C4fm 4 sota

Those rh770 are great antennas. I use it on my baofeng and my old icom HT. They just a bit heavy to leave in HT on the walk down.

Team ConFusion were out in force today with Gun, The Cloud and Shining Tor all activated on C4FM. It was sunny but very cold out.

As Fusion is getting an airing on here Yaesu give talks to clubs, free of charge, about fusion and C4FM.
They are coming to my club end of April bringing fusion 2 repeater and handhelds with fusion, C4FM capabilities.

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Many thanks for the info about the high-gain whip antennas, Matt. I’ve ordered one of the cheap ones from China (only £6.79 … what could possibly go wrong?) and I’ll let you know how I get on with it. It is for my Wouxun KG-UVD1P.

Walt (G3NYY)

I’ve no intention of putting a bigger alternative antenna on my handheld. If I want to do that, then I’ve already got an MFD and a SOTA Beam - and an SMA to BNC adaptor.

No, for me the beauty of the handheld is that it is what it is. It is an all-in-one small, lightweight, comapct VHF transceiver that fits inside my coat pocket with nothing sticking out, even when zipped up. So if I plan to do a handheld activation, then I’m going to maximise the benefits of weight/size/convenience. If I want better performance, then the better equipment comes along in a rucksack.

Saying that, I do seem to be getting out, even so.

Saturday 24th February 2018 - Gun G/SP-013 & The Cloud G/SP-015

The route to Gun summit was frozen solid and therefor much easier and more pleasant than usual. Just five contacts were made on this one, four on 2m FM (analogue) including S2S with Paul M0PLA/P on Brown Clee Hill G/WB-002. Only one QSO on 2m C4FM (Fusion), but it was S2S with Richard G3CWI/P on Shining Tor G/SP-004. Is a Fusion S2S a SOTA first? Probably not, but at least it was a first for us.

Apart from the bitter cold, it was a very lovely morning with fantastic bright sunshine and blue sky. When I arrived on the summit of The Cloud, Richard G3CWI/P was still toughing it out on Shining Tor G/SP-004 - an unusually lengthy activation for him, especially considering the significantly subzero temperature!

This time, there was a relative feast on C4FM of five QSOs, including the S2S with Richard. This figure was matched with the same on analogue FM.

A very nice morning’s SOTAing, ahead of another huge game for Macc Town at the Moss Rose. That’s the next stop today.

86 posts in, we still do not if DV gives better performance than FM in the real world.

Of course it doesn’t. It all seems a bit pointless to me, unless you want to play with repeaters.

Walt (G3NYY)

After detailed analysis of my results I have concluded that sometimes it does, and sometimes it doesn’t.

It does offer some new facilities though.

A lot of people would say the same about amateur radio generally.The point of hobbies is to do an activity that you enjoy. I have never seen much need for further justification of what I do.

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I would be intrigued to see the quality of the photos that could be sent using the Data jack and Camera Microphone! You could see the view that the activator sees, certainly a nice idea of what they’re experiencing!

Does the FT-70 come with a socket for the camera mic?? Has it got a space for a Mini SD card??

I know the FT1D and the FT2D have this facility as do the mobile rigs

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I think the answer is no and no for the FT-70. You were a good signal on SP004 on C4FM today btw.

Thanks for the info Richard, I couldn’t hear either you nor Tom, I was running 50 watts C4FM into a 4 ele at 30" AGL. Shining Tor is normally a doddle from here, what antenna did you use??

I was using a low vertical dipole, Tom was on a rubber duck. Both running 5 W.

30inches? Is that the problem?

Hi Matt, I assumed you could hear, as you were calling me? I called you back but no response.

Andy - that is indeed your question, but it isn’t my interest nor my experiment. However, my initial thoughts are that if there is no obstacle then C4FM does better than FM both in terms of distance (more efficient mode) and audio quality (because it’s digital - so if the signal arrives at all, then it sounds great). If there is some obstacle, then FM is better as it still arrives readable, but with lower strength or with noise, or both. Digital if it is obstructed from getting there, is badly broken.

