Radio prob

[Russ]

it's been a mth or 2 , me trusty jab has been hangered. ( regularly hand turned ) The other day found time to blow out the cob webs, she just started.....battery low, anyway...I'm receiving perfectly, but several guys were reporting my transmissions were unreadable.

 

So........what's going on, .....radio tech guy, or was just low battery.

 

 

[frank marriott]

Yes Russ

 

When battery is low Tx is not good (at least with the micro air radios )

 

I don't know if they run on a 10v rail or not but certainly I have seen this on a couple of different aircraft.

 

Charge battery and all good in the ones I have dealt with.

 

Happened on a training aircraft reasonably regularly with long taxis before upgrading the charging coils to series from parallel (which increases the rate at low RPM)

 

 

[Yenn]

On a non radio topic. Is it a good thing to regularly turn over an engine that is not being used.

 

I consider it better to leave it alone, especially if it is a Jab or a Lycoming. They both have the camshaft above the oil level and turning the motor over will wipe the oil off the cam and could lead to spalling of the cam and followers.'Of course if you were really turning the motor over it should spread oil everywhere.

 

 

[dutchroll]

I guess it's possible but I would've thought with the alternator running you'd have a good bus voltage to provide normal transmit power, even if your battery was low.

 

I've started my plane with very low battery voltage (air start system so it only needs enough power to crack open the air solenoid valve) and the radio, once the engine was running, has been fine.

 

 

[frank marriott]

I guess it's possible but I would've thought with the alternator running you'd have a good bus voltage to provide normal transmit power, even if your battery was low.I've started my plane with very low battery voltage (air start system so it only needs enough power to crack open the air solenoid valve) and the radio, once the engine was running, has been fine.

Yes Duchroll that is normal, with an alternator and with radios using a 10v regulated supply voltage, I "suspect" the micro air radios don't have this supply rail (but I am guessing there- haven't got a circuit diagram) and the charging circuit before the upgrade does not supply sufficient charge voltage below about 1800rpm and takes a while to get battery voltage up to 12v.

 

Certainly low battery condition gives the results as reported by Russ.

 

 

[Russ]

Ok...I've plugged in the 240v charger, let's give it 48hrs and see what the radio then does. ( oddessy is 7 yrs old, might be time to change it also ) lets see.

 

 

[frank marriott]

Ok...I've plugged in the 240v charger, let's give it 48hrs and see what the radio then does. ( oddessy is 7 yrs old, might be time to change it also ) lets see.

Heard all sorts of stories about long life from these batteries, but I changed mine at 6years, still working fine, but didn't want to run the risk of a problem when out in the sticks. I considered 6 years trouble fee was still good value.

 

 

[Jabiru Phil]

Had the same problem when my last battery packed it in.

 

Started with jumper leads. Whilst radioing my taxi intentions the radio went dead on Tx.

 

It gave a squealing sound!

 

Aborted the flight, installed new battery.

 

PHIL.

 

 

[Russ]

Well then....should the battery hold a good charge for 6...8 weeks, or my now situation indicate battery has indeed reached its use by date ??

 

( engine was noticeably sluggish on startup )

 

Side note here........was at a rural farming expo last yr, one exhibitor was expousing his " battery rejuvenating additive" .....in essence, it cleaned/ removed buildup on the plates etc etc, his presentation was well attended.

 

 

[biggles]

Don't muck around with it Russ , 7 years is not too bad, and you don't want problems, particularly on your trip out West . I got 7 years out of mine before it started being unreliable . I charged it a few times but you need a more sophisticated charger than mine, consequently the charge didn't last. I finally bit the bullet and ordered a new one which will probably see me out ..... Bob

 

 

[Russ]

Agreed......ordering a new battery today.

 

 

[Russ]

Ok.....battery fully charged, radio receives perfectly....transmissions are 1 out of 5, chaps in circuit all report same.

 

This now situation is new, radio has performed ok for last yrs.

 

Fellow flyer says....the intercom unit ( jab installed ) is most likely the cause ???

 

Ok....any ideas please guys.

 

Have pulled radio out, sending to tech folks for checking.

 

 

[skeptic36]

See : http://www.recreationalflying.com/threads/mgl-v6-transmit-problem.144491/#post-539148

 

 

[ron dunn]

I think it's a good idea (regardless of battery type) to run a trickle charger full time if the aircraft is not used for long periods. They only pump a few milliamperes in and then keep the battery topped up.

 

 

[karcsi18854]

it's been a mth or 2 , me trusty jab has been hangered. ( regularly hand turned ) The other day found time to blow out the cob webs, she just started.....battery low, anyway...I'm receiving perfectly, but several guys were reporting my transmissions were unreadable.So........what's going on, .....radio tech guy, or was just low battery.

Russ... there is an identical saying in Hungarian. I had a similar problem and changing batteries fixed the problem. Keep in touch