¿ªÔÆÌåÓý

ctrl + shift + ? for shortcuts
© 2025 Groups.io
  1. SoftwareControlledHamRadio
  2. Messages
Expanded Topics Messages Polls
Date
Power Amp Efficiency

 

I have 3 ways of measuring power; Direct LPF output on Tek Scope, RMS voltage out of Pearson current monitor, an HP363 Taidacent power meter.? I get 9.7 +/-0.9 watts out at 7.2MHz.? My DC power in to the amp is 20.0 wt for an efficiency of 47%.? Is that what others are seeing?
dave, n3ds
Re: New book

 

Thanks, John!

Jack, W8TEE

On Thursday, April 17, 2025 at 06:17:45 AM EDT, John Owens K1JO via groups.io <johnowenschina@...> wrote:


Thanks Jack. The automated message from Amazon told me to keep the old book and they would send a new one :)...I wonder if they will send a new Old one.
When the New new one arrives, I will write a nice review. Thanks for the great work!
John K1JO

--
Jack, W8TEE
Re: No SSB output

 

PTT working, it goes into TX and amps increase, relays click.
I2C checked out on all but BPF which I am using 3rd party BCD to control.
Audio hat works fine for RX.
Tim?
?
Re: No SSB output

 

Are you certain that your PTT button is working? You should hear relays click when you press it. If the PTT button is working, then a lack of signals out of the audio hat implies that the hat is not working for some reason. I'm assuming that the I2C connection to the audio hat did not have a fault on the BIT screen at boot?

On Wednesday, April 16th, 2025 at 9:15 PM, Tim via groups.io <w4yn@...> wrote:

Put scope on the IQ out pins and I don't detect and signals when in TX IQ calibrate
Tim
Re: New book

 

Thanks Jack. The automated message from Amazon told me to keep the old book and they would send a new one :)...I wonder if they will send a new Old one.
When the New new one arrives, I will write a nice review. Thanks for the great work!
John K1JO
Re: Just curious. . .

 

¿ªÔÆÌåÓý

You gain some slow memory to store stuff in¡­

?

?

Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ

?

Owner - Operator

Big Signal Ranch ¨C K9ZC

Staunton, Illinois

?

Owner ¨C Operator

Villa Grand Piton ¨C J68HZ

Soufriere, St. Lucia W.I.

Rent it:

?

Moderator: North American QRO Group at Groups.IO.

Moderator: Amateur Radio Builders Group at Groups.IO.

?

email:? bill@...

?

?

From: [email protected] <[email protected]> On Behalf Of Duane B via groups.io
Sent: Wednesday, April 16, 2025 10:45 PM
To: [email protected]
Subject: [SoftwareControlledHamRadio] Just curious. . .

?

But do you gain anything by populating 1 or 2 of the 8Mb SPI memory chips on the Teensy?? Or do you loose? some functionality by doing that?

?

Just curious.

?

Thanks,

Duane - K5CA
Just curious. . .

 

But do you gain anything by populating 1 or 2 of the 8Mb SPI memory chips on the Teensy?? Or do you loose? some functionality by doing that?
?
Just curious.
?
Thanks,
Duane - K5CA
Re: New book

 

Yeah, I did too, but twice received the wrong book. I have redone the submission from scratch and I should be hearing within 72 hours. It will have a new ISBN number, which means we lose all of the nice reviews we had up until now. To all those who took the time to say nice things about the book, a huge Thank You from Al and I.

I will post when the new book is ready to ship.

Meanwhile, they have been good about taking books back.

Jack, W8TEE

On Wednesday, April 16, 2025 at 09:14:16 PM EDT, John Owens K1JO via groups.io <johnowenschina@...> wrote:


I just received the wrong one, the old one that I already have :(
Strange, as I waited until the purchase page had the new cover with the black T-41.
John K1JO

--
Jack, W8TEE
Re: No SSB output

 

Put scope on the IQ out pins and I don't detect and signals when in TX IQ calibrate
Tim
Re: New book

 

I just received the wrong one, the old one that I already have :(
Strange, as I waited until the purchase page had the new cover with the black T-41.
John K1JO
Re: No SSB output

 

Yes they are. Step through the circuit starting at the audio hat. Do you see the 750 Hz audio tone on the I and Q outputs of the audio hat? Then, walk through the transmit chain on the RF board and find where the signal disappears.

