[Amps] Pre-Distortion Linearizer

[Roger (K8RI)]

On 5/4/2013 7:36 AM, Joe Subich, W4TV wrote:
>
> On 5/4/2013 9:37 AM, Colin Lamb wrote:
>> The breakthrough may be when one manufacturer begins marketing their
>> low end transceiver with a -35 db IMD rather than a -25 db one.  That
>> would give a distinct marketing advantage.
>
> The problem is that manufacturers are not going to be able to produce a
> "low end transceiver" - at least at the low end price point - that has
> all the features demanded by the marketplace.  The technology simply
> does not exist to make a broadband (no tune), 100W output amplifier
> that runs on 11V (low end of a battery life) and achieve -35 dB in the
> final and do it for even 10% more than the current crop of $900 rigs.
> Add other requirements like reasonably clean phase noise performance,
> acceptable (~80 dB) 2 KHz receive IMD, and acceptable ~100 dB) blocking
> dynamic range and it is simply not possible from a cost perspective.
>
> $900 rigs are there for a reason ... that's all that many amateurs will
> pay.

I'll try again.. I was about ready to hit send and the UPS decided to 
run a self test..and failed.  One of these days I need to replace the 
battery

There are many hams who have to look for used versions of those $900 rigs.

At-any-rate:  I have a Yaesu 897D, An Icom 756Pro, and a Yaesu 
FTDX5000MP. They are bout equally spaced across the price range from the 
bottom to the top and there is a marked difference in performance at 
each step although each has a place in the present lineup.

The 897D is a backup as well as a handy "go" rig. Noise suppression and 
adjacent channel rejection stink, IM isn't great, and I dislike menu 
driven rigs. But as I said, it handy although it's generally collecting 
dust.

The 756 Pro was about half way between the other two rigs in price.
The 756 Pro is light, makes a good portable rig, works very well, no 
problem with leading edge spikes, and has a great band scope that lets 
me see sigs that don't move the S-meter (although just barely) adjacent 
signal is wayyy better than the 897D but pretty poor compared to the 
5000MP. Transmitter gets good reports, but IM is nothing to brag about.

I thought the receiver sections were comparable until I set them up on 
an A/B switch.  I was impressed with the 5000MP, but really disappointed 
with the 756 Pro.

The 5000MP has outstanding adjacent channel rejection and one of the 
cleaner signals on the bands. If you only operate SSB and CW it's fairly 
easy to set up.  To get the most out of it, better study the manual as 
you are now looking at a lot to learn and will find out why it has so 
many knobs/controls. If not careful you can set one up to sound 
terrible.

It's a whole 200 watt station in one heavy box.

That's my view and experience of the price spread for what it's worth.

73

Roger  (K8RI)

>
> 73,
>
>      ... Joe, W4TV
>
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