I've got a CRT Micron 2M/70CM transceiver that I'm looking at modifying to allow the front panel to be mounted remotely. A quick peek inside shows the front panel uses a short length of 10-way FFC connects the panel to the radio - 20624 0.5mm pitch forward pin layout.
Back of faceplate with FFC disconnected
FFC
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What I'm exploring is if it would be practical to mount the fascia on the dash, then run suitable cable to the main body of the radio in the NSR of the car where I have appropriate power and can run a sensibly short length of co-ax to the antenna. What I'm trying to avoid is excessive lengths of antenna co-ax, which is usually the problem when you have your transceiver in the front of the car and your antenna cable exits at the rear. More co-ax = more signal loss and SWR issues.
Has anyone any experience of running 5m or thereabouts of FFC? I'm guessing I would be better off finding some connectors and using some shielded cable with 5 twisted pairs rather than unshielded FFC over that kind of distance.
Or should I just sell the transceiver and buy a Yaesu 300DR or similar which is designed to operate with a remote faceplate, albeit the prices are I know it's not considered "kind" to say no these days, but no. Just no, ok? And if it's not ok, still no.
5th Jun 2022 1:59 pm
Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10683
It’s unlikely you will be able to significantly extend that and it still work trouble free
I figure I have two obstacles to consider. First is the increased resistance over distance - and I can't find any datasheets that give any info on resistance. Second is EM interference, which I could counter with the use of shielded cable, but from taking a look at a Yaesu cable that is used for remote head on one of their current model it doesn't seem to use shielded cable, just twisted pair.
May have to put this on the "don't be so cheap Al, buy the right kit" pile. I know it's not considered "kind" to say no these days, but no. Just no, ok? And if it's not ok, still no.
5th Jun 2022 5:33 pm
Green Land Rover
Member Since: 21 Oct 2017
Location: Stourbridge
Posts: 412
I agree with Pete K. The increased capacitance by extending the cable will affect the digital signals driving the display.
I think the FT-8100 can run with a remote display.
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How often do you need to use the head unit controls? In other words have you considered extending the mic cable instead? You should have a better chance of even buying something ready made off the shelf. Is it an RJ-45 plug? You could still have the head unit reasonably accessible in the boot for control if necessary.
Edit: for example
Ethernet Extension Cable 5M, ShinKey Cat6 Shielded Male to Female Cat 6 Ethernet Extender Cable Adapter RJ45 Cords (5M)
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5th Jun 2022 6:13 pm
epninety
Member Since: 12 Oct 2012
Location: Hampshire
Posts: 329
I've extended FFC out to 2m length before, while carry high speed differential digital video signals, with no problem, but that was about the limit, for that application.Likewise Gigabit ethernet over 1m ffc with measurable degradation to the waverforms, but not enough to be measurable in the data thoughput.
Without a circuit diagram, or direct experience on that exact radio, any answer is mostly guesswork.
There's two ways to answer the question, either find out what signals are on the ffc, or just buy an ffc and try it.
Twisted pair isn't going to help you unless the signals are differential and you know which signals are which.
My guess would be it's most likely that the main unit 'intelligence' lies on the display PCB, and there the ffc carries audio, low speed signalling and likely IIC or SPI signals to control the PLLs and the like. If thats the case, you still have the same problem, IIC (and to a lesser extent SPI) don't like to run over long cables. There are ways to get around that, but it's probably more work and money than you want.
Cheapest, quickest solution would be to buy some better coax for the antenna and use that.
BTW more coax = more signal loss as you say, but more signal loss technically means less SWR issues
(Every extra 1dB of feeder cable loss means 2dB increase in return loss from the radios point of view (1dB on the way up, 1dB on the way back), so an improvement in SWR.
How often do you need to use the head unit controls? In other words have you considered extending the mic cable instead? You should have a better chance of even buying something ready made off the shelf. Is it an RJ-45 plug? You could still have the head unit reasonably accessible in the boot for control if necessary.
Edit: for example
Ethernet Extension Cable 5M, ShinKey Cat6 Shielded Male to Female Cat 6 Ethernet Extender Cable Adapter RJ45 Cords (5M)
Less the controls, many of which can be used from the handset/mic. It's the dual-watch feature where being able to see the second channel "spike" on the signal strength meter that comes in handy.
I'm leaning towards just grabbing an FTM300 before the price increase that's expected with the next batch. Much simpler way of doing it! I know it's not considered "kind" to say no these days, but no. Just no, ok? And if it's not ok, still no.
BTW more coax = more signal loss as you say, but more signal loss technically means less SWR issues
(Every extra 1dB of feeder cable loss means 2dB increase in return loss from the radios point of view (1dB on the way up, 1dB on the way back), so an improvement in SWR.
