[R-390] R-390 digital readout

[Gordon Hayward]

Hi all, I've done the offset frequency counter in hardware with an old RCAF receiver but now would use the Propeller microcontroller. I've used these for accurate frequency counters in my crystal biosensor work. It can do 4 counters independently at upto 20 MHz (good to 1Hz depending on its crystal timebase) and then put the frequencies together in software for the R390A receive frequency display. I haven't done this yet but its on my list of fun things to do. The only gotcha is how to bring the frequency signals out of tghe R390A without drilling and blasting.

Cheers, Gord VE3EOS

________________________________
From: r-390-bounces at mailman.qth.net <r-390-bounces at mailman.qth.net> on behalf of Larry H <larry41gm at gmail.com>
Sent: Saturday, April 13, 2019 6:56:53 AM
To: Larry J. Haney; R-390 Forum; jm
Subject: Re: [R-390] R-390 digital readout

Jose,  The R390A uses a 17 mh 1st oscillator for below 8 mh.  The 2nd
crystal oscillator is always used and generates 24 different frequencies
for each of the 32 bands.  The VFO (3rd osc) generates a frequency between
2.455 and 3.455 mh, depending where the rx is tuned at in each 1 mh band.
Have fun.

Regards, Larry

On Sat, Apr 13, 2019 at 2:04 AM jm <josemic at gmail.com> wrote:

> Many thanks Larry.
>
> I have two frequency meters in my hd180a. The first one for the double
> conversion offsets 455 kc. The second one, for the triple conversion
> offsets 3035 khz. I switch from one to the other depending on the band.
>
> But I realise that in the case of the 390 is particularly complicated.
>
> Regards
>
>
> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> Libre
> de virus. www.avast.com<http://www.avast.com>
> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail>
> <#m_4906996513158222944_DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
>
> El sáb., 13 abr. 2019 a las 9:58, Larry H (<larry41gm at gmail.com>)
> escribió:
>
>> Jose, the R390's are dual or triple conversion depending on the received
>> frequency and therefore are a big challenge for a designer of a digital
>> readout system.  There is no one point where one composite oscillator
>> signal could be obtained for what you want.  Someone made one a few years
>> ago, but have not seen it lately.  You might search the R390 archives for
>> info.
>>
>> Regards, Larry
>>
>> PS:  The subject line of your original post is meaningless - please fix.
>>
>> On Sat, Apr 13, 2019 at 1:01 AM jm <josemic at gmail.com> wrote:
>>
>>> Hi fellows
>>>
>>> I use a frequency meter with my tube receivers. Every set has its
>>> peculiarity but until now I have managed with the HQ-180, Transoceanic
>>> (transistors) and Hallicrafters sx99.
>>> The trick is to locate the oscillator signal,  offset the IF and the
>>> thing
>>> works.
>>> But... what about the 390? variable IF, lots of crystals. I have to
>>> confess
>>> that I'm lost.
>>>
>>> Is there an easy way to connect the frequency meter in a point in which
>>> the
>>> oscillator signal could be found for all mhz positions?. What  would be
>>> the
>>> IF value  to offset ?
>>> I know that the challenge in this receiver is to obtain the maximun
>>> sensitivity and precision via calibration but that's not my league yet
>>> and
>>> meanwhile I think that a good solution is the frequency meter.
>>>
>>> Regards and sorry for a beginner's question.
>>>
>>> Jose
>>> EA8DCP
>>>
>>>
>>>
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