R8600 Icom IC-R8600 v AOR 8600 Mk2

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#21
I think we are getting similar results with the preamp on and mine seems to break squelch at a slightly lower level without the preamp. If I get time I'll connect an audio dBm meter and find the point where a 30% modulated 1Khz tone produces 10dB more audio than no signal present.

Bottom line is the VHF AM sensitivity is just fine and that coupled with its world class narrow and wide spaced dynamic range and super low LO phase noise means there should be few receivers that could top it for VHF aircraft reception. If you want to see how my personal 8600 does on HF, see the 17th receiver down on this list: Receiver Test Data For some reason Rob Sherwood's personal 8600 did much better and ranks the second best receiver he has ever tested.

For AOR-262, I would really go through all the menus again to see if some setting is causing the problem. If not then send it in to be looked at so you can enjoy it at full specs.

Reading this thread concerned me a bit. I never really use my R8600 on VHF air band more than extremely causally, just occasionally going to the local airport Unicom. So I really had not checked out the R8600 in AM and VHF.


I do not have a SINAD meter. I do have a HP 8640B and a software audio power meter (on the soundcard of one of my machines). So, what follows may not be a true 10 dB S+N/N measurement, but should be somewhat close.


R8600 was set to: 124.000 MHz, AM mode, Default FIL 1, AGC OFF, Pre Amp was tried both ON and OFF, NB, NR, ATT, IP+, NOTCH all OFF.

HP 8640B set to: 124.000 MHz, Internal AM modulation, 1000 Hz, 30% modulation.


I took the audio out of the R8600 directly to the line input of the sound card. I set the audio power meter software REFERENCE to 0 dB (raw number was about -36 dB) with Squelch OFF and no RF signal input to the R8600.

R8600 Pre Amp OFF, Squelch set to 30% (just killed static):
-118 dBm, 0.28 uV, broke squelch with usable but somewhat scratchy audio.

R8600 Pre Amp ON, Squelch set to 30% (just killed static):
-130 dBm, 0.07 uV, broke squelch with scratchy audio.

R8600 Pre Amp OFF, Squelch OFF, Audio Power meter REF set to 0 dB with no signal present:
-112 dBm, 0.56 uV, 10 dB increase in Audio Power meter

R8600 Pre Amp ON, Squelch OFF, Audio Power meter REF set to 0 dB with no signal present:
-120 dBm, 0.22 uV, 10 dB increase in Audio Power meter


Again, I am not going to claim this is a 100% valid 10dB S+N/N measurement, but it should be in the ball park.

It looks to me like the R8600, at least my copy, is adequately sensitive in the VHF Air Band.

T!
 
Joined
Oct 22, 2005
Messages
187
#22
I think we are getting similar results with the preamp on and mine seems to break squelch at a slightly lower level without the preamp. If I get time I'll connect an audio dBm meter and find the point where a 30% modulated 1Khz tone produces 10dB more audio than no signal present.

Bottom line is the VHF AM sensitivity is just fine and that coupled with its world class narrow and wide spaced dynamic range and super low LO phase noise means there should be few receivers that could top it for VHF aircraft reception. If you want to see how my personal 8600 does on HF, see the 17th receiver down on this list: Receiver Test Data For some reason Rob Sherwood's personal 8600 did much better and ranks the second best receiver he has ever tested.

For AOR-262, I would really go through all the menus again to see if some setting is causing the problem. If not then send it in to be looked at so you can enjoy it at full specs.
That performance differential between the two different 8600s suprises me, though at that level no doubt those differences are small. Still, I wonder what range of variation there is between the 8600s out there.
 

Token

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#23
That performance differential between the two different 8600s suprises me, though at that level no doubt those differences are small. Still, I wonder what range of variation there is between the 8600s out there.
Really, that apparent difference is just a factor of what they are sorted on, in this case narrow spaced dynamic range. If you sorted that list on almost any other factor measured the two radios performed very similarly.

And even at that, the worse of the two radios did exceptionally well. 10 years ago the worse of those two radios would have been number one on the list, 5 years ago the worse of those two radios would have been in the top 4 on the list.

And then there is the fact that most of the other radios on the list were sample sets of one. How many of them would have shown similar variations if more units were tested? We are talking about performance that just a short time ago only came at the highest end of professional, deep pocket, equipment. And while the R8600 is not cheap, by any means, it does not compete with the new cost of really high end scientific and military gear, while it is coming closer than ever before in performance.

