Messages

61

The RF Workbench / Re: Pushing a SHORT Antenna With Loading Coil

« on: July 24, 2024, 2052 UTC »

Hey Brian.

Thank you for the reply.

Re adding capacitance in “ parallel “ with the antenna: Since this antenna is only a single wire I can certainly see how I could wire a variable cap in series to it.

I am not sure how one would wire a var cap in parallel to a single wire antenna.

A var cap could, I suppose, be wired in parallel to the single winding loading
coil.Perhaps such an arrangement could / would influence the antenna itself.

But the antenna tank coil in the radio has a great deal of flexibility: it can have the var cap in series or parallel. It also has a wide range of taps for Z experimentation.

If, in a hypothetical, the load had a parallel wired var cap on it, it would seem to redundant to the functions that could be achieved in the radio’s antenna tank coil.

Since this is an occasional use endeavor it is preferable to keep the var cap count down to two- if all possible.

Re Slinky: I would like the actual 35 ft antenna run to be as thin and discrete as possible.The far end would be attached to the guy wire of a small telephone only wooden pole  ( no power lines on pole) .It is NOT authorized and technically, NOT supposed to be there.

A Slinky would probably give a bit more of a visual profile than I would like.Also , one is much better off RF wise with the brass ( or even gold) plated Slinkys.Tough to find and a little deeper than I want to go.

Anyways, it’s really fun to bounce ideas around .

OT , my people are from Galway.

Again, I REALLY appreciate your looking at my post.

Thanks,

NQC

62

The RF Workbench / Pushing a SHORT Antenna With Loading Coil

« on: July 24, 2024, 0058 UTC »

Hey All,

Kind of between a rock and a hard place.

The only spot on my apartment building property to try a wire antenna is a run limited to 35 ft long and  maybe 9 ft up at  the far end sloping to around 6 ft up at the radio end.

I would like a temporary “ set up, use and then take  down “ type of arrangement for a GOOD double tuned crystal set Dx  use at night, every now and then.


These limitations present a pretty dismal prospect, especially for the low end of the broadcast band.But pretty much all I have to work with.

Ideally 100 ft long and 30+ ft up is what one wants for crystal sets.



“Generally” ,short antennas need inductance (and overly long ones need capacitance).

So I am not sure if there is any role for series variable capacitance anywhere in the feed line .

 

This antenna MAY just be crying out  for inductance only.

 But it as also WAY  off from optimal design specs .

So I am definitely open to other unforeseen factors,ideas and  viewpoints.

FWIW , the radio’s antenna tank coil can be switched for parallel or series variable cap .There is also a full range of coil Z taps for the feed line.

But in the case of a short antenna I understand parallel tuning the radio’s ant coil is the way to go.





Just looking for opinions and ideas as to whether a simple loading coil ( it must be located at the radio end)  is really going to perk things up enough to be worth my while.

I am thinking that trying to goose such a short and low antenna into “ some” measure of improvement simply by inserting a “magical “ / “cure all “ load may really not cut it.

IF ( IF) I did go for it, I would envision something BIG  diameter (2-3 ft ?) with the turns spread out as much as is practical , yet still have a decent inductance.A compromise of turn spacing would be necessary ( ie 1-3” ?).

Is my load design off base?

Maybe a half baked LONG shot, but does anyone have any ideas of even a prayer of improvement on such a crumb ball antenna?

I know receive antennas are FAR less critical vs. transmit antennas.

Yet I still kind of feel like I am really pushing the envelope.

Obviously, I can experiment on my own, but just looking for ideas from other folks.

My ground may end up being a 25 ft bare copper run laid in the garden and kept wet.

So at least the ground return may
be “ good” with a ( hopefully) low resistance.

ANY input is welcome.

de NQC

63

North American Shortwave Pirate / Re: WDOG 6925 USB 0118 UTC 22 JUL 2024

« on: July 22, 2024, 0147 UTC »

0137Z .Poor on indoor antenna.

Unknown music in QSB.

