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Spektrum DX-7

Old 05-28-2007, 07:13 PM
  #2101  
callen
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Default RE: Spektrum DX-7

With the test button on I get barely 30 paces if I point the antenna directly at the plane. Turn it a little and not a problem. This is on different planes. Anyone else experience this.
Old 05-28-2007, 07:33 PM
  #2102  
Bob Pastorello
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Default RE: Spektrum DX-7

Normal to lose a lot of sensitivity when the tip is pointing directly.... that's the lowest area of transmitted power. The "hole" of the "doughnut" pattern.

I fly now with my antenna bent straight up at 90*. NO problems either range checking or flying.....
Old 05-28-2007, 07:51 PM
  #2103  
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Default RE: Spektrum DX-7

Keep looking, its there but on page two or three....the part # is EXRA501...just got one at the local hobby shop...be sure to click on the 'all products' tab at the top of the Expert product page or you will get only the best sellers....tough web site to navigate....

Randy
Old 05-28-2007, 08:17 PM
  #2104  
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Default RE: Spektrum DX-7

The part # is EXRA501.....no t....
Old 05-30-2007, 12:29 AM
  #2105  
rino
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Default RE: Spektrum DX-7

What do you guys think about using the switch that comes with the Spektrum rx with 5 821's on a 90 sized plane. My 5 cell nimh can do 20 amps burst. I'm using the Elite 1500 cells. I know the 821's can pull 1.2 amps each stalled which gives me a max theoretical load of about 6 amps if I stalled all control surfaces at one time. I do some wicked 40+ mph tumbles that just might get me there too. The only thing is that the stock Spektrum 3 wire switch is made with 24 guage wire like all JR switches - including the nicer delux one - and I think 6 amps would be the limit with this sized wire. I called HH and they say 9 amps is OK with this switch but from other wiring standards I have read 6 or 7 amps would be pushing it. Any ideas on a better switch for the job that doesn't cost an arm and a leg. Keep in mind this isn't a 33% bird and doesn't warrant a $200.00 solution.

I know EMS makes a switch that uses 22 guage as well as Hitec and Hobbico but they are not 3 wire and I'm a little afraid of Hobbico stuff.

Opinions welcome.
Old 05-30-2007, 05:11 AM
  #2106  
Bob Pastorello
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Default RE: Spektrum DX-7

Maxx Products sells a 22ga HD integrated charging switch. Three wire. All I've used for years. Very reliable, very "industrial strength", costs $15.
Old 05-30-2007, 10:57 AM
  #2107  
rino
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Default RE: Spektrum DX-7

I checked Maxx. I'll have to check again.
Old 05-30-2007, 06:49 PM
  #2108  
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Default RE: Spektrum DX-7

http://www.maxxprod.com/mpi/mpi-4.html

ORIGINAL: rino

I checked Maxx. I'll have to check again.
Old 06-01-2007, 10:40 AM
  #2109  
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Default RE: Spektrum DX-7

Is it just me or have you guys noticed that often subjects we are discussing on this forum cause advertisements to flash with products related to the discussion. Look at the ads right now on this page and the content of the discussion. Is this coincidental or is big brother watching.

Jeff
Old 06-01-2007, 12:28 PM
  #2110  
rino
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Default RE: Spektrum DX-7


ORIGINAL: jramirez

Is it just me or have you guys noticed that often subjects we are discussing on this forum cause advertisements to flash with products related to the discussion. Look at the ads right now on this page and the content of the discussion. Is this coincidental or is big brother watching.

Jeff
I think it's a conicidence but I see JR and Saito stuff right now. Wierd.
Old 06-01-2007, 12:37 PM
  #2111  
rino
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Default RE: Spektrum DX-7

Aerobob,

Found it thanks. I also found one from smart-fly.com off of an ad here. They have cool stuff.
Old 06-02-2007, 09:57 AM
  #2112  
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Default RE: Spektrum DX-7

Hey guys, Hello from Hell, or at least it is hot enough over here to be hell. I hope everyone is enjoying not getting shot down and for the most part glitch free flying. I get to miss the summer of flying and Im bummed about it. So all of you make sure not to whine about flying conditions. Its too hot and windy every day to fly a model without it basically exploding. One thing we did learn about over here is impedence. Listen to Dick on the battery stuff. We had some high impedence batteries over here, and they are basically useless for any type of high demand. Combined with already hot conditions, the resistance internal in the battery wont allow the release of enough trons for adequate power for simple little toys and things like that. By the way, if you put 2 packs in parallel, the impedence is 1/2 of 1 battery pack of the same make. Thats why 2 packs can deliver more power in general. Exception is the A123's a single pack can melt a 10 guage wire. they are strong and stable. Im going to convert over to them when I get home. Im sold.... bye bye regulators.

