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

donate to eham
   Home   Help Search  
Pages: [1]   Go Down
  Print  
Author Topic: IC-7610 TX Performance Video & Screenshot  (Read 1401 times)
VK3BL
Member

Posts: 1376


WWW

Ignore
« on: December 03, 2017, 01:43:43 AM »

Hey Everyone,

I used my CleanRF 2K Sampler, SDRPlay RSP2 & Bird 8201 to measure the real world / SSB TX purity performance of the IC-7610.

Here is the video: https://www.youtube.com/watch?v=Wgkv1Gyq4wg&feature=youtu.be

Here is a screenshot: https://ibb.co/eu1xQG
« Last Edit: December 03, 2017, 01:46:53 AM by VK3BL » Logged

J.D. Mitchell - VK3BL / XU7AGA - http://vk3bl.wordpress.com
KW4CQ
Member

Posts: 264




Ignore
« Reply #1 on: December 03, 2017, 05:57:57 AM »

Beautiful, Jarrad.  I believe I can live with -31.2 dBm.
Nice job.
Bob KW4CQ
Logged
KA4DPO
Member

Posts: 819




Ignore
« Reply #2 on: December 03, 2017, 08:28:03 AM »

well done Jarrad, thank you.
Logged
VK6HP
Member

Posts: 186




Ignore
« Reply #3 on: December 06, 2017, 01:36:22 PM »

Jarrad, it's an interesting video and gives a good general idea of the 7610 performance.  The voice loop gives a sanity check measurement and, since you invite comments, I would encourage you to augment the results with those from some standard checks, to allow some easier (approximate) comparisons across radios and within the options in the 7610.  Just having a stationary, leveled input signal helps a lot, regardless of individual preferences.  As well as the test you did, I like to use both a white noise source and a two-tone source.  I sometimes use an actual noise source but a gain-leveled audio sweep generator, running asynchronously with my lab swept spectrum analyser in averaging mode works well, too.  In the latter case there is an absolute amplitude offset dependent on the "probability of intercept (POI)"of the spectrum analyser but that's of no consequence for IMD and similar relative measurements. I'm guessing that your SDR setup is FFT based and you don't have the POI consideration, but the leveled source and decent averaging are still considerations of course.

I am one of those people who have invested in a high-end LDMOS amplifier and I'm currently looking for an SDR transceiver.  I've been holding off until the 7610 becomes better known, despite a preference to use a pre-distortion based system.  I'm certainly interested in seeing the 7610 lower-drive-level IMD characterized.  Being something of a hardliner in terms of transmitter cleanliness, I didn't have the same immediately positive reaction to the full-power result you derived; I was a bit underwhelmed given the 2017 epoch and the AUD5k+ price point.  But I remain interested in the ICOM radio and it would do it justice to see some more results, so keep up the great work.

I may have even talked to your 7610 if you were using it for the FT8 contact the other night. FT8 is a bit like playing slot machines, but it's less harmful Smiley

73, Peter.
« Last Edit: December 06, 2017, 01:51:53 PM by VK6HP » Logged
VK1AZ
Member

Posts: 26




Ignore
« Reply #4 on: December 07, 2017, 07:04:48 PM »


I may have even talked to your 7610 if you were using it for the FT8 contact the other night. FT8 is a bit like playing slot machines, but it's less harmful Smiley

73, Peter.

Hi Peter, I'm sure I've seen you in the FT8 waterfall via my IC7610, got a few VK6's in the log but missing yours so far.

I liked the slot machine analogy due to the addictive nature of it. It also gives me a chance to be on late at night when everyone is asleep or shouldn't be disturbed.

I too will be intrigued with the lower drive level measurements with a future LDMOS amp on the books when the credit card recovers. I don't have any of the gear to carry out measurements these days since I've been out of Telco radio comms for 25years now.
Logged
VK6HP
Member

Posts: 186




Ignore
« Reply #5 on: December 08, 2017, 07:00:06 AM »

Phil, I think the contact with Jarrad was one of my very first few FT8 contacts - I was just testing the system and getting the power levels etc set correctly on 20m.  So yes, I'll look forward to working you when I get back to Australia.

I might also have mentioned that in fact the transmitted audio from the first 7610 in my local sewing circle sounds exceptional, after some efforts by the proud owner to get it right.

I realized I'd described my method of measuring the audio to RF response with the AF sweeper, but clearly a second source is added for IMD measurements in that mode.

The good thing about some of the test gear these days, including my Chinese spectrum analyser, is that it's so multi-talented: many fewer boxes needed in the shack.

