Ham Radio - W7IUV pre amp on my junk box magnetic loop for receiving

[@paulschmolke188]

You answered my circuit question with this demo. W7IUV is the source.

[@gertkok2113]

Love the shirt Kevin, and yet another great video.

[@texasvarmint9542]

Considering the 10dB insertion loss, wasn't that only 10dB gain with the 5 volts? I have the 80/160 meter version and it does a very good job on my flag rotatable antenna. Good videos - very informative. Thanks 73, Jim - W5SWV

[@eduardopower5254]

happy 4th of July buddies

[@mavamQ]

I tried to see the signal to the the noise floor, I couldn't see any difference between with the amp on or off, and then when the mini whip was on, the scale changed making the comparison impossible. Anyway, I don't see where the amp helped, it's still the signal over the noise that matters, if the amp increases both, it changes nothing.

[@robertdimuzio1585]

Kevin my W7 is from Czech Republic so the config is different than yours. The hula loop is connected to the SO 239 then to W7 then to RSP 1A then to laptop with SDR UNO software. -First I am a new HAM and can only do plug and play (no schematics). -have marginal receptivity with/without the W7. You report just the opposite. -I asked tech at the outlet. He had a hunch --there was no power source for the W7 even though the board had two empty holes for +VGC and -GND but needed schematics to confirm values and power source. -Sadly, this is where COVID 19 intervened. -I emailed the manufacturer and he responded with pages of technical data that was beyond the scope of my limited expertise. --nevertheless I found info that is of probable relevance. Under TUNING he states connect supply voltage desired from 12-14 volts and bias current should be from 60-85 mA. -Is this sufficient info from which you can recommend a power source and instruct me on how to connect it to the W7? Thank you for taking the time to assist me. Greg D

[@Flagrazi]

The Mini whip antenna is omni, magloop is bi-directional. it's not a fair comparison. What kind of mini whip you are using? I can't make it work, I've tried everything. 73

[@wd8dsb]

Hi Kevin, The W7IUV preamp has an input and output impedance reasonably close to 50 ohms based on my measurements, and if properly matched to the source and the load the gain is indeed approximately 20 dB (I have measured it at 21 dB). LTSpice modeling yields an approximate gain of 21.7 dB. You mention insertion loss, but there is no insertion loss since the device you are inserting is an amplifier with an overall gain greater than 1. As I mentioned above if you do proper input and output impedance matching, the gain should be approximately 20 dB. Just FYI, Don (wd8dsb)

[@groundzero.]

ordered a w7iuv pre-amp and an rtl-sdr. time to play around with a receive setup. i have a high noise floor here but seam to get out quite well with my home made EFHW. not sure if im going to use a switch and use it with my radio or use the rtl-sdr. questioning over load issues with having a separate receive setup on when transmitting, such as recovery time before it can" hear" properly again.

[@loughkb]

If you can set up a T/R relay to ground the input to the receive antenna when you're transmitting, it should work seamlessly.

[@theodoresears4369]

Can you transmit with preamplifier inline?

[@gonkeyhughes]

love your videos kevin i learn a lot from them on all you put up . do you learn anything in the makeing of them from amature radio electronics or post production as your presetation is we learn together i like that might like a video on how i make youtube vids from you how you do it best regards g0myd in uk

[@loughkb]

+mighty gonk hughes I already did. Go back through the videos on my page and look for the thumbnail with the video camera. Title is My Video Production Workflow, or something like that.

[@rlmillr]

I am wondering how both of these compare to your long wire.

[@loughkb]

+rlmillr maybe I'll do a shootout video in a few days.

[@brazilianbroadcaster3109]

Congratulations Kevin. I´m trying to follow your test conditions. I could see that you´ve used Cubic SDR V. 02.2. Would you mind telling us the SDR hardware interface model and brand? Thanks. PU1-SFB - RJ - BRAZIL.

[@loughkb]

I was using an SDRplay RSP2, if I remember correctly.

[@wa2ftv]

Where can you purchase the W7iuv pre-amp circuit board? W7IUV's website is down for maintenance.

[@loughkb]

Doing a Google search for w7iuv preamp, I saw some listed on ebay.

[@wa2ftv]

@@loughkb Found a kit supplier. Thank You.

[@unklewink]

Question: When you were running the comparison between the mini whip and the active magnetic loop on 15 mhz WWV, what was the aim of the loop at the time? Was it optimized for Fort Collins?

[@loughkb]

It's plane was east to west, so yes.

[@unklewink]

Thanks, Kevin. Just curious. Obviously, that would be a factor in the comparison.

[@yenaurapourtoulmonde]

Would be more appropriate if you would consider S/N ratio

[@63snampook]

exactly ! that's what really counts !!

[@EdEditz]

How can you display signal strength on Cubic? I don't see any scale in dBm or dBFS or something like that on my computer.

[@loughkb]

On the left side of the spectrum display it shows the current range of that part of the display. I zoomed in on that in the video.