However, there are a few radios on that list that did have multiple samples tested, and the R8600 does have the largest variation (for both wide and narrow dynamic range) of any of the ones I noticed at a quick glance. You have to wonder if there is something off, just a tad, on the first one tested. At that level of performance it would only take a very small issue to skew such results.

One thing to consider, the two radios tested are from different blocks.

The better testing one is from the US market, cell phone blocked, 02 block, and the worse testing one is from the GOV only, no frequency limitation, 04 block. I do not know how Icom runs the production of these radios, but it would not surprise me if they were produced at different times, in different production runs, possibly (because of time) with different parts lots. I believe I saw indication that the first of the 04’s were produced before the first of the 02’s, and I know at least a couple of people who pre-ordered radios ended up with 04’s even though they should not have, this might indicate they were produced in different batches.

But if the above is not true, and Icom builds them all on the same line at the same time, just burning a ROM/PROM/FPGA differently, and assigning the block number based on that, then the question of variability is even larger, since, except for block number, the two radios would only be 11 apart in serial number.

Just thoughts.

T!
 
Joined
Oct 22, 2005
Messages
187
#24
Really, that apparent difference is just a factor of what they are sorted on, in this case narrow spaced dynamic range. If you sorted that list on almost any other factor measured the two radios performed very similarly.

And even at that, the worse of the two radios did exceptionally well. 10 years ago the worse of those two radios would have been number one on the list, 5 years ago the worse of those two radios would have been in the top 4 on the list.

And then there is the fact that most of the other radios on the list were sample sets of one. How many of them would have shown similar variations if more units were tested? We are talking about performance that just a short time ago only came at the highest end of professional, deep pocket, equipment. And while the R8600 is not cheap, by any means, it does not compete with the new cost of really high end scientific and military gear, while it is coming closer than ever before in performance.

However, there are a few radios on that list that did have multiple samples tested, and the R8600 does have the largest variation (for both wide and narrow dynamic range) of any of the ones I noticed at a quick glance. You have to wonder if there is something off, just a tad, on the first one tested. At that level of performance it would only take a very small issue to skew such results.

One thing to consider, the two radios tested are from different blocks.

The better testing one is from the US market, cell phone blocked, 02 block, and the worse testing one is from the GOV only, no frequency limitation, 04 block. I do not know how Icom runs the production of these radios, but it would not surprise me if they were produced at different times, in different production runs, possibly (because of time) with different parts lots. I believe I saw indication that the first of the 04’s were produced before the first of the 02’s, and I know at least a couple of people who pre-ordered radios ended up with 04’s even though they should not have, this might indicate they were produced in different batches.

But if the above is not true, and Icom builds them all on the same line at the same time, just burning a ROM/PROM/FPGA differently, and assigning the block number based on that, then the question of variability is even larger, since, except for block number, the two radios would only be 11 apart in serial number.

Just thoughts.

T!
Thanks for that very interesting and informative reply, appreciate it.

I contacted Icom with the issue described above in my r8600. They said they could not duplicate the issue in their lab and it could be static build up or antenna/grounding issues or other accessories attached to the radio. I operate the receiver with an AOR SA7000 wideband antenna and a Yaesu-1023 power supply with no other accessories attached. The issue is intermittent, didn't see it this morning.
 
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#28
Aor-262 - Have you ever performed this test by powering OFF the AOR when you notice the problem on the 8600?

I've had radios that were too close together scanning the same bands or listening to the same freq get clobbered when their IF freqs interfere with each other.

Sometimes just separating the units solved the problem - although when I first started out and using thing like a simple bnc-tee connector to a single antenna for both units - the leakage between the two units via the un-isolated tee was an issue too. Here I'm assuming you are using TWO separate antennas for each unit.

So right the 8600 is an SDR radio - but maybe some junk from the AOR is desensing the 8600 just a wee bit ?

Just wondering if the AOR is too close to the Icom - and/or a common shielding or shared ground leakage path is cropping up between the two .....
 
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#29
Okay so have you tried this yet? I didn't see any update in that older thread.
@devicelab

I kinda gave up on that idea in the end because people replying were replying with ideas and saying things way over my head. It just got way too technical for me -- especially when someone started talking about deep discharge cycles of a battery that doesn't do it any good and in order to maintain a healthy battery it should be kept topped up a minimum of 50% all the time -- go back and read all the messages; you'll need a Degree in Batteries to understand it. :rolleyes:
 
Joined
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Messages
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#30
Aor-262 - Have you ever performed this test by powering OFF the AOR when you notice the problem on the 8600?

