https://hamradioforum.net/ en Mon, 03 Jun 2019 17:13:09 GMT vBulletin 60 https://hamradioforum.net/images/misc/rss.png https://hamradioforum.net/ https://hamradioforum.net/threads/8952-Found-the-antenna-now-what?goto=newpost Thu, 30 May 2019 01:26:57 GMT OK, I found a Mosley CL-33 that I am going to install on my tower. Before I put it up I want to refurbish it. I live on a sea water front property.... OK, I found a Mosley CL-33 that I am going to install on my tower. Before I put it up I want to refurbish it. I live on a sea water front property. I will be opening up every joint cleaning and treating with Penetrox and inspecting the integrity of the trap coil forms and R and R as needed...if needed.

But I am wondering about the surface of the elements. When Aluminum ages it forms an oxide coating that is protective of the aluminum. Unlike rust, it doesnt continue to get worse. But the coating may increase the surface resistance of the elements. So I am wondering if just leaving it alone is best OR polishing it and painting it with a protective coat of cold galvanizing zinc paint or something else would be a good idea. Penetrox is just zinc filings in a waterproof grease and it works pretty well down here on the coast but would not stick to unprotected surfaces very long.

I would just as soon not take it back down for a while. ]]> Antennas jimisbell https://hamradioforum.net/threads/8952-Found-the-antenna-now-what https://hamradioforum.net/threads/8951-Chameleon-Antenna?goto=newpost Wed, 29 May 2019 21:55:48 GMT I am using a newly purchased Chameleon antenna the complete vertical element with the supplied ground stake. I live in an HOA. I installed it as... I am using a newly purchased Chameleon antenna the complete vertical element with the supplied ground stake. I live in an HOA. I installed it as instructed. Using my rigs built-in antenna tuner my SWR is flat across all the bands but I am not radiating. My tuner is making my radio happy but the antenna is not resonating. I called CQ for an hour nothing heard!* Next step must be radials. I purchased a 20-inch square steel plate, connected the steel plate to the ground stake and ran proper length radials off the steel plate 2-4-6-8 radials. I am not being heard! What do I have to do to make this antenna resonate?
Frustrated but never giving up!
Terrence Franck N9BMM ]]> Antennas Advisesoonest https://hamradioforum.net/threads/8951-Chameleon-Antenna https://hamradioforum.net/threads/8950-Comet-H-422-Longer-element?goto=newpost Wed, 29 May 2019 10:18:32 GMT Hi :) I have the Comet H-422 multi band dipole for HF, and wondering why there’s a requirement to keep one of the last 40m elements 200/300m longer... Hi :)
I have the Comet H-422 multi band dipole for HF, and wondering why there’s a requirement to keep one of the last 40m elements 200/300m longer than the other?
It’s supposed to be 300mm longer on one side if it’s assembled in the V configuration, or 200mm if it’s straight.

Other than that, the elements are identical. The longer element is supposed to be connected to a particular terminal of the supplied balun, marked with a red dot.

The reason I ask, is that the supplied balun was later replaced with the Comet CBL-2500, which has no markings to differentiate it’s output terminals,
and I suspect the extra length for one terminal is somehow made up with wire inside the original balun.

Cheers, VK4FAST. ]]> Antennas xArt https://hamradioforum.net/threads/8950-Comet-H-422-Longer-element https://hamradioforum.net/threads/8949-Small-enough-Yagi-FM-antenna-to-mount-flat-on-vehicle-roof-to-override-FM-radio?goto=newpost Wed, 29 May 2019 04:32:04 GMT Is there a Yagi FM antenna small enough to be mounted flat on a vehicle roof for a low profile? And would it work when mounted flat (horizontal)... Is there a Yagi FM antenna small enough to be mounted flat on a vehicle roof for a low profile? And would it work when mounted flat (horizontal) instead of vertical?

