QRP Rig
 

I have built a Tiny Tornado on 40m. It TX and RX fine. I have my ICOM751
tuned to 7.040 for help in tuning. I notice that when I turn the Tornado on,
I get a solid tone. It does transmit fine, but when I release the key, I get
this solid tone. Anyone else experience this?

Thanks,
Doug / KB8M

QRP Rig
 

Doug Birky wrote:
I have built a Tiny Tornado on 40m. It TX and RX fine. I have my ICOM751
tuned to 7.040 for help in tuning. I notice that when I turn the Tornado on,
I get a solid tone. It does transmit fine, but when I release the key, I get
this solid tone. Anyone else experience this?

Thanks,
Doug / KB8M


Doug

That is normal, got the same thing in mine. Its the oscillator that runs
all the time.

Nels W0TUP

QRP Rig
 

Arlon Nelson wrote:
Doug Birky wrote:
I have built a Tiny Tornado on 40m. It TX and RX fine. I have my ICOM751
tuned to 7.040 for help in tuning. I notice that when I turn the
Tornado on,
I get a solid tone. It does transmit fine, but when I release the key,
I get
this solid tone. Anyone else experience this?

Thanks,
Doug / KB8M


Doug

That is normal, got the same thing in mine. Its the oscillator that runs
all the time.

Nels W0TUP
Sounds like a Direct-Conversion Rx./Tx. set-up to me. Where the Local
Oscillator is the same as the Rx/Tx Frequency. The ICOM751 should
normally be Zero-Beated to the signal in SSB Mode. But using Incremental
Tune to set the Side-Tone in CW Mode else you would end up chasing a CW.
signal up and down the band. The other source of the problem might be RF
leakage from an unshielded Tiny Tornado, radiating back through the Rx
Rf stage ! This was how German Submarines were detected, even during
"Radio Silence" in WW2. They were leaking the LO (Rx +/- IF) back to the
antenna in the RX mode. This was Cured by an extra RF stage between the
antenna and the first mixer. This is how unlicensed TV sets were
detected in Great Britain, BC (before Cable).

Yukio YANO VE5 YS

QRP Rig
 

Doug Birky wrote:
I have built a Tiny Tornado on 40m. It TX and RX fine. I have my ICOM751
tuned to 7.040 for help in tuning. I notice that when I turn the Tornado on,
I get a solid tone. It does transmit fine, but when I release the key, I get
this solid tone. Anyone else experience this?

This is a direct-conversion receiver: the beat-frequency oscillator
operates just off the 7.040MHz frequency. Enough of it leaks out of the
unit (especially depending on what kind of case you put it in) to be
picked up by your IC-751.

--
Doug Smith W9WI
Pleasant View (Nashville), TN EM66
http://www.w9wi.com