dittle fsg 71M squelch issue

[[email protected]]

Hi all, am having an issue with my new to me dittle radio. worked fine for two flights now on startup it breaks squelch for a while even with the switch set correctly. it lasted about 15 minutes then went normal. The next flight it only did that for 5 minutes. after reading the manual it says nothing about being able to adjust auto sq setting. Is there a way to increase the auto squelch? or could the internal battery be getting low? I did the usual turning of stuff to rule out interference from other equipment.

[Dan Marotta]

Just a guess, but some radios have a squelch adjust pot that's reachable
with a small screw driver.Â* Look for a small sticker covering the hole
in the case of the radio behind the panel.Â* Note: I've seen two pots on
some radios and I don't know what the other one is for.Â* Hopefully you
can slide the radio out of the panel and attempt to adjust the pot while
connected and turned on.Â* Mark the original location so you can return
the setting if it doesn't work. It might also be a good idea to talk
with an avionics shop that is familiar with the radio and/or find a
maintenance manual for it.

On 9/25/2017 8:51 AM, wrote:
> Hi all, am having an issue with my new to me dittle radio. worked fine for two flights now on startup it breaks squelch for a while even with the switch set correctly. it lasted about 15 minutes then went normal. The next flight it only did that for 5 minutes. after reading the manual it says nothing about being able to adjust auto sq setting. Is there a way to increase the auto squelch? or could the internal battery be getting low? I did the usual turning of stuff to rule out interference from other equipment.

--
Dan, 5J

[MN50]

On Monday, September 25, 2017 at 7:51:25 AM UTC-7, wrote:
> Hi all, am having an issue with my new to me dittle radio. worked fine for two flights now on startup it breaks squelch for a while even with the switch set correctly. it lasted about 15 minutes then went normal. The next flight it only did that for 5 minutes. after reading the manual it says nothing about being able to adjust auto sq setting. Is there a way to increase the auto squelch? or could the internal battery be getting low? I did the usual turning of stuff to rule out interference from other equipment.

Walter Dittel had a service bulletin, N0. 20/97 regardting the auto squelch.. There is a copy of the bulletin on DG Flugzeugbau that shows the location of the said potentiometer.

http://www.dg-flugzeugbau.de/Data/TN-DG/service-infos/1997-20-e.pdf

MN

[MN50]

On Monday, September 25, 2017 at 7:51:25 AM UTC-7, wrote:
> Hi all, am having an issue with my new to me dittle radio. worked fine for two flights now on startup it breaks squelch for a while even with the switch set correctly. it lasted about 15 minutes then went normal. The next flight it only did that for 5 minutes. after reading the manual it says nothing about being able to adjust auto sq setting. Is there a way to increase the auto squelch? or could the internal battery be getting low? I did the usual turning of stuff to rule out interference from other equipment.

Correction - DG service bulletin

[Dan Marotta]

....And I just recalled that the other pot is for side tone which is
unimportant unless you use a headset.

On 9/25/2017 10:49 AM, MN50 wrote:
> On Monday, September 25, 2017 at 7:51:25 AM UTC-7, wrote:
>> Hi all, am having an issue with my new to me dittle radio. worked fine for two flights now on startup it breaks squelch for a while even with the switch set correctly. it lasted about 15 minutes then went normal. The next flight it only did that for 5 minutes. after reading the manual it says nothing about being able to adjust auto sq setting. Is there a way to increase the auto squelch? or could the internal battery be getting low? I did the usual turning of stuff to rule out interference from other equipment.
> Walter Dittel had a service bulletin, N0. 20/97 regardting the auto squelch. There is a copy of the bulletin on DG Flugzeugbau that shows the location of the said potentiometer.
>
> http://www.dg-flugzeugbau.de/Data/TN-DG/service-infos/1997-20-e.pdf
>
> MN
>

--
Dan, 5J

[Gianni Isotope]

Have you by any chance added additional instruments recently, such as a flight computer or electronic vario? Noise from the cabling can cause your radio to break squelch, often intermittently. I had this problem with my Dittel FSG71M after installing an LXNAV S80 and Nano. It went away after rerouting the new cables farther from the radio.

[[email protected]]

Hi MN, I cant seem to find the pdf file you specified it took me directly to there tech notes section for the gliders. And they may have renamed/numbered I found nothing with 1997 or 20 on it.

And no I havent added anything new. I will try and turn my phone off next time it happens as that was the only thing I didnt try.

[JS[_5_]]

On Monday, September 25, 2017 at 11:34:15 AM UTC-7, wrote:
> Hi MN, I cant seem to find the pdf file you specified it took me directly to there tech notes section for the gliders. And they may have renamed/numbered I found nothing with 1997 or 20 on it.
>
> And no I havent added anything new. I will try and turn my phone off next time it happens as that was the only thing I didnt try.

The old FSG71M is particularly bad at rejecting noise from other instruments.
I'm having similar issues with a 71M and LX V3 vario.
A current radio would fix it.
Jim

[[email protected]]

On Tuesday, September 26, 2017 at 5:38:30 AM UTC+10, JS wrote:
> On Monday, September 25, 2017 at 11:34:15 AM UTC-7, wrote:
> > Hi MN, I cant seem to find the pdf file you specified it took me directly to there tech notes section for the gliders. And they may have renamed/numbered I found nothing with 1997 or 20 on it.
> >
> > And no I havent added anything new. I will try and turn my phone off next time it happens as that was the only thing I didnt try.
>
> The old FSG71M is particularly bad at rejecting noise from other instruments.
> I'm having similar issues with a 71M and LX V3 vario.
> A current radio would fix it.
> Jim

As Gianni commented, breaking squelch as described is very likely to be noise issuing from another device. (FLARM devices typically take up to 15 mins for first GPS initialization, 1 to 5 mins to locate satellites and update microSD card).

