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Author Topic: New here, and my journey building a SW xmtr  (Read 2304 times)

Offline Josh

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Re: New here, and my journey building a SW xmtr
« Reply #30 on: September 24, 2018, 2338 UTC »
If you feed a 1wl antenna at the end with coax, you may need an xformer as the coax is typically low z and the feed point of the 1wl antenna is about 2k ohms or even higher.
Conveniently located near Vincennes Indiana.

Offline fieldstrength1947

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Re: New here, and my journey building a SW xmtr
« Reply #31 on: September 25, 2018, 0010 UTC »
Carrier on at 0005 UTC, audio fully on at 0010. Would appreciate any contacts.

Offline fieldstrength1947

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Re: New here, and my journey building a SW xmtr
« Reply #32 on: September 25, 2018, 0021 UTC »
For reference, I'm starting to think that my crystal is not exactly on frequency, either that or my antenna isn't tuned, or something. Changing the position of the variable cap changes the frequency a little, so I can get it spot on, but then my audio goes away and the carrier goes weak.

It seems to be on 6782 kc.

Offline radiogaga

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Re: New here, and my journey building a SW xmtr
« Reply #33 on: September 25, 2018, 0028 UTC »
I'm seeing signals at 6779.5, 6781.3 and 6781.7...... too weak for any modulation

rgg

Offline fieldstrength1947

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Re: New here, and my journey building a SW xmtr
« Reply #34 on: September 25, 2018, 0031 UTC »
Could be either one of those last two. Just boosted the volume a little just up to the point of distortion.

Offline radiogaga

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Re: New here, and my journey building a SW xmtr
« Reply #35 on: September 25, 2018, 0037 UTC »
Off at 0036?

Offline fieldstrength1947

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Re: New here, and my journey building a SW xmtr
« Reply #36 on: September 25, 2018, 0045 UTC »
Nope... maybe wait about 30 minutes or an hour, might get better skywave propagation then.

Offline fieldstrength1947

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Re: New here, and my journey building a SW xmtr
« Reply #37 on: September 25, 2018, 0054 UTC »
I can see my carrier on a WebSDR 575 miles away! Woo!!

Confirmed by turning it off and on and watching the carrier disappear and appear again. Now I feel like I've accomplished something. Couldn't hear any modulation though. Plus now it's faded out... oh well.

Was able to confirm by this that it is on 6781.7 kc.

Offline JimIO

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Re: New here, and my journey building a SW xmtr
« Reply #38 on: September 25, 2018, 0317 UTC »
6780 is in one of the ISM bands, same (or similar) as 13560.

https://en.wikipedia.org/wiki/ISM_band

Offline JimIO

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Re: New here, and my journey building a SW xmtr
« Reply #39 on: September 25, 2018, 0332 UTC »
"i would tend to believe using highly shielded coax as feedline to the dipole is akin to bringing the TX right at the center fed part of the dipole."

I've seen things that should work not work and things that should not work work before.

Offline Stretchyman

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Re: New here, and my journey building a SW xmtr
« Reply #40 on: September 25, 2018, 0618 UTC »
You'll need more power, simples....

Antenna wise a full wave dipole isn't 50R at the centre, stick to half wave or odd multiples of, 3 half wavelengths give 50R and a clover leaf pattern BTW.

Str.
« Last Edit: October 08, 2018, 1423 UTC by Stretchyman »
'It's better to give than receive' so why RX when you can TX!

                            Buy one from me, NOW!

Great discounts on ALL my transmitters if purchased via HFUnderground


                                              ;)

Offline fieldstrength1947

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Re: New here, and my journey building a SW xmtr
« Reply #41 on: September 25, 2018, 0840 UTC »
Off at 0838 UTC.

Perhaps one more short test during the daytime tomorrow.

Offline ChrisSmolinski

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Re: New here, and my journey building a SW xmtr
« Reply #42 on: September 25, 2018, 1114 UTC »
Testing in a bit here on 6780 kc starting at about 0000 UTC.

My overnight SDR recordings are 6800-7000 kHz, so I missed your test transmission.
Chris Smolinski
Westminster, MD
eQSLs appreciated! csmolinski@blackcatsystems.com
NRD 545 / netSDR / AFE822x / AirSpy HF+ / KiwiSDR / 670 ft horizontal loop / 500 ft northeast beverage / 270 ft west-south-west beverage / 300 ft south beverage / 43m / 20m / 10m  dipoles / Crossed Parallel Loop

Offline TheRelayStation

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Re: New here, and my journey building a SW xmtr
« Reply #43 on: September 25, 2018, 1233 UTC »
"i would tend to believe using highly shielded coax as feedline to the dipole is akin to bringing the TX right at the center fed part of the dipole."

I've seen things that should work not work and things that should not work work before.
as strange and as illogical as it may sound and be, my current antenna setup works very well and better than expected after a few years of trying different antenna and feedline configurations.
6880 Khz AM 50W/500W - shortwavepirate@aol.com

Offline moof

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Re: New here, and my journey building a SW xmtr
« Reply #44 on: September 26, 2018, 2139 UTC »
Yeah don't believe quite all of the book values and antenna voodoo you read.  An inverted v 20 feet up in the center and legs just off the ground to 6 feet up is only supposed to give NVIS.  Why then have I seen 10 watts cover well over 1000 miles?  Magic resonance I guess.  My first 2-3 watt crap build was heard (poorly) almost the entire N-S distance of the US in the daytime, tossed center wire 20-25 feet high over a limb, edges maybe even touching the ground.