Using and Mounting Cheap Antenna in Apartment

[KC9CVF]

So a friend of mine had a spare CB antenna that I traded him for a six pack. It seems to work okay on receiving, but I can't get it to come into a reasonable SWR range and therefore successfully transmit. Yes, I know it's a CB antenna, but that's not far from 10 meter, which is the only place I can go on HF right now anyway.

Here's the weak-stick: Power Comm CB Ant Kit 1000w 3ft Black

I live in an apartment on the south corner, top (fifth) floor. No balcony, and the building is all concrete and brick. Where and how would be the best place to mount this? At the moment it's bolted down to a stainless wheely cart thing, and I doubt that's a decent way to do it.

 

[doctordialtone]

Where and how would be the best place to mount this?

At your mother's house.

If that's not available - near as possible to a window.

 

[KC9CVF]

Too bad they live in an area with a completely whacked out HOA.

Clearly.

I'm mostly aiming at:

This thing was designed to attach to a vehicle; is it expecting to be bolted to something metal to function as a ground plane or radial type thing, or should it be insulated when mounted?

Vertical or horizontal - does it matter given it's end-fed?

I guess if it's designed to be bolted to metal, I could just bolt it to my mothers wheelchair, too. Plenty of it there.

 

[W5lz]

If you shorten an antenna you also shorten it's usable frequency range. A typical 10 meter 1/4 wave antenna is about 8 feet long. If you shorten that to about 3 feet long you will not be able to move very far from it's resonant frequency at all. That's with a 10 meter antenna, since you're using an 11 meter antenna the usable frequency is really going to be 'off'.

That vertical part is only half the antenna, the other half is the 'ground'/counterpoise/metal you mount the thing on. It isn't going to hurt anything if that 'other half' is too large, as in a typical vehicle. It really does make a difference if it's too short though. Then it get's complicated.

I would suggest your friend do some studying about antennas, how/why they work, it really isn't that simple so reading here isn't going to do a lot of good.

 

[KC9CVF]

I acquired the antenna as a short-term solution while I try to choose one and get permission for an antenna up on the roof. I'm trying to figure out ways to improve its capability given the compromise of circumstances here.

He's only in play because it was on his truck, but now it's in my apartment.

So the shorter it is in terms of fraction of wavelength, the narrower the resonance bandwidth, for lack of a better term, will be? (forgive me if my vocabulary is incorrect, just trying to learn here)

 

[prcguy]

Can you hang about 9ft of wire downward from a window? If so stick the whip mostly vertical and angled away from the building a little out the window and connect 9ft of wire to the braid of the coax and let it hang down. That will make a mostly vertical dipole.

 

[KC9CVF]

9ft might cut it close to hanging in front of the window underneath me. I'm assuming it can't be horizontally offset from the whip or it would eliminate benefits of extending it like that.

Connect it to the braid? Would connecting it to the mount work as well, since that shows continuity with the outer part of the PL-259?

 

[KC9CVF]

Can you hang about 9ft of wire downward from a window? If so stick the whip mostly vertical and angled away from the building a little out the window and connect 9ft of wire to the braid of the coax and let it hang down. That will make a mostly vertical dipole.

Tried that and it didn't really do anything. However, I tried connecting it to the point to where the whip connects to the mount (above an isolation gasket/ring thing), slung that out the window, and that seemed to do quite a bit. The antenna tuner actually managed to tune it down to better than 2:1 at about 28.4MHz

 

[prcguy]

That's the basic idea, I didn't know you had a mount for the whip. Try measuring the resonant frequency of the setup, then you can trim it to the exact freq you want and you many not need the tuner at that point.

Tried that and it didn't really do anything. However, I tried connecting it to the point to where the whip connects to the mount (above an isolation gasket/ring thing), slung that out the window, and that seemed to do quite a bit. The antenna tuner actually managed to tune it down to better than 2:1 at about 28.4MHz

 

[KC9CVF]

Yeah it's got a clamp-type mount, one that would likely go on the arm of a mirror or some other horizontal bar. What's a good way to find the resonant freq?

I've also gotta sort out a ground too, since my apartment is ridiculously noisy, and that cheap power supply probably isn't helping anything.

