Date   

Re: So what is the Consensus

g4abx
 

All interesting stuff Steve and thanks to this group:

My 7000 is mainly used in the shack -- and because it used to run so warm I installed another little fan resting on top forcing air into the existing fan aperture -- and powered by the antenna plug on the back. It cost all of $3 and has zero impact on the fabric of the rig. No internal mods no resistors no nothing. It just sits there quietly doing its 'thing' and even on digital modes the rig never gets out of the 'green' (I only run 50 watts max)

Its great to have a resource like this. 
Many thanks

73
Bruce G4ABX


Re: So what is the Consensus

Steve W3AHL
 

The problem isn't that the SWR changes during tuning are reflected back to the driver,  but how the SWR affects the ALC loop.  Here are some of the contributing factors, but not all apply to all stations obviously.
  1. Many hams don't understand how autotuners work, their limitations and what loads their antennas present to the autotuner.  This result in abuse of the tuner circuits and the radio.  If you open an autotuner and see inductors that have turned brown due to overheating or capacitors that are darkened or have signs of arcing across the PCB due to excessive voltage, the tuner is being misused.  Harder to see are signs of excessive arcing on the relay contacts that contribute to excessive RF spikes during tuning cycles.  
  2. All of the above indicate that the RF signal being presented to the radio is possibly causing damage.  Maybe not immediate failure, but often latent defects in components that eventually fail for no apparent reason at that time.
  3. Many hams use tuners that do not ensure the radio TX power is reduced to 10 watts during tuning.  There were many tuning interfaces (especially for mobile antennas, which are a challenge to tune due to low impedance and narrow bandwidth) that applied incorrect voltages to the tuner interface, which affected temperature control circuits at the CPU by increasing the reference voltage above 3.3 VDC.
  4. Both the PA and Driver MOSFETs are designed to foldback their power output as the SWR they see increases, up to 20:1.  This power foldback of course signals the ALC to increase IF gain, which can result in big problems during autotuning when relay contacts are often bouncing 2-4 times and then dramatically changing the load on the next tuning cycle.  The ALC becomes erratic (this isn't just a problem with the 7K), power bounces around and the tuner circuit has trouble arriving at a good tuning solution sometimes.  So the operator tries again!
  5. Autotuners usually have memory of prior successful LC solutions for given frequency bands, but many hams use multiple antennas for the same band, with a switch ahead of the tuner.  So switching from a High-Z end fed to a Low-Z vertical for a memorized frequency will select the worst possible LC combination, then do a complete rescan.  Often both antennas present a reactive impedance well outside the rated ability of the tuner, but it can still be tuned to a usable SWR.  But the excessive current or voltage takes its toll on the tuner and eventually the radio.
  6. The Driver tends to be the weaker link in the TX chain because it covers the entire HF-UHF range and operates in class A mode, which is less efficient, but lower distortion.  It also seems to be more sensitive to misadjustment or drift of driver gain per band and other TX adjustments.  I have not been able to observe any specific problems with driver signals during tuning cycles, but it is hard to look at lower level signals adjacent to 100-watt PA circuits.  You have to use a scope probe that eliminates the ground lead and uses a spring ground probe that attaches to the grounding collar right at the tip of the probe.  But that only works if the appropriate ground for the signal being observed is within a few tenths of an inch of the circuit access point.  I can see the ALC overshoot effects mentioned in a previous post, but I didn't see the driver levels approach max spec levels.  But I wasn't testing under worst case scenarios, since I didn't want to destroy my radio....
  7. I have not looked at the very early radios, so they may have had problems I'm not aware of.  My oldest 7K was purchased 11/2006.  I have attempted to repair one of the very early radios, but the least of its problems were driver failures.  That was the radio that made me decide to stop repairing 7K's for others!
  8. My experience over the past 14 years leads me to believe that at least half of most radio failures are due to poor installation and operator error / lack of knowledge.  Many hams have no idea of the basics of antennas, connectors, grounding , antenna choice, etc.  
Steve, W3AHL


Re: So what is the Consensus

Steve W3AHL
 

Below is a repost of my notes from 2013 on driver failures.   I tried to gather more info from users that reported problems, but didn't get much useful detail.  There seemed to be some connection to running to low TX power, antenna tuners into non-resonant antennas and questionable station grounding.

I have also noticed subtle changes in the pre-driver board layout and design as the Main PCB artwork changed.  That circuit has always appeared somewhat unstable to me when trying trouble shoot it.  I don't know if later rev Main board actually improved the pre-driver stability issues I observed.

