Tag Archives: noise

ARRl Sweepstakes 2017 – Roundup

The 2017 ARRL Sweepstakes was this weekend. I had some personal issues to deal with on Saturday and did not actually start working the contest until Saturday evening, 5 hours after the start of the contest. At this time of day 20m and up were closed down at the QTH. I started by working on 40m and spent most of my time there. The 40m 1/4 wave vertical worked great.I made contacts easily and the exchange was copied 100% about 95% of the time. I tried 80m on both the vertical and the DXtreme end fed and while both tuned up initially, there were problems when it came time to actually make contacts. The auto-tuner would start trying to re-tune every time I went to transmit. I only made one contact on 80m to North Texas. I worked Saturday until about 11:30 pm.

I ran a few more contacts on 40m early on Sunday morning before I left for church service. I picked up again in the early afternoon and started working on 20m and 15m. 20m was very busy and there was considerable QRM. 15m was open but there were significantly fewer stations. I struggled to make contacts initially but after about an hours they started to come in easily. I suspect that this was due to propagation changes. I quit around 5:30pm after making a few final contacts on 40m.

All in all, I worked the contest for only 6 hours and 33 minutes, made 124 QSO’s across 63 of the 83 available sections. I worked enough “rare” states that I completed my ARRL WAS for the phone endorsement using only LoTW confirmations.

What worked:

  1. Very pleased with the 1/4 wave vertical, with the IC-7300 and received several complements on my audio quality.
  2.  The Timewave ANC-4 has become easier and easier to setup and use. It is very valuable when noise conditions changes during the day. I am finding it to be effective at reducing shack noise.
  3. N1MM logger+ is very very handy for contest especially with the spectrum display on the PC with the IC-7300

What I need to improve:

  1. I don’t have a capability to work 80m and below effectively. This is a problem that I need to address as there were rich contact opportunities on 80m during the evening hours. I thought I could use the DXtreme for this purpose as I did in 2015 but I suspect there is something with that antenna that has changed. It may be time to bring it down.
  2. My foot gets tired using the foot switch. I switched back to the hand switch occasionally but I need a better switch for this purpose.
  3. Need to work on adjusting the receiver when there are many stations close in causing QRM.

I don’t really compete in contests for the prizes or fame. I work contests to test my setup over various bands and look for areas that I can improve. I think I was successful in that this year. That being said I was only 20 sections from a clean sweep mug so who knows? maybe next year?

 

 

 

Advertisements

Initial impressions of the Timewave ANC-4 Antenna Noise Canceller

My used Timewave ANC-4 arrived yesterday from Ebay. It lacked a power connector which fortunately I had in my junk box. I wired the cable up and added some power poles. It came with an antenna that consists of about 8 feet of wire connected to the center pin of an RCA plug. I set this up roughly vertically inside the shack. The unit must be grounded to work effectively with this wire antenna. I fiddled with it awhile but did not have much luck in reducing noise initially. Per the manual, the first thing to try was ensure that the sense antenna was picking up the noise at about the same amplitude as the main antenna. The receiver is setup to an unused frequency and the noise level measured on the S-meter. The phase and noise gain controls are fully CCW. The  main antenna was disconnected and the noise gain adjusted until it matches the S-meter reading  measured previously. The main antenna is then reconnected and the phase control is adjusted until a null is found.

This took awhile to figure out but with the IC-7300 it is easy to see the results on the waterfall. As you get close to a null the background on the waterfall will darken and signals will become more distinct. I estimate that the change is about a 2 S unit reduction in noise. I have run the unit on 20m WSPR and over a 1 hour period had 42 unique spots compared to N5CEY’s 21 unique spots.

So initial results look promising. I will need to work more with this and collect some data on to its effectiveness.

Noise!

Here I go again, a noise hunt. Since getting the IC-7300 I have been able to observe various noise conditions on various bands. Most of what I see is broadband and pulsing. This causes horizontal stripes to appear on my waterfall. Noise blanking has no effect. There are other less frequency types that show up. Sometimes there is a “chirp” signal that will scroll across the band showing up as vertical stripes. Other times a similar chirp begins mid band and slowly works down a few kc then starts to move up a few kc. I have tried to track local noise sources in the shack with only mixed results. To devices that produce some noise are the Ipad and the 21″ monitor though these seem to be limited in range. I shut off various noise sources including the computers, drives, cable modem and Wifi hub but did not see a significant reduction in noise levels.

I decided to try something a bit different. I found a Timewave ANC-4 noise reduction unit for a decent price on Ebay and have ordered it:

anc4

The idea of these devices is to use a sense antenna to sample the local noise and then combine it with the signal from the main antenna such that the amplitude is the same but reversed 180°:

Noise-Canceller_thumb

I have heard mixed reviews on these types of units dependent largely on the sense antenna and its ability to sample the offending noise. I will be giving this a try and will report on how well it works in my situation.

