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How good can a RAIN GUTTER be on HF bands? Since moving to a "retirement community" last year I have been searching for a reasonably good HF antenna. I have tried a few 10-20 ft verticals (not well hidden) and a 140 ft long wire end-fed wire (which everyone can see). So how about a commercial aluminum (painted) rain gutter. I feed it with 50 ft RG8X into a Palomar Engineering 9:1 UNUN with two counterpoises: 15 ft and 30 ft. I have a wide-range tuner in the shack, so now SWR issues. Well, it is "hidden" and it does tune up on 160m, 40m, 30m, 17m, and 10 meters with SWR < 2.5:1 but that may mean it is just "lossy" (the UNUN). I'll give it a try this weekend with Fldigi, running no more than 25 watts on CW, PSK, and Olivia/Thor modes. I'm really curious about 160m at night - I have never operated on that band. Are there "watering holes" (freq) where different sound card modes hang out? Seems like everything is FT8 these days. 10m should be easy, as it is both vertical and horizontal polarization. Here are Nano VNA SWR and RETURN LOSS graphs. I plot RETURN LOSS as a negative number to have the same shape as the SWR curve. I did one run from 1.8 to 8 MHz, and the other run from 8 to 30 MHz. I'm excited about this new antenna. No one can "see it". But how well will it work? de k3eui barry

For your rain gutter antenna ensure section are firmly connected together. I put a self taping screw through where sections overlapped because I was experiencing arching at 100 watts. I included the downspouts. It was a 2 story house. It was about 280 ft of radiator fed at the bottom of a downspout. It worked fine on 10-80 meters. Didn't try 160 because I used a 2.5 mile long 4 ft tall chain link fence for that band. The fence was also connected to the coax shield of my rain gutter antenna. Recently I've heard an HOA ham used a mag loop decorated to look like a dream catcher. It was mounted on a box to hide the rotor & used a remote tuner. All cables were buried. Of course HOA hams are also using flag poles. I no longer live in an antenna restricted town. Good luck Sent from AOL on Android

de k3eui Barry Kennett Square PA Due to my high noise level (over S9) on 80m and 40m, I often will use the REMOTE SDR at k3fef.com (NE PA) for digital sound card nets like the PA NBEMS or MidAtlantic NBEMS. To check the accuracy of the k3fef radio, I tune it to 14.999 MHz and click on USB (upper sideband) Since WWV carrier is right on 15.000 MHz, by tuning 1 kHz low on the k3fef VFO, I will hear a steady tone (15.000-14.999) of 1 kHz or 1000 Hz on the sound card output of k3fef.com on the internet connection. This is not the beep beep tones that WWV sends out at the start of each second. This is the steady BEAT FREQ of WWV when the K3FEF VFO is purposely tuned 1 kHz low on the k3fef dial. That audio from k3fef is piped into a second sound card on my home computer, and I use FLDIGI to monitor that sound. Choose the Fldigi mode "FREQ ANALYSIS" . The waterfall of Fldigi shows the steady tone close to 1000 Hz (it also shows the beep-beep audio sounds +/- 500 Hz off but ignore that) But if the steady tone is not exactly on 1000 Hz on the FLDIGI Waterfall, then the VFO at K3FEF is off just a bit on upper sideband mode. (do not use AM or LSB or lower sideband for this test) I allow the FLDIGI FREQ ANALYSIS mode a minute or so to center in on that steady tone, and it tells me that rather than 1000.00 Hz (if k3fef.com VFO were really accurate) the the audio is at 1004.689 Hz (see attached image) So that tells me that the VFO at the remote SDR K3FEF is "off" (high) by about 4 or 5 Hz. That is, the bfo at that radio at k3fef.com is just a bit "off". No one likely cares about a 5 Hz "error" at 15 MHz,ut it does throw off copy of MFSK32 signals we use on the NBEMS nets. I either have to move the center frequency of the FLDIGI WF to the center of the signal coming from k3fef.com or I can adjust the VFO frequency at k3fef.com to compensate for the 5 Hz "error" in that VFO. Either way works. Not bad!!

The last sound card to calibrate via the Fldigi WWV mode is a 10 yr old USB Sound Blaster that has very low noise. I usually use this sound card with a RSPduo SDR (hardware) which tunes HF, VHF, UHF and all modes. Right now, this is set to CHU Canada on 7850 kHz upper sideband with a 2 kHz filter BW. Fantastic signal into the Phila region of SE Pa. After setting the sample rate to NATIVE and the corrections in Fldigi to 0 ppm, the result was nearly perfect after ten minutes. So all of my sound cards now have "calibrations" in ppm with the largest one +65 ppm. Has anyone found a large calibration correction (hundreds of ppm) using the WWV (5, 10, 15, 20 MHz) or CHU (7850 kHz) time ticks? de k3eui

Tonight we used THOR 32 mode on the CCAR UHF FM net. (Chester PA) Thor modes consist of 18 tones, sent one at a time, at 32 baud. This is a modest audio bandwidth - about 600 Hz. Here is what the RF Spectrum looks like, received on a SDR in Kennett Square. Spectrum Analyzer is by Andrew (free). You can clearly see the first three "sidebands" on this FM modulationThe modulation around the carrier is the PL tone sidebands of 100 Hz The 8 kHz is just for scale - not the true bandwidth. de k3eui barry2

