LW HF LONGWIRE PROJECT Experiment #2

[rinkerk]

Hello all.
I have a mostly "homebrew" 70' longwire end fed with a 9:1 WinRadio longwire "transformer" ( multiband Balun)
Been using this on several receivers for some time now. It really works well using RG6 coax ( 50' to the shack.) This is a receive only antenna.
Impediance matching using an MFJ-959C Tuner Preamp.
Dont need the tuner or the preamp with the Icom R75 but it does improve reception on the Grundig Sat-800.
I just got in another WinRadio logwire matcher and plan to set up a 300+ lenght longwire running the opposite direction of the 70' sloping longwire I'm using now.
These longwires are approx. 40 ft AGL at my QTH, Using a 20' mast mounted on a tripod on the roof.
I plan to use the 300' longwire for the LF band. This one will be almost horizontal, using a PVC mast about 20' at the end. ( so it will slope just a little)
Anyone use the WinRadio longwire balun? I expect after the ground system I'm installing at my QTH, it will be a better match for LF beacon Dx MW, and the lower HF bands.
Any input for you all experimenting with HF antenna configs would be much appreciated.
I also monitor the VHF UHF band using a Scantenna, and plan on putting up another VHF antenna. I think I want to either build or just buy a discone for the scanners.
It's driving the YL a little crazy righ now, but we have enough space in the back yard to do this.
(She'll get over it soon)
Regards,
Kevin

 

[kb2vxa]

Hi Kevin and readers,

Feel free to take advantage of my 40 odd years of experience as an SWL in the following comments.

"I have a mostly "homebrew" 70' longwire end fed with a 9:1 WinRadio longwire "transformer" ( multiband Balun)"

70' is hardly a long wire, rather it's a random length wire. That is quite sufficient for shortwave and medium wave reception but another 100' would bring it closer to resonance on MW. No, that wouldn't improve SW one bit. Since it's an unbalanced antenna and coax is unbalanced feedline the balun is superflous and rather upsets the system. For that matter so does the coax unless you're feeding the antenna at ground level and the outer braid is grounded at the antenna feedpoint. Random and long wires have no feedline, they're connected directly to the receiver or through a tuner which must be grounded for it to work correctly.

"Been using this on several receivers for some time now. It really works well using RG6 coax ( 50' to the shack.) This is a receive only antenna."

Actually the way you have it set up the whole shebang is acting as an antenna.

"Impediance matching using an MFJ-959C Tuner Preamp."

There is no such thing as impedance matching to a receiver, it only comes into play when transmitting. Besides, the preamp output impedance can be anything from 600 to 2,000 ohms and is not adjustable. What you're doing is not so much tuning the antenna as amplifying signals.

"Dont need the tuner or the preamp with the Icom R75 but it does improve reception on the Grundig Sat-800."

That's because the Icom is a communications receiver of superior quality while the Grundig is not, rather it's designed for the casual shortwave broadcast listener.

"I just got in another WinRadio logwire matcher and plan to set up a 300+ lenght longwire running the opposite direction of the 70' sloping longwire I'm using now."

Forget the "matcher", like I said it's defeating your purpose and since 300' is about the right length for longwave reception I wouldn't use something designed for shortwave. You'll end up with tremendous signal loss for some technical reasons beyond the scope of this discussion.

"These longwires are approx. 40 ft AGL at my QTH, Using a 20' mast mounted on a tripod on the roof."

You can't expect to get them any higher and doing so would accomplish little, you'd have to go up about 300' to 400' to notice any improvement on LW. That's a very strange world of groundwave and antenna efficiency, LW stations use verticals which puts a 400' tower out of the picture for you.

"I plan to use the 300' longwire for the LF band. This one will be almost horizontal, using a PVC mast about 20' at the end. ( so it will slope just a little)"

That's exactly what it's for, just connect it directly to the Icom (no coax, no tuner) and make sure the receiver's "gnd" post is grounded. Likely you'll do very well with that sort of arrangement.

"Anyone use the WinRadio longwire balun?"

Note: it's long wire, not longwire.

Please, there is no such thing as a "long wire balun", a balun matches a BALanced antenna to an UNbalanced transmission line and a long wire is unbalanced to begin with.

"I expect after the ground system I'm installing at my QTH, it will be a better match for LF beacon Dx MW, and the lower HF bands."

Not a match at all, rather a counterpoise which completes the antenna system. A balanced antenna requires no earthing while an unbalanced one does. Every radiator requires a counterpoise, a dipole being balanced one side against the other has it's own counterpoise while a long wire being unbalanced works against ground as it's counterpoise. Think of it as "counterbalance" or "counterweight" in mechanical terms and you get the meaning in electrical terms.

"Any input for you all experimenting with HF antenna configs would be much appreciated."

Does my 40 years of experience help? (;->)

"I also monitor the VHF UHF band using a Scantenna, and plan on putting up another VHF antenna. I think I want to either build or just buy a discone for the scanners."

Both are excellent VHF/UHF antennas but construction can be tricky without proper tools and materials. I suggest a groundplane made from 19" long 1/16" dia brazing rod and an SO-239 flange mount connector to start. It works well on VHF/UHF but like most antennas gets flaky on 800MHz. Just use a gob of silicone caulk to waterproof the insulator and wrap the connector securely with tape. The coax will go up through the mast and the antenna sits nicely atop it without funky mounting brackets. Hey, you CAN solder, can't you? (;->)

"It's driving the YL a little crazy righ now, but we have enough space in the back yard to do this."

I hope you have a dog house, it might come in handy. (;->)

 

[rinkerk]

Thanks for your input on this project.
Forgive me for being away from this thread as I',ve been working away from the QTH for a few weeks.
In response to using coax as an input for receivers, as you know there are two schools of thought on the subject.
For many years I simply ran random lenghts using a siingle wire lead to the high impediance inputs on various receivers with great results.
They were working great but very noisy at most freqs below say 12000 KHZ and below.
I started looking and visiting amateur operartors in my area and as far east as Florida.
For receive only random wires, the group agreed that using a longwire with a good ground system matched with " impediance matching" type "BALuns" worked well.
At my QTH and the configs I wrote about in My intial post, this end fed (using The simple 9:1 impediance longwire match) actually does a good job when using both the SAT8 and the IC75.
The 300ft wire works well at the LW FREQS as well. Both using this config as well.
I appreciate your 40 yrs of experience and would like to "pick your brain" about this topic.
Best regards,
Kevin

 

[USAPatriot]

FWIW, I was running a longwire with my old WR-1000i reciever, which if I recall covered 5hz -1.3Ghz. The wire was pretty much as you described, about 300' attached to a rather large Balun. I probably would have run an even longer wire but space was an issue. From the house to the long fence, down the fence and over the greenhouse, across the back fence, back up the opposite long fence and back to the house. While most of the wire was a mere 8' off the ground, parts of it were close to 20 as it went over the greenhouse (I was a commercial Orchid grower at the time). I really found no shortcomings in the system. If I recall the wire was #8 solid core.