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 Post subject: My new frequency counter is a radio
PostPosted: Mar Tue 02, 2010 9:24 pm 
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Location: Mission Viejo, southern California
I have an old Philco 077 signal generator. It works, but it is not possible to calibrate it precisely, as the error on each scale varies. Instead of a regular frequency counter, I stopped into a Radio Shack while in LA for work, and for $165 (the tax in LA is high), walked out with a Grundig G3 Globe Traveler. I just tried it with the 077 and it works beautifully. All I did was lay the radio on top of the end of the signal output cable, then set the radio to the desired frequwency (455kHz, 10.7 MhZ, etc.) and tune the frequency generator until the 400Hz tone came in loud and clear on the radio. It is also a nice portable radio.

This was not my idea - credit goes to the man iwht the radio videos on youtube:
http://www.youtube.com/profile?user=All ... eRadio#g/u

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PostPosted: Mar Wed 03, 2010 12:44 am 
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Location: New Jersey
I'm guessing you're putting the radio in CW mode with the BFO and just zero-beating the signal generator against it to get your frequency? I've done that to get signal frequencies before. It only works with an accurate radio though.

I use my scope for a frequency counter input. I have an old 6 digit counter from my CB days that actually works extremely well. Amazingly it reads fine down to about 200 kc. The scope has an output for the counter, and provides enough amplification that I can read frequencies without having silly signal levels on the scope.

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PostPosted: Mar Wed 03, 2010 2:38 am 
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The link is bum but this is the video that would help you, starting at about 0:50

http://www.youtube.com/watch?v=5ZwTrZJZUVM

The way he does it is good for about 100hz or so, using AM and signal strength meter. You can do better in SSB. This sounds confusing but it is not bad.

You tune your new SW radio to Time WWV (5Mhz and 10Mhz) and listen to the tone. You set the radio in SSB adjust BFO (SSB control) so the SSB whine is null, either side will give a high or low tone (not the 500/600hz WWV tone but BFO tone). Once you get that set, go to 455Khz (still in SSB and don't touch the SSB BFO). You now adjust the signal on the Generator so you are in the null. If the Signal Gen is off it will give you that low or high whine. This is better than the full AM CW with a signal strength meter.

A better method is to follow the same steps, with SSB, but use a freeware program called Spectran. You use the output of the radio headphone into the computers sound card. Again tune in WWV and listen to the 500hz or 600hz audio tone. Adjust the SSB BFO to get right on Freq... with Spectran open you will actually see it. It is better than the ear, but you will also hear the null. Now go to 455Khz and again don't touch the SSB BFO. Now set the Signal Gen so you get the Null and the typical 400Hz modulation is showing on spectran right on 400hz. This can get very close.

Step three you will get tired of this and buy a freq counter. :roll:

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Tube: AM/FM Zeniths, RCA, TrueTone table tops; Transistor: Kaito KA1103, TenTec RX320D, Pioneer SX780


Last edited by gmcjetpilot on Mar Wed 03, 2010 3:28 am, edited 2 times in total.

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 Post subject:
PostPosted: Mar Wed 03, 2010 2:40 am 
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Location: Mission Viejo, southern California
The radio is a small portable, so there is no BFO control. It has many nice features, but the two key ones are that it is a Phase-Locked-Loop (PLL) design, so should be very accurate, and any frequency can be entered using the keypad. I just listen for when the 400Hz tone from the signal generator is loudest. I could also put a volt meter on the earphone output if I wnated to eb mroe rpecise. John Kusching had brought his counter over, and we wrote own a few items (e.g. set the 077 on 462kHz to get 455 Khz output). The radio makes it even easier, and I do not need to be concerned with variations in output from the signal generator due to temperature, etc. The radio has a very wide range, receiving all the way up in the the current aircraft frequencies.

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 Post subject:
PostPosted: Mar Wed 03, 2010 5:05 am 
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FStephenMasek wrote:
The radio is a small portable, so there is no BFO control. It has many nice features, but the two key ones are that it is a Phase-Locked-Loop (PLL) design, so should be very accurate, and any frequency can be entered using the keypad. I just listen for when the 400Hz tone from the signal generator is loudest. I could also put a volt meter on the earphone output if I wnated to eb mroe rpecise. John Kusching had brought his counter over, and we wrote own a few items (e.g. set the 077 on 462kHz to get 455 Khz output). The radio makes it even easier, and I do not need to be concerned with variations in output from the signal generator due to temperature, etc. The radio has a very wide range, receiving all the way up in the the current aircraft frequencies.


Your radio has SSB and even has Sync mode. Any way nice new radio and the PLL radio is golden for more than just setting your Signal Gen. I do suggest SSB Zero Beat method, even by ear, it is way more accurate than just using it with signal strength meter and ear in CW.

You can use your radio as a signal tracer. Set it to 455 Khz and you can sniff for the IF on your radio and will hear the audio from the station being tuned (of the the oscillator/mixer is working). Just wave the antenna near the radio cans and tubes. I had a radio that was not working (audio) because of a bad IF. However the DE1103 on 455Khz was picking it up the station. So I knew at least the Converter and at least first IF was working due to the volume of the audio.

Tune your tube radio to a station, add 455 Khz to the stations Freq, and tune that in your PLL radio. You should hear the oscillator with the antenna near the converter tube. (Also try subtracting 455 Khz from the station freq)

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Tube: AM/FM Zeniths, RCA, TrueTone table tops; Transistor: Kaito KA1103, TenTec RX320D, Pioneer SX780


Last edited by gmcjetpilot on Mar Wed 03, 2010 5:21 am, edited 2 times in total.

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 Post subject:
PostPosted: Mar Wed 03, 2010 5:13 am 
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Location: Mission Viejo, southern California
Thanks for the suggestion. It does have SSB.

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many of my radios http://s269.photobucket.com/user/FSteph ... t=3&page=1


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 Post subject:
PostPosted: Mar Wed 03, 2010 5:29 am 
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Joined: Jul Wed 22, 2009 8:32 am
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FStephenMasek wrote:
Thanks for the suggestion. It does have SSB.


From your manual it has "synchronous detector":

"The synchronous detector can be used when listening to AM (medium wave) and shortwave broadcast stations. It may help to minimize interference and to improve the signal quality. While listening to a station press the SYNC button. SYNC appears in the display as does USB or LSB to the right. You can sync on the Upper or Lower sideband by pressing the U/LSB button and noting which selection gives the clearer reception or improves the audio. Turn the synchronous detector off while tuning stations or when it’s not needed. Using the WIDE/NARROW button may also help. Using the synchronous detector does not always minimize interference or improve the signal. To turn the synchronous detector off, press the SYNC button."

Have fun!

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Tube: AM/FM Zeniths, RCA, TrueTone table tops; Transistor: Kaito KA1103, TenTec RX320D, Pioneer SX780


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