 

[prcguy]

While not the best practice, you can turn your radio down to a few watts in FM mode, put the meter in SWR mode and sweep the frequency while transmitting to see where it dips. Its better practice to spot check a bunch of individual freqs and ID your station during each transmission, but it takes longer.

Yeah it's got a clamp-type mount, one that would likely go on the arm of a mirror or some other horizontal bar. What's a good way to find the resonant freq?

I've also gotta sort out a ground too, since my apartment is ridiculously noisy, and that cheap power supply probably isn't helping anything.

 

[KC9CVF]

Yeah. Worth a shot when I've got some spare time.

Wonder if I could hear you this time, now that the antenna's in a better spot. (even if it's still not properly set up for 20m)

 

[prcguy]

I'm available on and off today for radio testing. I can transmit now from So Cal, Dallas TX or Boston MA areas and you should be able to hear one of those.

Yeah. Worth a shot when I've got some spare time.

Wonder if I could hear you this time, now that the antenna's in a better spot. (even if it's still not properly set up for 20m)

 

[KC9CVF]

TARDIS grade. How do you manage to be in three places at once?

More a curiosity than anything, as I was able to pick up a fair amount of traffic on 20m with just the whip when I was out of town, but I haven't heard anything here at home.

 

[prcguy]

I'm in So Cal right now in front of an HF radio, then I have a remote radio in TX and MA with the control heads for those radios in front of me controlling the radios through the Internet.

There is a solution for your antenna problem, find a friend or relative that will host a radio in a good location for antennas, then plant a RemoteRig there and control it from your apartment.

TARDIS grade. How do you manage to be in three places at once?

More a curiosity than anything, as I was able to pick up a fair amount of traffic on 20m with just the whip when I was out of town, but I haven't heard anything here at home.

 

[KC9CVF]

Well, I'm assuming since it's in a window/along the side of the building, my antenna will be somewhat directional. I have three windows pointing in two directions, and this one faces pretty much dead-on southwest. I chose that for ease of use of the gear as well as it being the only one without a taller building across the street.

 

[prcguy]

Let me know when you want me to transmit again. It might be good to listen for 6 area calls, then I will try from So Cal since your antenna points that way. I can also simulcast from all three locations, but some people will get an echo from the Internet delay.

Well, I'm assuming since it's in a window/along the side of the building, my antenna will be somewhat directional. I have three windows pointing in two directions, and this one faces pretty much dead-on southwest. I chose that for ease of use of the gear as well as it being the only one without a taller building across the street.

 

[KC9CVF]

Okay I'm back on station. Cat decided to go get wet and walk around on my computers.

Anyway.

Two more things before that:

Would it be fair to conclude I have a Tx/Rx "fan" if you will, of ~<90 degrees in each direction from SW given the position of antenna and construction of building?

How's the S meter supposed to read, generally? I'm assuming very low when there's no traffic on that frequency, but mine appears to be floating quite high, around 5-6 at 14.338 and down around 2 at 28.420.

 

[prcguy]

Hard to say what your antenna pattern is. With wiring in the walls and metal here and there its probably mostly directional away from the window. Your S meter readings say you have more noise on 20m compared to 10m. That's normal but since your antenna is really bad at 20m I would expect less noise. You could have something in the building or nearby creating extra noise on 20m and elsewhere.

Right now I have an S 5 noise level on 20m in So Cal with a Hex Beam and in Dallas, TX its S 2 with a 40-10m end fed and in Boston, MA its S 0 with an 80-10m dipole. Noise will depend on your antenna, surroundings and band conditions.

Okay I'm back on station. Cat decided to go get wet and walk around on my computers.

Anyway.

Two more things before that:

Would it be fair to conclude I have a Tx/Rx "fan" if you will, of ~<90 degrees in each direction from SW given the position of antenna and construction of building?

How's the S meter supposed to read, generally? I'm assuming very low when there's no traffic on that frequency, but mine appears to be floating quite high, around 5-6 at 14.338 and down around 2 at 28.420.

 

[KC9CVF]

I have so many electronics in here it's ridiculous. Wonder if any of it's from 200+ WiFi access points within usable range.

There's a contact map I was checking out at dxmaps showing an absolute ton of cross-country contacts on 20m, and a number of what appears to be nearly 1,000 mi contacts on 10m.

Anyway, where should I listen at?