Why do I pick up the Hams best on the 4.5s

[dragon48]

I'm having fun listening to Ham radio conversations. My radio can scan in 0.5 kHz steps and I always get the best reception for a conversation when I hit the second click of a 4, such as :


3.7164 and 3.7644, so I'm listening on 3.7164.5 and 3.7644.5


Is this a standard for folks to transmit on these frequencies, or is it a quirk of my radio to pick them up like this?

Thanks

 

[Token]

I'm having fun listening to Ham radio conversations. My radio can scan in 0.5 kHz steps and I always get the best reception for a conversation when I hit the second click of a 4, such as :


3.7164 and 3.7644, so I'm listening on 3.7164.5 and 3.7644.5


Is this a standard for folks to transmit on these frequencies, or is it a quirk of my radio to pick them up like this?

There is no "standard", hams can tune to and use any frequency in their authorized range. However most tend to stop on full kHz steps such as 3716.0 kHz or 3764.0 kHz. I noticed that your audio recording of the WLO signal in the other thread was a few hundred Hz off, so it is possible your radio is slightly off freq.

You can confirm your frequency calibration on a known frequency station, like WWV on 2500, 5000, 10000, or 15000 kHz. Tune to one of them with a strong signal in AM mode, say 5000 kHz at night. Change from AM to USB and to LSB, if your radio is correctly calibrated there may be a change in sound (caused by different filters) but NOT in pitch. A change in pitch of the audio signal indicates something is not aligned. If you can measure the pitch change you can determine the "delta" for your radio, and know the correction factor to apply.

T!

 

[dragon48]

There is no "standard", hams can tune to and use any frequency in their authorized range. However most tend to stop on full kHz steps such as 3716.0 kHz or 3764.0 kHz. I noticed that your audio recording of the WLO signal in the other thread was a few hundred Hz off, so it is possible your radio is slightly off freq.

You can confirm your frequency calibration on a known frequency station, like WWV on 2500, 5000, 10000, or 15000 kHz. Tune to one of them with a strong signal in AM mode, say 5000 kHz at night. Change from AM to USB and to LSB, if your radio is correctly calibrated there may be a change in sound (caused by different filters) but NOT in pitch. A change in pitch of the audio signal indicates something is not aligned. If you can measure the pitch change you can determine the "delta" for your radio, and know the correction factor to apply.

T!

I can't pick up any of the frequencies that you posted, but as a test, I tuned in to 5920 kHz (WHRI) which came in as a full signal. I cycled through all of the available modes (WFM, NFM, SFM, WAM, AM, NAM, USB, LSB, CW) and recorded the output. I can't tell if there are any meaningful changes in pitch. Can you please give a listen and let me know if something is off.

https://soundcloud.com/user-437184959/5920-khztest

I'm curious - what tool did you use to analyze my WLO signal?

Thanks

 

[mancow]

What radio?

 

[dragon48]

What radio?

AOR 8200 MK111

 

[ridgescan]

OP-like Token said, when you can get them do a short video or soundcloud of the WWV time station frequencies in USB, then switch to AM, then switch to LSB on 5, 10, 15mHz.-at least two of those that come in well. Catch the voice and tone within each mode. We will be able to see if your BFO is off-frequency and on what mode(s). Or at least, do this on a known broadcast SW frequency you get strongly.

 

[mancow]

AOR 8200 MK111

It's off frequency. Most AORs are.

 

[dragon48]

OP-like Token said, when you can get them do a short video or soundcloud of the WWV time station frequencies in USB, then switch to AM, then switch to LSB on 5, 10, 15mHz.-at least two of those that come in well. Catch the voice and tone within each mode. We will be able to see if your BFO is off-frequency and on what mode(s). Or at least, do this on a known broadcast SW frequency you get strongly.

OK - I'll try different times..

Ty

 

[dragon48]

It's off frequency. Most AORs are.

If it is off a little, I don't mind. I don't rely on the broadcasts for any work—this is just a hobby. I do however want to play around and test more so i can determine exactly how much it is off.

 

[Token]

I can't pick up any of the frequencies that you posted, but as a test, I tuned in to 5920 kHz (WHRI) which came in as a full signal. I cycled through all of the available modes (WFM, NFM, SFM, WAM, AM, NAM, USB, LSB, CW) and recorded the output. I can't tell if there are any meaningful changes in pitch. Can you please give a listen and let me know if something is off.

https://soundcloud.com/user-437184959/5920-khztest

I'm curious - what tool did you use to analyze my WLO signal?

Thanks

I used Spetrogram 16 to look at the WLO recording, however there are a number of programs that could do the same thing, including Audacity.

The FM modes are almost never used on shortwave, and when FM is used it is NFM. AM, NAM, USB, LSB, and CW are the modes you want to use on shortwave.

I don't know how close to correct freq WHRI was, but assuming they were on frequency and with your recording it does appear your radio is off frequency a bit. Roughly 530 to 640 Hz off and upwards shifted. So when you tune to the correct sound in USB you are reading 600 Hz low, for example a signal on 14230.0 kHz would sound normal if you tuned to 14229.4 kHz on your display. And in LSB a signal on 7230.0 kHz would sound normal when tuned to about 7229.4 kHz on your readout.

T!

 

[ridgescan]

That would drive me up a wall. I get all bent if my truck's steering wheel is even slightly off-center. Last time I got an alignment I returned 3 times till they got it perfect. Thank goodness all my receivers are user-adjustable.

 

[majoco]

Using the Mk1 ear to determine if your radio is "on frequency" is tricky especially SSB as the error in the main tuning can be offset by retuning the "clarifier". Like Token, I use WWVH in the evening, display the recovered audio on a Speclab or similar, set the 400Hz tone on AM, then check that it gives the same tone on LSB and USB. I use a similar method to set my frequency standards against WWVH.
You should be able to reset the oscillators in your AOR 8200 test equipment like that.