Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

   Home   Help Search  
Pages: [1] 2 3 Next   Go Down
  Print  
Author Topic: New QRO 8877  (Read 13359 times)
N4RSS
Member

Posts: 260




Ignore
« on: August 02, 2012, 12:26:58 PM »

See bottom of page:

http://www.qrotec.com/

I want one
Logged
K2DC
Member

Posts: 1377


WWW

Ignore
« Reply #1 on: August 03, 2012, 02:54:06 AM »

Wow!  Clean and simple.  Hard to beat that.

73,

Don, K2DC
Logged
W1QJ
Member

Posts: 1464




Ignore
« Reply #2 on: August 03, 2012, 03:40:49 AM »

See bottom of page:

http://www.qrotec.com/

I want one

Ha, that's funny,  Ray waited for Pat to hang it up and then copies the HF-2500 with an 8877 instead of 2  3CPX800 tubes.  That is a clone of that amp.  I guess he put an access door underneath to get to the power supply.  Hope he did.  When it goes out of warranty I'll be glad to repair these.  Nothing new here in this baby.  Even the control board looks the same.  Maybe Pat sold his old partner what was left of his stock.
Logged
N4RSS
Member

Posts: 260




Ignore
« Reply #3 on: August 03, 2012, 06:36:41 AM »

See bottom of page:

http://www.qrotec.com/

I want one

Ha, that's funny,  Ray waited for Pat to hang it up and then copies the HF-2500 with an 8877 instead of 2  3CPX800 tubes.  That is a clone of that amp.  I guess he put an access door underneath to get to the power supply.  Hope he did.  When it goes out of warranty I'll be glad to repair these.  Nothing new here in this baby.  Even the control board looks the same.  Maybe Pat sold his old partner what was left of his stock.

Or maybe he drew heavily from his own HF-2500DX whose power supply is accessible through the top
Logged
NO2A
Member

Posts: 806




Ignore
« Reply #4 on: August 03, 2012, 09:14:42 AM »

The dual 3-500ZG amp doesn`t deliver full output in cw no matter how hard you drive it. The HF-2500 draws 25 amps? That seems excessive for 1500 watt output. Curious what the `8877 draws.
Logged
WB2WIK
Member

Posts: 20614




Ignore
« Reply #5 on: August 03, 2012, 09:23:29 AM »

See bottom of page:

http://www.qrotec.com/

I want one

Ha, that's funny,  Ray waited for Pat to hang it up and then copies the HF-2500 with an 8877 instead of 2  3CPX800 tubes.  That is a clone of that amp.  I guess he put an access door underneath to get to the power supply.  Hope he did.  When it goes out of warranty I'll be glad to repair these.  Nothing new here in this baby.  Even the control board looks the same.  Maybe Pat sold his old partner what was left of his stock.

I must be missing something.  The "3KDX" photos don't show a tuned input circuit anywhere.  WTF? Wink
Logged
K8AXW
Member

Posts: 3910




Ignore
« Reply #6 on: August 03, 2012, 09:28:01 AM »

Absolutely a work of art!  One fault I see with the 3-500 amp is the cooling method.  The fan (shades of Heathkit SB-220) blows hot air from on tube onto the second tube before exiting the enclosure. 
Logged
N4RSS
Member

Posts: 260




Ignore
« Reply #7 on: August 03, 2012, 09:36:39 AM »

The dual 3-500ZG amp doesn`t deliver full output in cw no matter how hard you drive it. The HF-2500 draws 25 amps? That seems excessive for 1500 watt output. Curious what the `8877 draws.

I think I have 25 amp fuse in mine and pushes 2400 into a dummy load
Logged
N4RSS
Member

Posts: 260




Ignore
« Reply #8 on: August 03, 2012, 09:37:55 AM »

See bottom of page:

http://www.qrotec.com/

I want one

Ha, that's funny,  Ray waited for Pat to hang it up and then copies the HF-2500 with an 8877 instead of 2  3CPX800 tubes.  That is a clone of that amp.  I guess he put an access door underneath to get to the power supply.  Hope he did.  When it goes out of warranty I'll be glad to repair these.  Nothing new here in this baby.  Even the control board looks the same.  Maybe Pat sold his old partner what was left of his stock.

I must be missing something.  The "3KDX" photos don't show a tuned input circuit anywhere.  WTF? Wink

I didn't see any filter capacitors either in any of the pictures
Logged
W1QJ
Member

Posts: 1464




Ignore
« Reply #9 on: August 03, 2012, 09:57:29 AM »

See bottom of page:

http://www.qrotec.com/

I want one

Ha, that's funny,  Ray waited for Pat to hang it up and then copies the HF-2500 with an 8877 instead of 2  3CPX800 tubes.  That is a clone of that amp.  I guess he put an access door underneath to get to the power supply.  Hope he did.  When it goes out of warranty I'll be glad to repair these.  Nothing new here in this baby.  Even the control board looks the same.  Maybe Pat sold his old partner what was left of his stock.

I must be missing something.  The "3KDX" photos don't show a tuned input circuit anywhere.  WTF? Wink
Looks like a broad band input to me.  never saw that before with an 8877, ok, so the rest is pretty much the same.
Logged
G3RZP
Member

Posts: 4743




Ignore
« Reply #10 on: August 03, 2012, 10:28:52 AM »

Filter caps under the rectifier board. Tuned input adjustments visible in the rear panel shot.

But what gives with FCC Part 15 compliance notice on the back? What is that needed for? An amp that big 'must not cause interference' indeed!
Logged
K0CWO
Member

Posts: 419




Ignore
« Reply #11 on: August 03, 2012, 11:31:02 AM »

"The dual 3-500ZG amp doesn`t deliver full output in cw no matter how hard you drive it."

What dual 3-500ZG amp are you referring to?

I have a QRO HF-2000 with RF Parts 3-500ZG's in it that are two years old.  The following is what I get on 40 meters (7.2 MHz) driving the HF-2000 with 95 watts RTTY/CW from a Yaesu FT-950 into a Palstar DL2K dummy load:


4150 plate volts at idle

3750 plate volts under load (95 watts of RTTY/CW drive).  That produces 800 mills of plate current (3750 X .8 = 3000 watts input).

Seems to deliver full output to me using a 50% efficiency figure.


I don't have any lab accurate watt meters here but my Palstar AT5K and Ameritron AWM-35 certainly indicate 1500 watts out with the above scenario.

For what it is worth.

73, k0cwo     
Logged
NO2A
Member

Posts: 806




Ignore
« Reply #12 on: August 03, 2012, 12:20:26 PM »

I was referring to the specs for the HF-2000. They claim 1500 output for ssb but 1200 for cw. Might just be a typo.
Logged
K0CWO
Member

Posts: 419




Ignore
« Reply #13 on: August 03, 2012, 12:26:04 PM »

I see.  Lots of things in some of these manuals don't jive Wink.

73, k0cwo
Logged
W1QJ
Member

Posts: 1464




Ignore
« Reply #14 on: August 03, 2012, 01:15:14 PM »

Are you sure about that 4150v idle plate current?  Are you sure it's not 3150 and 2700 you mean.?
Logged
Pages: [1] 2 3 Next   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!