I've had radios that were too close together scanning the same bands or listening to the same freq get clobbered when their IF freqs interfere with each other.

Sometimes just separating the units solved the problem - although when I first started out and using thing like a simple bnc-tee connector to a single antenna for both units - the leakage between the two units via the un-isolated tee was an issue too. Here I'm assuming you are using TWO separate antennas for each unit.

So right the 8600 is an SDR radio - but maybe some junk from the AOR is desensing the 8600 just a wee bit ?

Just wondering if the AOR is too close to the Icom - and/or a common shielding or shared ground leakage path is cropping up between the two .....
@hertzian

I've discussed what you've said before - I've often wondered when I see people's Shacks that have many many receivers all stacked next to each other, on top of each other - all lined up like Soldiers on Parade ... they all generate their own RF Interference. My AOR 8600 sits next to my IC-R8600 with a gap of about 8 inches. If I tune my AOR to a frequency of say 0.909 kHz AM I get a slight buzzing sound on that frequency which stops if I power off my R8600. However, there is still an audible buzzing sound on that frequency - until I physically turn off the power supply which is the supplied Icom AD-55 for the R8600 - then the frequency is perfectly clear. I have tried running my R8600 with no other power source switched on - that is everything else in the room is off and still the same results.
 
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#31
Bottom line is the VHF AM sensitivity is just fine and that coupled with its world class narrow and wide spaced dynamic range and super low LO phase noise means there should be few receivers that could top it for VHF aircraft reception.
I wonder why Icom publish such a poor spec for it, could there be a large variation between units where some need 5.6uV and some only 0.5uV in AM mode, or maybe they just made a typo in the spec?
 
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#32
I kinda gave up on that idea in the end because people replying were replying with ideas and saying things way over my head.
All you need is either a 12v AGM battery or a standard car battery (at greater cost.) Then you just need a $25 12v trickle charger.

Here's an example: Universal 12v 12 AH Deep Cycle Sealed Lead Acid Battery w/ F2 Connectors

I use to power my ICOM 7000 back in the day with one of these. I would charge it up during the day (while I'm at work) and then use it for a few hours each night.

I don't know if it's included but the only trick might be locating the 13.8v dc power connector the R8600 uses...
 

Token

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#33
I wonder why Icom publish such a poor spec for it, could there be a large variation between units where some need 5.6uV and some only 0.5uV in AM mode, or maybe they just made a typo in the spec?
That looks suspiciously like a typo to me, or maybe a mistake in converting from one unit to another, so an order of magnitude error (decimal in the wrong place). Where did you find the spec of 5.6uV?

T!
 
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Messages
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#34
All you need is either a 12v AGM battery or a standard car battery (at greater cost.) Then you just need a $25 12v trickle charger.

Here's an example: Universal 12v 12 AH Deep Cycle Sealed Lead Acid Battery w/ F2 Connectors

I use to power my ICOM 7000 back in the day with one of these. I would charge it up during the day (while I'm at work) and then use it for a few hours each night.

I don't know if it's included but the only trick might be locating the 13.8v dc power connector the R8600 uses...
@devicelab

I've no problem paying the price of a brand new car battery. As you know the R8600 is supplied with a bare ended power cable that would usually be connected to the screw or push in connectors of a dedicated preferably non-switching regulated power supply ... linear type. My only concern is connecting the R8600 directly to a car battery means there's no control over the voltage / amps, no protection such as overloading or anything else that might happen. Any problem with that battery and it's power output means the R8600 is only relying on its own internal protection and if that failed I'm left with a smoking 2,500 mini fire. I'm sure connecting the R8600 directly to a battery is fine. Anyway, we'll go back to the battery thread if you want to continue as we're going off track of this thread. I'll let you know how I get on if I decide to get a battery. :D
 
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#35
Any problem with that battery and it's power output means the R8600 is only relying on its own internal protection and if that failed I'm left with a smoking 2,500 mini fire. I'm sure connecting the R8600 directly to a battery is fine.
If you get a AGM battery 12v 12a battery there won't be any issues. If you are inclined to be so paranoid then add inline fuses (15v/5A) to your DC cable. It's not rocket science.

But yes, a [good quality] linear power supply would be a much better solution -- albeit an expensive one.
 
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#36
If you get a AGM battery 12v 12a battery there won't be any issues. If you are inclined to be so paranoid then add inline fuses (15v/5A) to your DC cable. It's not rocket science.

But yes, a [good quality] linear power supply would be a much better solution -- albeit an expensive one.
@devicelab

Appreciate your advice. Thanks for your help along the way.
 