Insight from running 20m WSPR

The 40m vertical has been deployed for the past few months supported by a 10m SOTAbeams travel mast. It has held up well to the abuse of constant use over the summer. We had a few windy days last week and some of the seconds of telescoping pole retracted so I had to bring the whole thing down to fix. During this time I ran the 20m vertical on its own using 20m WSPR for receive only. Over this two day period I was comparing with Cliff’s (N5CEY) 20m WSPR station about 15-20 miles away near Bayview. Cliff consistently gets a larger number of unique spots as well as a larger amount of DX calls with his setup. Cliff is in a rural setting while I am in the middle of the city. What the WSPR data is telling me is that my noise floor is higher so I am not receiving as well as Cliff does out in the country. I took some measurements with the IC-7300 at various times of day and found the following noise floors:

Band Time
1800 UTC 2100 UTC 1300 UTC
80m S3 S4-S5 S6
40m S6 S6-S7 S9+5
20m S1 S2 S4-S5
17m S3 S3-S4 S5
15m S3 S1 S7
12m S2 S0 S3
10m S1-S3 S1 S5

These measurements were made with no preamp on 20m and below. All others had preamp #1 engaged. Friday night was awful, S9+ noise on 40m! Dick, WB5B said it best: “WSPR is telling you that you have a noise problem!” Doh!

The RA0SMS Mini-Whip Antenna

I just received a mini-whip antenna from RA0SMS in Russia.The mini-whip is an active receive antenna that is particularly useful in the low bands. I plan to set this up outside and up as far as I can get it. I’ll use 75Ohm cable TV feed line to bring it in the shack and connect it directly to the SDR play receiver. I have been sharing the discone with my VHF rig and the SDR play so I switch between them when I need the SDR as a panadapter. I am hoping this antenna will work well so I can dedicate it to the panadapter function on HF. The antenna consists of the external antenna and circuitry in a PVC case and a small bias-t box to send 12V up the cable to power it.Here is what it looks like after I unboxed it:

IMG_0713

ARRL DX SSB Contest

As I have stated before, I am a causal contester. The ARRL DX SSB contest was running this weekend and I used it as an opportunity to test the vertical 31 foot antenna as an end fed with a 9:1 balun with the IC-7100 radio and tuner. I figured this would be good to test on 20m during the day and 40m at night. I didn’t join in until Saturday afternoon and found that nearly all the action was on 15m which tuned up well on the antenna. There was also activity on 10m and 20m. All told I made around 30 contacts using “search and pounce” all of which were DX stations. Sunday morning I tried 40m and made a JA contact, my first on 40m! I was hearing Indonesia as well.

All in all good results of my antenna and rig. This shows that a multiband antenna is very useful to adjust to changing band conditions and that the increased receive sensitivity is being put to good use.

As always, I am shocked to hear so much activity on contest days on bands that one usually thinks are dead. I may start making a point to call CQ on these bands and see if anyone is listening. I may be surprised!

Busy Week on 20m WSPR

I have been running experiments on various antennas this week on 20m WSPR. NO5V is my current base antenna, the Ultimax DXtreme 53 footer up about 20 feet and horizontal. NO5V/1 is the EFHW tuned for 20m and NO5V/2 is the same wire as the EFHW but run as a non-resonant end fed with a 9:1 matchbox and about 30 feet of coax as counterpoise. I am also able to compare this data with that from N5CEY who is running a 1/4 wave vertical at his QTH about 20 miles from here. I will be looking at formally crunching the data but what is apparent is that the current base antenna is not as sensitive on receive as the vertical antennas. This is based on the WSPR Challenge results and A vs. B listening tests. The verticals are nearly equal in receive capability with the EFHW marginally the best. Both of my verticals compare well with N5CEY’s 1/4 wave vertical but he still seems to have a slightly more sensitive system as he gets better signal reports on WSPR from more DX stations.I plan to setup my own 1/4 wave vertical this week to evaluate before I turn my attention to the S9V31.

I did a quick test on 40m in the NO5V/2 configuration and was getting good 40m results as well.

Noise Raises its Ugly Head

I am seeing some weird noise on mainly the low bands here with the new vertical antenna. It is fairly broadband and the rig’s noise blanker seems to effectively null it but I would like to track down the source.The weird part is that is seems to go away on it’s own during daylight hours and return in the evening. I haven’t been able to track a specific time yet. I suspect somethjing here in the shack is causing the problem. I walked around the property yesterday with a battery powered receiver and I see the noise coming from the wall around my workstation. I suspect a bad patch cable as this has caused problems before and I did add some patch cables that may be a bit dodgy.