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Author Topic: Fodder for Zenki - Trashy Ham Transmitters Rated  (Read 81708 times)
N9FB
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Posts: 2362




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« Reply #45 on: October 22, 2014, 08:51:40 AM »

A big issue that I always like to raise in the radio comparisons found on the web (both ranking transmitter and receiver performance) is that they are a single test sample.

^this^ is a huge point.   just because rig X was cleaner than rig Y in the test does not automatically mean your rig X is cleaner than someone else's rig Y.  Factor in the variations created by individual operator xmt settings and measurable chaos ensues  Cheesy

were all the rigs in the test brand new or at least the same age and mileage?


Thanks for highlighting this.  With respect to manufacturing variability only, I haven't had the time to put together a comparison but there is sufficient data in QST reviews to get an idea of the differences.  For example, reviews exists for the Yaesu FT-897D/FT-857D, the ICOM IC-7410/IC-9100 and other such transceivers which have identical HF receiver/transmitter boards but show some differences in individual testing.  The comparison between the FTdx-9000 Contest and 9000D reviews is also insightful.

I once had two FTdx-5000D's in my shack and it was interesting to notice the differences between the two.  One could not just duplicate all of the settings and expect the same result.  One was very sensitive to RFI, the other was not.  One appeared to have gain compensation when the preselector was engaged.  The other showed gain on some bands and about 3 dB of loss on others (Yaesu didn't seem too interested in my findings, but that's another topic).  These differences were really concerning because I was only left to wonder how the performance varied in areas that I don't have equipment to measure, such as transmitter phase noise or receiver dynamic range.

i thank both you and NZ4ZN for elaborating more about variation between same manufacture & model units.  that leads me to this important question:  Do manufacturers get a heads up that a rig is wanted by the ARRL for review & testing purposes? If so, don't they then send an example of model X that is the cleanest one they can produce?  Same question regarding the ones Sherwood Engineering uses for their tests...

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W1BR
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« Reply #46 on: October 22, 2014, 10:57:45 AM »

I thought it was standing ARRL policy that all radios used for review were bought off the shelf, just to avoid concerns that a manufacturer supplied radio might have received some special attention at the factory.

Also, the ARRL was auctioning off the test radios after reviews were published. Most companies require the return of evaluation units (except for kits or antennas.)  I think that practice has been in place for quite  a few years.

Pete
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NR9R
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Posts: 172




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« Reply #47 on: October 22, 2014, 01:05:40 PM »


Quote

Do manufacturers get a heads up that a rig is wanted by the ARRL for review & testing purposes? If so, don't they then send an example of model X that is the cleanest one they can produce?  Same question regarding the ones Sherwood Engineering uses for their tests...


This point has also fascinated me.  Try this.  Grab ten random QST reviews of HF transceivers from the last few years and look for the review mentioning something about the first unit tested showing unusual performance that lead to getting a second unit.  I'd have to search through the reviews to get some examples but I do recall that even the recent review of the Hilberling transceiver required a replacement second unit for testing.   
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OH6I
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« Reply #48 on: October 23, 2014, 02:53:20 AM »

I also recall that some Ten Tec radios going back to factory from ARRL because some problems...?

Jari
OH6I
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N0XAX
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« Reply #49 on: October 28, 2014, 10:48:58 PM »

So the ARRL says so huh? Do you know what the ARRL  letters really stand for? Anal Retentive Retired Lids. A bunch impotent old men that think they know everything there is to know about amateur radio! Where's my barf bag?
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KG4NEL
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« Reply #50 on: October 29, 2014, 09:18:18 PM »

Very interesting read. It confirms something I've heard in practice for a few years now - our Field Day site is an 8-9A typically, and with several CW and digital transmitters on the air at the same time, the phone ops have a rough go of it. The hash out of '80s-era Kenwoods and Icoms is unbearable.
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K9MHZ
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« Reply #51 on: December 29, 2014, 07:37:45 AM »

I fit in here some where as I'm an Elecraft K1 fan boy but have to admit to the lack of all round ruggedness and cheap wobbly feel of it's VFO knob and buttons.....

I admire your candor and balanced outlook.  I'm a recovering Icom cheerleader.  Still have much of their current gear, but this spring will be filled with researching HF gear from all sources, and probably getting something at Dayton.  Icom won't be the presumptive favorite, as they've made some very frustrating moves in recent years.  They seem to like poking the bear (ham radio consumers) to see what will happen.  Meanwhile Kenwood and yes, Elecraft have been putting out some really nice stuff, electronically at least.