I have two 7K's (circa 2006 and 2010) and have never had a driver failure.  I have replaced several drivers for local hams over the years, but couldn't find a likely cause of the failure.  Some had no/poor station grounding and I'm not aware of repeat failures after that was fixed, but I haven't stayed in touch with many of them either.
------------------------------------------------------
2013 Notes:

There have been several theories on why the driver board fails along with suggested "fixes", but none seemed based on sound technical analysis, in my opinion.  Here are my rambling thoughts on what I think I know about the situation, with no solid conclusions at the end, unfortunately....

 

The board you replaced is the Driver.  The pre-driver FET's are on the PA board and boost the IF output enough to drive the Driver FET.

 

Others have reported failures while running at lower power levels.  This would seem to suggest a problem with the ALC loop perhaps.  Several radios have a problem with the ALC control delay allowing full power for a few milliseconds before ALC reduces the gain of the IF stages.  This is especially a problem when driving an amplifier.  I haven't seen evidence of this in the 7K, except when compression is on perhaps. 

 

The gain is constant in the pre-driver, driver and PA circuits, regardless of the TX PO.  Power control is accomplished by the ALC signal changing the bias of the IF stages that supply the drive. 

 

Whenever the Driver board or associated circuits on its input or output, you should perform the relevant TX Adjustments per the Service Manual.  See Section 4-4 Drive/Final Idling Current.

 

The Driver runs as a class A amp and setting its idle current (as above) is essential for proper linearity AND to ensure it doesn't dissipate excessive heat.   

 

I suspect there is some truth in owners saying that poor grounding contributes to the problem, especially when there is a high SWR being tuned with an autotuner that is rapidly switching the L-C networks trying to find a match.  The early stages of tuning where the L-C matching may actually increase the mismatch can generate some pretty high voltages when the reactance is much higher than 50 ohms.

 

I only run resonant antennas and only use a tuner for portable operation -- and never have had a driver failure on either 7K after almost 7 years on one and 3 years on the other.  In my opinion, a G5RV is a poor antenna technically.  Yes, you can make contacts on it and just about anything else you string up in the air, but it can be more than a little unpredictable the way most hams have them installed.

 

I have tried looking for a weakness in the Driver chain several times and didn't find anything suspicious.  But I didn't try to destroy my radio with high SWR and an autotuner.  The ALC circuit does encompass multiple control inputs and the loop goes from the SWR detector near the antenna connector, back to the IF stages on the Main board.  So poor grounding of the system (radio, tuner, lightning suppressor, and any equipment connected to the radio) is easier to fix than to figure out how or why it causes the problems. 

 

Also critical is good grounding of the circuit board to the chassis via TIGHT mounting screws and to the outer case via the ground springs.  It is easy for the ground springs to get mashed in and not contact the case adequately.

 

Another area to look at is excessive RF getting into your digital audio input, resulting in power spikes before the ALC can reduce the IF gain.  The best cure for this is proper system grounding, but more importantly, minimizing RFI in the shack by using resonant, matched antennas with effective common-mode chokes at the feed point.  Also, routing low-level signal cables away from RF and power cables and never in parallel.  Use of proper ferrite chokes on the audio cables helps.

 

The best resource for analyzing these issues is at:

 

http://www.audiosystemsgroup.com/K9YC/K9YC.htm

 

Read and reread the first document listed:  " A Ham's Guide to RFI...

 

There was a subtle change in the Driver board in 2010 that removed a 10pf cap to ground on the FET's output.  And there is now an OPTIONAL R103 (100 ohm)in series with the Driver FET's gate input, but the parts list says it is only for EUR, FRA and ESP country code models. Neither of my radios has either change installed.

 

I don't believe the driver is likely to fail due to ventilation problems in normal installations.  90% of the heat is dissipated into the chassis heat sink.  Some owners have reported inadequate thermal compound on that interface, but I have not seen that in the 4-5 radios that I've looked at.  The driver FET isn't being pushed hard at all, thermally.  I do replace the white thermal compound with a very thin film of Arctic Silver compound if I have the Driver board removed.  And I make sure the thermal spread, FET and chassis make "perfect" contact before screwing them back together.

 

It will probably be several months before I have time to revisit possible causes of Driver flame outs.  I'm sure many others will add their experience and opinion with Driver failures.  Unfortunately, I feel many of these problems are often related to the individual's unique installation of everything that makes up the radio system.  Which is why there are some many different experiences and conclusions drawn among users.

