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 Post subject: Re: I like my new Panasonic RF-3100 better than the RF-2200
PostPosted: Sep Thu 16, 2021 1:05 pm 
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Their ad claims PLL tuning but, unlike most PLL receivers, tuning in a station involves an analog tuner (not PLL) on my RF-3100. Of course, band switching is part of the "tuning" process in the grand scheme of things.

Dave


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 Post subject: Re: I like my new Panasonic RF-3100 better than the RF-2200
PostPosted: Sep Thu 16, 2021 4:43 pm 
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Dave Doughty wrote:
Their ad claims PLL tuning but, unlike most PLL receivers, tuning in a station involves an analog tuner (not PLL) on my RF-3100. Of course, band switching is part of the "tuning" process in the grand scheme of things.

Dave

Thanks, Dave!

For an analog, it is amazingly stable!

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 Post subject: Re: I like my new Panasonic RF-3100 better than the RF-2200
PostPosted: Sep Thu 16, 2021 6:16 pm 
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Dalton wrote:
Dave Doughty wrote:
Their ad claims PLL tuning but, unlike most PLL receivers, tuning in a station involves an analog tuner (not PLL) on my RF-3100. Of course, band switching is part of the "tuning" process in the grand scheme of things.

Dave

Thanks, Dave!

For an analog, it is amazingly stable!
I think that's because the analog tuner only has to cover very small band segments the way mblack described, in this case, 1 Mhz for each shortwave band. I believe the AM and FM broadcast bands on this set do not involve the PLL system at all. I could be wrong.

Dave


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 Post subject: Re: I like my new Panasonic RF-3100 better than the RF-2200
PostPosted: Sep Thu 16, 2021 10:42 pm 
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Here is the 34 page service information and schematic, so we can judge better than a guess.


Attachments:
panasonic_rf-3100_sm.pdf [10.59 MiB]
Downloaded 17 times

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 Post subject: Re: I like my new Panasonic RF-3100 better than the RF-2200
PostPosted: Sep Fri 17, 2021 12:22 am 
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Thanks for posting the manual. It has a 4-gang tuning cap (2 for AM/SW and 2 for FM) and analog oscillator coils for AM, SW, and FM. The PLL system selects each MHz shortwave band. No more guessing.

Dave


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 Post subject: Re: I like my new Panasonic RF-3100 better than the RF-2200
PostPosted: Sep Sat 18, 2021 1:53 am 
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fifties wrote:
Here is the 34 page service information and schematic, so we can judge better than a guess.


Thanks, fifties!

This will surely come in handy!

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 Post subject: Re: I like my new Panasonic RF-3100 better than the RF-2200
PostPosted: Sep Sat 18, 2021 1:55 am 
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Dave Doughty wrote:
Thanks for posting the manual. It has a 4-gang tuning cap (2 for AM/SW and 2 for FM) and analog oscillator coils for AM, SW, and FM. The PLL system selects each MHz shortwave band. No more guessing.

Dave

So my perception of stability on m.w. is not due to the PLL, I take it.

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 Post subject: Re: I like my new Panasonic RF-3100 better than the RF-2200
PostPosted: Sep Sat 18, 2021 3:21 am 
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A search says the 3100 is single conversion to 455KHz on the AM band. So the local oscillator goes up to only a few MHz. Same as any average AM radio. Easy to be stable, but nothing special.

You can watch stability on the frequency readout. It shouldn't change much, and only on the least significant digits.

Dave said in an old message that the switches on Panasonic radiis tend to get dirty.


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 Post subject: Re: I like my new Panasonic RF-3100 better than the RF-2200
PostPosted: Sep Sat 18, 2021 4:33 am 
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mblack wrote:
A search says the 3100 is single conversion to 455KHz on the AM band. So the local oscillator goes up to only a few MHz. Same as any average AM radio. Easy to be stable, but nothing special.

You can watch stability on the frequency readout. It shouldn't change much, and only on the least significant digits.

Dave said in an old message that the switches on Panasonic radiis tend to get dirty.


