President Grant 2 - FM Deviation Adjustment

[delboyonline]

The FM audio is a little low on the Grant 2 so here's the adjustment pot!

For information only!

Do at your own risk!!!!

[163TM847]

It makes life alot easier when the VR's are marked with what each one does, Saves the twiddlers turning them all to find the right one , Remember though that it is Deviation and shouldnt be adjusted too high or you may over deviate and for people on the receiving end over deviating can sound awful and annoying.

[Mudslinger]

I remember back int he old days, when it was the done thing (at least in these parts) to turn the deviation right upto maximum.

If you had a radio with a ceramic filter they sort of sounded ok, but if you had a crystal filter fitted then they sounded awful as the crystal would cut of parts of their speech.

[cb4ever104]

as the crystal would cut of parts of their speech.

That could be a blessing depending on who it was

[PoisoN]

It has been reported that FM modulation is slightly set too low compared to am ssb and lsb so it may want tweaking slightly.

[delboyonline]

I only had to turn it up by about a quarter turn to get lovely strong audio.

Two minute job but be very careful, the pot is tiny.

[simonthewizard]

It has been reported that FM modulation is slightly set too low compared to am ssb and lsb so it may want tweaking slightly.

President always set FM "low" as it falls within the legal spec so that's why sounds low. AM is set stronger and SSB too. As at the moment and before July there are more markets than just the UK, so where there are AM and SSB legal users they set it up that way so is stronger than FM.

I asked at Stabo and that was the reply, so if you want quote it then remember was not me was them who told me

[Coppernob]

So what is the spec for my deviation meter 2.5khz ?
Would be interesting to see just what they set as,as standard.
Regards Coppernob.

[PoisoN]

It has been reported that FM modulation is slightly set too low compared to am ssb and lsb so it may want tweaking slightly.

President always set FM "low" as it falls within the legal spec so that's why sounds low. AM is set stronger and SSB too. As at the moment and before July there are more markets than just the UK, so where there are AM and SSB legal users they set it up that way so is stronger than FM.

I asked at Stabo and that was the reply, so if you want quote it then remember was not me was them who told me

Thats ok simon i turned mine up slightly (not full) sounds great just need a very small screw driver and a gentle hand. So far i have no Complaints with my G2 I like that the anl/nb/hicut works on all bands and theirs a substantial difference too. Unlike my Cre 8900 where you only really notice on Am. I get no problems with it in the car though.

[Tarambor]

So what is the spec for my deviation meter 2.5khz ?
Would be interesting to see just what they set as,as standard.
Regards Coppernob.

2.5kHz is the standard in the UK.

[Mudslinger]

I have a feeling that the CEPT and later specs for deviation were lower than 2.5Khz, although I could be wrong.

[13EL121]

2 kHz maximum in germany for all new transceivers. Older had 2,2-2,5 kHz before EU...

[RogerD]

Does the deviation directly correspond to the recovered audio voltage at the other end, so that double deviation gives double the voltage gives 6dB more loudness? Do I understand that right?

So if the modern standard is 2kHz but is probably set somewhere closer to 1.5 to play it safe, and everyone usually cranks it up to at least 3 to meet the real on-air convention, that makes a 6dB difference? Which from memories of VU meters on tape recorders would make a fair noticeable difference (but maybe not a vast one - I think 10dB is required for something to be perceptually 'twice as loud')?

[PoisoN]

Simon ive just had mine on a dumy load for the first time it was doing exactly 4watts fm but only 1 watt talk power on ssb and 5 watts pep !! Definately turned down for UK market! i had to tweak the alc and the amc to get 12 watts.

[Tarambor]

but only 1 watt talk power on ssb and 5 watts pep

How were you measuring it, with a proper peak hold meter or a normal one?