Bob, How do you like the 9channel JR? Is it pretty close to the current 9303 programming?
Old 06-02-2007, 10:05 AM
  #2113  
Bob Pastorello
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Default RE: Spektrum DX-7

Goose!!!!! GLAD to see your name popup....hope things are well. What I'm using is a modularized-9303. The "full design" 9303 likely won't see daylight till July/August or so. Sorry to confirm that you have learned more about battery impedance. Bummer. But good info....

My 9303 works just dandy, used all existing AR 7000's from the DX 7 days, nearly all settings transferred with no change.

Try to stay cool, if that's possible. God speed.
Old 06-02-2007, 11:22 AM
  #2114  
Ed
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Default RE: Spektrum DX-7

Impedence is a very important, but often ignored point. It determines just how much of a load your pack will accept without browning out. And yes, running parallel packs cuts impedence in half. IE - Two 10 mOhm packs in parallel equals 5 mOhms.

FYI - http://www.hangtimes.com/index.html is one of the few battery vendors that list impedence. The lower the better.

> Jim
Old 06-02-2007, 01:38 PM
  #2115  
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Default RE: Spektrum DX-7

thx bob,
Im out of commission until late summer. I think I will put a dx9 on pre order. I did get to see it at toledo just before I came over here. It looked great. Im going to use it on my rebuilt 3w 330. I bought one that John McNees and Tom had built a few years prior, so John and I are going to redo it and fly the crap out that 40% er with the DX9/9000.

Cant wait to get home and crank up the ol trusty suky. Its a DX7 veteran now. nary a problem up until I hangared it. The only glitch we had was the elevator lockup on a 6100, sent it in got a new program. lucky not too much damage on the brio. was able to spin it into the tall weeds, broke the cowl, thats all.

anyway you all have fun this summer, I will try to stay cool. I will check in from time to time. see yall at spiderman or something in late october.

by the way, check out the new yellow aircraft F-22. I got an upclose on it. now just hit the lottery.
Old 06-02-2007, 02:50 PM
  #2116  
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Default RE: Spektrum DX-7

Jim, I have heard this point mentioned often, but do not agree with it.
If memory serves me correctly, when you use Nodal analysis, the battery is an open not a short.
With that said, the current may be cut in half when using parallel packs but the effective resistance remains the same.
I am going on 25 year old memory cells and could be wrong, but that is how I remember it.

Packs in parallel will reduce the current by half, not reduce the internal resistance by half.
If wrong, I do stand corrected.

ORIGINAL: GeeBeeJim

Impedance is a very important, but often ignored point. It determines just how much of a load your pack will accept without browning out. And yes, running parallel packs cuts impedance in half. IE - Two 10 mOhm packs in parallel equals 5 mOhms.

FYI - http://www.hangtimes.com/index.html is one of the few battery vendors that list impedance. The lower the better.

> Jim
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Old 06-02-2007, 03:45 PM
  #2117  
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Default RE: Spektrum DX-7

OK, I have a battery pack question....I'd like to use this pack with the Spektrum radio.

It's a 5-cell, 2700ma nimh reciever pack. Sanyo cells. My charger measures the ma going in when charging, and it indicated about 2650ma of charge. When discharged to test the capacity with a 500ma load, the capacity comes out to about 2160ma. When discharged under a 250ma load, the capacity is about 2575ma. I do not think the ma going "in" is relevant, as long as it is consistant. The Supertest has a 125ma setting but I've not tried that yet.

So, is the difference in capacity at the different discharge values a result of internal resistance?? I just can't imagine what else it might be....