If you wind your squelch up to reject the initial interference then the radio will obviously then permanently reject all weaker transmissions as well.

Short term, it might be better to switch on early and wind speaker volume down initially.
Long term, you need to determine if the Dittle radio's squelch setting has drifted or some device is radiating interference.

Often each device is radiating a bit of interference, some more than others.. When it finally gets annoying / breaks squelch it is hard to determine which one is causing the most interference.
I have found that holding a hand-held aviation band radio (with squelch off / set very lightly) next to the instruments / wiring / microphone stalk is quite revealing. Often interference varies between radio channels. (Does the same squelch problem happen if you change radio frequencies?).

I have had success reducing squelch breakthrough from instruments using the following methods - Tightening screw terminals, cleaning / reseating connectors and fuseholders, reseating radio in cradle, replacing dodgy power switches, replacing end of life batteries, routing radio wiring away from nav wiring, ensuring the radio is on its own fuse and not sharing with nav gear, ensure radio and nav ground/negative wiring is really good, clipping ferrite noise suppressors onto suspect cables. (The clip-on ferrite noise suppressors are remarkably good, especially if you have enough wire to get 2 or 3 turns of wire through them). Be VERY careful if unplugging cables, it is very, very easy to let the smoke out if you plug them back in incorrectly.

Display panels, powerbanks and 12 to 5v converters are frequently very noisy.
Panel mount USB cables and microSD card sockets sometimes cause problems, try removing the cable / card if not vital.

Good luck, radio interference is a hard one, it often gets worse every time we introduce more distractions into our cockpit. As Jim suggests, modern radios have been designed to reject noise from modern instruments, older radios may benefit from having ferrite suppressors clipped onto the radio and nav gear leads.
Max

[[email protected]]

The pot is R428, value 1k. Sorry don't have a pic but you'll find a link to the circuit on this page:

http://strato.co.nz/pik20/dittel/dittel.html

As others have indicated, make sure nothing else is causing too much external noise. Cheers JR

[[email protected]]

thanks guys, I ordered a new replacment internal battery, just because if I open it up to fix that I might as well put a new one in :) Ill fly it a few times to see if it remains a issue.

[[email protected]]

On Saturday, September 30, 2017 at 11:31:12 AM UTC+10, wrote:
> thanks guys, I ordered a new replacment internal battery, just because if I open it up to fix that I might as well put a new one in :) Ill fly it a few times to see if it remains a issue.


Service Info No. 20/97 Adjusting Squelch Sensitivity of Dittel Radios in DG motorgliders (if necessary)
https://www.dg-flugzeugbau.de/wp-content/uploads/filebase/Data/serviceinfos-en/1997-20-e.pdf

[Bob Gibbons[_2_]]

On Mon, 25 Sep 2017 07:51:21 -0700 (PDT), wrote:

>Hi all, am having an issue with my new to me dittle radio. worked fine
>for two flights now on startup it breaks squelch for a while even with the
>switch set correctly. it lasted about 15 minutes then went normal. The
>next flight it only did that for 5 minutes. after reading the manual it says
>nothing about being able to adjust auto sq setting. Is there a way to
>increase the auto squelch? or could the internal battery be getting low?
>I did the usual turning of stuff to rule out interference from other equipment.
>
>---
>This email has been checked for viruses by AVG.
>http://www.avg.com

I have had to retire 2 FSG71M radios with what sounds like a similar
problem. Following reception of a transmission, the radio would behave
as if the squelch had been turned off, with the typical hiss coming
out of the speaker.

Key to recognizing the problem I had is that if I tapped the transmit
button, the squelch would come back on, and the hiss would disappear.
This would work for a while, until the problem would repeat a few
minutes later.

My final guess was that this was a transmit/receive relay failure as
detailed in 3U's very informative website.
https://sites.google.com/site/threeuniform/dittel-fsg71m

Never finding a suitable relay replacement, I finally gave up on the
71M and installed a new gen Dittel KRT-2 radio (8.33kHz, 2278
channel). 4 mike inputs available for both dynamic and standard
(electret) mikes, dual watch, and 100 channel memory.

Well suited to Dittel replacement in that an adaptor is available to
make the install plug-compatible with FSG71M.

Over a year so far and very satisfied.

Bob

[[email protected]]

Issue has not reappeared. currently when I turn it on it breaks squelch then goes silent. previsouly it didnt go silent for 10-15 min. I used the same procedure of turning on sn10, 302, powerflarm and then radio. So time will tell thanks for all the advice Ill keep you all informed if it returns.

CH ASW 27

[Dave Springford]

Did anyone keep a copy of this service bulletin - DG has changed their website and the link below is no longer valid.

email to me please if you have it

dave"at"foxonecorp"dot"com

Thank you!

>
> Walter Dittel had a service bulletin, N0. 20/97 regardting the auto squelch. There is a copy of the bulletin on DG Flugzeugbau that shows the location of the said potentiometer.
>
> http://www.dg-flugzeugbau.de/Data/TN-DG/service-infos/1997-20-e.pdf
>
> MN