Cox/sanwa radio

049kid Wed Jan 08, 2025 2:58 pm

Higang,I came across an AM 2 channel cadet radio in working condition.? Is it ama legal,if not I will use for redneck field flying down my road,any suggestions on lighter servos and Battey pack.thanksi appreciate an ideas ,stay warm!

cmulder Wed Jan 08, 2025 5:16 pm

"AM" is the "modulation" system; Its the Frequency and power output you have to confirm to be legal where you live.
72 mhz is still legal i assume in the states but others more local better confirm it.
Also the power of these is so low that the change they cause any interference is minimal.
You should more worry about other interfering with you while flying.

One warning about the cox sanwa system is that you can not use modern servo's and switches / batteries. without modifications
The negative i think is the center pin and the posetive is on the edge of the reciever.
Today its the other way around and you will damage any servo if you plug it in without changing the pins over.
Servo's that have those pins changed over should work.
The same if you plug in a modern battery / switch; you will damage the reciever.
Also if you use a more modern reciever battery pack get a 4.8v / 4 cell verson NOT a 6 volt ; a fully charged 5 NiMH cell pack gives more then 6 volt and that can damage the servo's or reciever.
If you use a BEC set it to 5 volt to be save but do not go over 6 volt

If you use the old servo's its possible the grease on the gears has dried out and became hard.
This will strip the gears when you power them that way.
take the cover off and clean the old grease off; i use the grease sold by futaba but there is other that should work well too.
Just make sure its fully syntetic that works with plastic.

Then bevore your first fight do a range check; its possibe the capacitors in either the transmitter or reciever have degraded and then the range wil be far less (or none at all) They can be changed if you have the correct soldering gear.
Also the reciever antenna wire insulation might have become hard and brittle or there might even be a break in the antenna wire.
again a range check should show that.

Besides that sure should work Wink

049kid Thu Jan 09, 2025 11:27 am

Thanks for the tips cm,I found a 4 cell 700 mah aaa nimh pack that should lighter.i will lube servos as you suggested,there not super large,should be ok for my 1/2a needs.i definitely will check range.thank again .Sam

sosam117 Thu Jan 09, 2025 1:33 pm

I still have "two" of the Cox/Sanwa Cobra three channel radios on channel 46 (72.160?)

As for the wiring to the servos, the positive (red wire) is on the one end as is the wiring on the very old Airtronics radios (pre 1999)
Besides the plugs are very different to the "universal" plugs that are used today.

If you need any servos look/ask for the "old" Airtronics/Sanwa servos along with the "old" switch hardware that would correspond to the old wiring.

That is another thing.
The charging plug on the transmitter is setup differently too, if you insert a nicad rechargeable pack in the Tx.

I still have plenty of the "old" servos, switches, chargers, and stuff that I have put away as the 2.4gig has less problems.

cmulder Thu Jan 09, 2025 3:12 pm

049 kid mentions "Cadet" as name and that is the version bevore the "Cobra" single stick.
It has a 4 AA size battery holder that you can not remove and there is also no charge port.
Best is to use standard batteries or NiMH cells and charge them outside the transmitter.
Make sure the battery voltage meter is in the right white part and you might have to use normal single use batteries for that.
Keep in might you are "technically" not allouwed to change anything on the transmitter "design" and that would include replacing the battery holder or adding a charge port.
Also look if it has one of those "AMA" labels (assuming you are in the states.
It used to be common to send in your transmitter for testing to see if the performance was still good.
Also look at the circuit board if its clean or has signs of corrosion; mine has some slight contamination

cmulder Thu Jan 09, 2025 3:16 pm

The battery holder was stuck so i assumed it was part of the tx
It has a 8 cell holder.
No charge port though so still better to try with "loose" aa batteries first just 8 of them

Embarassed

sosam117 Fri Jan 10, 2025 3:48 pm

OK, you have the Cadet.
The battery holder is part of the circuit board.

For the batteries you can used rechargeable nicads.
I have had no problems with them as I use the eneloop cells (Panasonic and Sanyo)

I got the charger and the 4 cells from Batteries of America, and they have lasted for me for over 5 years:

I have a newer Airtronics Tx (Aquila) that uses six "AA" batteries, and I can get many days of flying before recharging the cells.
The battery holder looks to be the same as my "newer" Airtronics Tx battery holder which is not removable, and it takes 6 cells.

https://batteriesamerica.com/products/bq-cc17-4bk-3hcca?_pos=5&_sid=84ee36f69&_ss=r

049kid Fri Jan 10, 2025 6:12 pm

Thanks sosam117, that looks like a good deal.fresh batteries & charger,plus if I read it right it will also charge aaa cells.great I won't have to buy one time use throw away,

sosam117 Sat Jan 11, 2025 1:33 pm

I have two of the chargers as the airborne batteries are 4 cell "AAA" in that Cobra radio besides the 6 cell "AA" the Tx takes

And like you said.

I can charge the "AA", then when the light goes out on the charger, I swap out the "AA" and then charge the "AAA" airborne batteries.

Another thing to know is that you can charge two "AA" in one side and have the 2 "AAA" on the other side.
Or mix and match?

These eneloop batteries have done well for me for years.

How long?
Well, I picked up the chargers and batteries (combo) at the Toledo Expo show back in 2016.

You'll be more than happy with the charger/batteries --- I have!

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