 

Steve, W3AHL


Re: Strength of the IC7000

wb0m
 

Strength of the IC7000 
From: Bob Hoffmann, K4CQO

"I guess it makes sense to use the woodworking saying: "measure twice, cut once" for antenna connections -- the SWR of the units cannot be used to let you know if the right antenna is connected.

Hi Bob, 

Don’t worry:  You’re not alone. I’m a big user of the phrase “I cut it twice and it’s still too short”. (HI!). 

73,
Jeff/wb0m
Nebraska


Fabricate driver board ???

k2zc@...
 

I am repairing a radio for a friend. The driver board is burnt to a crisp the fet is literally welded to the heat sink. I'm aware that the board is no longer available. I am tempted to fabricate one from double sided pc board. It's not a complicated circuit. I'm curious if anyone else has tried this and been successful.


Re: Strength of the IC7000

 

HF to the outside, VHF to the inside. Probably better to color code the antenna leads maybe with inside VHF - outside HF


On Mon, Jun 1, 2020 at 8:28 AM Bob Hoffmann, K4CQO <rjhoffmann@...> wrote:
OK, I have to eat crow here, but wanted to saw how tolerant the IC7000 is and how well the MAT-TUNER mat-180H works. 

I do have the HF and VHF antennas labeled -- including the connectors and the coax, but after unplugging them for a lightening storm and reconnecting them, I manager to switch the whip that I use for VHF and Ultimax antenna that I use for HF. That went on for weeks -- actually do not remember how long it was switched.

I was wondering why the connection to the repeater was not going too well, and when I connected the HT for the DMR net and I could hear the connection very well, but when connecting to the repeater, I had lots of packet loss. The antenna tuner was able to get SWR to 1.5 for all of the bands -- including 160m -- while I was to the dual band 2m / 70 cm whip. I was surprised that I was able to get out at all!

Anyway, the IC7000 is doing fine, and now the S-meter is doing a lot better job of showing signals on HF than it was when connected to the dual band whip. I think that I need to put in a color coded label ... but I can say that the IC7000 and the antenna tuner are able to handle antennas that are no where near to the advertised bands without any apparent damage. I do have the power output set at 75-80%, but did put it up to 100% for the 2m net in order to be heard. I guess it makes sense to use the woodworking saying: "measure twice, cut once" for antenna connections -- the SWR of the units cannot be used to let you know if the right antenna is connected.



--
J.D. Barron


Strength of the IC7000

Bob Hoffmann, K4CQO
 

OK, I have to eat crow here, but wanted to saw how tolerant the IC7000 is and how well the MAT-TUNER mat-180H works. 

I do have the HF and VHF antennas labeled -- including the connectors and the coax, but after unplugging them for a lightening storm and reconnecting them, I manager to switch the whip that I use for VHF and Ultimax antenna that I use for HF. That went on for weeks -- actually do not remember how long it was switched.

I was wondering why the connection to the repeater was not going too well, and when I connected the HT for the DMR net and I could hear the connection very well, but when connecting to the repeater, I had lots of packet loss. The antenna tuner was able to get SWR to 1.5 for all of the bands -- including 160m -- while I was to the dual band 2m / 70 cm whip. I was surprised that I was able to get out at all!

Anyway, the IC7000 is doing fine, and now the S-meter is doing a lot better job of showing signals on HF than it was when connected to the dual band whip. I think that I need to put in a color coded label ... but I can say that the IC7000 and the antenna tuner are able to handle antennas that are no where near to the advertised bands without any apparent damage. I do have the power output set at 75-80%, but did put it up to 100% for the 2m net in order to be heard. I guess it makes sense to use the woodworking saying: "measure twice, cut once" for antenna connections -- the SWR of the units cannot be used to let you know if the right antenna is connected.


Rail mounts for IC-7000

George Kokolakis, SV3QUP
 

Hello to all,
I designed a pair of rails for my IC-7000 which can be either 3d printed or cut out of metal using a CNC. I have uploaded the desing to thingiverse here:https://www.thingiverse.com/thing:4405251.

73, SV3QUP George


Re: Seen these Auto ATU's

ronald keller
 






On Monday, May 25, 2020, 2:04 PM, montanaaardvark <boblombardi@...> wrote:

(I think I just hit a wrong button and got dumped - sorry if this is a dupe)

Do those "ATU-100 mini tuners by N7DDC" have a claimed impedance range?  You know, like the Icoms that have them have always claimed 3:1 VSWR.

