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eHam Forums => Software Defined Radio => Topic started by: W6RMK on January 02, 2014, 03:29:04 PM



Title: Transmitter performance
Post by: W6RMK on January 02, 2014, 03:29:04 PM
Interesting article from Leif SM5BSZ

http://www.sm5bsz.com/dynrange/dubus313.pdf

Measurements on Flex 1500, other radios..



Title: RE: Transmitter performance
Post by: K9IUQ on January 02, 2014, 05:26:11 PM
Interesting article from Leif SM5BSZ

This article will make K-3ers ecstatic and Flexradio 5K/1500 owners looking for a way to debunk/spin the info..  :D

Stan K9IUQ


Title: RE: Transmitter performance
Post by: K5TED on January 02, 2014, 05:52:45 PM
No doubt. Great article and kudos for taking the time to do all the testing. I'll keep my Flex. Haven't had any complaints from 300kc down the band..



Title: RE: Transmitter performance
Post by: PJ2BVU on January 02, 2014, 08:03:54 PM
... I'll keep my Flex. Haven't had any complaints from 300kc down the band..

...  Flexradio 5K/1500 owners looking for a way to debunk/spin the info..  :D
Stan K9IUQ

Spot on, Stan.
Ted: If another Flexer was sending all this crud on your frequency you wouldn't even know what hit you as your panadapter is only 192K wide (96K on each side of your frequency). May be you could if you have 2 RXes but I guess you wouldn't dare to look  ;D

Jean-Claude PJ2BVU


Title: RE: Transmitter performance
Post by: KA4POL on January 02, 2014, 10:11:05 PM
This article will make K-3ers ecstatic and Flexradio 5K/1500 owners looking for a way to debunk/spin the info..  :D

With all the knowledge and experience that Leif got I'd like to see how they'll do it  ;D


Title: RE: Transmitter performance
Post by: K9IUQ on January 03, 2014, 05:31:09 AM
I'll keep my Flex. Haven't had any complaints from 300kc down the band..

Attitudes like yours is exactly why transmitter performance does not improve from the manufacturers..

Does anyone but me remember the CW 160/80 meter transmit spur debacle on the Flex 5K? Flexers would spin "It is no problem for me as I don't operate cw or 160 meters." This serious problem was ignored by Flexradio for 3 years and was only fixed because of a ham that repeatedly complained publicly about the problem.

Nothing gets fixed unless people complain and rock the boat. Flexradio is not the only company to operate in this manner.

Stan K9IUQ



Title: RE: Transmitter performance
Post by: KA4POL on January 03, 2014, 06:48:09 AM
It may be worthwhile to ask ARRL as they also are criticized in this paper. It is a very good idea to enforce testing of modern transmitters to include these criteria. This would in turn force the manufacturers to pay more attention on their design flaws.


Title: RE: Transmitter performance
Post by: K9IUQ on January 03, 2014, 01:32:24 PM
This would in turn force the manufacturers to pay more attention on their design flaws.

Zenki has been posting about this for a long time. Could Zenki be --------?

Stan K9IUQ


Title: RE: Transmitter performance
Post by: ZENKI on January 31, 2014, 04:02:47 PM
I am alive and well. I am busy building  a yacht. Not much time for ham radio these days. Looking forward to playing ham radio in the  tropics surrounded by seawater.
I suppose when  i come back after 5 years, the ham transmitter performance will be  the same poor standards or maybe even worst.

I read in the RSGB Radcom about the  efforts by good hams and engineers who are trying to improve the EMC test and measurement procedures to reduce radiated interference from things like LED light and Plasma TV's. The momentum in professional circles seem to be gaining  towards tighter EMC standards for radiated and conducted emissions.  Then we come back to hams and their own standards and nobody wants to do a thing about improving our own standards. Hams then  wonder why they get treated with so little respect from the authorities. We  cant even get our equipment to the very basic professional standards set by the ITU, we carry on like we all handicapped and living in a world using old 3rd world technology because we cant do  any better.  Then our standards for aspiration is no better than a RM Italy CB amplifier for transmitter standards. We fast becoming dinosaurs because ours skill set  and understanding of these simple standards is so backward.

All current HF radio manufacturers  are improving their transmitter standards because of the strict requirements of digital HF. Hams think that they can defy the laws of physics by using equipment that will have inferior BER's on future HF digital models. Improving transmitter standards will help both analog and digital performance. Again so many hams dont get because they stuck in their CB mind set.



Title: RE: Transmitter performance
Post by: KA4POL on January 31, 2014, 11:28:09 PM
I am busy building  a yacht.


With your high quality demands, will the yacht ever be finished?  ;D


Title: RE: Transmitter performance
Post by: HAMMYGUY on February 01, 2014, 12:35:53 PM
This would in turn force the manufacturers to pay more attention on their design flaws.

Zenki has been posting about this for a long time. Could Zenki be --------?

Stan K9IUQ

Anybody who has been around this forum for a length of time probably has a good idea who "Zenki" is.  His style of writing, attitude, very knowledgeable posts, and disappearance of another certain member are all excellent clues.  


Title: RE: Transmitter performance
Post by: N2DTS on February 01, 2014, 06:55:14 PM
Its not just sdr's, I picked up a Ten Tec Argonaut 5 which is a nice little radio with great receive audio, and the TX is not bad, but it puts out a boat load of hash on frequency.


Title: RE: Transmitter performance
Post by: ZENKI on February 14, 2014, 03:57:57 AM
Ten Tec Argonaut  6 and Eagle would have  been best buys in ham radio if the transmitters  had a better standard of design in regards to their performance.
The Ten Tecs have sufficient receiver performance for most hams. Its just a shame that TenTec chose to  use such a poor transmitter designs in these 2 radios.
Same goes for the Orion, nice receiver shocking transmitter that  caused a lot of splatter.

Ten Tec need to use high voltage mosfet PA's and abandon 12 Volt bipolar  CB style transistor amplifiers. This is before we start talking about TX phase and spurious noise.
If a radio has got good RX phase noise and has a noisy TX its clearly a design problem that can be fixed.

Its not just sdr's, I picked up a Ten Tec Argonaut 5 which is a nice little radio with great receive audio, and the TX is not bad, but it puts out a boat load of hash on frequency.



Title: RE: Transmitter performance
Post by: N2DTS on February 14, 2014, 11:36:11 AM
I don't have the info with me, but the Argonaut 5 uses an analog to digital converter, then processes the signals (RX and TX) in a dsp chip, then does another digital to analog conversion, along with some mixers I think.

I am not sure what the hash is coming from, its like white noise within the passband.
Its not a problem with the final transistors, and I am not sure it would make sense to use high voltage output devices on a 20 watt pep small radio.

I can see why it makes sense to run anything that might be portable off 12 volts, but something designed for base operation could be higher voltages...drive the cost up though I suppose.