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Old 31st May 2018, 10:52 am   #1
Aztecboy
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Default 9R-59D Band Spread confusion

I am certainly being very dumb here as I have never owned a set with Band Spread before.

In the operations manual, it clearly states on 2 occasions that the Main Tuning reads "accurately" when the Band Spread is set at 100 on the lowest visible scale.

So if the set is tuned to 7MHz, this means the Band Spread is already reading at the far end of its scale (tuned fully clockwise)

In my mind I have these 2 dials as always additive which has to be wrong.

This must be why a (3.5MHz) crystal calibrator is required.
My guess is the Band Spread would be set to 7MHz and the Main Tuning tweaked until it finds the 7MHz harmonic from the calibrator.
Once set, the Band Spread will read correctly.

Apologies, I am catching up after a long time away but am I close?

Many thanks

Ted
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Old 31st May 2018, 11:04 am   #2
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Default Re: 9R-59D Band Spread confusion

On the main dial the band spread sections are marked in black. Set the main dial to the HF end of the band spread section and leave it there. Now use the band spread dial to set the frequency.

Note that the 7MHz band spread section is split into two.
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Old 31st May 2018, 4:52 pm   #3
Aztecboy
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Default Re: 9R-59D Band Spread confusion

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Originally Posted by Station X View Post
On the main dial the band spread sections are marked in black. Set the main dial to the HF end of the band spread section and leave it there. Now use the band spread dial to set the frequency.

Note that the 7MHz band spread section is split into two.
Thank you Graham

I think I understand it now. It is clear that the set is over indicating by 200khz when compared to the same station on my digital Sony SF7600D.

This is turning into quite a (fun) learning curve! I don't have a signal generator anymore that I could use to calibrate it as per the service manual.

I have started to look at the AD9850 DDS Sig Gen kits although there are some mixed reports on them. There is one that is programmed to work in the amateur bands, I am reading up on it now.
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Old 1st Jun 2018, 2:18 pm   #4
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Default Re: 9R-59D Band Spread confusion

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Originally Posted by Station X View Post
On the main dial the band spread sections are marked in black. Set the main dial to the HF end of the band spread section and leave it there. Now use the band spread dial to set the frequency.

Note that the 7MHz band spread section is split into two.
Just to clarify this, the manual says to set to main dial to one of the markings A to E. This actually amounts to the doing the same thing I originally said.
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Old 1st Jun 2018, 4:03 pm   #5
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Default Re: 9R-59D Band Spread confusion

When you are NOT using the band spread dial (IE when wanting to tune outside the amateur bands, the bandspread dial MUST be parked in the correct position, which the manual tells you is 100 on the lower dial.

At all times the set is tuned by both dials. The scales on the bandspread dial only make sense when the main dial is parked in the correct position for the bandspread scale you want to use.

The scales on the main dial only make sense when the bandspread dial is in its parked position.

So you should only ever move one dial away from a parking place at any one time and you need to know the parking places. For amateur bands. put the main tuning in the correct parking place and use the bandspread dial. For frequencies that there is no bnadspread scale for, park the bandspread and use main tuning only.

To be honest, bandspread tuning is a fiddle and the bandspread scale accuracy is upset by even a small error in parking the main tuning. I simply avoided bandspread sets and went for radios with good enough gearboxes not to need bandspread.

Make sure the bandspread dial is parked as per the handbook because this could be a cause of your 200kHz reading error on the main scale. Check carefully before embarking on realignment.

David
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Old 1st Jun 2018, 4:20 pm   #6
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Default Re: 9R-59D Band Spread confusion

Also worth making sure that the grease in the tuning-knob assembly isn't dried-out-and-sticky: the bandspread spindle runs down the centre of the main tuning and if the grease has hardened it gives drag between them so causing one control to turn when you adjust the other.

Although I disassembled cleaned and regreased mine to minimise 'stiction' I still found it was only too easy to accidentally tickle the main-tuning when trying to adjust the bandspread - so to fix this I cut out a felt disc and fitted it between the back of the main-tune knob and the front panel, to add a bit of extra friction.
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Old 1st Jun 2018, 5:15 pm   #7
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Default Re: 9R-59D Band Spread confusion

You need to use the band spread control on these sets if you're to have any hope of tuning in an SSB signal. The bandspread uses a separate tuning capacitor. It's not a reduction gear.

These sets are much maligned as glorified domestic sets, but they do have a BFO and a product detector. I rather like mine.

Main problem I've had with the tuning is that the drive cords tend to stretch on one side and contract on the other after the tuning has been set.
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Old 2nd Jun 2018, 2:26 pm   #8
Aztecboy
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Default Re: 9R-59D Band Spread confusion

Thank you all so much for your comments.

David
Since Graham enlightened me (thank you), this is how I am now operating the set.
However a foreign station found at 7.345Mhz on my Sony ICF-7600D is reading 7.5Mhz on the 9R-59D with BS set at 100. I still haven't had a chance yet to test other bands but I will do a few more checks to ensure my findings are correct.
in any case tt will be about a month before I have received and built my QRP 5W CW transceiver/sig gen/freq counter which I will use to re-calibrate the set if needed.

I can see now the need for the calibrator circuit to get accurate band spread readings on the on amateur bands.

G6Tanuki
Funnily enough my band spread shaft all but seized on Wed. I took a few sheets of kitchen roll and pressed a hole through the middle using the tuning shafts in order to protect the case. A few squirts of WD-40 around the BS shaft did the trick. BTW I found positioning the knobs carefully on the shafts stopped them interfering with each other, but your felt pad sounds like an excellent idea. I must also pick you brains about coil wax at some point!

Ted
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Old 2nd Jun 2018, 4:42 pm   #9
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Default Re: 9R-59D Band Spread confusion

Plan B is to extract a little LO signal from it to put into a frequency counter (programmed with an IF offset) Ignore the scales, use the counter and treat bandspread as fine tuning.

Counter kits are generally available and cheap.

David
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