Sunday, September 17, 2017

First Use of the Emtech ZM-2 Antenna Tuner

HF propagation conditions currently suck, but I wanted to try out the Emtech ZM-2 anyway. My first use would be with a random length antenna.

Earlier today I stopped at Harbor Freight and picked up a one pound spool of aluminum welding wire for ten bucks before the 20% off coupon. We've used such welding wire on our camping trips upstate with good results. In fact, my friend who owns the property we camp on built an 80M dipole with it and strung it about 5 feet off the ground, supporting it with fence insulators. Reception on that antenna is excellent and he's made some contacts as well. It's been there over a year and is still usable.

To support my random wire antenna today I used my 31 foot Jackite kite pole with about 50 feet of the welding wire. I also ran a ground line about 25 to 30 feet and held it down with a big screwdriver as a stake.

The wire was so light that the tip of the mast didn't noticeably droop. The antenna was running approximately East-West, and the ground ran out towards the NE.

Aluminum welding wire is light and easy to work with. As seen with my friend's 80M dipole, it'll last long if its not under much strain. It's cheap enough that if you needed to abandon a random wire antenna made from it, that wouldn't cause concern.

My back patio station today was my 2013 MacBook Pro running FLDIGI and WSJT-X, the ZM-2, Yaesu FT-817ND, and Signalink USB digital interface. I also had a CAT cable for rig control.

I followed the instructions in this video to work the tuner. I found it difficult to see the red LED even though it was overcast, so I need to verify that it's in fact working. Maybe it was luck, but by tuning for maximum noise I really didn't have to tweak anything. When I hit transmit, the rig didn't complain about high SWR.

I briefly tried 40M but had issues getting the antenna to tune on that band. It might be the length of the wire, but again I had issues seeing the LED SWR indicator light up.

As I mentioned, HF propagation is really in the crapper. Before setting up out back, I'd done some work inside using my Icom 7200 and the Ultimax 100 end fed on my roof. The random wire seemed more sensitive, based on the number of PSK31 stations that I saw. However, 20M was mostly dead.

After spotting a number of other stations on 20M PSK31 I closed out FLDIGI and fired up WSJT-X to do some WSPR. On 5 watts, I was in fact getting out.

The screenshot is from WSPR Watch running on my iPhone

This table shows the WSPR stations I received in about 10 minutes of listening.

Timestamp Call MHz SNR Drift Grid Pwr Reporter RGrid km az
 2017-09-17 19:28   8P9HA   14.097165   -17   0   GK03fb   0.1   KB3MNK   FN20ic   3378   336 
 2017-09-17 19:28   K7POF   14.097124   -8   0   DM34sr   10   KB3MNK   FN20ic   3312   68 
 2017-09-17 19:28   W6WGF   14.097119   -7   1   EM12rw   5   KB3MNK   FN20ic   2053   61 
 2017-09-17 19:28   VE4WSC   14.097103   -12   3   EN19ku   5   KB3MNK   FN20ic   2019   114 
 2017-09-17 19:26   WA5IWB   14.097094   -14   0   EM10qh   1   KB3MNK   FN20ic   2215   55 
 2017-09-17 19:26   K7RE   14.097146   -10   0   DN84am   1   KB3MNK   FN20ic   2395   92 
 2017-09-17 19:26   K5FRT   14.097012   -21   0   EM10td   0.2   KB3MNK   FN20ic   2206   54 
 2017-09-17 19:24   8P9HA   14.097137   -19   0   GK03fb   0.1   KB3MNK   FN20ic   3378   336 
 2017-09-17 19:24   K6KWI   14.097060   -21   0   DM13cu   20   KB3MNK   FN20ic   3802   67 
 2017-09-17 19:24   N0IJK   14.097052   -19   0   EL19ao   5   KB3MNK   FN20ic   2365   54

I am cautiously optimistic about the Emtech ZM-2 tuner but I need to figure out why I'm not seeing the LED SWR indicator light. My next experiment with it will be with a dipole to be constructed using some 450 Ohm window line that I bought yesterday at Ham Radio Outlet.

Wednesday, September 13, 2017

Emtech ZM-2 Antenna Tuner

Last Saturday I ordered a pre-built Emtech ZM-2 antenna tuner with UHF connectors and it arrived today.  I wanted something a bit smaller and lighter than my LDG YT-100 for use with my Yaesu FT-817ND. Additionally, I wanted a tuner that would work with either coax cable fed antennas, balanced line antennas, or even just a random length wire with a ground.

Unlike the LDG, the Emtech unit is a manual tuner using a Z-match circuit. However, based on several videos I've watched and reviews I've read, it's quick to tune and gives you a wide choice with antennas and feedlines. (See here for a good discussion of Z-match circuits.)

Weather permitting, I am hoping to try it out this coming weekend. In the interim, here's a good video from W2AEW on how to operate the ZM-2.

Sunday, September 10, 2017

NOAA Radio Propagation Dashboard

Currently, HF propagation is terrible, largely due to solar activity. This NOAA Radio Propagation Dashboard helps explain why.