Don, what a cool device and way to demonstrate how airwaves work. I would imagine this is kind of like rabbit ears for radio with an amp in the middle..... very very nice.
Hi Don, I love seeing old circuits being revisited, and constructed from old electronics magazines such as ‘Practical Wireless’, and ‘Practical Electronics’ (those magazines were often referred here in the UK as, “Camm’s comics.”). They often make fun projects (which most of them were intended). Thank you for sharing my friend. Regards, Phil.
Phil - these old magazines are a fun read and many of the circuits really add value even today. I hope you have being doing well and thanks again for reaching out. All the best to you. Don
That's a nifty little circuit right there, thanks for showing it to us! The only AM signal booster I have personally tried is a Select-A-Tenna passive loop antenna, which inductively couples to the radio like your Q-Multiplier.
Matt - it works great and it’s a simple build. The larger the ferrite rod the better. I tried some 4 to 6 inches in length and 1/4 inch in diameter and the results were not great. Hope you’ve been doing well. Best, Don
@@RestoreOldRadios Sorry, I would not have the schematic. I don’t own one [ yet ], but it is in their catalog - one of their “pride-n-joy” products: “ Twin Coil Ferrite AM Antenna signal booster “ Runs $100,oo Seems a similar setup. All I know is that people that own them are sold on them. 📻🙂
How come there is no FM Q multiplier circuit to help improve FM reception or a SW or LW Q Multipler circuit? Great reception there on those low power stations. Maybe this Easter you might be able to hear those part 15 AM stations in your neighborhood with that circuit.
I’ve never heard of one for FM. SW & LW is possible, just build the oscillator to work at the IF frequency. An article that summarizes this at: randysbench.files.wordpress.com/2020/03/ives_q-mult.pdf Best, Don
Thanks for the video Don. I do have a question. You mention this as working for transistor radios. Would it not also work for a tube radio? Or is the inductive coupling such that it is not effective for the higher impedance of a tube radio's antenna circuitry?
I just posted a video with a different Q-Multiplier circuit and it does work with an AA5 radio with a loop antenna. You can view the video at: Q-Multiplier Circuit - A Simple Circuit to Improve AM Radio Reception Works w/ AA5 or Transistor... th-cam.com/video/Kc76MNpFDB0/w-d-xo.html Thanks again for your question. All the best. Don
Hi Don, I am a bit confused. I thought that "Q" referred to the quality of a coil. When the author called this a "Q" multiplier, did he mean another meaning or does it mean the selectivity of the radio. Is this an antenna amplifier or a device meant to increase the selectivity? My ignorance aside, it makes a dramatic improvement and I enjoyed seeing it. Thanks, Ian
Ian - you are correct as the quality factor of the coil is improved by regeneration/amplification of the received signal and adjusting the feedback increases the Q factor of the ferrite antenna, which to your point reduces the bandwidth and increases the amplitude of the carrier then the enhanced signal is coupled to the receiver through inductance. Mr. Bollen reported seeing an increase from a Q factor of 100 to over 1000 using this circuit. Hope this helps. Best, Don
@@johnwilson6298 No, I think of a receiver vith a positive reaction to increase the gain. Part of thr amplified HF signal is reinjected on the input of the HF amplifier. If the reinjected signal is too high the HF amplifier becomes an oscillator.
Hi Carl - the station frequency. The LC circuit resonates across the AM ( Broadcast) band and through inductance couples with the internal ferrite loop in the transistor radio that is tuned to the same frequency. Best, Don
What a great little circuit Don, thank you for all of your expertise and ideas sir.
Gregg - thanks for watching. Building those old circuits and tweaking them if applicable is a lot of fun. Best, Don
Very impressive Don. I seen some homebrew units for old Am ham receivers. Thanks for sharing.
Thanks Buddy. I’ve got a few old transistor radios to check out and this should come in handy down the road or a night of DXing. Best, Don
Don, what a cool device and way to demonstrate how airwaves work. I would imagine this is kind of like rabbit ears for radio with an amp in the middle..... very very nice.
Good comparison Ron. I figure Doug (Mosslack) will add this to his list of builds with the number of transistor radios he has collected. Best, Don
@@RestoreOldRadios I agree. I always tease Doug that he will have to buy another dryer to expand the MFP :) Good stuff Ron
@@rciancia Good one LOL
Hi Don,
I love seeing old circuits being revisited, and constructed from old electronics magazines such as ‘Practical Wireless’, and ‘Practical Electronics’ (those magazines were often referred here in the UK as, “Camm’s comics.”). They often make fun projects (which most of them were intended). Thank you for sharing my friend.
