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Re: [Amps] Pre-Distortion Linearizer

To: amps@contesting.com
Subject: Re: [Amps] Pre-Distortion Linearizer
From: "Roger (K8RI)" <k8ri@rogerhalstead.com>
Date: Sat, 04 May 2013 14:34:32 -0700
List-post: <amps@contesting.com">mailto:amps@contesting.com>
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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