Author Topic: VE7BPO's 10 mhz trf rx question  (Read 1453 times)

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Offline luckyflyerTopic starter

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VE7BPO's 10 mhz trf rx question
« on: July 20, 2016, 05:43:59 pm »
I'm a new member here on eevplog, it looks like a great site full of useful info. I'm gathering up parts to build ve7bpo's 10 mhz trf wwv receiver. Can anyone that has built this rx tell me what guage of wire is used for L2 & l4?
« Last Edit: July 20, 2016, 08:00:34 pm by luckyflyer »
 

Offline jopie

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Re: VE7BPO's 10 mhz trf rx question
« Reply #1 on: July 20, 2016, 07:18:06 pm »
Hi Luckyflyer,

wire size is not critical for these coils, their purpose is to decouple DC and AC. 22-26 AWG should be okay.

Regards,
Joop PG4I
 

Offline luckyflyerTopic starter

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Re: VE7BPO's 10 mhz trf rx question
« Reply #2 on: July 20, 2016, 08:02:40 pm »
Great,thanks jopie!
 

Offline G0HZU

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Re: VE7BPO's 10 mhz trf rx question
« Reply #3 on: July 20, 2016, 08:16:30 pm »
I think you could get rid of the choke coil L2 and relocate L3 to where L2 was and the performance would be pretty much the same. i.e. I think you could get the same performance in terms of front end preselection and save on having to wind and fit L2. You might also have to increase the value of CV2 to make sure you can tune for 10MHz. To get it even closer you could also reduce the value of the 2k resistor across the L2 location if you want to get the same amount of damping. L2 will be fairly lossy at 10MHz so the 2k resistor would need to be reduced to keep the damping the same. But you would save on having to hand wind and fit L2 if you relocated L3 to where L2 is :)

I'm not sure you 'need' L4 either.  If you replaced the 2k resistor here with a 1k resistor and simply removed L4 the circuit would probably work in a similar manner at 10MHz. You'd drop a few volts across this resistor but I'm not sure that would matter much for small signal reception.
You could also save/delete the 1meg resistor and 0.001 cap at the input and just connect L1 direct to the gate of the mosfet.
« Last Edit: July 21, 2016, 12:12:35 am by G0HZU »
 

Offline luckyflyerTopic starter

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Re: VE7BPO's 10 mhz trf rx question
« Reply #4 on: July 21, 2016, 09:25:03 pm »
I agree that there is certainly room for experimentation with this circuit, hence the desire for the spectrum analyzer. 
 


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