[Amps] FCC Denies Expert Linears' Request for Waiver of 15 dB Rule

[Manfred Mornhinweg]

Cathy, Jim, and all,

> I have seen many, many online posts asking for an all-mode VHF/UHF
> rig that doesn't include HF.  These used to be available, but have
> disappeared.

Such rigs appeared on the market at a time when there was a growing 
swarm of active ham satellites in orbit. Yaesu brought out the three 
band FT-726R, and shortly later the four band FT-736R. Kenwood offered 
the three band TS-790, while Icom entered competition with the very 
expensive three band IC-970, and then added the more affordable two-band 
IC-820. All these radios were intended for satellite operation, offering 
full-duplex crossband operation and crossband transponder frequency 
tracking. The FT-726 needed an optional module for this. The three 
latter radios also had computer control interfaces.

Around 1990 it looked like amateur satellite operation was here to stay, 
and that made many hams, including myself, buy such a radio, which 
created the marked for these models. I bought an FT-736R, complete with 
the optional band modules for 6 meters and 23cm, and used the 6m module 
as an IF for a 13cm converter. This gave me fully computer-controlled, 
multimode access to all four bands used on satellites at the time.

But in the later 1990s ham satellite development started to decrease, 
being pushed aside by private and institutional Cubesats posing as ham 
sats. The manufacturers tried to keep sales up by offering radios that 
could sort of operate on the more basic sats, but also had HF, such as 
the FT-847 and the TS-2000. This was in the age of warped front panels, 
that looked like they got too close to a heater.

As ham satellite activity collapsed after 2000, satellite operation was 
no longer an important selling point, and so we came to see radios that 
offer HF/VHF/UHF multimode coverage, but without significant 
sat-specific functionality.

> Bells and whistles are cheap, cheap, cheap.  The cost of adding them
> is negligible because they're mostly just firmware. 

Exactly.

> But when you want
> higher power, better filtering, higher frequencies, etc. -- anything
> that could be called "performance" -- the cost rises because the cost
> of the raw components needed rises.

With SDR this changes. In many aspects the performance of SDRs can be 
improved just by software.

> The major reason why transverters are the popular option above 6M is
>  that even most of the dedicated VHF/UHF transceivers weren't very
> good. Anyone who works those bands seriously uses transverters with
> very low noise preamps.

The FT-736R indeed has a rather poor noise figure, but it has amply 
sufficient dynamic range and selectivity, at least for my location. And 
it actually makes little sense to include top notch preamplifiers in an 
UHF radio, to give it a 0.4dB noise figure, because the coax 
transmission line between the antenna and the radio will totally kill 
that performance! So, the usual technique is to put that 0.4dB NF 
preamplifier in a weathertight box and mount it at the antenna 
feedpoint, then send the far more robust preamplified signal down the 
line to the radio. At that level, a 7dB noise figure in the radio, or 
even higher, is no problem. That's the design philosophy behind these 
radios - and they feature support for such preamplifiers, having a 
switch on the front panel that allows applying 12V power to the antenna 
input of the currently active receiver.

I have heard that some people living close to UHF radar stations had 
trouble with the dynamic range of these radios, but this problem likely 
affected only a few users.

So, I would say that the RX performance of this radio is fine.

On the other hand, I have to agree that the FT-736R wasn't very good, in 
terms of reliability. Mine went through over 20 failures! Most of them 
in the first years of use, later it more or less stabilized. I was able 
to repair most of them myself, but right now there is still a popcorn 
noise problem affecting mostly the 70cm band RX, which I haven't been 
able to track down. This problem appeared roughly in 2003 or so...

The local radio club has one of these too, and last time I checked, 
nearly nothing of that radio worked. It hasn't got any maintenance in 
over 20 years. Since there are no really usable sats, there is no demand 
for VHF/UHF SSB operation, and the club station now uses newer FM 
radios, while keeping the FT-736 as fancy decoration.

Frankly I don't have any use for SSB on 2m and higher either. Nor for 
UHF. I'm now using my FT-736R just to access the regional VHF repeaters. 
What a waste! And the bulk of my activity on the air, which in the 1990s 
was concentrated on sats and packet radio, has reverted to 40m SSB 
ragchewing.

Manfred

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