RSP2 - A bit confused with connecting antennas

Useful information regarding antennas for SDR products.
espenfjo
Posts: 3
Joined: Fri Dec 28, 2018 7:48 pm

RSP2 - A bit confused with connecting antennas

Postby espenfjo » Thu Jan 03, 2019 7:45 pm

Hi,
I am a bit confused with connecting antennas to my RSP2 for HF/MW usage.

I have tried to build a coax dipole using RG58, each element being around 10meters. It should be similar to this design, using about 13-18m of rg8 as a feed line.Image

Reading the "RSP2 – Guide to using the High Z Port" leaves me with more questions than answers. Initially I would have thought that I should connect the braid to GND and N, and the center connector to P. This gives me (almost) no signal, and a noise floor below -140dBm. Removing the braid from GND/N gives me some signal, and a noise floor around -100dBm. This is stable enough to receive 80m FT8 signals from around 1500-2000 KM around me (Most of wester Europe as Im situated in southern Norway). This is however worse SNR and fewer signals than what I get with a 1.5m antenna (the one to the left). Image

This has left me a bit bummed, as I would have expected the dipole to outperform the antenna whip by far. I've also tried disconnecting the dipole, and just leaving the feed line, it makes more or less little difference.

Since I do not have a BALUN/UNUN (Its somewhere in the mail), or any toroids, should I try and connecting it to ANT A instead?
Last edited by espenfjo on Thu Jan 01, 1970 12:00 am, edited 0 times in total.
Reason: No reason

Spider
Posts: 4
Joined: Sun Jul 02, 2017 4:40 am

Re: RSP2 - A bit confused with connecting antennas

Postby Spider » Fri Jan 04, 2019 2:06 am

Dear espenfjo, I would suggest the the rg58 feedline be attached to Input A. The HiZ input is just that. Input A expects to see a low (50ohm) feed. Regards, spider vk2tti.
Last edited by Spider on Thu Jan 01, 1970 12:00 am, edited 0 times in total.
Reason: No reason

Mike2459
Posts: 135
Joined: Mon Jul 24, 2017 8:24 pm

Re: RSP2 - A bit confused with connecting antennas

Postby Mike2459 » Fri Jan 04, 2019 6:22 am

You can use the A input.The A & B antenna ports are both 50Ω inputs. You will get better performance on the Hi-Z port with a balun (4:1 turns ratio) to match 50Ω to the 1000Ω impedance at the Hi-Z port. My balun is connected to P & N with nothing on the G terminal.

Reason: No reason


Return to “SDR Antennas”

Who is online

Users browsing this forum: No registered users and 3 guests