This causes the opposite sideband suppression level to climb; a fact you can clearly hear if you tune off the main frequency.

By no means are transceiver problems related to just Kenwood. Icom, Yaesu, and all of the rest, have design problems from time to time. In some cases, they go on and on over several models and years, before things get 'fixed'. After all, there is an R&D expense issue with any for-profit company, and the consumer pays the price.

Alan, KØBG
www.k0bg.com
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WB5JEO
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« Reply #10 on: October 30, 2009, 07:34:24 AM »

I'll make some accommodation for air flow. I guess I'd give them a pass on a lot of the heat problem. At the time, all the makers were trying to develop more compact rigs, and that meant playing the heat issue pretty close to what they figured was the critical line. And it's not really practical to put a radio into real-world service for a few years prior to release. I have no idea if they do any environmental chamber testing, but with price an issue, that testing that's commonly done for mil-spec stuff probably isn't cost-effective, since it's a major project in itself to do it right. It's like the joke sign says - you can have it cheap or you can have it right, but you can't have it right and cheap. And of course it wasn't specifically designed for mobile service. True commercial mobiles typically become outdated long before they die, even when trunk mounted in a patrol car with the trunk crammed with other stuff through all sorts of temperature extremes. I don't recall many of the old Motorolas just up and dying without being electrically abused, and even that was rare, even among the tube and dynamotor units of the 60's.
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N2IK
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« Reply #11 on: November 10, 2009, 06:21:56 PM »

Remember also that public safety grade Motorola radios cost about ten times what ham radios cost. I would have no radios if I had to pay what the public service grade radios cost.

73 de Walt N2IK
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