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#37
That looks suspiciously like a typo to me, or maybe a mistake in converting from one unit to another, so an order of magnitude error (decimal in the wrong place). Where did you find the spec of 5.6uV?
Well in the QST review they published AM sensitivity numbers as well. I'm not sure what this number is but they say 6.32 uV but then per band they mention @ 120 Mhz it's 1.64 uV and 0.68 uV with the preamp off and on. I guess the 6.32 value is an average over the 1.8 Mhz - 3 Ghz range..?
 
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#38
This is interesting to know since an 8600 may be in my near future ...

Ok, below 30mhz it is an sdr. Above 30 mhz, it is conventional double (or triple above 1ghz) superheterodyne. The AOR 860mkii has a 2nd IF of 45.05mhz, whereas the Icom 8600 has a 2nd IF above 30 mhz of 46.35 mhz. Eh, close but I can't imagine the Icom being desensed by the AOR's IF.

Which leads to possible bandpass filtering differences. I'd have to look up the bandpass filter ranges for the Icom to see if possibly airband is also included in the same bandwidth as FM broadcast. If that bandpass filter is that wide, perhaps you live near an FM flamethrower broadcast station, and maybe would benefit from an FM Notch?

Just guessing here since I don't know what the actual bandpass ranges in the Icom are. Is the RF gain control usable for fm modulation above 30 mhz? If so, does reducing the rf gain improve the signal level and quality?

Just thinking out loud here ...
 
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#39
Simple battery fun for the Icom 8600 for about 6-8 hours of fun (or emergency backup!)

1) 18 to 22ah AGM battery. Commonly used for old school jump-starters.
2) Voltmeter you can hang off it: A DROK or similar small digital voltmeter - sips about 10mah in use.
3) Deltran Battery Tender "agm" charger. Use only on battery, not while powering the radio at the same time, ie don't have the Icom on while you are charging the batt just to be safe. Nobody wants a $30 agm charger failing and taking out your $$ Icom.

DON'T BLOWUP YOUR ICOM: be absolutely sure of wiring polarity. Not sure how the Icom would react to wrong polarity hookup, other than blowing a fuse. Sometimes it can take out something inside before the fuse blows. Use the supplied permanent hookups that come with the Deltran (or other charger), rather than just the clamps. You'll get it right 500 times in a row, but then comes that day you go reverse polarity. :(

Operation: Place the DROK voltmeter on the battery when you are using it. Do not let it fall below 12v during use. Recharge at that point (or any voltage higher than that). Be sure to charge for at least a day or two when first getting the battery. Do not let battery sit around discharged after a listening session, even if it is only for an hour. Charge it back up.

Even though the DROK (or similar) little voltmeter draws very little current in use, do not leave it on the battery forever when not using it.

This isn't meant to be a totally exhaustive battery tutorial, but just something to have some fun, and with stuff you may be able to get right at your auto parts store. It could be the start of something much bigger and is actually quite a fun sideline to the radio hobby itself.

We all gotta' start somewhere, and unfortunately, as you've seen, TMI or too much info can take the fun out of it learning along the way.
 
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#40
The 8600 does not act like other receivers in the presence of strong in band signals. I can be monitoring a lower 2m frequency in the 145MHz range while transmitting in the 147MHz range with a base antnena close to the 8600 antenna and the 8600 doesn't seem to care. It just keeps receiver whatever is 2MHz away from where I'm transmitting.

Every other radio I've used like this was trashed by my 2m transmissions 2MHz away and could not receive under those conditions.

This is interesting to know since an 8600 may be in my near future ...

Ok, below 30mhz it is an sdr. Above 30 mhz, it is conventional double (or triple above 1ghz) superheterodyne. The AOR 860mkii has a 2nd IF of 45.05mhz, whereas the Icom 8600 has a 2nd IF above 30 mhz of 46.35 mhz. Eh, close but I can't imagine the Icom being desensed by the AOR's IF.

Which leads to possible bandpass filtering differences. I'd have to look up the bandpass filter ranges for the Icom to see if possibly airband is also included in the same bandwidth as FM broadcast. If that bandpass filter is that wide, perhaps you live near an FM flamethrower broadcast station, and maybe would benefit from an FM Notch?

Just guessing here since I don't know what the actual bandpass ranges in the Icom are. Is the RF gain control usable for fm modulation above 30 mhz? If so, does reducing the rf gain improve the signal level and quality?

Just thinking out loud here ...
 
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