Thanks, Jim. A lot of these gadgets aren't as useer-friendly to me as an ol' sweeper and scope.
I bought up an estate a few years ago and had two of those BY HT's. I guess you have to load software from your PC to even enter a frequency. I sold them and kept my Yaesu FT-470 :-)
Steve Wedge, W1ES/4
Time flies like an arrow.? Fruit flies like a banana.
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On Wednesday, March 6th, 2024 at 5:37 PM, Jim Shorney <jimNU0C@...> wrote:
You are mainly interested in S21 logmag. You will want to do a calibration centered on 5.645 MHz with probably 30 KHz or so span. You can set your stimulus centered on 5.645 using Center/Span settings. Turn off all but one of the traces, and set the trace for format S21 Thru > LOGMAG. Connect the filter between the two ports with very short coax pigtails and you should see a nice picture. You can very the width of the sweep by changing the Stimulus Span. I was thinking that the firmware might have the ability to print the filter bandwidth parameters but I may be thinking of the Midnight SNA. You can dive deeper with the NanoVNA-app or nanovna-saver software. If you want to save screen shots you need software. NanoVNA-app is probably best for beginners. You need to jump through some hoops to get nanovna-saver running on Windows or Linux.
My TinySA shows about -10 dBm out of the NVNA at 5.645 MHz so it should be plenty safe.
You can also measure return loss other parameters if you want to get more advanced but this will get you started. There has been a fair amount of discussion in the NanoVNA group about this also.
73
-Jim
NU)C
On Wed, 06 Mar 2024 14:01:49 -0800
"Steve Wedge, W1ES/4 via groups.io" w1es@... wrote:
I¡¯ve been having trouble trying to figure out how to set up the NVNA to check filters. I¡¯ve found nothing really online. Any suggestions? Those menus are a challenge to me.
Steve Wedge, W1ES/4
Time flies like an arrow. Fruit flies like a banana.
Sent from Proton Mail for iOS
On Wed, Mar 6, 2024 at 15:48, Jim Shorney <[jimNU0C@...](mailto:On Wed, Mar 6, 2024 at 15:48, Jim Shorney <<a href=)> wrote:
We'll try this again, without the fat figered ENTER key...
Not particularly. I used the raw output of my NanoVNA-H and Midnight SNA. I would have to dig up what those values are.
This does not answer your question but I posted a bunch of 7-Line NVNA sweeps here:
/g/DRAKE-RADIO/album?id=262658
73
-Jim
NU0C
On Wed, 06 Mar 2024 12:21:32 -0800
"Jerry Kessler" N4JL.cw@... wrote:
Jim,
Any guidance as to maximum signal level for sweeping these Drake filters?
Thanks,
Jerry, N4JL
-----Original Message-----
From: [email protected] [email protected] On Behalf Of Jim Shorney
Sent: Wednesday, March 6, 2024 12:22 PM
To: [email protected]
Subject: Re: [DRAKE-RADIO] Drake SL-2300 2.3-5645kHz Filter Testing
Wes,
Comments inline below.
On Wed, 06 Mar 2024 07:03:50 -0800
"Wes Winkler via groups.io" wewinkler@... wrote:
I got a couple of Drake SL-2300 2.3-5645kHz Filters at a swap meet and am
contemplating testing them with a NanoVNA. I have three concerns.
1) Can I directly connect the filter to the Nano VNA? I am mainly
concerned about damaging the filter due to the signal input signal level.
Yes. I have done it with several TR7 filters with both a NVNA and a Midnight
SNA. They both agree closely with sweeps done with two different HP 8594E
spectrum analyzers with the tracking generator option. You could use an
inline 50 Ohm attenuator on the NVNA output if you are really worried about
the signal level but I have had no issues.
2) I reviewed the TR-7 manual but it not immediately obvious which is the
input, and which is the output of the filter.
The filters are symmetrical. It doesn't matter. If you really want to know
you can trace the signal path on the block diagram and the schematics to
figure out which port is which by visually inspecting the filter board.
3) An idea of what the input/output impedance termination should be? I
may need matching transformers for the Nano VNA test.
50 Ohms. You can directly connect to the NVNA.
Attached are some samples done within the past couple of months of NOS eBay
filters. One is a screen cap of an Inrad 4 KHz, the other two are sweeps of
a late production Drake labeled SL2300 done with nanovna-saver software in
Linux.
You can also bench test the filters from your radio without taking them off
the filter board. All you need is a source of around 10 volts to activate
the filter you want to test and a source of -4 or so to bias off the unused
filters. I used by bench supply for the + voltage and a 18650 lithium-ion
cell for the - voltage.
73
-Jim
NU0C
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73
-Jim
NU0C
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73
-Jim
NU0C