NQC

64

North American Shortwave Pirate / Re: WIND 6951 USB 2349 UTC 14 Jul 2024

« on: July 15, 2024, 0103 UTC »

Weak music 0102 Z

NQC

65

North American Shortwave Pirate / Re: Voice of the Sons of Liberty 6955 AM 2208 UTC 14 JUL 2024

« on: July 14, 2024, 2322 UTC »

Missed the boat.

SSTV 6955 at  2321Z

66

MW Loggings / Re: KXEL AM 1540 Waterloo IA

« on: July 14, 2024, 0255 UTC »

Hey Pinto,

Thanks for the info.

de NQC

67

North American Shortwave Pirate / Re: WIND Radio 6966 USB 0034 UTC 14 2024

« on: July 14, 2024, 0130 UTC »

Weak SSTV 0130 z

68

North American Shortwave Pirate / Re: WDOG 6960 AM 0122 UTC 14 JUL 2024

« on: July 14, 2024, 0126 UTC »

Hey All,

Very weak at Boston , bits of music , voice a bit better but mostly unreadable and CW 0123 Z

de NQC

69

North American Shortwave Pirate / Re: Radio 48 6850 USB 2319 UTC 13 JUL 2024

« on: July 14, 2024, 0120 UTC »

Hey All,

QSB , but overall BIG in Boston on indoor antenna at 0109 Z.

Also, a bit of SSTV on 6955.

de NQC

70

MW Loggings / Re: KXEL AM 1540 Waterloo IA

« on: July 12, 2024, 1542 UTC »

 Hey Pinto,

It sounds like you have a good  crystal set up.You've got a lot of  the important design features that are conducive to Dx  : double tuning, reduction drives, good ant/gnd, etc.

Crystal set sometimes got a bad reputation because there are a TON of dismal designs out there , folks build these and then when it stinks, the entire crystal set idea also stinks.

With a  crystal set you have to get it right  the first time and squeeze out  every nanowatt, there is no "making up " for a loss by doing it "that much better" further down the  chain. Gone is gone in an Xtal set .

My crystal sets  were actually quite simple, but used TOP grade parts and extreme attention to good construction practices. Admittedly, 90 % of my info was lifted form NSA gear design folks , RADAR techs, B'cast station engineers, etc, etc. I made some "discoveries " but did it 90% THEIR way, because it WORKED.

My antenna was great, but my ground was marginal ( 2nd floor heating pipe) . Still, I never needed a trap stage and got serious Q's  (  maybe 450 or 500  loaded at 1710 Kc  and quickly a LOT  better below  1200 Kc- 750 loaded at 530 Kc ? ).  The big litz  set placed in the top 10% (essentially "worldwide" ). A few  of the other guys in the xtal group did  better though .

All of the rigs from the old days were eventually "recycled", for one big stupid reason and another very valid reason. So basically , I am starting from scratch again . I have an Heath CR-1 crystal set ("fair" performer at best)  and also a few toy class rigs  .

Factory rigs here are DX44 and ATS 803a with Slect-A- Tenna loops for now.

Just put in a BIG magnet wire order for different projects ( crystal and otherwise).

One more question, what are you using for your audio chain from the detector out put - "crystal"Hi Z piezo   earphones  direct ? / matching transformer to  headphones ? (type ?)

de NQC

71

MW Loggings / Re: KXEL AM 1540 Waterloo IA

« on: July 12, 2024, 0215 UTC »

Hey Pinto.

I have copied KMOX in the past, but did it on car radio when going to the darker areas ( away from Boston light pollution) in East Central MA  while looking for a comet.

WBNW / Concord is simply too strong to kill in here Eastern MA, it’s on the same heading as MOX, so no null is possible.But their directional pattern allows you to escape to the back side if you go maybe 35 miles West of Boston.

MOX was banging in very well ( with hockey game, if I recall correctly) .This was my only copy of MOX from MA.

KCJJ isn’t easy, but if prop is up it can do OK.Got them a “ number “ of times.

WBZ , when peaked on my old ( gone) antenna was + 55 here.It was so ear splitting loud on the big litz crystal set,I had to bleed off the excess audio.

OT, I have been pretty much out of the crystal set activity ( and serious factory rigs) due to the big antenna coming down.I have lot of NICE crystal set parts and hope to get something going again in a few months on some “ improvised “ antennas.I am sure they won’t be like the old super big/ super high sky wires though.

