Aaron KU6Z Blog

Picked up a SDRPlay RSP1b, and trying it out with a few configurations.

RSP1b on mac with SDRconnect which works fine, but the features are so basic it just doesnt have much use.

So moving on to Windows 10 and SDRuno. SDRuno is much more feature rich and I could see myself using it full screen on a 4k monitor when search the bands.

I found a video about near field coupling and tried testing TX and RX at same time on my antennas (OCF 40m and Comet CHA250HD). The RSP1B picks up 2.5dbm@5w and 11dbm@100w which is over the 0dbm limit (10dbm for 10sec bursts). Therefore, I will not be using the RSP1B when TX on my FT-710. I’m looking into a SDR switch to protect the SDR when transmitting.

Next is OpenWebRX+ which I tried on a Raspberry PI 3b, and though it ran the software ok, the CPU was just not enough, so the audio was very broken, and not usable. Some people say better heatsink and power supply will help, but I decided to move it to my Proxmox 8 server running on a Intel Core i5-12400 and using Ubuntu 22.04 in a VM and just mapped the USB RSP1B device to the KVM instance. It works great! It worked so well, that I also added my RTL-SDR and plugged in the Diamond X50, so I can monitor VHF/UHF antenna and HF antennas at the same time.

OpenWebRX+ is very feature rich, here are my favorites: Aircraft ADS-B decoding and showing on the map, Packet decode of APRS, FT-8/FT-4/WSPR background decode and PSKreporter.info reporting.

I ordered a Palomar 40m Sky Loop that was supposed to come with 144ft of wire, but they sent me 114ft. So I decided to make it a 40m OCF Dipole since it only needs 66ft. I cut the wire to 11ft + 55ft to match the Palomar 40m OCF instructions

Looks like it is doing best on 15m, but the comet seems to hear better on most the other bands.

SWR looks a bit low on 40m with 2.0 SWR at 6.5Mhz, so I should shorten it.

SWR for the bands are: 2.6 on 7Mhz, 1.6 on 20m, 3.6 on 17m, 1.6 on 15m, 2.7 on 12m, 1.0 on 10m, and 1.4 on 6m

Wow, what a difference getting the Comet CHA250HD mounted away from the house made.  It dropped the noise level and improved listening by 3-4S units.  It is now very competitive with the G5RV jr, and beats the G5RVjr on 10m by 3db ,12m by 4db ,15m by 15db, 17m by 3db, and 80m by 2db in FT8. G5RVjr wins on 20m by 2db and 40m by 1db.

I tried mounting it without radials, then with radials. The radial increased signal by at least 1S unit across all bands! So just the ground mount helped, but radials improved it.

I used the DX Commander manual suggestion of installing 16x 5m radials at the base.

Below is a picture of what the profile of the hill looks like.

Here is a terrain map of the hills around my house (at the red pin):

Facing north:

Facing East:Facing South:Facing West:

I got out my 20m dipole and thought I’d try to convert it into a 10m sky loop. I had to add about 3ft to the end of the dipole, and join it together to get it to tune to 28.1Mhz. I hung it from my chimney and it was in a triangle configuration.

After doing some A/B tests between the G5RVjr and 10m Sky loop, the noise level was 4 S units higher, and FT-8 contacts were from 8-14db lower on the loop. I decided to remove it . The loop was just not a good performer compared to the G5RVjr, even the Comet CHA250HD worked better, and that is a noisy antenna. I know it would have performed better if it were up higher and away from the house, but not an easy task. I’ll but more effort into the 40m loop and try to get it more horizontal.

I had a G5RV Jr in my box, but it need to be repaired. I installed 15.6′ of new ladder line and 1:1 balun. I checked the SWR with my NanoVNA-H4 and found it has low enough SWR at 2.1@ 28.275Mhz (10m) , 1.7@14.100mhz (20m), 2.0@7.275mhz (40m)

This antenna is expected to work well on 40-20-15-10m bands according to https://www.wireantennas.co.uk/hf-g5rv-jr-antenna

Checking the ft-8 on 10m, 20m and 40m bands showed it was working significantly better than the Comet CHA250HD. 15m is the only band that the Comet worked better.

Here is the whole HF band, with dips at 40, 20,15 and 10m.

40m SWR is at 1.4

20m SWR is at 1.785

15m SWR is 4.008

10m band SWR starts at 1.96

Picked up a Yaesu FTM-200DR VHF/UHF, so I can try out YFM/C4FM digital mode and Wires-X. Also got a pi-star MMDVM hotspot board  to put on my Raspberry Pi 3B.

