Search found 37 matches
- Wed Sep 18, 2019 9:54 pm
- Forum: Spectrum Analysis
- Topic: Setting up SDRuno to detect Amateur VHF tone coded squelch frequency?
- Replies: 3
- Views: 187061
Re: Setting up SDRuno to detect Amateur VHF tone coded squelch frequency?
Hi, Here's what I did. Tuned for a signal from a transmitter and looked at the audio spectrum. I zoomed in on the audio spectrum as much as I could to get the best chance of catching the PL tone. Note that I engaged the FMAP button. When I keyed up, the tone was really obvious. Since we know PL tone...
- Sun May 26, 2019 9:56 pm
- Forum: SDR Antennas
- Topic: Busy night of 40 meters
- Replies: 4
- Views: 67507
Re: Busy night of 40 meters
I think the point the OP was trying to make is the amount of CW in such a small span. That's what the WPX does for a band.
- Tue May 14, 2019 11:05 am
- Forum: SDRplay related
- Topic: MFJ 1708SDR question
- Replies: 4
- Views: 24834
Re: MFJ 1708SDR question
Hi NewYork, OK so 50dB isolation is probably about right for a single relay although I'm a little surprised it's not higher as the SDR input is grounded. I wonder what input you were using? The Hi-Z input picks up a lot of radiated signal. One option you have is to add some attenuation into the SDR ...
- Sat May 11, 2019 10:30 pm
- Forum: SDRplay related
- Topic: MFJ 1708SDR question
- Replies: 4
- Views: 24834
Re: MFJ 1708SDR question
Hi NewYork, I don't have this switch and looking at the manuals (incl the B variant) I don't see any isolation specifications but I can offer some suggestions. Easiest thing, ask MFJ what the isolation is for your unit. They should know but if you don't get a satisfactory answer you can do you own t...
- Fri Feb 08, 2019 8:11 pm
- Forum: SDR Antennas
- Topic: Extending the range of a Discone antenna down to 3.6 MHz
- Replies: 52
- Views: 229274
Re: Extending the range of a Discone antenna down to 3.6 MHz
Thank you both. An excellent experiment.
- Fri Feb 08, 2019 12:45 pm
- Forum: SDR Antennas
- Topic: Extending the range of a Discone antenna down to 3.6 MHz
- Replies: 52
- Views: 229274
Re: Extending the range of a Discone antenna down to 3.6 MHz
Hi Glovisol, Yes it seemed to me that the electrical earth may be acting as an antenna for things other than interesting radio signals. I have seen noise carried by mains wiring cause significant noise on HF. Normal noise reduction techniques using ferrite cores applied to the wiring brought a great...
- Thu Feb 07, 2019 7:54 pm
- Forum: SDR Antennas
- Topic: Extending the range of a Discone antenna down to 3.6 MHz
- Replies: 52
- Views: 229274
Re: Extending the range of a Discone antenna down to 3.6 MHz
Here is the detailed report: 1) The antenna is mounted on a 1.8 m steel pole which goest through the roof and is mounted with two steel brackets to a wooden beam of the roof. There is an elecrical (not RF!)) ground tied to the pole which was wired ages ago and is connected to the general electrical...
- Mon Jan 21, 2019 8:55 pm
- Forum: General
- Topic: Your MFJ-1708B-T/R Switch Experiences
- Replies: 4
- Views: 30548
Re: Your MFJ-1708B-T/R Switch Experiences
The RSP2pro comes in a metal box but also comes at a price. As has already been mentioned not everyone needs such heavy shielding.Ruben_NB4R wrote: I don't know why the SDRPlay don't make this standard practice if it is so needed.
Ruben_NB4R
- Wed Nov 14, 2018 8:22 pm
- Forum: SDRplay related
- Topic: Bias-t voltage
- Replies: 5
- Views: 28005
Re: Bias-t voltage
I think the reason for the 5V bias voltage is understandable.
As someone mentioned there are lower voltage circuits of the mini-whip https://www.g8jnj.net/activeantennas.htm
As someone mentioned there are lower voltage circuits of the mini-whip https://www.g8jnj.net/activeantennas.htm
- Sun Nov 11, 2018 12:22 pm
- Forum: SDR Antennas
- Topic: A FOOLPROOF ANTENNA SWITCH
- Replies: 30
- Views: 302555
Re: A FOOLPROOF ANTENNA SWITCH
Hi All, Thanks for the comments and suggestions. It shows that even in a simple circuit there may be room for improvement. Here then is the revised circuit with bypass caps and back EMF diode across the relay coil. I was lazy this morning and left them out. Not surprised that I was caught. :) RX iso...