My Second 'Mini-Whip' Antenna - Does it Even Work?

[@erin19030]

I use a two 12 volt Lithium Ion batteries alternately , one to power my E antenna , while the other battery is on charge. The real secret to make this work better is an antenna height of two stories above the earth . Do not add more wire or if you do make the length a straight one meter vertically above the top of the antenna body. There is no amplification in the at box, just a 12 volt regulator. to power my E antenna . The most important technique is attaching a very good earth ground wire into the ground and attaching it to the at box ground terminal. On my roof I placed two units , one at each end of the roof. One E is active and one standby. These E antenna devices are sensitive and do fail easily with lightning discharges.

[@JonAhlquist]

Fixing problems with Chinese mini-whips: Perhaps the Chinese factory reversed the polarity between the power plug in the case and the bias-T board. See 7 to 9 minutes into kzbin.info/www/bejne/g6bIn3aBe6hgn6s Next, the bias-T board of some units has a capacitor C3 which is supposed to stop DC from reaching the receiver, however the printed circuit board designer mistakenly ran a conducting strip under C3 from one connection of the capacitor to the other so that C3 does nothing. To repair, you must unsolder C3, break the connection under C3, and resolder C3. For details, see kzbin.info/www/bejne/b3vXq6pohq6prZI Another problem is that the input transistor in the original PA0RDT mini-whip schematic is a J310 JFET, but some Chinese mini-whips replace this with an unknown type of bipolar transistor. See kzbin.info/www/bejne/qqfSgHSNfc5-aJI Therefore, if you purchase a mini-whip from China, be prepared to correct construction errors before the antenna can function as PA0RDT designed it. Lastly, regarding the multiple comments on this video by Greg-et2dp, this appears to be impossible now. At least I can no longer leave more than one comment per KZbin video. I found this out when I was trying to answer a question that someone asked me yesterday about a comment I had posted a year ago, and KZbin would not post my answer. In fact, I had made several comments/questions about that video a year ago, and they were all still there. However, when I tried to answer the recent question by editing my year-old comment to include the answer to the recent question, both my year-old comment disappeared as well as the recent question about that comment.

[@randomsteve4288]

32:30 The thing to take away from this video is probably that 80% of the RF noise Jim experiences in the shop comes from his botched up LED lighting and the power supplies he is using. That is why I only use the cheapest dollar store LED spots or bulbs. They have no switched power supply and ride the mostly unsmoothed rectified AC with just a linear current regulator clipping the current. This design is easy to modify for lower LED current ( longevity) and less flicker by changing resistors and the mains filter cap. (Refer to BigClive channel for details) These cheap LED offer good illumination and absolutely no RF noise, unlike the fancy LED spots, bulbs or light bars using switch mode supplies. And regarding his high quality HP power supply; Even if it is a linear regulated supply, in many cases an effort is made to reduce power dissipation by using a switched preregulator. Some older designs arounf LM723 use an SCR on the raw unfiltered bridge rectified output of the transformer to phase angle control(!!) the DC on the reservoir cap before it enters the linear regulator. The downside of the design was RF noise from the current spikes that went along with the SCR striking. On very small loads this preregulation design could even go into into a discontinous mode where it would replenish the main cap only once after several 100ms, making for a chopping wideband RF interference. For more info read up on Linear Technology App Notes AN32 and AN30 and the pdf document hpapplicationnoteawiderangingpowersupplyofcompactdimensions and the website preregulator-circuits-for-linear-power-supplies

[@paulswift700]

Hi Jim. I have one of these antennas. I bought it some time ago but not long ago I put it up. Yes it does work but it's very poor reception on the higher ham bands but better at the low end which is very surprising. De HS0ZLQ, G0MIH.

[@erin19030]

My E antenna works the best with my bench operated Delco tube radio, employing an RF amplifier and permeability tuning.

[@randomsteve4288]

03:18 I take it Jim has no clue how remote power to an active antenna works. His comment that the power insertion box "just contains a diode" is hilarious. The key components in such adapters providing power over coax to an active antenna are coils and caps. In its most basic form one coil between power supply input and center conductor of the antenna-going coax allows DC to run up to the antenna head, but blocks any received RF entering backwards into the supply (where it would radiate or get shorted by output filter caps). And a cap between the center conductor of the antenna-going coax and the receiver-going coax prevents the DC feeding the active antenna from feeding also downstream toward the receiver. There is no diode needed in that. The only job for a diode may be LED and a reverse supply polarity protection. Ofc you can add various degrees of complexity by providing extensive input voltage filtering and regulation as well as some form of overvoltage protection to the system caused by nearby lightning strikes. But bottom line; stating with confidence that there is just a diode in that adapter box is nonsense and makes one wonder if Jim is eligible of having a ham licence.

[@silverXnoise]

Maybe go elsewhere if Jim distresses you so much?

[@hestheMaster]

@randomsteve4288 You should email him with your advice! He doesn't look at the comment section, well almost never ,99% of the time.

[@tommybewick]

I'm beginning to think this Greg-et2dp account is an alternative account that Jim has to post comments on his own channel and try to get the algorithm to point people to his channel. What the hell are these ridiculous comments that are exactly the same on every one of his videos?

[@hestheMaster]

He is a mentally slow older man living in a mobile home in Wisconsin. He is even doing the exact same posts on Mr. Carlson's channel. The exact same stuff.

[@K7MD]

If you follow other vintage radio folks, you will discover that “Greg’s” spam is all over KZbin. Similar nonsense.

[@hestheMaster]

He is an older adult who resides in a Wisconsin mobile home and has retardation issues. He even does this in Mr. Carlsons Lab comment section too.

[@randomsteve4288]

​​@@K7MD despite Greg spamming other channels, an honest youtuber would delete Gregs comments and block him. Both out of fairness for other content provider who dont get "greg-tricking-the-algorhytm" traffic, and to keep the comments section clean.

[@K7MD]

@@randomsteve4288 Agree.

[@stevec5000]

Mini whip antennas are a scam! I got one and it wouldn't pick up anything while a MLA-30+ works pretty well on a tripod on the ground.

[@erin19030]

The cable you are using is a 75 ohm impedance cable, the manufacturer supplies 50 ohm cables and plenty of length as well. You really should match impedances.

[@erin19030]

This E device is merely a pre amp and will not work miracles. It’s basically designed to improve the signal to noise ratio. Don’t expect wonders, a good proper long wire antenna is still the best solution.

[@erin19030]

I think your SDR device is crap. Using a known good receiver for signal reception comparison is a better work around. My tests were all made on the AM band only. I cannot atest for HAM Band reception.