K4 on AM

[Jim Brown-10]

On 3/2/2020 11:22 AM, Adrian wrote:
> I can get a new FTDX3000 for $2000 from the local Yaesu dealer, which
> seems way better value to get 100w operating option.

It's usually cheaper to build an inferior product.
>
> I know some IMD fussy types that use the FTDX, so on your comments Jim,
> I may have to investigate further.

Using a rig that splatters as badly as this and most other el-cheapo
rigs is being VERY inconsiderate of your fellow hams by taking up three
times as much space on the band as you should. And here in the former
colonies, it's actually a violation of FCC Rules to occupy more
bandwidth that needed for the mode of transmission in use. A proper SSB
signal is 2.7-2.8 kHz; these rigs have that much splatter on both sides
of their legal signal.

73, Jim K9YC

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[Adrian-3]

Thanks for the heads up Jim. I have cancelled that idea. I am looking at the FTDX101MP now.
It is expensive, but available locally here in VK, and seems to have excellent specs.

I did look at the K4 which I think with ATU and our taxes,  would be about $8389.84 imported into Australia, and probably in a year or so
regarding the waiting list. The FTDX101MP (200w) is $6K locally.

I was going to ask if a 200w version may be optional for the K4, but I think that would not be popular for the USA market.

Thankyou again.

Adrian ... vk4tux

-----Original Message-----
From: Jim Brown [mailto:[hidden email]]
Sent: Tuesday, 3 March 2020 6:18 PM
To: Adrian; [hidden email]
Subject: Re: [Elecraft] K4 on AM

On 3/2/2020 11:22 AM, Adrian wrote:
> I can get a new FTDX3000 for $2000 from the local Yaesu dealer, which
> seems way better value to get 100w operating option.

It's usually cheaper to build an inferior product.
>
> I know some IMD fussy types that use the FTDX, so on your comments
> Jim, I may have to investigate further.

Using a rig that splatters as badly as this and most other el-cheapo rigs is being VERY inconsiderate of your fellow hams by taking up three times as much space on the band as you should. And here in the former colonies, it's actually a violation of FCC Rules to occupy more bandwidth that needed for the mode of transmission in use. A proper SSB signal is 2.7-2.8 kHz; these rigs have that much splatter on both sides of their legal signal.

73, Jim K9YC


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[Jim Brown-10]

But it's not a "rule" based on communications, which is what ham radio
is all about. Almost 100 years ago, Bell Labs, the premier engineering
entity on the planet, published extensive research showing that audio
frequencies below 400 Hz contribute almost nothing to speech
intelligibility, but can waste 2-3 dB of transmitter power. As I'm sure
you know, losing 3 dB is equivalent to reducing the effective power of
our rig or amp by half! 30-40 years ago, I was working with broadcasters
using multiband processing systems.

I too am a retired professional in the field of pro audio, where I made
my living designing high quality sound systems for public spaces. One of
my specialties was designing systems for acoustically difficult spaces,
and a long established "rule" for such systems was to limit audio
response below 500 Hz. By contrast, the "rule" you cite is aimed at
"pleasing" audio, NOT speech intelligibility.

I've always set my TXEQ for max cut of the 50, 100, and 200 Hz band, 6
dB cut of the 400 Hz band, a few dB peak of the top two bands, then set
COMP for indicated 10 dB gain reduction on peaks. I do lots of
contesting and some DXing, and consistently get very good audio reports.
Think of it this way -- improving signal to noise ratio makes audio
easier to listen to, far more that transmitting excessive bass and
losing that power.

73, Jim K9YC

On 3/2/2020 6:01 PM, W2xj wrote:
> There is an old rule that the product of the lowest and highest audio frequencies should be between 450,000 and 500,000 (depending on which ‘expert’ you ask).  Under that rule, a 3 KHz audio response should have a low end response of 150 Hertz for a balanced sound.

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