On Wednesday, April 16th, 2025 at 7:45 PM, Tim via groups.io <w4yn@...> wrote:

Is the 750hz and 2 tone frequencies generated in Audio Hat?
Still mucking around trying figure out why no carrier in SSB mode.
Tim?
?
Re: No SSB output

 

Is the 750hz and 2 tone frequencies generated in Audio Hat?
Still mucking around trying figure out why no carrier in SSB mode.
Tim?
?
Re: New book

 

I will check back later this week, and if it looks correct I will order, and of course you will get a review.
?
--
73 Greg KF5N
Re: New book

 

Oddly, two people have written that they received the right book. Even harder to figure out now. I just went through the entire process again and updated everything, including the ad narrative (which has 4SQRP still selling a kit). I should get word back within 72 hours that all is well. The bad news is that about 165 very good book reviews will no longer be tied to the book...it starts over.

Jack, W8TEE

On Wednesday, April 16, 2025 at 01:38:14 PM EDT, Greg KF5N via groups.io <greg.electricity@...> wrote:


Amazon needs to be hammered on again.? They are not getting it done correctly.
?
--
73 Greg KF5N

--
Jack, W8TEE
Re: New book

 

Glad to hear it...thanks!

Jack, W8TEE

On Wednesday, April 16, 2025 at 02:44:53 PM EDT, Duane B via groups.io <dbrantley@...> wrote:


I did, finally, receive a copy of the NEW book.? Received it last week.? I meant to post up about it but had a senior moment and forgot too.? Amazon even told me to keep the old copy.
?
Duane - K5CA

--
Jack, W8TEE
Re: New book

 

I did, finally, receive a copy of the NEW book.? Received it last week.? I meant to post up about it but had a senior moment and forgot too.? Amazon even told me to keep the old copy.
?
Duane - K5CA
Re: New book

 

I'll find out soon. Mine new version is supposed to arrive today.
Re: New book

 

Amazon needs to be hammered on again.? They are not getting it done correctly.
?
--
73 Greg KF5N
T41-2 and K9HZ Power Amplifier Measurements

 

I've been working on a system to accurately evaluate HF linear power amplifiers.? It took quite a while to figure out how to get the system working.
Here's the first tangible results in the form of a spreadsheet:



There are 3 worksheets.? The first "PA out cal" is nothing more than measurements between reference plane 1 (PA output), reference plane 2 (radio output), and the input of the power meter.
Sheet #2 is the "Small Balun" version of the T41-2 Power Amplifier (final + driver).? Sheet #3 is the K9HZ amplifier I built here a couple of years ago.
?
PEP output powers are not as high as expected.? Remember to halve the PEP numbers to get average power.? Quite low!
?
Note that the K9HZ PA drops to below 2 watts average power on the higher bands.? The amplifier was tuned up according to the build instructions.
The critical thing seems to be the bias current for the final transistors is probably too low at 250mA each.
?
I've seen comments by others that the part used in the final amplifier (Mitsubishi RD16HFF1) needs quite a bit of quiescent bias current for decent linearity.
Thus I've tuned the T41-2 Power Amplifier to a bias of 700mA each.? You can see the total current drain in the last column of the measurements.
?
I would be interested to compare my measurements to other's evaluations.? Here is a video summary of the measurement system and procedure:
?
The system:
?
The measurement procedure:
?
?
--
73 Greg KF5N
Re: New book

 

Nor should you. But the problem is that the ad shows the new cover:
Inline image
and I can't figure out how that happened since we updated it April 4th. After 2.5 hours on the phone with Amazon and Kindle Direct, they don't know either.

Jack, W8TEE

On Wednesday, April 16, 2025 at 01:17:32 PM EDT, Greg KF5N via groups.io <greg.electricity@...> wrote:


I want a new copy, but I'm not going to order one from a page which says April 18 2024.
?
--
73 Greg KF5N

--
Jack, W8TEE
421 - 440 of 33846