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]   Go Down
  Print  
Author Topic: Ensemble RXTX and the like  (Read 4927 times)
VA2PBJ
Member

Posts: 162




Ignore
« on: August 26, 2013, 05:47:55 PM »

How clean is the output on these devices? Are you going to make a big spectral mess over the air when you bring it up to 50-100w, assuming you have a clean linear?
Logged

7 3 Peter VA2PBJ
WS4E
Member

Posts: 204




Ignore
« Reply #1 on: August 28, 2013, 12:35:29 PM »

How clean is the output on these devices? Are you going to make a big spectral mess over the air when you bring it up to 50-100w, assuming you have a clean linear?

It does not have any output filtering, so it does needs to have low pass filters added to the output.     You will find the 2nd and 3rd harmonics will exceed the legal limits (-30db I think) as they get amplified without bandpass filters added.  

BTW, the proper place to put the bandpass filters is AFTER THE AMP.  Any good quality amp will have proper bandpass filters builtin to its output, only the cheap poor quality CB amps will not have filters built in.

Also, keep in mind most amps require a higher driving wattage than the RXTX can put out, an amp has to be specifically designed for being driven with low power/qrp rigs.

Filters and amplifier kits from these guys are popular with the softrock community:

http://site.hfprojectsyahoo.com/home
http://www.hfprojectsyahoo.com/
http://www.communication-concepts.com/


I always liked this kit as a possible addition to an RXTX.  It has built in filters, and its designed to be driven from very low power like the RXTX.
http://site.hfprojectsyahoo.com/hf_packer-amp
« Last Edit: August 28, 2013, 12:46:51 PM by WS4E » Logged
VA2PBJ
Member

Posts: 162




Ignore
« Reply #2 on: August 28, 2013, 04:51:05 PM »

I didn't think it had any final bp on it. Thanks for the confirmation.

That last link is a golden one. 30w is more than enough for what I wanted to do.
Logged

7 3 Peter VA2PBJ
K5TED
Member

Posts: 699




Ignore
« Reply #3 on: August 28, 2013, 06:37:46 PM »

I find it amusing that more than 10 years after the introduction of a real clean SDR, people are still screwing around with these toys and wondering why they don't meet spec...

Logged
VA2PBJ
Member

Posts: 162




Ignore
« Reply #4 on: August 28, 2013, 07:21:00 PM »

1) Making a commitment of 2k-5k is pretty big if all I have experienced is units with knobs. I may not even like it.
2) As a second rig, "don't care, wanna play" is a big influence. I'm not looking to replace anything.
3) Opinions in this place can be a bit prejudicial at times. There is nothing like kicking the tires first, if you can.
4) Getting a rig under 1w is not terribly exciting for me. 15-30w is enough to play with some minor DXing and enough to wet my appetite.


This is a hobby that I enjoy tinkering with things. That's why I took it up.
Logged

7 3 Peter VA2PBJ
KB1GMX
Member

Posts: 716




Ignore
« Reply #5 on: August 30, 2013, 05:23:19 PM »

I have the Ensamble RXTX and unless your talking about something else C24/C25/C26 and L2 and L3 are a low pass filter and it easily meets all relevant standards for amateur use (here in the USA).

If you amp it up to higher power that amplifier must have its only filters as well.

The WA2EBY/K5OOR amp would take the 1W to about 25-35 with plenty of headroom.
The base amp module is bradband so it still requires a switchable (or single band) filter
at the output.


Allison
Logged
Pages: [1]   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!