True.

These have been well cleaned, which probably helps.

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 Post subject: Re: I like my new Panasonic RF-3100 better than the RF-2200
PostPosted: Sep Sat 18, 2021 1:00 pm 
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Dalton wrote:
So my perception of stability on m.w. is not due to the PLL, I take it.
The PLL system in the 3100 contributes to the stability of the shortwave bands which are as stable as the MW (broadcast) band in my radio.

Dave


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 Post subject: Re: I like my new Panasonic RF-3100 better than the RF-2200
PostPosted: Sep Sat 18, 2021 3:00 pm 
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Now at our flea market this one is sold in perfect condition for 400 bucks. But I'm not ready to pay so much for a radio in a plastic case)

https://www.ukrboard.com.ua/ru/board/m-2683029/panasonic-rf-3100-dr-31/

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 Post subject: Re: I like my new Panasonic RF-3100 better than the RF-2200
PostPosted: Sep Sat 18, 2021 4:12 pm 
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At 6M, an NC-270's local.oscillator is running at at about 50MHz. That is hard to make stable.

But many people used 6M converters,crystal controlled, to convert 6M down to say 14MHz, where tye receiver can more easily be stable. Stability is easier the lower the frequency.

Better receivers had this scheme, tuning say 3-4MHz, with a converter inside to get the other bands. Not just better stability, but but it's easier to get a linear tuning and accurate frequency by havint the tuneable oscillator tune a small and constant slice. Many general coverage receivers had fkur bands, broadcast and 3 shortwave. And each was a 2:1 tuning range.

But you need a crystal for each range, and that's expensive. Hence synthesizers.

I thought the RF-3100 worked this way, but I couldn't find a block diagram. The service manual says the first IF is 10.695, a fixed IF. So now I'm thinking a more complicated scheme.


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 Post subject: Re: I like my new Panasonic RF-3100 better than the RF-2200
PostPosted: Sep Sat 18, 2021 10:42 pm 
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Dave Doughty wrote:
Dalton wrote:
So my perception of stability on m.w. is not due to the PLL, I take it.
The PLL system in the 3100 contributes to the stability of the shortwave bands which are as stable as the MW (broadcast) band in my radio.

Dave

Thanks Dave.

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 Post subject: Re: I like my new Panasonic RF-3100 better than the RF-2200
PostPosted: Sep Sat 18, 2021 10:44 pm 
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US7IGN wrote:
Now at our flea market this one is sold in perfect condition for 400 bucks. But I'm not ready to pay so much for a radio in a plastic case)

https://www.ukrboard.com.ua/ru/board/m-2683029/panasonic-rf-3100-dr-31/


I agree, that is much too expensive for this radio.

Great to gear from you!

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 Post subject: Re: I like my new Panasonic RF-3100 better than the RF-2200
PostPosted: Sep Sat 18, 2021 10:49 pm 
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mblack wrote:
At 6M, an NC-270's local.oscillator is running at at about 50MHz. That is hard to make stable.

But many people used 6M converters,crystal controlled, to convert 6M down to say 14MHz, where tye receiver can more easily be stable. Stability is easier the lower the frequency.

Better receivers had this scheme, tuning say 3-4MHz, with a converter inside to get the other bands. Not just better stability, but but it's easier to get a linear tuning and accurate frequency by havint the tuneable oscillator tune a small and constant slice. Many general coverage receivers had fkur bands, broadcast and 3 shortwave. And each was a 2:1 tuning range.

But you need a crystal for each range, and that's expensive. Hence synthesizers.

I thought the RF-3100 worked this way, but I couldn't find a block diagram. The service manual says the first IF is 10.695, a fixed IF. So now I'm thinking a more complicated scheme.


Thanks, mblack!

I have an NC-183D with 6 meters, and 2 lesser Hallicrafters with 6, and have yet to hear a thing on them.

I will be setting up my ICOM 551D very soon, so we shall see if it's because the old tubers are deaf on 6.

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