Search found 75 matches

by Roger
Mon Jun 18, 2018 3:39 pm
Forum: SDRuno
Topic: Mute SDRUno during transmit
Replies: 2
Views: 121

Re: Mute SDRUno during transmit

If you connect SDRuno to the FT-450D via Omni-Rig when you transmit the FT-450D will send a command to Omni-Rig that it is in transmit mode and this will be passed to SDRuno so that it will automatically mute.
by Roger
Sat Jun 09, 2018 8:45 pm
Forum: SDRplay related
Topic: Two instances of HDSDR?
Replies: 4
Views: 277

Re: Two instances of HDSDR?

This question just got a lot stranger. I just realized the dealer sent me an RSPduo instead of an RSP2. Will it even work at all on HDSDR with one RX? No rush the VHF contest doesn't start for another 18 hours. :roll: Jay The RSPduo will only work with SDRuno 1.23 right now. SDRplay tech support ha...
by Roger
Tue Jun 05, 2018 7:28 pm
Forum: SDR Antennas
Topic: Newbie RF frontend protection Qs
Replies: 26
Views: 2985

Re: Newbie RF frontend protection Qs

Sadly, filament globes take ages to achieve maximum resistance and even when they do the resistance value is not even a tiny speed bump from the point of view of the value and time of fast rising voltages as per not so close lightning or PTT keying of transceivers into nearby antennas. https://www....
by Roger
Mon Jun 04, 2018 4:55 pm
Forum: SDR Antennas
Topic: Newbie RF frontend protection Qs
Replies: 26
Views: 2985

Re: Newbie RF frontend protection Qs

How has the N8VB FEP circuit I posted earlier performed in HF contest stations with kilowatt transmitters nearby? From this link... http://valentfx.com/vanilla/discussion/443/suggestions-for-protection-from-nearby-transmitting-antenna "Here is some advice from Gunnar, SM3SGP, who manages the Ki...
by Roger
Thu May 24, 2018 2:28 am
Forum: SDR Antennas
Topic: Newbie RF frontend protection Qs
Replies: 26
Views: 2985

Re: Newbie RF frontend protection Qs

The diodes will clamp the RF input to less than 1 volt zero to peak (app. +10 dBm) unless they are damaged due to excess current. The 1n4148 is rated for 300 ma continuous maximum forward current and a repetitive peak forward current of 500 ma with surge up to 2 amps. The tungsten bulb acts like a f...
by Roger
Wed May 23, 2018 5:25 pm
Forum: SDR Antennas
Topic: Newbie RF frontend protection Qs
Replies: 26
Views: 2985

Re: Newbie RF frontend protection Qs

The filament bulb is there to act as a fuse to protect the diodes if the RF level is too high. When cold the bulb resistance is very low so RF signal attenuation is low. If the signal level gets too high the resistance of the bulb will increase and for very high signals will burn out and protect the...
by Roger
Tue May 22, 2018 10:05 pm
Forum: SDR Antennas
Topic: Newbie RF frontend protection Qs
Replies: 26
Views: 2985

Re: Newbie RF frontend protection Qs

You also might add a 10K or so resistor from the input to ground. This helps bleed off rain static.
by Roger
Tue May 22, 2018 5:58 pm
Forum: SDR Antennas
Topic: Newbie RF frontend protection Qs
Replies: 26
Views: 2985

Re: Newbie RF frontend protection Qs

You need more than two diodes for protection if the levels are quite high. Some designs use a small incandescent bulb in series.

prot.PNG
prot.PNG (24.68 KiB) Viewed 901 times
by Roger
Tue May 22, 2018 5:53 pm
Forum: SDRuno
Topic: SDRuno and TS-590SG
Replies: 2
Views: 301

Re: SDRuno and TS-590SG

See my reply in the other thread....
by Roger
Tue May 22, 2018 5:52 pm
Forum: SDRplay related
Topic: RSP1a with TS-590SG
Replies: 6
Views: 673

Re: RSP1a with TS-590SG

You need to make sure that the LO Lock in SDRuno is not on. If you switch bands using the keypad buttons it will go into LO Lock. You have to unlock the LO if you do this or you can't switch bands from the other program..

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