RAIN GUTTER ANTENNA on upper HF bands I've been experimenting with a variety of HF antennas here at my new QTH at Crosslands Retirement Community in Kennett Square, PA. I have some space limitations, but live on the first floor of a two-story apartment building. Lots of RFI from everywhere inside the building - S9 on 80m and 40m, less noise on 20 and 10m. I have a 140 ft end-fed wire with a 49:1 UNUN which tunes up easily on 80/40/20m and not so well on 17m/15m/10m. This end-fed is horizontal, low to the ground (winds among trees) and is good for high-angle NVIS radiation on 80/40m. I use it on the PA NBEMS net (3583 kHz) and on the Mid-Atlantic NBEMS net (7068 kHz) I'd like to get up something with a low-angle signal for DX on 20/17/10m bands. But can I keep any HF antenna "hidden"? What I am now trying is the aluminum rain gutter for our building, vertical for about 20 ft, makes a right angle turn and runs horizontally for about 20 ft. The coax attaches at the base of the gutter, near ground, to a 9:1 UNUN with a sheet metal screw into the gutter for a decent electrical connection. So overall, about 40 ft of thick (painted) aluminum gutter radiating element - in the shape of an inverted L and not resonant on any ham band. Lowest SWR around 16 MHz. It looks like it might work out on the 30m band as well (10.1 MHz). I have a Palomar Engineering (500W rating) 9:1 UNUN on 50 ft RG8X coax into the shack (closet). I have one counterpoise wire about 20 ft long attached to the UNUN ground terminal. Then a good manual tuner in the shack to an HF rig for very low SWR on any band. Here is what I see on my Nano VNA from 10 - 30 MHz: not bad SWR (under 2.5:1) in the shack on 20/17/15/10 meters. I'll give it a try over the next few weeks and see if the local noise is more/less on these bands, compared to my 140 ft end-fed. I'm often running QRP on these bands, CW and digi modes only. de k3eui barry

Setting up your 2m/70cm FM rig with an external Sound Card It is easy to under modulate or to over modulate an FM rig with an external sound card. If you can monitor your own signal, the old guideline was that the sound card audio should be NO LOUDER than the audio with your own microphone using your own voice. But that is very crude. Sounds like VARA FM and 8PSK do not sound anything like a human voice - so begin with a simple TUNE signal. Here is an optimally modulated THOR 22 signal sent on 2m FM (145.690 MHz) with an Icom 2820 dual-band FM rig and a DRA SR (Masters Communications sound card). The THOR22 audio is centered at 1500 Hz on the Fldigi waterfall. RF Spectrum interpretation: When the amplitude of the RF carrier (vfo at 145.690) equals the amplitude of the pair of first sidebands (+/- 1.5 kHz from carrier) then the "MODULATION INDEX" is 1.5 (Bessel method) The DEVIATION of the signal is established as the product of the modulation index multiplied by the audio frequency. Using the 1500 Hz TUNE in Fldigi, that comes to a deviation (1.5 x @1500 Hz audio) of 2.25 kHz (a bit conservative) Since this signal was sent with the Icom 2820 set to 1200 baud (TX) then the radio's transmit "PRE-EMPHASIS" will add amplitude to higher pitch audio at a rate of + 6 dB/octave. So the deviation is a bit more for any audio at 2000 Hz, a bit less for any audio at 1000 Hz, if the mode is that wide (say a 1 kHz mode like MFSK64) But since THOR22 is only 500 Hz wide, this "pre-emphasis" of the TX signal at 1200 baud plays almost no role. The deviation is about 2.2 kHz for the entire THOR22 signal. The width marker (12 kHz) on the image is just for SCALE value - not a true bandwidth. Note each additional sideband pair is WIDER - how come? We can use the first Saturday of each month for those ops in the Phila region to test their 2m FM deviation using the repeater on 147.270 (N3KZ) with a PL 77 Hz on the input only. But NOT in April due to a SET exercise. de barry2 k3eui

*On tonight's CCAR UHF FM net (446.525) the net control took checkins with THOR32* *I don't think I've ever seen THOR32 on FM nets (18 tones sent one at a time at 32 baud) * *It was fast, clean, and sounded great.* *Here is the AUDIO spectrum (not the RF spectrum) captured by the FLDIGI Audio Spectrum option* *I am receiving this at 9600 baud (pin 4 on the 6 pin MINI DIN data port) or wide flat audio * *and sound card is a DigiRig Mobile V1.9 (which works very well with the Icom 2820 rig)* * * *de k3eui barry2*

at http://www.w1hkj.com/alpha/linsim/ linsim-2.0.5.03.dmg linsim-2.0.5.03.tar.gz linsim-2.0.5.03_setup.exe readme.dmg.txt readme.txt EVENTS * add event log dialog * fix exit thread handler bug * add events OFFSET correction * change sign of correction * correct resampling of source wav 73, David W1HKJ