Regards, Phil.
Phil - these old magazines are a fun read and many of the circuits really add value even today. I hope you have being doing well and thanks again for reaching out. All the best to you. Don
That's a nice little antenna booster for sure Don, very impressive.
Thank you Jim. Another fun build as well. Best, Don
That's a nifty little circuit right there, thanks for showing it to us! The only AM signal booster I have personally tried is a Select-A-Tenna passive loop antenna, which inductively couples to the radio like your Q-Multiplier.
Matt - it works great and it’s a simple build. The larger the ferrite rod the better. I tried some 4 to 6 inches in length and 1/4 inch in diameter and the results were not great. Hope you’ve been doing well. Best, Don
A radio within a radio, lol, cool stuff there buddy!
Thanks for watching and reaching out Tony. All the best. Don
This is similar to the C.Crane antenna, isn’t it ❓
Pretty cool.
📻🙂
Jeff - I’m not sure how the C. Crane circuit is configured. Would you have a reference to the schematic or other...? Best, Don
@@RestoreOldRadios
Sorry, I would not have the schematic. I don’t own one [ yet ], but it is in their catalog - one of their “pride-n-joy” products:
“ Twin Coil Ferrite AM Antenna signal booster “
Runs $100,oo
Seems a similar setup.
All I know is that people that own them are sold on them.
📻🙂
How come there is no FM Q multiplier circuit to help improve FM reception or a SW or LW Q Multipler circuit? Great reception there on those low power stations. Maybe this Easter you might be able to hear those part 15 AM stations in your neighborhood with that circuit.
I’ve never heard of one for FM. SW & LW is possible, just build the oscillator to work at the IF frequency. An article that summarizes this at: randysbench.files.wordpress.com/2020/03/ives_q-mult.pdf Best, Don
Thanks for the video Don. I do have a question. You mention this as working for transistor radios. Would it not also work for a tube radio? Or is the inductive coupling such that it is not effective for the higher impedance of a tube radio's antenna circuitry?
I tried an AA5 with a loop antenna and didn’t get significant gains, but let me try this again and I’ll reply back ASAP. Best, Don
I just posted a video with a different Q-Multiplier circuit and it does work with an AA5 radio with a loop antenna. You can view the video at: Q-Multiplier Circuit - A Simple Circuit to Improve AM Radio Reception Works w/ AA5 or Transistor... th-cam.com/video/Kc76MNpFDB0/w-d-xo.html Thanks again for your question. All the best. Don
@@RestoreOldRadios thanks Don, I look forward to watching the video. And I really appreciate your contracting me with the link!
Hi Don,
I am a bit confused. I thought that "Q" referred to the quality of a coil. When the author called this a "Q" multiplier, did he mean another meaning or does it mean the selectivity of the radio. Is this an antenna amplifier or a device meant to increase the selectivity?
My ignorance aside, it makes a dramatic improvement and I enjoyed seeing it.
Thanks,
Ian
Ian - you are correct as the quality factor of the coil is improved by regeneration/amplification of the received signal and adjusting the feedback increases the Q factor of the ferrite antenna, which to your point reduces the bandwidth and increases the amplitude of the carrier then the enhanced signal is coupled to the receiver through inductance. Mr. Bollen reported seeing an increase from a Q factor of 100 to over 1000 using this circuit. Hope this helps. Best, Don
@@RestoreOldRadios I understand now. Thanks Don.
Another cool tiny project! Is this similar to an active powered antenna? Thanks! ~Jack, VEG
Thank you Jack. Best, Don
It seems similar to a reaction receiver.
Thanks Alain. I’m not familiar with a reaction receiver, but by definition you are correct. All the best. Don
Do you refer to a TRF (tuned radio frequency) receiver ?
@@johnwilson6298 No, I think of a receiver vith a positive reaction to increase the gain. Part of thr amplified HF signal is reinjected on the input of the HF amplifier.
If the reinjected signal is too high the HF amplifier becomes an oscillator.
I just realised that screwytube unsubbed many channels for me. Very wirtd? I have to resub many.
Don - great to hear from you and thanks for subscribing again. I hope you are doing good. All the best. Don
Is this using the IF or the station frequency?
Hi Carl - the station frequency. The LC circuit resonates across the AM ( Broadcast) band and through inductance couples with the internal ferrite loop in the transistor radio that is tuned to the same frequency. Best, Don
You come up with some really curious ways of improving radio reception. Thanks for the look, enjoyed!
Thank you John. It’s a pretty nifty circuit from the past that definitely works well. Best, Don