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6m Larcan Conversion

yeah thats why i was saying on 6 it cant take the power, which is something i realized while ordering it, but then i thought an extra filter before the amp, or just to have, wouldn't hurt. I supose stubs is my only choice, i dont know enough about them tho, the best coax i could use would be lmr 400 at the moment.
 
Im interested in making the QRO 50 MHz Low Pass Filter designed by K1WHS. But having trouble finding the 50 pF 15kv doorknob capacitors, anyone know where i can aquire some?
 
Using two in series in theory will provide 50pF. You would have to determine experimentally how well it works. Once you start playing at VHF capacitors will display inductance and placing them in series may not work as you hope. (In a similar manner, inductors can appear as capacitors) Let me dig in the garage to see if I have something available.
 
Ok thanks, as per my email. anything you have of relevance youd like to get rid of i would consider purchasing, just depends on what you have and prices etc. Whenever your better you know how to reach me.
 
Just bought 3

Hello folks,

This is really an interesting thread, sorry it seems to have stopped a month or so ago. Does anyone have their Larcan on the air yet?

I am awaiting the arrival of 3 Larcans (lo-lo) and have been reading as much about them as possible. With respect to some of the questions that have been posed previously in this thread,

* About using an attenuator to ensure that the output from an FT847 will not overdrive the Larcan: there is an internal adjustment in the rig, you need to remove the cover to get to it, but you can set maximum output at 5 watts or 10 watts or whatever for HF, 6, 2, and 70cm.

* About a source for the 50pf doorknobs for the LPF: as mentioned in Lance's article, they are available from Fair Radio and from Dr Alex. Also check eBay, e.g., Capacitor, CRL, Doorknob, 50 pF @ 7.5 Kvdc, Tesla, new | eBay. Does anyone know if such large and expensive caps are necessary? What voltage rating is needed? I note that W6PQL used small looking caps for the LPF on his kilowatt solid state amp, see 1 KW 2M LDMOS Amplifier

* About those HP 50v blade power supplies, see this one:
HP 226519-001 ESP 120 Bladesystem Power Supply ESP120 226519-501 406424-001 | eBay
The seller accepted my offer of $26, with free shipping.

* If this power supply is too noisy, as it has been for some (apparently happens if antenna is relatively close to the p/s), this EMI filter was suggested: SAE EMI FILTER STB-20 (20A, 115/250 VAC) NEW | eBay

I am planning to try to convert mine to 2m and have already started to order the needed parts. I have posted my Mouser and Newark shopping carts at:
https://groups.google.com/forum/?fromgroups#!topic/larcan-6m-amplifiers/agU-8ZJBGYs
If anyone has a better source for the capacitors, especially the 2.7pf, 24pf, and the 200pf, or has any to sell, please let me know.

The thing that scares me the most is that several people have posted and written about blowing one or more of the FETs, which cost $100 each. Has anyone come up with a clever way of providing them with greater protection? Lowering the amperage of the fuses has been suggested.

73, Bill NZ5N
 
The original RF output connector on the PA appears to be a type of modified DIN female that is missing the locking collar with the treads so it can be a push on connector. The regular DIN male should push right onto this connector although it won't lock.
 
Shockwave said:
The original RF output connector on the PA appears to be a type of modified DIN female that is missing the locking collar with the treads so it can be a push on connector. The regular DIN male should push right onto this connector although it won't lock.
Click to expand...


The best thing to do is replace the input connector with either a BNC connector and replace the output connector with either an SO-239 or a type N. It is easy to do and solves the problem of having a non-secure connector on the output.



nz5n said:
Hello folks,

This is really an interesting thread, sorry it seems to have stopped a month or so ago. Does anyone have their Larcan on the air yet?

I am awaiting the arrival of 3 Larcans (lo-lo) and have been reading as much about them as possible. With respect to some of the questions that have been posed previously in this thread,

* About using an attenuator to ensure that the output from an FT847 will not overdrive the Larcan: there is an internal adjustment in the rig, you need to remove the cover to get to it, but you can set maximum output at 5 watts or 10 watts or whatever for HF, 6, 2, and 70cm.

