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Receive Preamp using 2N5109.

N

Naysayer

Solder Balls
Mar 6, 2020
227
178
53
New York
Has anyone experienced this receive preamp that uses a 2N5109? Sold online in 2 versions: with and without relays.
I ordered one without relays and intend to install it when I replace my coax. I'll figure out something to take it out on xmit maybe another RF Keying board by nomad (they are handy).
Datasheet for the 2n5109 shows: 400mA max Base and Collector current; 40v max Collector with 20v max Emitter V for a total 1W max dissipation. Apparently, 2n5109's get hot. (Melt snow?) I noted the PCB itself is marked "9-12 volts" nowhere near the 40 / 20 datasheet max V for the 5109.
Found reference to circuit credit for W7IUV claiming 20db gain at 13vdc.
Will try this and report back soon.
 

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Naysayer said:
Has anyone experienced this receive preamp that uses a 2N5109? Sold online in 2 versions: with and without relays.
I ordered one without relays and intend to install it when I replace my coax. I'll figure out something to take it out on xmit maybe another RF Keying board by nomad (they are handy).
Datasheet for the 2n5109 shows: 400mA max Base and Collector current; 40v max Collector with 20v max Emitter V for a total 1W max dissipation. Apparently, 2n5109's get hot. (Melt snow?) I noted the PCB itself is marked "9-12 volts" nowhere near the 40 / 20 datasheet max V for the 5109.
Found reference to circuit credit for W7IUV claiming 20db gain at 13vdc.
Will try this and report back soon.
Click to expand...
Do you know if that is the device that was used in an HF preamp circuit, from a 70's or 80's ARRL handbook? I think it was, but not sure.
 
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No sir, I do not. Maybe the Wayback Archive?
I'm preparing to rebuild feedline & antenna relay switch and UNUN needs another 240/43 core so I'm trying to get everything I need so I make the changes while I have box on bench. I'm fearful of a QRO drive by mistake ruin preamp. Need relay failsafe so preamp out of line. I just started the search. Soon but I'm going to need a bigger weatherproof box to start. With components spaced-out I can replace preamp board if I find better in future.
Old material on topic "Active Antennas" Ulrich L. Rohde and T.T.N. Bucher, co-authored Communications Receivers: Principals and Design Rohde-Schwarz Type HE010
10KHz-80MHz Active Antenna that incorporated a preamp
 
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Naysayer said:
No sir, I do not. Maybe the Wayback Archive?
I'm preparing to rebuild feedline & antenna relay switch and UNUN needs another 240/43 core so I'm trying to get everything I need so I make the changes while I have box on bench. I'm fearful of a QRO drive by mistake ruin preamp. Need relay failsafe so preamp out of line. I just started the search. Soon but I'm going to need a bigger weatherproof box to start. With components spaced-out I can replace preamp board if I find better in future.
Old material on topic "Active Antennas" Ulrich L. Rohde and T.T.N. Bucher, co-authored Communications Receivers: Principals and Design Rohde-Schwarz Type HE010
10KHz-80MHz Active Antenna that incorporated a preamp
Click to expand...
I'll need to dig out an old handbook.
 
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Naysayer said:
No sir, I do not. Maybe the Wayback Archive?
I'm preparing to rebuild feedline & antenna relay switch and UNUN needs another 240/43 core so I'm trying to get everything I need so I make the changes while I have box on bench. I'm fearful of a QRO drive by mistake ruin preamp. Need relay failsafe so preamp out of line. I just started the search. Soon but I'm going to need a bigger weatherproof box to start. With components spaced-out I can replace preamp board if I find better in future.
Old material on topic "Active Antennas" Ulrich L. Rohde and T.T.N. Bucher, co-authored Communications Receivers: Principals and Design Rohde-Schwarz Type HE010
10KHz-80MHz Active Antenna that incorporated a preamp
Click to expand...
The preamp in the handbook, uses a 2N5179, I was close.
 
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From the picture, I assume these circuits are almost the same.

The 2015 handbook has a post mixer amplifier that uses the 5109. Looks like the same style circuit except that the one in this handbook adds a resistive pad at the output to isolate the amplifier from the reactance of the crystal filter input.

The circuit from the ARRL handbook also appears here (with slightly different part values as the one in my handbook).
 
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Trying to place preamp board in mast-mounted relay box holding a DPDT latching relay to select 10-40 OCF or aluminum 20m dipole. Also in box is newly built 2 core 4:1 Balun (w/ 1:1 series connected) as per the design suggested by TRX Labs (a prolific YT site by European gentleman with many Radio repair/Tech videos).
I had to include additional relay to add/remove preamp (and it’s 12vdc) from circuit board. Keeping negative VDC separate from ground, bypass caps, considering choke not sure if needed.
At dentist gotta go it’s my turn now
Pic soon
 
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