It is currently Sat Jul 21, 2018 6:04 am

Click the link below to visit the site sponsor

The Ham Radio Shop




Post new topic Reply to topic  [ 20 posts ]  Go to page Previous  1, 2
 Icom 7300 SSB average power mod 
Contributor 2017
User avatar

Joined: Sat Feb 09, 2013 8:32 am
Posts: 282
Location: Near Folkestone, Kent - JO01nd
Feedback: 5 (100%)
Reply with quote
Post Re: Icom 7300 SSB average power mod
Yo!

Yes, it seems to me that if the output of the DAC cannot exceed a given level then, provided you build-in some headroom for safety, you don't actually need ALC on the PA.

I've started another thread about this.

I really don't know what I'm talking about, but I'm trying to get a handle on it.

Rob.


Sat Jun 10, 2017 1:17 pm
Profile Send private message

 Icom 7300 SSB average power mod 
Contributor 2017
User avatar

Joined: Mon Aug 18, 2014 3:50 pm
Posts: 3468
Location: IO95DA Newcastle Upon Tyne
Feedback: 15 (100%)
Reply with quote
Post Re: Icom 7300 SSB average power mod
G0UOO wrote:
Yo!

Yes, it seems to me that if the output of the DAC cannot exceed a given level then, provided you build-in some headroom for safety, you don't actually need ALC on the PA.

I've started another thread about this.

I really don't know what I'm talking about, but I'm trying to get a handle on it.

Rob.

Hi Rob, you could still overdrive the input to the DAC however I am sure Icom have built in some headroom for this an adequate filtering - once it has been converted from analogue to digital then they will simply manage levels and filtering in the code.
But as for the digital to analogue output then if the register is set to 0xFF (255) as an upper limit then it will never exceed that value even if you crank the dial up on the front of the radio.

Cheers

Rob.


Sat Jun 10, 2017 1:27 pm
Profile Send private message WWW

 Icom 7300 SSB average power mod 
Contributor 2017
User avatar

Joined: Sat Feb 09, 2013 8:32 am
Posts: 282
Location: Near Folkestone, Kent - JO01nd
Feedback: 5 (100%)
Reply with quote
Post Re: Icom 7300 SSB average power mod
Hi Rob,

Yes, it is very important no to go over-range at the input to the ADC at AF. That's why it seems reasonable to apply ALC here. From what I've read, many SDRs do this. I don't know that the 7300 does it too, but it can't be very different.

Good fun!

Regards,

Rob.


Sat Jun 10, 2017 1:33 pm
Profile Send private message

 Icom 7300 SSB average power mod 
Contributor 2017
User avatar

Joined: Sat Jan 23, 2016 7:24 am
Posts: 1300
Location: Blackpool. IO83lu
Feedback: 4 (100%)
Reply with quote
Post Re: Icom 7300 SSB average power mod
I think some people just need to understand that it's 100 watts PEAK.

_________________
https://www.qrz.com/db/G0SLV


Wed Sep 13, 2017 8:55 am
Profile Send private message

 Icom 7300 SSB average power mod 
Moderator

Joined: Fri Jul 20, 2007 1:02 pm
Posts: 14115
Location: IO83lb, Wrexham
Feedback: 16 (100%)
Reply with quote
Post Re: Icom 7300 SSB average power mod
G0SLV wrote:
I think some people just need to understand that it's 100 watts PEAK.

Isn't it interesting.
Of all the comments I've seen there seems to be a severe shortage of any proper testing having been done.
Lots of impressions using cheap tools, I'm reluctant to use the words "test equipment". :)

Mine seems to produce the contacts so I've not bothered to measure anything.
Perhaps I'll look at it, if I suddenly have time on my hands.

Cheers

Tony

_________________
50MHz and above from IO83lb


Wed Sep 13, 2017 9:43 am
Profile Send private message
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 20 posts ]  Go to page Previous  1, 2


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  
Powered by phpBB © phpBB Group.
Designed by Vjacheslav Trushkin for Free Forums/DivisionCore.