Home |
Search |
Today's Posts |
|
#1
|
|||
|
|||
jury rigged vhf receiver
JIMMIE wrote:
On Jan 23, 6:43 pm, Kenneth Scharf wrote: JIMMIE wrote: I was wanting to listen to VHF/UHF SSB. All of my present UHF/VHF radios are FM. I was thinking of rigging up a simple downconverter using a mini circuit mixer and my HP signal generator as the local oscilator that I can connect in front of my HF rig. I have an antenna mounted pre- amp that I think should suffice for my front end. Any foreseeable problems short of keying my transmitter while it is connected. Jimmie For best performance these mixers require a constant impedance at all three ports (usually 50 ohms). The preamp will provide this for the RF input and the output of your HP signal generator should have a 50 ohm selectable output. You may need to add an attenuator between the generator and the mixer if the HP does not provide a 50 ohm termination using a variable output. You will need to set the oscillator injection level to the mixers required 7dbm drive level for best conversion "gain". The output should go through a bandpass filter covering the IF frequency you are down converting to and provide a 50 ohm impedance. A duplexer network here is a good idea (provides a 50 ohm termination at the IF frequency and a low impedance (short) to ground to out of IF signals). Any reccomendation on the best mixer to use? Jimmie Here's one good to about 600 MHz. Been used a gazillion times in just about all VHF/UHF transverters at one time or another. If casual listening is all you need, hook it up just like you said...VHF/UHF antenna to the RF port, HP signal generator to LO port (set to +7 dBm output for this mixer and frequency appropriate for your IF frequency such as 116 MHz for 144 MHz to be 28 MHz out of the mixer) and connect the mixer IF pin to your HF radio antenna port. Probably a good idea to use capacitor coupling at each mixer port, something like 1000pF should work. http://www.minicircuits.com/pdfs/TUF-1+.pdf Scott N0EDV |
#2
|
|||
|
|||
jury rigged vhf receiver
Scott wrote:
JIMMIE wrote: On Jan 23, 6:43 pm, Kenneth Scharf wrote: JIMMIE wrote: I was wanting to listen to VHF/UHF SSB. All of my present UHF/VHF radios are FM. I was thinking of rigging up a simple downconverter using a mini circuit mixer and my HP signal generator as the local oscilator that I can connect in front of my HF rig. I have an antenna mounted pre- amp that I think should suffice for my front end. Any foreseeable problems short of keying my transmitter while it is connected. Jimmie For best performance these mixers require a constant impedance at all three ports (usually 50 ohms). The preamp will provide this for the RF input and the output of your HP signal generator should have a 50 ohm selectable output. You may need to add an attenuator between the generator and the mixer if the HP does not provide a 50 ohm termination using a variable output. You will need to set the oscillator injection level to the mixers required 7dbm drive level for best conversion "gain". The output should go through a bandpass filter covering the IF frequency you are down converting to and provide a 50 ohm impedance. A duplexer network here is a good idea (provides a 50 ohm termination at the IF frequency and a low impedance (short) to ground to out of IF signals). Any reccomendation on the best mixer to use? Jimmie Here's one good to about 600 MHz. Been used a gazillion times in just about all VHF/UHF transverters at one time or another. If casual listening is all you need, hook it up just like you said...VHF/UHF antenna to the RF port, HP signal generator to LO port (set to +7 dBm output for this mixer and frequency appropriate for your IF frequency such as 116 MHz for 144 MHz to be 28 MHz out of the mixer) and connect the mixer IF pin to your HF radio antenna port. Probably a good idea to use capacitor coupling at each mixer port, something like 1000pF should work. http://www.minicircuits.com/pdfs/TUF-1+.pdf Scott N0EDV For what it's worth, that's the same mixer used in the Elecraft K2 receiver section. |
#3
|
|||
|
|||
jury rigged vhf receiver
On Jan 24, 10:51*am, Kenneth Scharf wrote:
Scott wrote: JIMMIE wrote: On Jan 23, 6:43 pm, Kenneth Scharf wrote: JIMMIE wrote: I was wanting to listen to VHF/UHF SSB. All of my present UHF/VHF radios are FM. I was thinking of rigging up a simple downconverter using a mini circuit mixer and my HP signal generator as the local oscilator that I can connect in front of my HF rig. I have an antenna mounted pre- amp that I think should suffice for my front end. Any foreseeable problems short of keying my transmitter while it is connected. Jimmie For best performance these mixers require a constant impedance at all three ports (usually 50 ohms). *The preamp will provide this for the RF input and the output of your HP signal generator should have a 50 ohm selectable output. *You may need to add an attenuator between the generator and the mixer if the HP does not provide a 50 ohm termination using a variable output. *You will need to set the oscillator injection level to the mixers required 7dbm drive level for best conversion "gain". *The output should go through a bandpass filter covering the IF * frequency you are down converting to and provide a 50 ohm impedance. A duplexer network here is a good idea (provides a 50 ohm termination at the IF frequency and a low impedance (short) to ground to out of IF signals). Any reccomendation on the best mixer to use? Jimmie Here's one good to about 600 MHz. *Been used a gazillion times in just about all VHF/UHF transverters at one time or another. *If casual listening is all you need, hook it up just like you said...VHF/UHF antenna to the RF port, HP signal generator to LO port (set to +7 dBm output for this mixer and frequency appropriate for your IF frequency such as 116 MHz for 144 MHz to be 28 MHz out of the mixer) and connect the mixer IF pin to your HF radio antenna port. *Probably a good idea to use capacitor coupling at each mixer port, something like 1000pF should work. http://www.minicircuits.com/pdfs/TUF-1+.pdf Scott N0EDV For what it's worth, that's the same mixer used in the Elecraft K2 receiver section.- Hide quoted text - - Show quoted text - Thanks all , I found some little boxes in my scrap pile withe 3 SMA connectors on each one. Plan is to get a couple or 3 of the mixers and mount them in the boxes. Having a mixer in a box may be fun to play with. Jimmie |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
(OT) : American Grand Jury .Org | Shortwave | |||
(OT) : American Grand Jury .Org | Shortwave | |||
Is Struble grooming Jury? | Shortwave | |||
Simple 4-Bander Five-Wire Shortwave Listener (SWL) Antenna - Rigged It : Horizontal -or- Sloper -or- Vertical | Shortwave | |||
Jury-rigged SMA connector | Antenna |