Im aligning a 25 ltd for the first time calls for dummyload, watt meter and modulation meter i know about that but where does the signal generator and osciliscope all go into at once.
-
You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.
Test equipment question
- Thread starter kaos513
- Start date
If its generating audio - mic jack
RF - antenna.
Just don't transmit into your signal gen unless it can handle it.
Scope? What are you measuring?
I have not looked at the alignment procedure so I am going to guess RF?
You need an RF sampler like a Bird 4275, etc.
RF - antenna.
Just don't transmit into your signal gen unless it can handle it.
Scope? What are you measuring?
I have not looked at the alignment procedure so I am going to guess RF?
You need an RF sampler like a Bird 4275, etc.
If you can list specific pieces of equipment you have we can tell you what else may needed to keep that equipment safe.
For example, if you use a communications test set that can handle 50 watts then you can connect that to the radio directly.
But if you use a Rigol SA, then you need an RF sampler+dc block OR attenuator+dc block because the input on the Rigol cant handle several watts on it's input.
(A DC block is just good practice when using an SA )
For example, if you use a communications test set that can handle 50 watts then you can connect that to the radio directly.
But if you use a Rigol SA, then you need an RF sampler+dc block OR attenuator+dc block because the input on the Rigol cant handle several watts on it's input.
(A DC block is just good practice when using an SA )
First off, you don't hook up the sig/gen to the radio when you are working on the tx side of testing. So why are you trying to hook all of that up at the same time? Do the tx first with the radio > rf sampler > o-scope (modulation/carrier test)/freq counter (pll align) > power meter > dummy load setup.
Once tx is all finished; then go on to doing rx.
Radio so-239 > sig/gen; radio audio out > sinad meter.
Once tx is all finished; then go on to doing rx.
Radio so-239 > sig/gen; radio audio out > sinad meter.
Last edited:
Do PLL testing first - Dummy load on antenna and place Scope and / or DVM to Test points - Mic has Mic just no audio - set to Channel 19 (Mid band) first in RX - TX side? Your scope is in side on a TP 3 or TP 4.
TP 1 is Ground (Negative)
TP 2 - Varactor Voltage (use DVM - Verify Channel 1 and Channel 40 also - Bare wire of R59 Adj. L15 as needed)
TP 3 - RX and VCO - Scope this - Tune to Ch 19 adj for Max - then tweak for Ch 1 and 40 for best waveform)
In TX mode
TP 4 - Channel 19 for best waveform - L17, L18 and L19 - Equalize for Channel 1 and Channel 40
That's pretty much what you'll need the Scope for PLL and TX - RX? - NB uses it at L19 C15 for best shape waveform...
Rest is by Wattmeter and if you have one SINAD for RX "volume" - 8 ohm Dummy load needed if SINAD used or DVM on S/RF meter leads - or just watch the show on the old analog S/RF meter diplay - just be sure RF gain is set to MAX for later on in the tuneup.
TX - Channel 19 - ADJ L17, L18, L19 and L14 for last step in chain, for best reading on Wattmeter (terminated with a Dummy Load)
Do the same for Channel 1 and Channel 40 to balance readings - may be necessary to Adj L10.
SET VR3 to show 3 to 4 (TX part of S/RF meter)
Set VR 2 to Mid-point (2nd IF Gain)
Set RF gain to MAX
Set Squelch to OFF
Set ANL/NB to OFF
RX - Channel 19 - Short Pin 1 to Pin 4 of Mic Jack if needed - place Sig Gen at antenna, set Channel on display and for 100uV 30% mod and tune L1, L2, L3, L4, L5, L6 and L7 - use AF VTVM or SINAD meter - or use S/RF meter look for maximum deflection
NB ON - Adj L19 for best waveform (Scope to C15 - closest leg towards L5) use S-Meter display or tap DVM onto S/RF meter leads...
If using AF VTVM or SINAD meter - on EXT SP Jack - 8 ohm termination - adjust VOLUME knob as needed.
Equalize RX - Channel 1 and Channel 40 - Adj L1 and L2 between channels for best equalized S-Meter reading balance. Reset Channel to 19.
Set VR2 to show S-9 on S/RF meter.
Set Sig Gen to 1000uV and Squelch to MAX - Adjust VR 4 until SQUELCH just opens
Disconnect Sig Gen at antenna - replace with Wattmeter and Dummy load - attach Microphone to Mic jack - Dynamike ON FULL - TX Mode - Adj L10 for 4~5Watt Deflection on meter - Channel 19, Channel 1 and Channel 40 - all should be equal - VR5 sets for 85 - 95% Modulation
The Above comes from my own notes...per their Tune-up manual..
HOWEVER, I know that folks would rather make it easy on themselves...
Get PLL stable and in Lock first L15 and L16 do that...
