Re: The Cricket Transceiver Futuristic Design


Wayne Steury
 

Good morning.  Through the comments of several I made some modifications to my Cricket.  I changed C9 to 180p and C10 to 470p.  Then I paralleled R1 with another 100K making 50K and paralleled R2 with a 1K to make .6K

It works with all crystals from KC9ON but lower power.  The best was my 3550 crystal that gives me about 400 Milliwatts. Using my old 3579 I now seem to get 1 watt on my MFJ-971 tuner.  I made a solid qso with someone last night. I was excited that it worked on 3550.  It shows about the same db on reverse beacon.

I am sure interested in technical comments. Nothing seems to get hot with my regular CW and K1EL keyer.

73's Wayne  N9EGT  Berne, IN  See me on QRZ.com




On 5/27/2017 1:22 AM, jwc123@... [4sqrp] wrote:
 

>Does the oscillator run ok with an HC49S, and with 180p at C9 and470 at C10?  Does it start ok both at 3580 and 3560? 
So far it's working with 3535 3550 3560 and 3579 - all HC49/s small cases, have not seen any startup issues.  Putting the 2 pin headers in those cap positions really helped out.

>How much power does it make with the small crystal? 
Power is much lower, about slightly less than 1/2W.  Currently using an MFJ949 for measurement but really need to swap it out with my Autek meter as the MFJ accuracy is horrid in the low range.

>Does Q2 get hot?
I will leave that with a "it all depends".  If you do about 60 seconds of normal keying at 10WPM, such as calling CQ, I have not felt any heat. Probably the duty cycle is enough to keep it cool.  But if you drop your shoe on the key it starts to get hot to the touch after about 10 seconds into a dummy load. I haven't left my shoe on the key any longer than that but would assume by 30 seconds full key down magic smoke will appear.

>Does it stay in Class E?
Probably not (see above).  Someone told me of a mod to one of the bias resistors around Q2.  I have not tried this mod yet and don't know if it's better or worse.  I'm off the bench for  summer activities so it may be a while before I starting playing around again.

Another thing I have not done yet is to measure the signal sensitivity. 

Overall it's an interesting, but challenging, circuit.  I know the manual states it was a minimalist design and built for a specific purpose but us hackers will be hackers :)


For the headers/sockets........
I don't plan on re-selling them as they are very cheap (penny candy).  However, when someone asks I do drop a few samples in an order when I have extras (usually do).  I get them from TaydaElectronics.com  Their shipping costs are pretty reasonable as well.  I think they are also on Ebay as Tayda2009.   Below are the part numbers:

40 pin breakway header A-197 $.15 - One is enough for 13 crystals.
3 pin straight female header A-1069 $.04
3 pin Right Angle female header A-1028 $.09
(A header and 10 sockets comes out to around $2.07 shipped from them - hard to beat!)

The clear Mini-Yack enclosure was a gift from VE3FWF.  He does not produce them commercially but his local library is lucky enough to have a laser cutter he has occasional access to.  He has also done ones for the Chinese Pixie and Super RM Rockmite.  The software is from www.makercase.com and his current enclosures are available from several places on my web site but here is a direct link to the zip file:   http://kc9on.com/wp-content/uploads/2016/04/VE3FWF-Enclosures.zip

If anyone is interested I have a Super RM Rockmite enclosure made from hardboard I promised to give away and will send to the first U.S. person to e-mail me off list (Foreign shipping starts at a whopping $9.50 and up.... Ouch!).  You can see a picture of the hardboard version here: http://kc9on.com/ham-radio/qrp-radios/chinese-qrp-kits-2/chinese-super-rm-rockmite-aka-octopus/

72 John kc9on




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