Whatever the case, I'm done being ANY company's ambassador.  We all remember rolling our eyes at the Collins boys, back when that gear was on top.  I guess we never change...just the equipment.
 


  
« Last Edit: December 29, 2014, 08:16:45 AM by K9MHZ » Logged
KH6AQ
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Posts: 7779




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« Reply #52 on: December 29, 2014, 11:46:55 AM »

Here's a modern transceiver that might meet with Zenki's approval:

The Palstar TR30A featuring 3rd order IMD of -48 dB PEP.

http://www.palstar.com/en/tr30a/

It looks interesting but the 800 Hz CW filter makes it useless to me. That's the widest (meaning worst) CW filter out there. Sales to CW ops must not be in the marketing plan.
« Last Edit: December 29, 2014, 11:49:15 AM by WX7G » Logged
ZS5WC
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« Reply #53 on: January 19, 2015, 03:57:38 AM »

 :)Interesting Post!.
I run the ICOM 7700 , and I know icom engineers spent a lot of time cleaning up the Local Oscillators-because ultimately a Dirty LO will affect all your wanted receiver characteristics and degrade them. This also means if your LO is dirty on RX, naturally your transmitter will suffer phase noise and composite noise on transmit.
So in the case of the TS-590s, (Which I had and sold-transmitter and RX audio issues), and The K3 -these rigs have the potential to be GREAT on transmit, and then we have the old 12v poor imd output stage which spoils the equation once again.
I get the point-and wonder when manufacturers will start taking notice..
Why not produce a K3-D with internal switching supply , 200w and 48 fet pa?.  hiHi.
(And broader RX audio on receive)

73 de William
ZS4L / ZS5WC
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K9MHZ
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Posts: 1725




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« Reply #54 on: January 19, 2015, 04:41:56 AM »

:)Interesting Post!.
I run the ICOM 7700 , and I know icom engineers spent a lot of time cleaning up the Local Oscillators-because ultimately a Dirty LO will affect all your wanted receiver characteristics and degrade them. This also means if your LO is dirty on RX, naturally your transmitter will suffer phase noise and composite noise on transmit.
So in the case of the TS-590s, (Which I had and sold-transmitter and RX audio issues), and The K3 -these rigs have the potential to be GREAT on transmit, and then we have the old 12v poor imd output stage which spoils the equation once again.
I get the point-and wonder when manufacturers will start taking notice..
Why not produce a K3-D with internal switching supply , 200w and 48 fet pa?.  hiHi.
(And broader RX audio on receive)

73 de William
ZS4L / ZS5WC

I guess I'm not following the logic of your post....you've thrown a lot into a single sentence.  Have you seen the spectral graphic displays of transmitted signals of the various rig types?  The 590S and K3 are 100-watt radios, while the 7700 is a 200-watt rig.  That's what drives the use of the higher supply voltages...the operating efficiency of the PA device at rated output.  Even so, when compared, the 7700 doesn't fare nearly as well as these 100-watt examples.  Up conversion is another area....it's not just about "cleaning up the local oscillators."     
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ZS5WC
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« Reply #55 on: January 19, 2015, 05:43:35 AM »

 :)What I was implying-with the good performance iro. Phase and composite noise of these rigs-why then spoil it with and poor performing final amp (IMD wise.)?. yes the low V. Pa does not affect the Composite noise.
Does anyone have the composite noise figures for the IC7700?.
I know its' TX 3rd order IMD is very much better at least than the 2 rigs mentioned above-at least 35dB (Manual says 40.) below PEP.
(They run insanely high quiescent bias on the Finals-3A+ at 48v!.)
I really fail to see how up conversion will assist in composite noise reduction-as far as I can figure-the more conversion stages-the more noise.

73! de William
ZS5WC / ZS4L.
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K9MHZ
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Posts: 1725




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« Reply #56 on: January 19, 2015, 04:26:17 PM »


I really fail to see how up conversion will assist in composite noise reduction-as far as I can figure-the more conversion stages-the more noise.

73! de William
ZS5WC / ZS4L.


I should have indicated that I was switching topics.....my fault for the confusion on that one.

I had a 7700, and am frankly trying to stay positive about that radio, else running the risk of boring the readership of these threads with my whines about the 7700, as well as Icom as a company.  It was a fun radio to use with lots of capability, so I hope you have the same experience as well.

Best,
Brad, K9MHZ

 
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