* About a source for the 50pf doorknobs for the LPF: as mentioned in Lance's article, they are available from Fair Radio and from Dr Alex. Also check eBay, e.g., Capacitor, CRL, Doorknob, 50 pF @ 7.5 Kvdc, Tesla, new | eBay. Does anyone know if such large and expensive caps are necessary? What voltage rating is needed? I note that W6PQL used small looking caps for the LPF on his kilowatt solid state amp, see 1 KW 2M LDMOS Amplifier

* About those HP 50v blade power supplies, see this one:
HP 226519-001 ESP 120 Bladesystem Power Supply ESP120 226519-501 406424-001 | eBay
The seller accepted my offer of $26, with free shipping.

* If this power supply is too noisy, as it has been for some (apparently happens if antenna is relatively close to the p/s), this EMI filter was suggested: SAE EMI FILTER STB-20 (20A, 115/250 VAC) NEW | eBay

I am planning to try to convert mine to 2m and have already started to order the needed parts. I have posted my Mouser and Newark shopping carts at:
https://groups.google.com/forum/?fromgroups#!topic/larcan-6m-amplifiers/agU-8ZJBGYs
If anyone has a better source for the capacitors, especially the 2.7pf, 24pf, and the 200pf, or has any to sell, please let me know.

The thing that scares me the most is that several people have posted and written about blowing one or more of the FETs, which cost $100 each. Has anyone come up with a clever way of providing them with greater protection? Lowering the amperage of the fuses has been suggested.

73, Bill NZ5N
Click to expand...

I haven't done much beyond the thought and planning stage. Basically life got in the way. I have several other projects going on too at the time including an antenna system rebuild on a new tower I put up last year.With no antennas up yet having an amp is a moot point. That along with regular spring time stuff that needs to be done around the house and yard has put the 6m project on a back burner. Hopefully it will be ready before the summer Es season comes to an end.
 
As i am in the Bahamas, i ship everything to my G/F in Canada, she is bring over a dual line section, meters, slugs, power supply, switches and doh das on the 30th, then i will commence my cabinate and fabrication, however i have been waiting over a month for my gulph alpha and directive systems beams to ship, which is holding up production and or need for the amp.
 
C6ANU,

We could probably work direct on 6 or 2m, I am near Ft. Lauderdale. Have had several QSOs with C6ANX, also named Mike, also in Nassau. Good luck with the project.

73, Bill
 
ok, I cant figure out who that is for the life of me, i will have 11 elements at 45 feet for 2m ssb and fm, i would love to work you! just waiting on this damn beam. i heard a repeater in Miami on my jpole at 40 feet last week, so i cant wait for 11 elements.
 
Bill, Michael, I need to get my butt in gear and get mine finished too. I think I am going to change output to an N, I was looking at this last night. The hex screws are metric and none of my wrenches would fit them. Off to Sears, I guess. I am thinking of just soldering a short piece of RG58 to the board in place of the connector, and running it to the T/R relays, as I plan on mounting the Dow Keys to the amp somehow. Have not even thought of a low pass filter yet. I am also worried about the HP supply generating noise.

Also, the HP supply I have needs 240 VAC mains. I do not think there is an option to rewire to 120 volts. At least not on mine.

Michael, let me know when you get your antenna up. I will make sure my 2 meter beacon is running on 144.282. There is also W4PLB/B on 144.277, in Orlando.
 
sounds great, i thought i was going to have to wait on my tower to put them up, i erected a 4th tower to hold them, and i poured it while i poured columns for an addition to my house, well boy was i wrong, ive poured, mounted, welded, erected the tower, and my beam isnt even done, so much for 3 weeks to delivery, thats been months ago at this point, however i know he will delivery, it is just WHEN.

i am not sure what im going to do for a 2m amp, it would be hard for me to gather all the parts for the larcan conversion and have them to be sent to me at once, i was looking at using an rm italy 2m amp, but then that might come in close to a larcan price range.
 

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