I know it's not considered "kind" to say no these days, but no. Just no, ok? And if it's not ok, still no.
5th Jun 2022 7:30 pm
James W
Member Since: 27 Mar 2008
Location: Riyadh, KSA
Posts: 3079
Go for the FTM300. Me and my radio chums are using C4FM digital loads and loads now it's fantastic. Loads of System Fusion repeaters and gateways around now too, I'll often be chatting with friends directly on digital on a local repeater and others further away (globally of you fancy) patch in easily via WiresX or a YSF reflector. So easy.
FWIW if you keep the box and bits, you can get almost all your cash back on Yaesu kit if you want to shift it on in future. It's a safe investment.
Good luck however you go with it
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5th Jun 2022 8:11 pm
KevinD3
Member Since: 05 Aug 2020
Location: Sutton Coldfield
Posts: 1277
If your trying to do this to keep the Ariel coax length as short as possible, is there a reason you’re mounting at the rear?
Got mine mounted on the dash and the Ariel goes through the front bulkhead grommet to the engine bay then up the front pillar, Ariel is mounted onto the front of the cargo rails.2008 HSE Stornoway Grey
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5th Jun 2022 10:12 pm
epninety
Member Since: 12 Oct 2012
Location: Hampshire
Posts: 329
D3 really isn't so big that this is much of a problem...
With the radio on the dash, and antenna near the tailgate, how much cable do you need?
If the feeder was 5m long, even RG58 will have a loss probably below 2.5dB at the maximum frequency of this radio, and only 1.1dB on 2 metres.
2.5dB is worth trying to improve upon if you regularly operate on 70cm. RG8X is cheap and improves the loss to 1.5dB. Plenty of other options, e.g. Aircell 7 (first example I found, though not one I've used) would get the loss below 1dB, and be a lot cheaper than a new radio!
If you've managed to lose 10m or more of cable under the third row seats, then maybe? I always remote mount a radio thats capable of it, even at HF, but I'm not sure the extra fraction of a dB while mobile would justify the cost jump to change radios.
Of course, if you just fancy a new radio, that's different.... we all understand that motivation
If your trying to do this to keep the Ariel coax length as short as possible, is there a reason you’re mounting at the rear?
Got mine mounted on the dash and the Ariel goes through the front bulkhead grommet to the engine bay then up the front pillar, Ariel is mounted onto the front of the cargo rails.
Freelander 2. Not possible to run up the A pillar, and the bulkhead grommets are pretty well full anyway. So needs to exit the cabin at the rear lights, up the B-pillar than towards centre of the roof.I know it's not considered "kind" to say no these days, but no. Just no, ok? And if it's not ok, still no.
D3 really isn't so big that this is much of a problem...
With the radio on the dash, and antenna near the tailgate, how much cable do you need?
If the feeder was 5m long, even RG58 will have a loss probably below 2.5dB at the maximum frequency of this radio, and only 1.1dB on 2 metres.
2.5dB is worth trying to improve upon if you regularly operate on 70cm. RG8X is cheap and improves the loss to 1.5dB. Plenty of other options, e.g. Aircell 7 (first example I found, though not one I've used) would get the loss below 1dB, and be a lot cheaper than a new radio!
If you've managed to lose 10m or more of cable under the third row seats, then maybe? I always remote mount a radio thats capable of it, even at HF, but I'm not sure the extra fraction of a dB while mobile would justify the cost jump to change radios.
Of course, if you just fancy a new radio, that's different.... we all understand that motivation
There's one thing to factor in, which is the frequencies for my commercial license make maintaining a sensible SWR a bit tricky if I want to retain use of the ham frequencies.
I've been allocated 164.nn, 169.nn and 173.nn mid and high band, 449.nn & 458.nn UHF. Now these would be used for reasonably short range stuff, so being a bit out on SWR for these isn't the end of the world, but it starts to seriously suck down on output given these frequencies are limited to 5W. I may be going back to plan A, which was 2 antenna and a switch.I know it's not considered "kind" to say no these days, but no. Just no, ok? And if it's not ok, still no.
6th Jun 2022 8:14 am
epninety
Member Since: 12 Oct 2012
Location: Hampshire
Posts: 329
I still can't see why you think a shorter feeder cable is going to make that problem any better?
2M of RG58, assuming 5W at 169MHz with SWR of 2.6 (which is as good as I get if I mid-tune for the ham frequencies) gives me 4.5W, vs 3.8W with 5M of the same cable.
Not huge drops in the grand scheme of things, but if £10 of ribbon cable gave me that 20% increase in output back, I'd be daft not to give it a go.
I'll park this one under "idle thoughts from a bank holiday weekend" and give it a thorough ignoring for the time being.I know it's not considered "kind" to say no these days, but no. Just no, ok? And if it's not ok, still no.
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