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KN-Q7A VRS CS


Mike
 

Group,


I have an old KN-Q7A that was on 7MHZ and I want to convert it to 21MHZ. I seen that the CS series possibly can do 21 MHZ and the CS Looks very similar.can I buy a CS lit for 21 MHZ and convert my KNQ7A?


Thank you


Mike WA3O


Adam Rong
 

Hi Mike,

It is possible to make the modification. Likely you will get about 2 watt PEP on 15 meter band. You will need to order the following from CRKITS.COM offline:
1 pcs 15m Sandwich digital VFO complete kit for IF 8.192 (please confirm IF)
4 pcs DIY7-21 coils to replace DIY7-7 (you don't need to replace the reworked DIY7-7*, do it carefully when you desolder)
4 pcs 150 pF cap to replace 470 pF in LPF
Reduce both T37-2 toroids winding from 15 turns to 8 turns in LPF
4 pcs 15 pF cap to replace 27 pF in both RX and TX BPF
2 pcs 3 pF cap to replace 2 pF in both RX and TX BPF
1 pcs BD139 driver transistor to replace D882
1 pcs IRF510 final MOSFET to replace IRF530
Total 32 USD including shipping. PayPal rongxh@...

Thanks,
Adam

于 2017-9-30 18:13, mikeymustang2000@... [CHINA_QRP] 写道:

 

Group,


I have an old KN-Q7A that was on 7MHZ and I want to convert it to 21MHZ. I seen that the CS series possibly can do 21 MHZ and the CS Looks very similar.can I buy a CS lit for 21 MHZ and convert my KNQ7A?


Thank you


Mike WA3O



n7rgw
 

You can make the conversion, but it might be more fun to just buy a CS-15/17 radio.  The filters are different and it is difficult to remove the DIY7-7 coils and replace them with DIY7-21 as well as the associated capacitors.
One thing that you might consider is my dual band option for a KN-Q7A or a CS-series radio.  It comes with the filters needed.  However, I have not checked out the 15 or 17 Meter filters, yet.  I will be doing that this week or next week, I hope.
But you can add the Sandwich to your radio now and get that part of the conversion working.  The Sandwich will give you full band coverage instead of partial band coverage.  You can order that from CRKITS.com or from me in the US.
My add: visit www.QRVTronics.com.


kb1gmx@...
 

hello,

I've done 10M with KNQ7A the mods are simple but the finals i used are:

RD06hhf as its a better performer at 30mhz.
Final was IRF510, properly matched it does well even at 6M.
a RD16HHF would be a good choice too.

Coils and caps were done with toroids and variables.  The VXO crystal 
is the bigger challenge for most, I had something that worked well for around
28.400 but a SI570 or 5351 is a good choice too.

The IRF530 I have driven that at 6M and with 24V and .6W drive it's 
good for about 9W.  The magic is that the gate impedence is very 
low due to the input C is high and you drive it like any  other power 
device at low impedances.  It doesn't lack gain even at low VHF.

Allison/kb1gmx


kb1gmx@...
 

I'm one that does SSB from scratch and modding my KNQ7A was more for the fun buying a 
kit that does more.

15M, since we are going down the sunspot cycle I'd expect most would opt for 17M or 20M.
Good to hear there are people that are not turned off by low solar numbers.  I say that having 
done very well the bottom of last cycle on 10M running QRP (4W) homebrew SSB.

FYI with a sharp eye and tweezers its possible to remove turns from the dy-7 coils.

allison/kb1gmx



Adam Rong
 

It is not easy to remove turns. You can buy DIY7-21 from me at 1.5 USD each plus reasonable freight.


Thanks,
Adam


On Oct 6, 2017 9:42 AM, kb1gmx@... [CHINA_QRP] wrote:
 

I'm one that does SSB from scratch and modding my KNQ7A was more for the fun buying a 

kit that does more.

15M, since we are going down the sunspot cycle I'd expect most would opt for 17M or 20M.
Good to hear there are people that are not turned off by low solar numbers.  I say that having 
done very well the bottom of last cycle on 10M running QRP (4W) homebrew SSB.

FYI with a sharp eye and tweezers its possible to remove turns from the dy-7 coils.

allison/kb1gmx



kb1gmx@...
 

it was easy enough for me and was done as I tend to be impatient.  I build 
with parts I have now rather than parts that may arrive some day.

Its more a matter of experience of my youth when money was scarce'
and I had to figure out how to do things because I could not buy what 
I wanted.  Often even if money was not an issue what I wanted was 
not available though local outfits.  So I learned how to do what what 
desired.

Solving problems of whats needed and what I have are part of what 
I enjoy of building.  It is a challenge.

Allison/Kb1GMX