I had around 110 US/ Canadian stations  and used to also get some Caribbeans  on the big litz / ( serious) Dx class crystal set.
I also built some pretty good SW Xtal sets as well, and one for VHF air band ( worked only   When “on top of “ tower or aircraft though). Also did one for FM, but pretty much only 6 to 10 mi range.Somewhat mushy  “sloped”  audio though , even on the strong stuff.

Could you describe your Xtal set  ?

de NQC

72

MW Loggings / Re: KXEL AM 1540 Waterloo IA

« on: July 11, 2024, 2109 UTC »

Hey Pinto,

Nice catch.

KXEL is a fringe ,if not deep fringe station here at Boston.
I usually pair up checking them with WHO.

Lately Dxing at my QTH has
been a “ challenge “ (understatement) for a few technical reasons .

But recently I did manage to pry my way out around to the Northeastern 1/4 of the U.S. on the bcast band.

One or two out a bit further ( ie WBT, WFED ).

Not great, but not horrible either.

de NQC

73

MW Loggings / Re: 650 WSRO (MA) Gone Dark (?) WSM Good Instead

« on: July 08, 2024, 2013 UTC »

Hey BoomboxDx,

I agree with you that when a station goes dark ( especially an analog station) it ISN’T a great thing.

As you mentioned,the media market IS changing. Frankly I am AMAZED how many lower powered stations have managed to stay on the air for this long.

Some are “ hobby “ stations run by wealthy folks ( at a loss ),  at least one around here is listener supported( contributions NOT tax deductible) and the rest run nearly all satellite programs and/ or a blizzard of local ads.

When a station makes less money, they usually run more ads, which can turn folks away, which forces them to run more ads. This can put a station into a real downward spiral.

 Also formally “ captive “ audiences ( ie the Greek language programming on one of our locals )may not be  as completely dependent on radio as they used to be .

The number of “non”  computer folks is shrinking.


 Even the local big rock n roll FM’ers (!!) here run WAY more ads than I care to listen to. I rarely listen to FM anymore.

This situation is even worse on AM.

Here maybe 10% of the ( BIG) AM’ers probably make 90% of the money anyways .

The small fry are probably mostly just covering their overhead and making little profit.

Again, in the case of SRO, even though they were “trying “, I pretty much felt ahead of time that the (second) move to digital was probably not going to save them .

They apparently didn’t have much of a market share to begin with and going over to fully digital ( which represented a VERY tiny amount of their already small audience) just didn’t work out.

There are only two music local AM’ers here that ( at NIGHT) are worth listening to.

Most of my AM dx here is  now just propagation checks , I don’t stay with anyone very long due to type of  programming content or the amount of ads or both.

Prop checks are still a lot of fun to me, but the dial usually spins around a lot if I am on dx.


de NQC

74

Weather / The Heat is ON !

« on: July 08, 2024, 1808 UTC »

Hey All,

Here at Boston we kind of dodged it for an extra 3 + weeks , compared than other parts of the country. But we seem to be “ in it “  now.

The jet stream seems to have fizzled out or moved North.Only a 50/50 chance for any more rain in the medium length future .

We HAD been doing good in the rain department , up until now. The Boston reservoir is full, so no anticipated problems for homes, but the farms just outside the water district could have some problems later on.

WITHIN the district, they are adding more and more users each year without any additional storage capacity.

So maybe it will become an issue at some years into the future.

We have a “ two” year supply at present consumption.

The only “ up” side is since the heat hit with a “ bit “ of “delay “ , in theory we will “ come out of it “ that much “ earlier “.

But aside from tropical systems we usually don’t get too much water in New England until the Winter and Spring.

So Fall may be “ cooler “, but still maybe dry.

FWIW, I was a 10 year volunteer at NWS Climate Research Station, Blue
Hill( Milton) MA.

I am an avid weather “ enthusiast “.

de NQC

75

Amateur Radio / Re: Hams Behaving Badly 7200 LSB 0122 UTC 8 JUL 2024

« on: July 08, 2024, 1749 UTC »

Hey All.

An interesting post.


NQC