I looked at a couple of eBay auctions and didn't see one.


Tnx,

Bob
--
W4ATM - 35 Miles south of the Kennedy Space Center
Retired RF Design Engineer
Now able to play with all the hobbies I never had enough time for


Re: Seen these Auto ATU's

montanaaardvark
 

On Mon, May 25, 2020 at 09:09 PM, Charles & Sandra Cohen wrote:
FWIW --

There's an extensive write-up of this N7DDC auto-tuner here:

http://radioaficion.com/news/automatic-antenna-tuner-kit/

But it doesn't give an impedance range.

Neat unit . . .  I'm not giving up my LDG Z-11 Pro.
Thanks Charles - at least I'm feeling more like it's not my Search Engine ability that got no results.  I looked in several places.  They'll tell you the component size range, but that's all I've found.

I know what you mean about your Z-11 Pro.  My IC-7000 sits on the AT-7000 that LDG made specifically for the radio. 
 

Bob
--
W4ATM - 35 Miles south of the Kennedy Space Center
Retired RF Design Engineer
Now able to play with all the hobbies I never had enough time for


Re: Seen these Auto ATU's

Charles & Sandra Cohen
 

FWIW --

There's an extensive write-up of this N7DDC auto-tuner here:

http://radioaficion.com/news/automatic-antenna-tuner-kit/

But it doesn't give an impedance range.

Neat unit . . .  I'm not giving up my LDG Z-11 Pro.

.   Charles / VA7CPC


Re: Seen these Auto ATU's

montanaaardvark
 

(I think I just hit a wrong button and got dumped - sorry if this is a dupe)

Do those "ATU-100 mini tuners by N7DDC" have a claimed impedance range?  You know, like the Icoms that have them have always claimed 3:1 VSWR.

I looked at a couple of eBay auctions and didn't see one.


Tnx,

Bob
--
W4ATM - 35 Miles south of the Kennedy Space Center
Retired RF Design Engineer
Now able to play with all the hobbies I never had enough time for


Re: Seen these Auto ATU's

Steve Sawicki
 

Interesting size and I like the power cell,can you provide the link as to the site.
Regards.
Steve
AB2ET


Re: Seen these Auto ATU's

 

By the way with an 8:1 SWr using RG8X at 7 mhz the losses would be 2.24dB or about 40%%.
100 watts in 53 watts at the antenna.
About 34% at 4 mhz, and 50% at 14 mhz, 60% at 28 mhz.
By the way I could measure this and the losses occur on receive as well.
Best not to give up that much when already handicapped in emergency and portable operations.
For that matter losses are losses at home as well.
A tuner at the antenna is more efficient in many ways due to mismatched currents in the shield as well with noise pickup etc.

On Mon, May 25, 2020 at 10:42 AM J.D. Barron via groups.io <jeter.d.barron=gmail.com@groups.io> wrote:
You are correct, but if you need the tuner anyway might as well put it where it will do the most good, especially if it is small and low power. In the camper I use for my emergency go box there is not a lot of excess space anyway,
I know that with the AS2259 the mast is actually a very low loss foam filled coaxial feedline that plugs together to get the height. This low loss mast plugs directly into the tuner in this case.


On Mon, May 25, 2020 at 10:24 AM Helmut Wabnig <hwabnig@...> wrote:


Have you ever measured "feed losses"?

This is like something from hell or evil devils.

In normal circumstances, that is, not extremely off VSWR,
the so called "feed losses" cannot even be measured with standard
cheap amateur radio equipment, so small they are.

If you have not tried it, you don't know.


OE8UWW





--
J.D. Barron



--
J.D. Barron


Re: Anything to look for

Paul Filardi
 

Fuse


On May 25, 2020, at 10:43, Paul Filardi via groups.io <Raritan36@...> wrote:

Also remember if use it at both ends


On May 25, 2020, at 09:24, Paul Filardi via groups.io <Raritan36@...> wrote:

When you hook up two batteries in parallel on a vehicle the weaker battery will always discharge the stronger battery to the point where it sucks both to zero the only way to do this properly is to separate them.   You can do that using a continuous duty solenoid so they are separated when the ignition is not on.  Wire the solenoid to any circuit that comes on with the ignition switch and your problem is solved you will not take out your good battery with a weaker battery


On May 25, 2020, at 05:53, Paul <pg321@...> wrote:



[Edited Message Follows]
[Reason: add]

80M mono right
2m/70cm left

Extra copper earth strap (unpainted atm) on left , there is one on the right also (painted) , they moved resonance the up by 10KHz .

