Icom IC-9700 PTT switching - something I do not understand.

EDIT - now that I have an IC-9700, here is my first view of it ..
 http://gm4fvm.blogspot.com/2019/07/ic-9700-first-look.html
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EDIT - This posting has now been made redundant after 2 years waiting by the DX Shop PTT multiplier - see here.
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I have, of course, been watching developments on the IC9700 front for some time. It looks like and interesting radio for those of us who work on both 144MHz and 430MHz, and adds 1296MHz for good measure.

Maybe I have got this wrong, but it appears to me that the 9700 cannot switch different linear amplifiers on its different bands.

This is not such a hard thing to do. My IC7100 can do it. You can switch the two pins on the 13-pin socket between either working HF and VHF separately, or 2m/70cms separately. This is something I do. The IC-7100 has a "standard" 13 pin Icom output socket. However, the IC9700 seems only to have the other "standard" 7-pin socket. This has many things which I don't need, like RTTY switching, but it only has one PTT output pin.

Here is how the IC-7100 does it (one output is called HSEND, and the other VSEND) ...

IC-7100 manual showing clearly how to set the two separate PTT outputs.

As usual, click the images to enlarge if necessary.

You select what you want in the settings ...

IC-7100 manual showing how to select the automatic PTT band switching.

I do not own an IC-9700 and I have to rely on the "basic" version of the manual published by Icom UK. This does not show almost all of section 2 which would reveal the details. However that manual does show an explanation of the pin outs for the accessory plug ...

IC-9700 "basic" manual showing just one PTT output.

Now, as I say, I don't have an IC-9700 so I cannot verify if they are indeed being supplied with the 7 pin socket. However, elsewhere in the manual there is an explanation of how to set the single PTT output to work on specific bands

IC-9700 "basic" manual showing how to set the single PTT output.

This is, of course, consistent with the wiring details shown in the other part of the basic manual. It appears from this that you can set the single PTT output to on or off on any specific band, any combination of bands, or none.

It seems strange to me that a rig with three RF outputs only has one output for switching linear amplifiers. With the IC-7100, for instance, I can set it up with my 2m amplifier on one RF socket, and my 4m amp on the other socket, and it decides which amp to key. The same goes for 2m and 6m, and I have had it set that way too. You could also do this in the IC-7100 for 2m and 70cms, using a diplexer, but I have never tried that. I would have thought that this would have been a pretty obvious arrangement for the 9700 too.

I do wonder why the 9700, a radio with three RF outputs on the back, has only one PTT output, whereas the IC-7100 has two RF outputs and has full flexibility as to which PTT works with which. Why does the 9700 have the 7 pin plug when even the IC-7300, which has only one RF plug on the back, has the 13 pin plug. The IC-9700 seems to have taken a step backwards here.

From what I can see, the IC-9100 also had the 13-pin socket and the two PTT output, so if I was was replacing an IC-9100 with a IC-9700 I would be pretty miffed about this. It was a development of the 7100 system, allowing some limited choice between some of the bands. Shown below, from the 9100 manual, is the paragraph I would have wanted to see in the 9700s manual ...

The IC-9100 manual showing how it should be done.

OK, I have not seen a UK version 9700, nor even a full manual. Hopefully some 9700 owner can come on and tell me that the rig did, eventually, sell with the 13 pin plug and even the basic connectivity of the 7100 or 9100. If so, I can happily delete this post.

Is this a deal breaker for me? Probably in the sense that an IC-9700 would be a very good single band rig for me, but I could not use its multi-band capability. Sure I could rig up a switch to turn the PTT between the amplifiers, but I would only need to make one mistake with that to blow up my mast head pre-amps. I did not go to all the trouble of sequencing them to risk sending RF up to them with no PTT active.

I do not rule out getting an IC--9700, but it would be limited by this issue. I cannot see myself going into the menu to change the PTT settings every time I change bands, and the consequences of forgetting or getting it wrong are too expensive to contemplate. And anyway, isn't this what a multi-band radio is supposed to avoid? If the feature was worth putting in the 7100 and 9100, why leave it out of the 9700?

I have thought up a circuit which would RF sense the outputs and turn the PTT in line with that. This would mean that only the first transmission would go without the matching PTT - thereafter it would stay switched until I changed band again. But how often would I need to do that before the pre-amps died?

If you do not use amplifers and pre-amps this does not matter to you. Until you come to sell it of course, when such things make or break second hand sales.

It seems to me that it would have been sensible for Icom to have carried over the socket, the circuity and the software from the IC-9100 to the IC-9700 so that the very many VHF-ers who have multiple linear amplifiers could use them. After all, Icom had already figured out how to do it more than five years ago on the IC-7100.

But then again, are the production models supplied as the manual I have seen suggests? I hope not.

73

Jim

GM4FVM (EDIT - not just linears, but SHF transverter control is affect by this issue too)