I’d have thought you’d have known all this though Andy? It’s basic and well known stuff about digital vs analogue.

I’m just enjoying it for what it is. It’s just as pointless as CW and SSB.

I know the theory and I know the differences observed and predicted are often very different.

As the voice repeater networking side of any DV system is moot for SOTA, then a major reason for using DV would have to be the fact the DV system should give an improved performance after FM starts to degrade. You should be able to have good quality comms using DV even though FM has become hard work to listen and understand.

A huge plus point of Yaesu’s system is the receivers auto switch between FM and the DV modes. So it’s not particularly arduous for one side to hit the mode button to switch between the FM and DV modes and for both sides to determine which mode works better for the particular case. The info that DV is more beneficial to SOTA activators than simple FM especially for minimal setup activations would be of huge interest to many here. It could be the benefit remains with FM or there’s nothing obvious in the data to suggest one over the other.

If it turns out there’s no benefit or FM is better, then it’s still been a journey worth taking. That doesn’t take anything away from using DV. But it may be greatly anticipated info by those wondering whether to punt or not. As it stands, this particular handy seems to be OK for normal SOTA use on 2m where we all know of the issues. It’s not an unreasonable price for a dual band handy good for SOTA with the benefit of DV. Or it’s a cheap way to get into DV with the advantage that it’s good for SOTA. Two ways of looking at the issue.

As I’ve said, I no longer have a dog in the race having sold, with great delight, my useless D-STAR radio. Useless in that on 2m it was no good for SOTA . If I was buying into DV now, then Yaesu’s system looks to be the best for amateurs. Autoswitching between DV and FM, best quality DV voice audio. Plus all the system/connected benefits if they appeal. It would be where my money would go. DMR seems more commercial in outlook. However, what I really wanted to do then and probably now with linked systems is not easy to achieve. The pragmatist in me uses something which does do what I need.

The CW/SSB debate is pointless as we all know the SNR benefit gained. This iissue is murkier because much of the theoretical work on DV systems for mobile comms is based on the premise of handling moving subscribers. Fusion and DMR leave D-STAR well behind for that. But we aren’t doing mobile use, we’re doing static use. So no, the difference in SOTA operations in DV vs. FM is fundamentally a valid thing to discuss, measure and report.

Well said, Andy, that is the crunch. I will be keen to hear the answer, if anyone actually sets out to do a SOTA style comparison!

As I said, that’s your question, but not one I am aspiring to answer. There are plenty of potential benefits of using Fusion vs analogue FM for SOTA quite aside from the signal (perceived) performance.

The beauty of Fusion is that it happily co-exists with analogue FM so everyone’s a winner.

My experience so far is that the theory you already know, is true in practice Andy, if that helps. But I’m looking at other aspects of Fusion to enhance my SOTA experience TBH. That comparison is of little interest as Fusion rigs do both anyway.

My observations (based on limited data) are that the results are what you would expect.

When the signal is strong, FM and Fusion are similar although the Fusion VOCODER makes the DV sound better than FM due to the completely silent background. When the FM signal is a bit noisy the Fusion system is best by far and when the FM signal is very noisy, the FM signal is best (below the level at which Fusion works).

The audio quality on Fusion is excellent - even on the Narrow setting (which most people use). It does not seem to suffer from the very artificial sounds that other digital voice system seem to suffer from. I have been a bit surprised at how nice it sounds.

The Yaesu handies seem to be factory-set to have a much higher receive audio level for Fusion than for FM so switching between modes gives the illusion that the Fusion signal is somehow stronger. This may be by design (?).

Fusion has added benefits over FM such as caller ID (callsign with name if you want) and a display showing the distance and bearing of the station that you are working (if they have a GPS equipped radio): fun features which might have some value. The other plus is the data capability although it’s unclear to me how accessible that might be. It should be possible to have voice and data running at the same time.

Digital Wires-X is pretty neat but is really only very usable if you have an FT2DR or a mobile.

Battery life on my FT2DR is much less than an FM handy but it is doing a lot more as it has APRS running too.


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