I work for an engineering company that has designed and manufactured a product that can override FM radio (with regulators permission).

It is used by ambulance drivers in the Middle East and Asia to send emergency messages to surrounding traffic. For example the ambulance driver can say "Ambulance approaching, move out of the way" and every car with an FM radio will hear the message up to 200 meters from the ambulance.

Our company has chosen a small vehicle mounted antenna that is omnidirectional but I would like to offer customers the option to use a directional yagi.
Sometimes omnidirectional range will extend too far to the sides of the Ambulance which may not be ideal certain situations like when driving on a very wide highway.

Ideally we would use a Log periodic Yagi with 87.5 – 108.0MHz (Wide-bandwidth), 7 dBd gain, 50 Ohm impedance.

But these can be 2.7m Long x 1.68m Wide, 30kg and would look crazy mounted flat on a car roof.

]]> Antennas russell888 https://hamradioforum.net/threads/8949-Small-enough-Yagi-FM-antenna-to-mount-flat-on-vehicle-roof-to-override-FM-radio https://hamradioforum.net/threads/8941-Old-School-2-element-Tribander-(10-15-20)?goto=newpost Fri, 24 May 2019 23:29:23 GMT I am looking for an old fashioned tri-band beam with band traps for sale cheap or a design for a home brew version. I would be single if I bought a... I am looking for an old fashioned tri-band beam with band traps for sale cheap or a design for a home brew version. I would be single if I bought a new one a $600 plus shipping. So am going cheapskate. I can build my own if I have drawings and tubing sizes etc. and I already have an 40 foot tower with work platform to put it on.

I have a triband bumper mount, trapped vertical, but I think the two element beam would work better. ]]> Antennas jimisbell https://hamradioforum.net/threads/8941-Old-School-2-element-Tribander-(10-15-20) https://hamradioforum.net/threads/8935-Long-range-external-WiFi-antennas-Any-experience-and-recomendations?goto=newpost Mon, 20 May 2019 12:09:39 GMT Does any one have any experience and recommendations on long range WiFi antenna. The kind of things I mean is using remote WiFi with an external... Does any one have any experience and recommendations on long range WiFi antenna. The kind of things I mean is using remote WiFi with an external antenna. I am particularly interested in experience in urban environments. Kind of thing I mean is like these (these are just from a fairly simple google).

https://uk.rs-online.com/web/p/produ...E&gclsrc=aw.ds
https://www.aliexpress.com/item/VOBE...chweb201603_52

https://www.aliexpress.com/item/150M...c1e4e164f843-2

https://www.aliexpress.com/item/2-4G...c1e4e164f843-4

https://www.aliexpress.com/item/2-4G...1e4e164f843-14

Or even simple own creations
https://www.youtube.com/watch?v=uxKwFDYKEnE ]]> Antennas 2e0sve https://hamradioforum.net/threads/8935-Long-range-external-WiFi-antennas-Any-experience-and-recomendations https://hamradioforum.net/threads/8932-velocity-factor-via-vector-impedance-analyser?goto=newpost Sun, 19 May 2019 02:19:39 GMT I got the bright idea of trying to use an N1201SA portable vector impedance analyser to find the velocity factor of some 300 ohm TV ribbon. I figured... I got the bright idea of trying to use an N1201SA portable vector impedance analyser to find the velocity factor of some 300 ohm TV ribbon. I figured just connect a random length of open circuit ribbon to the analyser, note the lowest frequency where the impedance peaked & that would correspond to half a wavelength. So I hooked up a 156mm length & noted the impedance peaked at 1094MHz. Now 1094MHz is a wavelength of 274mm, a half wavelength of 137mm. So my physical 156mm half wavelength line at 1094MHz has an electrical half wavelength of 137mm, meaning the velocity factor is 137/156=0.88. So far so good.