73 , Paul .
ps- so far mobile 80m ssb to ZL2 4155klm / 2100 miles, VK4 450klm up north a f call using 10w and 1 local 20klm :-)
Sigs were ZL2 him S9 me S5 , VK4 him 10 over me 9 to 10 , local him 30+ me 25+ .

<80M.jpg>


Re: Seen these Auto ATU's

 

You are correct, but if you need the tuner anyway might as well put it where it will do the most good, especially if it is small and low power. In the camper I use for my emergency go box there is not a lot of excess space anyway,
I know that with the AS2259 the mast is actually a very low loss foam filled coaxial feedline that plugs together to get the height. This low loss mast plugs directly into the tuner in this case.


On Mon, May 25, 2020 at 10:24 AM Helmut Wabnig <hwabnig@...> wrote:


Have you ever measured "feed losses"?

This is like something from hell or evil devils.

In normal circumstances, that is, not extremely off VSWR,
the so called "feed losses" cannot even be measured with standard
cheap amateur radio equipment, so small they are.

If you have not tried it, you don't know.


OE8UWW





--
J.D. Barron


Re: Seen these Auto ATU's

Helmut Wabnig
 

Have you ever measured "feed losses"?

This is like something from hell or evil devils.

In normal circumstances, that is, not extremely off VSWR,
the so called "feed losses" cannot even be measured with standard
cheap amateur radio equipment, so small they are.

If you have not tried it, you don't know.


OE8UWW


Re: Anything to look for

Paul Filardi
 

Also remember if use it at both ends


On May 25, 2020, at 09:24, Paul Filardi via groups.io <Raritan36@...> wrote:

When you hook up two batteries in parallel on a vehicle the weaker battery will always discharge the stronger battery to the point where it sucks both to zero the only way to do this properly is to separate them.   You can do that using a continuous duty solenoid so they are separated when the ignition is not on.  Wire the solenoid to any circuit that comes on with the ignition switch and your problem is solved you will not take out your good battery with a weaker battery


On May 25, 2020, at 05:53, Paul <pg321@...> wrote:



[Edited Message Follows]
[Reason: add]

80M mono right
2m/70cm left

Extra copper earth strap (unpainted atm) on left , there is one on the right also (painted) , they moved resonance the up by 10KHz .

73 , Paul .
ps- so far mobile 80m ssb to ZL2 4155klm / 2100 miles, VK4 450klm up north a f call using 10w and 1 local 20klm :-)
Sigs were ZL2 him S9 me S5 , VK4 him 10 over me 9 to 10 , local him 30+ me 25+ .

<80M.jpg>


Re: Anything to look for

Paul Filardi
 

When you hook up two batteries in parallel on a vehicle the weaker battery will always discharge the stronger battery to the point where it sucks both to zero the only way to do this properly is to separate them.   You can do that using a continuous duty solenoid so they are separated when the ignition is not on.  Wire the solenoid to any circuit that comes on with the ignition switch and your problem is solved you will not take out your good battery with a weaker battery


On May 25, 2020, at 05:53, Paul <pg321@...> wrote:



[Edited Message Follows]
[Reason: add]

80M mono right
2m/70cm left

Extra copper earth strap (unpainted atm) on left , there is one on the right also (painted) , they moved resonance the up by 10KHz .

73 , Paul .
ps- so far mobile 80m ssb to ZL2 4155klm / 2100 miles, VK4 450klm up north a f call using 10w and 1 local 20klm :-)
Sigs were ZL2 him S9 me S5 , VK4 him 10 over me 9 to 10 , local him 30+ me 25+ .

<80M.jpg>


Re: Seen these Auto ATU's

 

Here is my thought about this ATU and it's size.
I have been using either an MFJ 939 or LDG - 100 when portable and installing it at the base of the 30' telescoping fidhing pole with a set of radials spread out on the ground.
I have also used a crossed dipole NVIS antenna to good effect (a copy of the AS2259). Either requires a tuner. What I am thinking about is building one of these with some NIMH batteries and mounting it as a balun at the feed point so that the feed losses would be minimal. It would be possible to incorporate a "TEE" power inserter to get 12 volts to the unit and eliminate the batteries as well. 
Darn it, just when I thought I had finished with my project list.

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