6m Larcan Conversion

[avistar23]

Hahah that would be nice,

also about the ft847 internal power adjustment, i had heard rumors about a spike that the 847 sends out the moment it is put into tx, that the harris amps would go into standby from, even at its lowest power level, i did not think of the internal power adjustment, however, i wanted a safe way to have an attenuator, but a little head room, i did not like the bird prices, i was going to use to-220 style resistors, then i came across this little gem

Florida RF Labs: RF Attenuator - Fixed: Florida RF Labs: 33-1003-06.00: Attenuator, Fixed, Flange, DC to .75 GHz, 6dB, 100W, BeO,

they dont seem to *like* to sell one piece, but i got them to ship one to Canada to the wife, ez peasy lemon squeezy, now i have 6db of attenuation, which leaves me some headroom. after i find my perfect drive level, i will use the internal adjustment to cap it off where i normal set my dial on the front. that way it will be a fool proof hands-free turnover to QRO.

 

[WA8ZYT]

Nice, my 480 adjusts way down to 5 watts, I think. It does not have that spike problem, or so I have heard. Some of the Icom's do, as well.

Michael, when do you usually listen on 50.110?

 

[avistar23]

whenever i can, sometimes i leave it squelched for hours hoping, i have no set time as my schedule doesn't really allow for it.

 

[WA8ZYT]

Nice opening on 6 and 2 meters this morning. Worked some DX before going to work this morning.<<More audio>>

 

[avistar23]

Sequencer, power supply, relay, numerous meters, bird meter, slugs, etc etc etc arrived today, im just waiting on a dual line section to ship with one of my long over due antennas, cabinet construction should begin this week. cant wait to put this on the air.

 

[vo1ks]

Pictures please.

Sequencer, power supply, relay, numerous meters, bird meter, slugs, etc etc etc arrived today, im just waiting on a dual line section to ship with one of my long over due antennas, cabinet construction should begin this week. cant wait to put this on the air.

 

[avistar23]

Well here are some pics

a couple questions, i have been ASSURED this relay has been used many times for 6m QRO amplifiers, but as you see the leads inside of it, would i benefit by changing those wires to mini coax?

still waiting on my dual line section

I went with rectangle 30ua meters for the built in bird slugs because i liked how they matched my volt and amp meter much better.

sequencer is the pcb in the middle

i know the low pass wont handle the power, but i like old drake stuff so i ordered it anyway..

also got the bird 43 from a forum member as i felt it would be handy.

switches will be emergency shut off, and standby/transmit

 

[WA8ZYT]

Are you planning on using that relay for T/R? That is not a very good choice. You should use a Dow Key type coaxial relay.

 

[linearone]

Are you planning on using that relay for T/R? That is not a very good choice. You should use a Dow Key type coaxial relay.

Why?

at legal limit there is 5.4 amps @ 273 vac. A 5 amp relay at 250 volts would be fine. that relay looks to be 10 amp.

 

[WA8ZYT]

The rating of the relay has nothing to do with it.

It's an impedance matching thing. Those types of relays often do not play well with 10 meters, and certainly not 6 meters. There will probably be a mismatch between amplifier and transmitter. And transmitter and antenna, if the amplifier is bypassed.

The Heathkit SB-220 Linear Amplifier had one of those types of relays, and many reported problems on 10 meters with matching.

 

[Captain Kilowatt]

Why?

at legal limit there is 5.4 amps @ 273 vac. A 5 amp relay at 250 volts would be fine. that relay looks to be 10 amp.

At DC or 60hz it will be fine. At 50 MHz that is another story. The contact rating is not the issue. The lead length of the wire is.

The rating of the relay has nothing to do with it.

It's an impedance matching thing. Those types of relays often do not play well with 10 meters, and certainly not 6 meters. There will probably be a mismatch between amplifier and transmitter. And transmitter and antenna, if the amplifier is bypassed.

The Heathkit SB-220 Linear Amplifier had one of those types of relays, and many reported problems on 10 meters with matching.

Agreed.There are ways to change that relay by cutting the wires off that go to the common ports and soldering jumpers across a pair of contact levers so that the normal operation of DPDT is retained but the contact arrangement is different and the lead length is very short compared to what it was before being modified. Looking for a link to a picture of it as I write this. One such mod is in an older issue of the ARRL handbook and is shown on a homebrew 2m amp.

 

[avistar23]

If i use it it will be modified, At array solutions they told me they have used them down to 2m, i got it because it was available and its hard for me to get parts sent over to me, i hadn't made my mind up if i should use it yet. Dow key is still a possibility etc.

anyway here are some further advancements

 

[avistar23]

http://www.qsl.net/vu2msy/homebrew/Antenna_change_Over_for_2m_VU2EM.pdf

however i was contemplating changing the leads to Teflon coax or similar.

 

[avistar23]

other info here

Remote Coax Switch

 

[Captain Kilowatt]

http://www.qsl.net/vu2msy/homebrew/Antenna_change_Over_for_2m_VU2EM.pdf

however i was contemplating changing the leads to Teflon coax or similar.

other info here

Remote Coax Switch

That is the mod I was looking for regarding the relay. Glad you were already in the know on that one.