Next I noticed another impedance peak at 1980 MHz. This has me worried because I expected the full wavelength peak to be at 1094 x 2 = 2188MHz. The 1980 value gives me a velocity factor of 0.97 I get the feeling I'm missing something? ]]> Antennas VK2AJS https://hamradioforum.net/threads/8932-velocity-factor-via-vector-impedance-analyser https://hamradioforum.net/threads/8917-Receiving-2-Meter-from-a-distance-question?goto=newpost Thu, 09 May 2019 00:17:26 GMT Greetings,

Brand new to Ham Radio, so new I'm not even licensed yet (I have broadcast turned off so I can't even drop the radio and PTT by accident :) ) but I'm working on that!

Right now I'm interested in receiving 2 meter from as far away as I can because I'm interested in monitoring SkyWarn repeaters from distant counties.

National Weather Service Fort Worth can monitor and broadcast to a 42 county area in North Texas from Tarrant County (Beach and 820 for those wanting to look it up on a map) so I know it is possible to go a distance (although I know I probably won't be able to go that far because I don't have as many resources as the government).

I am in Plano (SW Collin county) and I have an N9TAX antenna that I've mounted on a PVC pipe 20' in the air. I don't plan on this being a permanent setup - I'm just trying to test different scenarios. With this I've been able to receive at most the next county over (approx 30 miles).

My current goal is to get from Plano to Decatur (Wise county) about 65 miles away, or Weatherford (Parker county) about 80 miles away.

From my limited research, it seems I have 3 general variables to play with: antenna height, antenna gain(or quality), or an antenna pre-amp.

My least favorite of these is height - due to city permits and cost. I did, however, read about someone that put a magnetic mobile antenna on one of their roof vents which would get me up to almost 30'... but what would the extra 10' buy me? Also, I have an aversion to getting up on the roof (and ladders in general).

Antenna quality I would be willing to spend up to about $100... but how low can I realistically keep it?

Antenna pre-amp is the biggest unknown to me right now... would a pre-amp help on the *receive* side (such as a Radio Shack HTA-20 2M preamp)? If a preamp is a viable option, what is the best value out there (cost vs. performance)?

Thanks for the help!
I'll post my callsign once I have one :) ]]> Antennas jclh https://hamradioforum.net/threads/8917-Receiving-2-Meter-from-a-distance-question https://hamradioforum.net/threads/8914-Dipole-support-question?goto=newpost Tue, 07 May 2019 21:15:03 GMT Cannot remember what the pole is called that stands above say a dipole to support a tubular dipole. Has line running from vertical pole out to... Cannot remember what the pole is called that stands above say a dipole to support a tubular dipole. Has line running from vertical pole out to dipole. all I can think of is gin pole but do not think that's right.:uncomfortableness: ]]> Antennas TallTree https://hamradioforum.net/threads/8914-Dipole-support-question https://hamradioforum.net/threads/8913-Beginner-question-on-reception-of-SW-HF?goto=newpost Tue, 07 May 2019 12:30:56 GMT Hi,

I am still somewhat a 'nubie'. I have various cheap radios such as a v115 (https://www.amazon.com/Retekess-Port.../dp/B01ARN28SQ) and a couple of TECSUNs (https://www.amazon.co.uk/Tecsun-PL-6.../dp/B004Q21I4U) and am trying to receive wefax and CW which I wish to pipe into software of various kinds. I am in a built up area but have almost no sucess in receiving such signals. These are received not so far away on web based SDRs. I have tried various Ariel enhancers such as the extended ariel that comes with the PL-606 and ariel extenders (https://www.ebay.com/itm/Origin-TECS...FIQAvD_BwE:G:s) (yes I know this if for FM) but with no joy.

Can anyone render any advise as to how to receive these signals at reasionable quality. I want to use small radios and not more bulky ones as I wish to do this mobile, specifically but not exclusivly at Sea. ]]> Antennas 2e0sve https://hamradioforum.net/threads/8913-Beginner-question-on-reception-of-SW-HF