73, Peter.
Logged
VK3BL
Member

Posts: 1376


WWW

Ignore
« Reply #6 on: December 09, 2017, 04:36:42 AM »

Jarrad, it's an interesting video and gives a good general idea of the 7610 performance.  The voice loop gives a sanity check measurement and, since you invite comments, I would encourage you to augment the results with those from some standard checks, to allow some easier (approximate) comparisons across radios and within the options in the 7610.  Just having a stationary, leveled input signal helps a lot, regardless of individual preferences.  As well as the test you did, I like to use both a white noise source and a two-tone source.

One of the reasons I haven't done a two tone yet is that I don't have confidence in any of my equipment's ability to produce a 2 tone signal with better than say -36dBc level of distortion.  Certainly, I found that the sound card built into my IC-7200 was dirtier in that regard than the transmitter's PA.  I once did hours of testing feeding my IC-7200 via USB and a software tone generator, and could never get any better than -20dBc despite fiddling with every level I could find.

Perhaps the solution is to generate the tones in a software program, then store them on a memory card as a WAV file and play them back through the voice keyer, like I did with the recorded loop. 

I'm open to suggestions on how to do a fair test; whilst its easy to 'see' -33dBc splatter on 40M during great ConDX, sometimes its worth the sanity check of putting that in 'audio terms': 0.05% THD. 

Considering all the AF devices I have are consumer grade (not to mention the issues with coupling them to the input of the radio's balanced mixer), its easy to understand why I'm reluctant to make 'measurements' which I cannot in good faith claim to accurately reflect the radio's performance.

2 tone testing etc is IMHO best left to those with the right calibre of lab grade equipment, but let me know your thoughts on the memory card idea.  In theory, the raw WAV bitstream should be converted to RF by the radio's RF DAC, and henceforth bypass any source issues.

All in all, I'm confident the measurements I've done so far reflect real world performance; I'm not confident that I could produce meaningful 2 tone results.
« Last Edit: December 09, 2017, 04:42:12 AM by VK3BL » Logged

J.D. Mitchell - VK3BL / XU7AGA - http://vk3bl.wordpress.com
VK3BL
Member

Posts: 1376


WWW

Ignore
« Reply #7 on: December 09, 2017, 01:22:27 PM »

Long story short, the above methodology worked a treat; worst case values:

100 Watts IMD5: -30dBc
50 Watts IMD5: -36dBc
25 Watts IMD3: -40dBc

And it gets better and better after that, so it would make a VERY clean transverter driver Smiley
Logged

J.D. Mitchell - VK3BL / XU7AGA - http://vk3bl.wordpress.com
VK6HP
Member

Posts: 186




Ignore
« Reply #8 on: December 10, 2017, 03:25:09 AM »

Thanks for the numbers, Jarrad.  Looks similar, or a bit better than, other decent solid-state 12V radios.  I'm travelling and don't have the relevant data with me but I seem to recall products of about -35dB when I measured the TS-590S, probably at a bit less than maximum power output. (I was setting up with a Collins 30L-1, so maybe 50-60W drive).

By the way, just to be clear, those IM product powers are relative to the two-tone power levels, right? You're not doing the old ARRL thing and referencing to the PEP?  I'm guessing not, or ICOM might as well call it a day Smiley
« Last Edit: December 10, 2017, 03:34:14 AM by VK6HP » Logged
VK3BL
Member

Posts: 1376


WWW

Ignore
« Reply #9 on: December 10, 2017, 04:43:10 AM »

Here is a link to TX Performance Pt 2: 2 Tone & White Noise Testing at all power levels.

Some very interesting stuff in the video for those unfamiliar with testing transceiver performance; well worth checking out:
https://www.youtube.com/watch?v=Sc_6ST5NK3k

And nope, definitely not doing the ARRL rubbish "PEP" method; which disagrees with every pan adaptor / waterfall made, ever.

I'm reasonably happy with my THP 2.5Kfx / IC-7610 combo which combined scores -35dBc @ 400 Watt PEP; respectable for a solid state setup without pre-distortion.  The THP is actually the limiting factor, rolling off to -30dBc @ 1200 Watts PEP. 

As much as I wanted a 200W / 75W Class A exciter its a waste of time and money without a good triode final stage, like the Alpha 87A (or anything using the 3CX800A7 pretty much).

All testing done strictly into a dummy load - a Bird 8201.  I can't stress that enough; the ONLY reason I took the THP that high was to demonstrate how combined system performance is what matters, and why headroom makes such a difference if one wants a clean signal when using solid state amps.
« Last Edit: December 10, 2017, 04:53:23 AM by VK3BL » Logged

J.D. Mitchell - VK3BL / XU7AGA - http://vk3bl.wordpress.com
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!