Get RX stable as above - VR2 (IF Gain) for best results not just "S-9" - NB and ANL are affected by this control too. L1 and L2 to balance out RX "noise" with L7
VR4 for Squelch as necessary
VR5 (if you go by the book) for Limiter action - affects L10...
If VR 5 is active (working) just adj L10 for max deflection on wattmeter when audio is applied - preferably using the stock mike with FM interstation "hiss" available with "Mute off" feature on many FM stereo receivers. (White noise)
VR3 for RF Power meter
VR1 for Signal meter (VR2 affects this control as well)
L16 may need to be tweaked/used for best performance balance between RX and TX.
TP 1 is Ground (Negative)
TP 2 - Varactor Voltage (use DVM - Verify Channel 1 and Channel 40 also - Bare wire of R59 Adj. L15 as needed)
TP 3 - RX and VCO - Scope this - Tune to Ch 19 adj for Max - then tweak for Ch 1 and 40 for best waveform)
In TX mode
TP 4 - Channel 19 for best waveform - L17, L18 and L19 - Equalize for Channel 1 and Channel 40
That's pretty much what you'll need the Scope for PLL and TX - RX? - NB uses it at L19 C15 for best shape waveform...
Rest is by Wattmeter and if you have one SINAD for RX "volume" - 8 ohm Dummy load needed if SINAD used or DVM on S/RF meter leads - or just watch the show on the old analog S/RF meter diplay - just be sure RF gain is set to MAX for later on in the tuneup.
TX - Channel 19 - ADJ L17, L18, L19 and L14 for last step in chain, for best reading on Wattmeter (terminated with a Dummy Load)
Do the same for Channel 1 and Channel 40 to balance readings - may be necessary to Adj L10.
SET VR3 to show 3 to 4 (TX part of S/RF meter)
Set VR 2 to Mid-point (2nd IF Gain)
Set RF gain to MAX
Set Squelch to OFF
Set ANL/NB to OFF
RX - Channel 19 - Short Pin 1 to Pin 4 of Mic Jack if needed - place Sig Gen at antenna, set Channel on display and for 100uV 30% mod and tune L1, L2, L3, L4, L5, L6 and L7 - use AF VTVM or SINAD meter - or use S/RF meter look for maximum deflection
NB ON - Adj L19 for best waveform (Scope to C15 - closest leg towards L5) use S-Meter display or tap DVM onto S/RF meter leads...
If using AF VTVM or SINAD meter - on EXT SP Jack - 8 ohm termination - adjust VOLUME knob as needed.
Equalize RX - Channel 1 and Channel 40 - Adj L1 and L2 between channels for best equalized S-Meter reading balance. Reset Channel to 19.
Set VR2 to show S-9 on S/RF meter.
Set Sig Gen to 1000uV and Squelch to MAX - Adjust VR 4 until SQUELCH just opens
Disconnect Sig Gen at antenna - replace with Wattmeter and Dummy load - attach Microphone to Mic jack - Dynamike ON FULL - TX Mode - Adj L10 for 4~5Watt Deflection on meter - Channel 19, Channel 1 and Channel 40 - all should be equal - VR5 sets for 85 - 95% Modulation
The Above comes from my own notes...per their Tune-up manual..
HOWEVER, I know that folks would rather make it easy on themselves...
Get PLL stable and in Lock first L15 and L16 do that...
Get RX stable as above - VR2 (IF Gain) for best results not just "S-9" - NB and ANL are affected by this control too. L1 and L2 to balance out RX "noise" with L7
VR4 for Squelch as necessary
VR5 (if you go by the book) for Limiter action - affects L10...
If VR 5 is active (working) just adj L10 for max deflection on wattmeter when audio is applied - preferably using the stock mike with FM interstation "hiss" available with "Mute off" feature on many FM stereo receivers. (White noise)
VR3 for RF Power meter
VR1 for Signal meter (VR2 affects this control as well)
L16 may need to be tweaked/used for best performance balance between RX and TX.
While I love the Sinad software meter you can get for to run on your computer you can also build a homemade RX test meter using an VU meter.
Parts you will need:
1- VU meter
1- 8 ohm 8RΩJ 20 watt Axial Ceramic Cement Power Resistor.
1- 1/8 inch Mono plug
Some small wire to hook it all up.
Here is what mine looks like:
I also added an S Meter to watch both while setting the RX cans to keep things in line. Very easy to build and use with your signal generator. Yeah its was all put into a cottage cheese bowl. I was lazy and cheap! LOL.
Parts you will need:
1- VU meter
1- 8 ohm 8RΩJ 20 watt Axial Ceramic Cement Power Resistor.
1- 1/8 inch Mono plug
Some small wire to hook it all up.
Here is what mine looks like:
I also added an S Meter to watch both while setting the RX cans to keep things in line. Very easy to build and use with your signal generator. Yeah its was all put into a cottage cheese bowl. I was lazy and cheap! LOL.