Search found 160 matches

by DanubeBCL
Sat Jul 01, 2017 8:37 am
Forum: SDR Antennas
Topic: Bias T and active mini-whip
Replies: 15
Views: 893

Re: Bias T and active mini-whip

A question in this context (I do not own an RSP2): Is the bias T voltage of the RSP2 "clean"? I have a Funcube pro+ and it's bias T is a horror. It can only (if ever) be used for VHF and above. Below is carries extreme USB noise and noise from the 5 V USB line. I have applied extra SMD cap...
by DanubeBCL
Fri Jun 30, 2017 6:44 am
Forum: SDRplay related
Topic: RSP2 LO 3rd harmonic spurious response only -20dBC
Replies: 17
Views: 999

Re: RSP2 LO 3rd harmonic spurious response only -20dBC

I think what Juha wanted to say is that they shoud have provided low pass filters behind the LO. My opinion: When someone expects high standards of a spectrum analyzer or monitoring receiver shouldn't he go better for a Rhode & Schwarz FSW8/FSW13 https://www.rohde-schwarz.com/us/product/fsw-prod...
by DanubeBCL
Thu Jun 29, 2017 8:06 am
Forum: SDR Antennas
Topic: Long Wire Antenna Performance Questions
Replies: 7
Views: 775

Re: Long Wire Antenna Performance Questions

When you only have room for 3 m poles you should inform yourselves about EWE antennas. There are many sources on the web, this one I just picked by chance: http://www.radiodx.com/articles/technical/antennas/it-had-to-be-ewe/ But EWEs are directional and work best for MW and lower SW bands. Have you ...
by DanubeBCL
Thu Jun 29, 2017 7:03 am
Forum: SDR Antennas
Topic: Long Wire Antenna Performance Questions
Replies: 7
Views: 775

Re: Long Wire Antenna Performance Questions

Can you please share some details? 1. height of metallic pole : 8 metres, base connected to ground rods, coaxial cable also grounded at the foot of the mast 2. height of wooden pole: appr. 14 m (a tree ;-) ) 3. turns and core for the two 1:1 balun: Appr. 30 turns of RG 178 coax. cable on an FT 140-...
by DanubeBCL
Thu Jun 29, 2017 6:33 am
Forum: SDRplay related
Topic: SDRplay_HDSDR download issues viruswarning
Replies: 6
Views: 571

Re: SDRplay_HDSDR download issues viruswarning

That's always the same story. Some virus scanners do a superficial job and are programmed sloppy. Indeed currently 6 anti-virus engines rate SDRplay_HDSDR_Installer_2.76_2.exe as an evil software. This is about the same hit rate as for software 4.1 for the well known Perseus SDR. The superficial &qu...
by DanubeBCL
Mon Jun 26, 2017 8:16 am
Forum: SDR Antennas
Topic: Long Wire Antenna Performance Questions
Replies: 7
Views: 775

Re: Long Wire Antenna Performance Questions

When reading your message I was totally confused which "wires" you did connect to what. But I try to visualize what you did. 1) What is the balun doing that suppresses BC AM overload? When your balun (which is in fact an unun for a longwire) suppresses overload it must be connected wrong. ...
by DanubeBCL
Sun Jun 25, 2017 5:50 pm
Forum: SDR Antennas
Topic: RA0SMS Miniwhip bad performance on SDRPlay
Replies: 28
Views: 6197

Re: RA0SMS Miniwhip bad performance on SDRPlay

This PS was a short time ago sold here in Germany under the label "Voltcraft". This Chinese PS has various names around the world. The term "linear adjustable" is misleading. It is a switched PS! In this German blog someone has dismantled the unit. It is not necessary to understa...
by DanubeBCL
Sun Jun 25, 2017 7:40 am
Forum: SDR Antennas
Topic: RA0SMS Miniwhip bad performance on SDRPlay
Replies: 28
Views: 6197

Re: RA0SMS Miniwhip bad performance on SDRPlay

All three wallplugs seem to be overchallanged for me. They have no or little headroom. Maybe the 100 mA type could work. But all three seem to be switched types and especially in the vicinity of an E field antenna (like the whip) RF noise must be taken into account. From the label alone you cannot s...
by DanubeBCL
Sat Jun 24, 2017 5:14 pm
Forum: SDR Antennas
Topic: RA0SMS Miniwhip bad performance on SDRPlay
Replies: 28
Views: 6197

Re: RA0SMS Miniwhip bad performance on SDRPlay

I have many power supplies that are labeled as 12-15V and 100-150ma but when measured, are nowhere near the printed output. All are over voltage and current. The current rating is not so important when it is above the 150 mA which are required. You can use a PS with 70 A rating although this is of ...
by DanubeBCL
Sat Jun 24, 2017 4:50 pm
Forum: SDR Antennas
Topic: RA0SMS Miniwhip bad performance on SDRPlay
Replies: 28
Views: 6197

Re: RA0SMS Miniwhip bad performance on SDRPlay

@Heinrich Opinions on this design? The antenna will certainly work. But as I said I would not trust the a BF998 or other dual gate. Better use a J310 and an old BG591 or BFU590 or a good original 2N5109. Stabilise the bias voltage for the J310 with a voltage regulator and make it adjustable for bes...

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