Category Archives: Amateur Ham Radio

Diamond SRHF 40A HT antenna review

I called Diamond to ask a questions about handheld antennas. I spoke to, I’ll call him W. We spoke for a good while and I ended up giving him an idea to help with counterfeit antennas. Imitation is the sincerest form of flattery, right? Anyway, he was pleased with my idea and to thank me, sent me an antenna of my choosing (thank you). I picked the SRHF 40A.

srhf40-wide

The problems with antennas for HT’s is that if you want to get a good one it needs to be long, and if you get a long antenna it’s hard to carry. When you try to carry a long antenna you get poked in the ribs, armpit or even you chin in some cases. It’s just not that practical to carry and 16″ or longer straight antenna on your person. This is where the SRHF shines, you can curl it up like in the image and video below, then extend it when you want to transmit. It’s the best of both worlds. It’s a good antenna too. I’ve been able to lower the output wattage on my radio and still hit and have a 5×9 or clear signal on the repeaters. I’ve even tried it on 6 meters and hit the repeater, but since no one monitors it I couldn’t get signal read. I am also able to receive clearly from it. Technically, this is a 2m – 70cm (440) antenna. It also receives on 120,150,300,450,800,& 900mhz bands.

diamond-antenna

When the antenna is curled up it measures just under 6″. Check out the video to see how you turn a 6″ antenna into a 16″ antenna.

This is the image they use in their literature it’s also found in online ham radio websites and catalogues. I’ve seen it several times, but thought why would I want to by a squiggly antenna? It didn’t occur to me when I looked at this model that it could be bent into many different shapes. I think that’s a hard point to get across in literature, but I think Diamond should have multiple photos and a more detailed descriptions so people don’t pass this one up.

srhf40

This is one of my favorite shapes to carry the antenna in. It wraps about my back and stays totally out of my way when I carry on my hip.

srhf-carry-shape

My only beef with Diamond is that on their website it’s listed as a Tri-band antenna. This is a dual band antenna. Why do they list it as Tri-band antenna? They also don’t give details as to what bands it receives on (RX) or what the third (TX) band is. I would like to see more details on their website. Here is the HT antenna page, and here is the specific product page.

Here are the specifications that came with the antenna.
Gain: 2. 15dBi(70cm) Max output: 10w Impedance: 50 ohms Connector: SMA
1/4 wavelength (2m), 1/2 wavelength (70cm)
Overall length 16″

A word of caution, there are a lot of imitation Diamond antennas out there, make sure you know what your getting.

Yaesu VX-8DR beyond mars modification

After using my radio for a while and making sure everything worked I decide to go beyond Mars (MARS\CAP). Here’s how it looks. Before I began I look up a video on a technique to de-solder small resisters. The term that came up with the video was SMD. I guess it has something to do with surface mounted electronics. It was a bit of a pain to remove this resister and I did end up adding more solder like in the video. I found the added solder conducted the heat more efficiently. I also turned up the heat fairly high. Not the highest, but maybe upwards of 78% of the total output.

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This is the resister as seen through a 16x loop

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To get to it I had to peel off the waterproof seal behind the battery. This is what it looks like to the naked eye.

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This is my setup. A lighted 5x magnifying glass sitting on top of a box.

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This is the view through the magnifying glass. This is what I saw when I desoldered the resister.

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This is the size of the resister compared to the soldering tip, and this was the fine tip attachment…

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This is the size of the resister as seen through a 5x magnifying glass after I removed it.

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This is what comes up on the radio after it’s turned back on. All the data and settings are erased. I still reset all settings after I was done, but I don’t think it was necessary.

Maldol MH-511 Antenna Review

maldol MH-511

This is a short 6m, 2m, 70cm antenna. The 4.5″ or so length of this antenna makes it very easy to carry my handheld radio. This is a shorter antenna, don’t expect better performance compared to the stock antenna. I was able to hit the local repeaters and receive, but it’s not as good, and it shouldn’t be.. The one thing that made this antenna cumbersome was the rubber coating. The┬árubber gets caught on clothing when it’s hooked on my belt. The stock antenna has a harder smooth plastic coating that does not grab clothing, and because of this I would choose the stock over this antenna.