Removed the resister to activate MARS bands so I can talk to my FRS radios in an emergency.

Just picked up a Comet CHA-250HD, and Yaesu FT-710 and will be on WSJT-X.

Checked SWR with my NanoVNA-H4 Vector Network Analyzer

Youtube video show the radiation pattern of the CHA250HD, and has gain on 15m, and loss on all the other bands:

Well, the temporary G5RV was such a success, I decided to make a more permanent install with 14 gauge wire.  I found out that the reason my original G5RV resonance was off, was i needed to tune the 300Ohm feed ladder line before adding the dipole legs.

The 31ft that most sites state for a G5RV was for a different velocity factor wire (like 450Ohm Ladder line), then the 300Ohm twinlead wire I got from Radio Shack (p/n 15-1175).  The stuff I got was supposed to have a Vf=0.82 according to the website and it calculates out to be 28.5ft, but i followed the instructions on vk1od’s website about optimizing a G5RV, which suggested put a 50Ohm resister on the end of the twinlead, and tuning it to 14.150Mhz with my MFJ-269 to get a more precise length. In the end  I had to cut off 3ft, shortening it to 28ft, which explains why resonance was so low.   Then I added the 51ft legs of the dipole, and tuned them to 14.150Mhz too.  Once I got it up on the roof, I get a 1.6SWR at 14.150Mhz.

I also decided to add a Unadilla W2AU 1:1 balun at the bottom of the G5RV, and have a 6 ft RG8x cable to the LDG Z11ProII tuner with 6xAA batteries inside, which then feeds a 50ft RG8x cable into the house to the radio. If you notice in the picture,  I have a FairRite Mix 31 Clamp-on choke with 6 turns to prevent common mode currents too. I keep the tuner in the box, out of the weather, but I’ll eventually get something a little more water tight.

I’ve been doing A/B antenna test between the DX-CC and G5RV and the biggest difference is in the noise level. The DX-CC constantly has about a 2S higher noise level then the G5RV across all the bands.  But the biggest improvement with using the G5RV has got to be 80m band, which I can hear stations, that would otherwise be buried in the noise on the DX-CC.  I think this has to do with the traps shortening the antenna and the fact the DX-CC is 20ft lower, probably getting more noise from the house electronics too.

My wife is a bit disturbed by the looks of the tall antenna, but I’m gunna keep it up there, as long as I am active looking for QSO’s or find something with better performance.

DX is looking good on 20m into Europe, which has always been difficult for me.

Next project is a 80m loop.

I put up the G5RV up on the 27ft pole, which puts it 20 ft above the DX-CC.

Resonance is off, maybe the wire stretched, I probably should put up the 14 gauge wire.

Here is the current resonances: 3.673Mhz @2.3SWR, 6.671Mhz @2.5 SWR, and 13.542Mhz @1.8 SWR.

I’ve gotten a few DX contacts on 15m JT65: JH3OWW (Japan) and LU8EX (Argentina) with strong reports of -06 and -09 respectively.

The signals are quite clear over the DX-CC, especially with 20ft more height it is hearing alot more with a lower noise level.  The fact that the G5RV is so light, with no balun needed at the top, the Jacklite pole does a great job holding it up.

I decided to make a cheap full size G5RV, using 31 ft of Radio Shack 300 Ohm foam core twinlead (100ft = $20), which is alot better then what was on the RadioWavz G5RV that I used to have that fell apart.

I used 102ft of telephone cross-connect wire, which is very small, maybe 24 gauge,  for the legs.  Mostly because it was free.  14 Gauge wire is about $53 per 500ft.  If the tests go well and I want to upgrade, I’ll put in the 14 gauge wire as a more permanent install.

I used the 27ft Jacklite pole, (31ft with the top 2 sections off, which makes it 27ft). The corners of the property are 98ft apart, so it just fits the 2 51ft legs of the G5RV. It is in a inverted V with feedline curved to the roof. Not sure what the radiation pattern is, probably skywave, since it is so low.

So far it looks like it is pretty deaf on 20m, a little better on 40m, and almost 1S better on 80m.

Next plan is to put it up on top of the chimeny, which would put the top at about 27ft+27ft = 54ft. Thats about 20ft higher then the DX-CC, I expect the G5RV will perform significantly better at that height.