Flew the Spektrum today with an 1100ma four cell pack. Four standard servos. Started with a full charge, 5.2 volts and after two flights the loaded airborne pack read 4.8 volts. I gave it a charge and flew again, no issues. The flights were about 10 to 12 minutes each....

Randy
Old 06-02-2007, 06:16 PM
  #2118  
Ed
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Default RE: Spektrum DX-7

ORIGINAL: Geistware

Jim, I have heard this point mentioned often, but do not agree with it.
From No BS Tech Tips & FAQ's > http://www.hangtimes.com/rcbattery_faq.html

Q: What's the big deal about 'Impedance'? What is it and what does it do?


A: Most folks react to the 'capacity' rating alone as being the biggest part of their decision in selecting a pack for their big aggressive birds. This can lead to big trouble on board the aircraft. Just as cells are evaluated for capacity, in high load applications you need to take into consideration what the cells voltage performance will be when loads are applied. All battery technologies react to servo loads with a voltage drop while the load is applied. It's really very simple.. the higher the cells impedance rating, the greater the voltage drop will be while servo loads are applied. Rule of Thumb for cell selection: Impedance Ratings are like a Golf Score. The lower, the better. Aircraft in agressive aerobatic enviornments employing digital or high torque servos should carry a cell impedance score of 10 mOhms or less. As an example, one of the most popular lightweight packs used in IMAC aircraft is the Sanyo HR 2700AUX.. plenty of capacity, but the impedance rate on the cell is 20 mOhms. Pretty high.. but if it's used in parallel with another 2700 pack the impedance rate is cut in half to 10 mOhms (and the available capacity is doubled). This is why you usually see this pack employed in parallel in IMAC birds and used without issues as a single pack in a giant Cub.

Now who am I going to believe ?

> Jim

Old 06-02-2007, 06:23 PM
  #2119  
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Default RE: Spektrum DX-7

nobs
Old 06-03-2007, 07:35 AM
  #2120  
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Default RE: Spektrum DX-7

Believe them.... but it doesn't mean it is true
Here is a link to using nodal.
http://www.swarthmore.edu/NatSci/ech.../mna/MNA1.html

Series resistance to DC power sources are not negated.
With this said, the internal voltage loss is a function of current.
Both of these are internet sources, but I will believe the one immediately above.

Better yet.... Forget what I said, I should just let believe as they may. That is what I do
Old 06-03-2007, 04:00 PM
  #2121  
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Default RE: Spektrum DX-7


ORIGINAL: Geistware

Better yet.... Forget what I said, I should just let believe as they may. That is what I do
That's what I also do. There is so much speculation here regarding the Spektrum systems, that one just needs to be careful of who he believes. I'll just continue to use what works best for me using my 3 AR-7000's. ( Going on 5 AR-7000's )

I try to help out where I can, but if no one wants to listen, then that's OK too. It's still a great place to come to and exchange information

> Jim
Old 06-03-2007, 05:08 PM
  #2122  
rmh
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Default RE: Spektrum DX-7

or swap yarns n discuss the latest gossip-
A treasure trove of founded n unfounded trivia.
Old 06-03-2007, 06:03 PM
  #2123  
Ed
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Default RE: Spektrum DX-7


ORIGINAL: dick Hanson

or swap yarns n discuss the latest gossip-
A treasure trove of founded n unfounded trivia.
And a mountain of mis-information.
Old 06-03-2007, 06:16 PM
  #2124  
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Default RE: Spektrum DX-7

You guys are bad! Its those poor guys who have been fighting low voltage issues that are the one's who are struck out there without any real answers. I kept reminding our radio impound to tell all 2.4 radio owners to check their low voltage constantly. We had no issues at Bomber Field this weekend.
Old 06-03-2007, 09:02 PM
  #2125  
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Default RE: Spektrum DX-7

ORIGINAL: FliteMetal

You guys are bad! Its those poor guys who have been fighting low voltage issues that are the one's who are struck out there without any real answers.


We had no issues at Bomber Field this weekend.
Sooner or later they'll catch on Ed.

Glad things went well at Bomber. I flew for 3 days at the big IMAA West Coast Festival last week. No issues there either. Spektrum is the only system that I will fly at big events from now on !

> Jim

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